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  • Why does my token return NULL and how can I fix it?(c++)

    - by Van
    I've created a program to get a string input from a user and parse it into tokens and move a robot according to the input. The program is supposed to recognize these inputs(where x is an integer): "forward x" "back x" "turn left x" "turn right x" and "stop". The program does what it's supposed to for all commands except for "stop". When I type "stop" the program prints out "whats happening?" because I've written a line which states: if(token == NULL) { cout << "whats happening?" << endl; } Why does token get NULL, and how can I fix this so it will read "stop" properly? here is the code: bool stopper = 0; void Navigator::manualDrive() { VideoStream video(&myRobot, 0);//allows user to see what robot sees video.startStream(); const int bufSize = 42; char uinput[bufSize]; char delim[] = " "; char *token; while(stopper == 0) { cout << "Enter your directions below: " << endl; cin.getline(uinput,bufSize); Navigator::parseInstruction(uinput); } } /* parseInstruction(char *c) -- parses cstring instructions received * and moves robot accordingly */ void Navigator::parseInstruction(char * uinput) { char delim[] = " "; char *token; // cout << "Enter your directions below: " << endl; // cin.getline (uinput, bufSize); token=strtok(uinput, delim); if(token == NULL) { cout << "whats happening?" << endl; } if(strcmp("forward", token) == 0) { int inches; token = strtok(NULL, delim); inches = atoi (token); double value = fabs(0.0735 * fabs(inches) - 0.0550); myRobot.forward(1, value); } else if(strcmp("back",token) == 0) { int inches; token = strtok(NULL, delim); inches = atoi (token); double value = fabs(0.0735 * fabs(inches) - 0.0550); myRobot.backward(1/*speed*/, value/*time*/); } else if(strcmp("turn",token) == 0) { int degrees; token = strtok(NULL, delim); if(strcmp("left",token) == 0) { token = strtok(uinput, delim); degrees = atoi (token); double value = fabs(0.00467 * degrees - 0.04); myRobot.turnLeft(1/*speed*/, value/*time*/); } else if(strcmp("right",token) == 0) { token = strtok(uinput, delim); degrees = atoi (token); double value = fabs(0.00467 * degrees - 0.04); myRobot.turnRight(1/*speed*/, value/*time*/); } } else if(strcmp("stop",token) == 0) { stopper = 1; } else { std::cerr << "Unknown command '" << token << "'\n"; } } /* autoDrive() -- reads in file from ifstream, parses * and moves robot according to instructions in file */ void Navigator::autoDrive(string filename) { const int bufSize = 42; char fLine[bufSize]; ifstream infile; infile.open("autodrive.txt", fstream::in); while (!infile.eof()) { infile.getline(fLine, bufSize); Navigator::parseInstruction(fLine); } infile.close(); } I need this to break out of the while loop and end manualDrive because in my driver program the next function called is autoDrive.

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  • jquery jumps to top on click event, return false or prevenDefault doesn't work

    - by Sebsemillia
    Hi, I have written a simple jquery script for a content slider. My problem is that the screen always jumps to the top position of the parent div when sliding the content. I've tried return false and preventDefault to cope with this effect, but the two just make the script not work anymore, nothing happens when I click the links.. So here is the jquery code: $(document).ready(function (){ var itemCount = $('.container div').size(); var itemWidth = $('.container div').width(); $('.container').wrap('<div id="AboutSlider"></div>'); $('#AboutSlider').css({'width':'640px', 'overflow':'hidden', 'position':'relative', 'height':'400px'}); $('#AboutSlider .container').css({'width':itemCount*itemWidth+'px', 'position':'absolute', 'height':'400px'}); $('.container .aboutContent').css({'padding-left':'0px'}); $('#AboutSlider .aboutContent').css({'width':'640px', 'float':'left', 'min-height':'400px'}); $('#AboutNav a').click(function(){ var integer = $(this).attr('rel'); $('#AboutSlider .container').animate({left:-640*(parseInt(integer)-1)}) $('#AboutNav a').each(function(){ $(this).removeClass('active'); if($(this).hasClass('button'+integer)){ $(this).addClass('active')} }); }); }); And here the respective html bit: <div id="Dienstleistungen"> <div class="left_column"> <h2>Meine Dienstleistungen</h2> <h3>KOMPETENZEN</h3> <ul id="AboutNav"> <li><h1><a href="#Kompetenzen" class="button1 active" rel="1" title="Frontend Entwicklung | Sebastian B&ouml;hme">&Uuml;berblick</a></h1></li> <li><h1><a href="#Frontend" class="button2" rel="2" title="Frontend Entwicklung | Sebastian B&ouml;hme">Frontend Entwicklung</a></h1></li> <li><h1><a href="#CMS" class="button3" rel="3" title="Content Management Systeme &amp; Online Shops | Sebastian B&ouml;hme">Content Management Systeme &amp; Online Shops</a></h1></li> <li><h1><a href="#SEO" class="button4" rel="4" title="Suchmaschinenoptimierung (SEO) | Sebastian B&ouml;hme">Suchmaschinenoptimierung (SEO)</a></h1></li> <li><h1><a href="#ScreenDesign" class="button5" rel="5" title="Screen Design | Sebastian B&ouml;hme">Screen Design</a></h1></li> <li><h1><a href="#Hand" class="button6" rel="6" title="Alles aus einer Hand | Sebastian B&ouml;hme">Alles aus einer Hand</a></h1></li> </ul> </div> <div class="container"> <div id="Kompetenzen" class="aboutContent right_columns"> <h1>&Uuml;berblick</h1> <p>Phasellus in massa. Curabitur dolor eros, gravida et, hendrerit ac, cursus non, massa. Aliquam lorem. In hac habitasse platea dictumst. Cras eu mauris. Quisque lacus. Donec ipsum. Nullam vitae sem at nunc pharetra ultricies. Vivamus elit eros, ullamcorper a, adipiscing sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> <p>Teng sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> </div> <hr /> <div id="Frontend" class="aboutContent right_column "> <h1>Frontend Entwicklung</h1> <p>Phasellus in massa. Curabitur dolor eros, gravida et, hendrerit ac, cursus non, massa. Aliquam lorem. In hac habitasse platea dictumst. Cras eu mauris. Quisque lacus. Donec ipsum. Nullam vitae sem at nunc pharetra ultricies. Vivamus elit eros, ullamcorper a, adipiscing sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> <p>Teng sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> </div> <hr /> <div id="CMS" class="aboutContent right_column "> <h1>Content Management Systeme &amp; Online Shops</h1> <p>Phasellus in massa. Curabitur dolor eros, gravida et, hendrerit ac, cursus non, massa. Aliquam lorem. In hac habitasse platea dictumst. Cras eu mauris. Quisque lacus. Donec ipsum. Nullam vitae sem at nunc pharetra ultricies. Vivamus elit eros, ullamcorper a, adipiscing sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> <p>Teng sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> </div> <hr /> <div id="SEO" class="aboutContent right_column "> <h1>Suchmaschinenoptimierung (SEO)</h1> <p>Phasellus in massa. Curabitur dolor eros, gravida et, hendrerit ac, cursus non, massa. Aliquam lorem. In hac habitasse platea dictumst. Cras eu mauris. Quisque lacus. Donec ipsum. Nullam vitae sem at nunc pharetra ultricies. Vivamus elit eros, ullamcorper a, adipiscing sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> <p>Teng sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> </div> <hr /> <div id="ScreenDesign" class="aboutContent right_column "> <h1>Screen Design</h1> <p>Phasellus in massa. Curabitur dolor eros, gravida et, hendrerit ac, cursus non, massa. Aliquam lorem. In hac habitasse platea dictumst. Cras eu mauris. Quisque lacus. Donec ipsum. Nullam vitae sem at nunc pharetra ultricies. Vivamus elit eros, ullamcorper a, adipiscing sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> <p>Teng sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> </div> <hr /> <div id="Hand" class="aboutContent right_column"> <h1>Alles aus einer Hand</h1> <p>Curabitur dolor eros, gravida et, hendrerit ac, cursus non, massa. Aliquam lorem. In hac habitasse platea dictumst. Cras eu mauris. Quisque lacus. Donec ipsum. Nullam vitae sem at nunc pharetra ultricies. Vivamus elit eros, ullamcorper a, adipiscing sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> <p>Teng sit amet, porttitor ut, nibh. Maecenas adipiscing mollis massa. Nunc ut dui eget nulla venenatis aliquet. Sed luctus posuere justo. Cras vehicula varius turpis. Vivamus eros metus, tristique sit amet, molestie dignissim, malesuada et, urna. </p> </div> </div><!-- AboutSlider --> </div><!-- Dienstleistungen --> somebody got any idea? Thanks a lot in advance!!

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  • I'm trying to return text from a .txt file using ajax

    - by saad
    I'm trying to get my first ajax script to work. The five images are all side by side. Whenever the user hovers the mouse over any of them, it sends a request to a .txt file on the server and the caption is displayed in the div#image_caption. The problem is, even when I mouse over the image, the caption does not display. I'm not quite sure what could be causing this. Here is the code <!DOCTYPE html> <html> <head> <style type="text/css"> div#images{overflow: auto;} img{float: left; width: 200px; height: 200px; margin-right: 15px;} div#image_caption {width: 1040px; height: 300px; margin-top: 30px; border: 2px black solid;} </style> <script type="text/javascript" src ="jquery-2.0.3.js"></script> <script type="text/javascript"> $(document).ready(function() { function show_caption(url) { //shows the caption once the mouse hovers over the image var asyncreq; if(window.XMLHttpRequest) { //IE 7+ and other browsers asyncreq = new XMLHttpRequest(); //define the request } else { //for IE 7- asyncreq = new ActiveXObject("Microsoft.XMLHTTP"); } asyncreq.open("GET", url, true); //give it properties asyncreq.send(); //send the request to the server asyncreq.onreadystatechange = function() { if(asyncreq.readyState == 4 && asyncreq.status == 200) { $("div#image_caption").html(asyncreq.responseText); //add the caption (response text from the file) to the box } } } //end of show_caption(url) function hide_caption() { //hides the caption once the mouse is gone $("div#image_caption").html(""); } }); </script> </head> <body> <h1>Hover over an image for more information.</h1> <div id = "images"> <img src="images/backg.jpg" mouseover = 'show_caption("backg_caption.txt");' mouseout = 'hide_caption();'/> <img src="images/Desert.jpg"mouseover = 'show_caption("Desert_caption.txt");' mouseout = 'hide_caption();'/> <img src="images/Penguins.jpg" mouseover = 'show_caption("Penguins_caption.txt");' mouseout = 'hide_caption();'/> <img src="images/Tulips.jpg" mouseover = 'show_caption("Tulips_caption.txt");' mouseout = 'hide_caption();'/> <img src="images/odji1.jpg" mouseover = 'show_caption("Desert_caption.txt");' mouseout = 'hide_caption();'/> </div> <div id = "image_caption"> </div> </body> </html>

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  • Model value not being set on return from View to Controller

    - by sagesky36
    I have a boolean model variable who's value is supposed to be set to TRUE in order to perform a process on return back into the Controller. It works absolutely fine on my local machine, but not on the remote web server. Can somebody PLEASE inform me what I am missing? Below is the "proof of the pudding": The boolean value in quesion is "ShouldGeneratePdf"; MODEL: namespace PDFConverterModel.ViewModels { public partial class ViewModelTemplate_Guarantors { public ViewModelTemplate_Guarantors() { Templates = new List<PDFTemplate>(); Guarantors = new List<tGuarantor>(); } public int SelectedTemplateId { get; set; } public List<PDFTemplate> Templates { get; set; } public int SelectedGuarantorId { get; set; } public List<tGuarantor> Guarantors { get; set; } public string LoanId { get; set; } public string DepartmentId { get; set; } public bool isRepeat { get; set; } public string ddlDept { get; set; } public string SelectedDeptText { get; set; } public string LoanTypeId { get; set; } public string LoanType { get; set; } public string Error { get; set; } public string ErrorT { get; set; } public string ErrorG { get; set; } public bool ShowGeneratePDFBtn { get; set; } public bool ShouldGeneratePdf { get; set; } } } MasterPage: <!DOCTYPE html> <html> <head> <title>@ViewBag.Title</title> <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <link href="@Url.Content("~/Content/kendo/2012.2.913/kendo.common.min.css")" rel="stylesheet" type="text/css" /> <link href="@Url.Content("~/Content/kendo/2012.2.913/kendo.dataviz.min.css")" rel="stylesheet" type="text/css" /> <link href="@Url.Content("~/Content/kendo/2012.2.913/kendo.blueopal.min.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.7.1.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/modernizr-2.5.3.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/kendo/2012.2.913/kendo.all.min.js")"></script> <script src="@Url.Content("~/Scripts/kendo/2012.2.913/kendo.aspnetmvc.min.js")"></script> </head> <body> <div class="page"> <header> <div id="title"> <h1>BHG :: PDF Service Generator</h1> </div> </header> <section id="main"> @RenderBody() </section> <footer> </footer> </div> </body> </html> View: @model PDFConverterModel.ViewModels.ViewModelTemplate_Guarantors @using (Html.BeginForm("ProcessForm", "Home", new AjaxOptions { HttpMethod = "POST" })) { <table style="width: 1000px"> @Html.HiddenFor(x => x.ShouldGeneratePdf) <tr> <td> <img alt="BHG Logo" src="~/Images/logo.gif" /> </td> </tr> <tr> <td> @(Html.Kendo().IntegerTextBox() .Placeholder("Enter Loan Id") .Name("LoanId") .Format("{0:#######}") .Value(Convert.ToInt32(Model.LoanId)) ) </td> </tr> <tr> <td>@Html.Label("Loan Type: ") @Html.DisplayFor(model => Model.LoanType) </td> <td> <label for="ddlDept">Department:</label> @(Html.Kendo().DropDownListFor(model => Model.ddlDept) .Name("ddlDept") .DataTextField("DepartmentName") .DataValueField("DepartmentID") .Events(e => e.Change("Refresh")) .DataSource(source => { source.Read(read => { read.Action("GetDepartments", "Home"); }); }) .Value(Model.ddlDept.ToString()) ) </td> </tr> @if (Model.ShowGeneratePDFBtn == true) { if (Model.ErrorT == string.Empty) { <tr> <td> <u><b>@Html.Label("Templates:")</b></u> </td> </tr> <tr> @for (int i = 0; i < Model.Templates.Count; i++) { <td> @Html.CheckBoxFor(model => Model.Templates[i].IsChecked) @Html.DisplayFor(model => Model.Templates[i].TemplateId) </td> } </tr> } else { <tr> <td> <b>@Html.DisplayFor(model => Model.ErrorT)</b> </td> </tr> } if (Model.ErrorG == string.Empty) { <tr> <td> <u><b>@Html.Label("Guarantors:")</b></u> </td> </tr> <tr> @for (int i = 0; i < Model.Guarantors.Count; i++) { <td> @Html.CheckBoxFor(model => Model.Guarantors[i].isChecked) @Html.DisplayFor(model => Model.Guarantors[i].GuarantorFirstName)&nbsp;@Html.DisplayFor(model => Model.Guarantors[i].GuarantorLastName) </td> } </tr> } else { <tr> <td> <b>@Html.DisplayFor(model => Model.ErrorG)</b> </td> </tr> } } <tr> <td> <input type="submit" name="submitbutton" id="btnRefresh" value='Refresh' /> </td> @if (Model.ShowGeneratePDFBtn == true) { <td> <input type="submit" name="submitbutton" id="btnGeneratePDF" value='Generate PDF' /> </td> } </tr> <tr> <td style="color: red; font: bold"> @Model.Error </td> </tr> </table> } <script type="text/javascript"> $('#btnRefresh').click(function () { Refresh(); }); function Refresh() { var LoanID = $("#LoanID").val(); if (parseInt(LoanID) != 0) { $('#ShouldGeneratePdf').val(false) document.forms[0].submit(); } else { alert("Please enter a LoanId"); } } //$(function () { // //DOM loaded // $('#btnGeneratePDF').click(function () { // DisableGeneratePDF(); // $('#ShouldGeneratePdf').val(true) // }); //}); //function DisableGeneratePDF() { // $('#btnGeneratePDF').attr("disabled", true); // $('#btnRefresh').attr("disabled", true); //} $('#btnGeneratePDF').click(function () { alert("inside click function"); DisableGeneratePDF(); $('#ShouldGeneratePdf').val(true) tof = $('#ShouldGeneratePdf').val(); alert("ShouldGeneratePdf set to " + tof); }); function DisableGeneratePDF() { alert("begin DisableGeneratePDF function"); $('#btnGeneratePDF').attr("disabled", true); $('#btnRefresh').attr("disabled", true); alert("end DisableGeneratePDF function"); } </script> Controller: [HttpPost] public ActionResult ProcessForm(string submitbutton, ViewModelTemplate_Guarantors model, FormCollection collection) if ((submitbutton == "Refresh") || (submitbutton == null) && (model.ShouldGeneratePdf == false)) { } else if ((submitbutton == "Generate PDF") || (model.ShouldGeneratePdf == true)) { } The "Alerts" in the script above come out to exactly what they should be on the remote server. The last alert shows that the value of the bool variable is "true". However, when I do page source views of the hidden variable, below is the result. The values of the hidden variable when the page loads and when the last alert button finishes are as follows: My local machine: The remote machine: As you can see, the value on my machine is set to true when the process executes. However, on the remote machine, it is set to false where it then doesn't excute. Why isn't the value in the model being returned as TRUE on the remote machine?

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  • jQuery .find() doesn't return data in IE but does in Firefox and Chrome

    - by Steve Hiner
    I helped a friend out by doing a little web work for him. Part of what he needed was an easy way to change a couple pieces of text on his site. Rather than having him edit the HTML I decided to provide an XML file with the messages in it and I used jQuery to pull them out of the file and insert them into the page. It works great... In Firefox and Chrome, not so great in IE7. I was hoping one of you could tell me why. I did a fair but of googling but couldn't find what I'm looking for. Here's the XML: <?xml version="1.0" encoding="utf-8" ?> <messages> <message type="HeaderMessage"> This message is put up in the header area. </message> <message type="FooterMessage"> This message is put in the lower left cell. </message> </messages> And here's my jQuery call: <script type="text/javascript"> $(document).ready(function() { $.get('messages.xml', function(d) { //I have confirmed that it gets to here in IE //and it has the xml loaded. //alert(d); gives me a message box with the xml text in it //alert($(d).find('message')); gives me "[object Object]" //alert($(d).find('message')[0]); gives me "undefined" //alert($(d).find('message').Length); gives me "undefined" $(d).find('message').each(function() { //But it never gets to here in IE var $msg = $(this); var type = $msg.attr("type"); var message = $msg.text(); switch (type) { case "HeaderMessage": $("#HeaderMessageDiv").html(message); break; case "FooterMessage": $("#footermessagecell").html(message); break; default: } }); }); }); </script> Is there something I need to do differently in IE? Based on the message box with [object Object] I'm assumed that .find was working in IE but since I can't index into the array with [0] or check it's Length I'm guessing that means .find isn't returning any results. Any reason why that would work perfectly in Firefox and Chrome but fail in IE? I'm a total newbie with jQuery so I hope I haven't just done something stupid. That code above was scraped out of a forum and modified to suit my needs. Since jQuery is cross-platform I figured I wouldn't have to deal with this mess. Edit: I've found that if I load the page in Visual Studio 2008 and run it then it will work in IE. So it turns out it always works when run through the development web server. Now I'm thinking IE just doesn't like doing .find in XML loaded off of my local drive so maybe when this is on an actual web server it will work OK. I have confirmed that it works fine when browsed from a web server. Must be a peculiarity with IE. I'm guessing it's because the web server sets the mime type for the xml data file transfer and without that IE doesn't parse the xml correctly.

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  • Hosting the Razor Engine for Templating in Non-Web Applications

    - by Rick Strahl
    Microsoft’s new Razor HTML Rendering Engine that is currently shipping with ASP.NET MVC previews can be used outside of ASP.NET. Razor is an alternative view engine that can be used instead of the ASP.NET Page engine that currently works with ASP.NET WebForms and MVC. It provides a simpler and more readable markup syntax and is much more light weight in terms of functionality than the full blown WebForms Page engine, focusing only on features that are more along the lines of a pure view engine (or classic ASP!) with focus on expression and code rendering rather than a complex control/object model. Like the Page engine though, the parser understands .NET code syntax which can be embedded into templates, and behind the scenes the engine compiles markup and script code into an executing piece of .NET code in an assembly. Although it ships as part of the ASP.NET MVC and WebMatrix the Razor Engine itself is not directly dependent on ASP.NET or IIS or HTTP in any way. And although there are some markup and rendering features that are optimized for HTML based output generation, Razor is essentially a free standing template engine. And what’s really nice is that unlike the ASP.NET Runtime, Razor is fairly easy to host inside of your own non-Web applications to provide templating functionality. Templating in non-Web Applications? Yes please! So why might you host a template engine in your non-Web application? Template rendering is useful in many places and I have a number of applications that make heavy use of it. One of my applications – West Wind Html Help Builder - exclusively uses template based rendering to merge user supplied help text content into customizable and executable HTML markup templates that provide HTML output for CHM style HTML Help. This is an older product and it’s not actually using .NET at the moment – and this is one reason I’m looking at Razor for script hosting at the moment. For a few .NET applications though I’ve actually used the ASP.NET Runtime hosting to provide templating and mail merge style functionality and while that works reasonably well it’s a very heavy handed approach. It’s very resource intensive and has potential issues with versioning in various different versions of .NET. The generic implementation I created in the article above requires a lot of fix up to mimic an HTTP request in a non-HTTP environment and there are a lot of little things that have to happen to ensure that the ASP.NET runtime works properly most of it having nothing to do with the templating aspect but just satisfying ASP.NET’s requirements. The Razor Engine on the other hand is fairly light weight and completely decoupled from the ASP.NET runtime and the HTTP processing. Rather it’s a pure template engine whose sole purpose is to render text templates. Hosting this engine in your own applications can be accomplished with a reasonable amount of code (actually just a few lines with the tools I’m about to describe) and without having to fake HTTP requests. It’s also much lighter on resource usage and you can easily attach custom properties to your base template implementation to easily pass context from the parent application into templates all of which was rather complicated with ASP.NET runtime hosting. Installing the Razor Template Engine You can get Razor as part of the MVC 3 (RC and later) or Web Matrix. Both are available as downloadable components from the Web Platform Installer Version 3.0 (!important – V2 doesn’t show these components). If you already have that version of the WPI installed just fire it up. You can get the latest version of the Web Platform Installer from here: http://www.microsoft.com/web/gallery/install.aspx Once the platform Installer 3.0 is installed install either MVC 3 or ASP.NET Web Pages. Once installed you’ll find a System.Web.Razor assembly in C:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies\System.Web.Razor.dll which you can add as a reference to your project. Creating a Wrapper The basic Razor Hosting API is pretty simple and you can host Razor with a (large-ish) handful of lines of code. I’ll show the basics of it later in this article. However, if you want to customize the rendering and handle assembly and namespace includes for the markup as well as deal with text and file inputs as well as forcing Razor to run in a separate AppDomain so you can unload the code-generated assemblies and deal with assembly caching for re-used templates little more work is required to create something that is more easily reusable. For this reason I created a Razor Hosting wrapper project that combines a bunch of this functionality into an easy to use hosting class, a hosting factory that can load the engine in a separate AppDomain and a couple of hosting containers that provided folder based and string based caching for templates for an easily embeddable and reusable engine with easy to use syntax. If you just want the code and play with the samples and source go grab the latest code from the Subversion Repository at: http://www.west-wind.com:8080/svn/articles/trunk/RazorHosting/ or a snapshot from: http://www.west-wind.com/files/tools/RazorHosting.zip Getting Started Before I get into how hosting with Razor works, let’s take a look at how you can get up and running quickly with the wrapper classes provided. It only takes a few lines of code. The easiest way to use these Razor Hosting Wrappers is to use one of the two HostContainers provided. One is for hosting Razor scripts in a directory and rendering them as relative paths from these script files on disk. The other HostContainer serves razor scripts from string templates… Let’s start with a very simple template that displays some simple expressions, some code blocks and demonstrates rendering some data from contextual data that you pass to the template in the form of a ‘context’. Here’s a simple Razor template: @using System.Reflection Hello @Context.FirstName! Your entry was entered on: @Context.Entered @{ // Code block: Update the host Windows Form passed in through the context Context.WinForm.Text = "Hello World from Razor at " + DateTime.Now.ToString(); } AppDomain Id: @AppDomain.CurrentDomain.FriendlyName Assembly: @Assembly.GetExecutingAssembly().FullName Code based output: @{ // Write output with Response object from code string output = string.Empty; for (int i = 0; i < 10; i++) { output += i.ToString() + " "; } Response.Write(output); } Pretty easy to see what’s going on here. The only unusual thing in this code is the Context object which is an arbitrary object I’m passing from the host to the template by way of the template base class. I’m also displaying the current AppDomain and the executing Assembly name so you can see how compiling and running a template actually loads up new assemblies. Also note that as part of my context I’m passing a reference to the current Windows Form down to the template and changing the title from within the script. It’s a silly example, but it demonstrates two-way communication between host and template and back which can be very powerful. The easiest way to quickly render this template is to use the RazorEngine<TTemplateBase> class. The generic parameter specifies a template base class type that is used by Razor internally to generate the class it generates from a template. The default implementation provided in my RazorHosting wrapper is RazorTemplateBase. Here’s a simple one that renders from a string and outputs a string: var engine = new RazorEngine<RazorTemplateBase>(); // we can pass any object as context - here create a custom context var context = new CustomContext() { WinForm = this, FirstName = "Rick", Entered = DateTime.Now.AddDays(-10) }; string output = engine.RenderTemplate(this.txtSource.Text new string[] { "System.Windows.Forms.dll" }, context); if (output == null) this.txtResult.Text = "*** ERROR:\r\n" + engine.ErrorMessage; else this.txtResult.Text = output; Simple enough. This code renders a template from a string input and returns a result back as a string. It  creates a custom context and passes that to the template which can then access the Context’s properties. Note that anything passed as ‘context’ must be serializable (or MarshalByRefObject) – otherwise you get an exception when passing the reference over AppDomain boundaries (discussed later). Passing a context is optional, but is a key feature in being able to share data between the host application and the template. Note that we use the Context object to access FirstName, Entered and even the host Windows Form object which is used in the template to change the Window caption from within the script! In the code above all the work happens in the RenderTemplate method which provide a variety of overloads to read and write to and from strings, files and TextReaders/Writers. Here’s another example that renders from a file input using a TextReader: using (reader = new StreamReader("templates\\simple.csHtml", true)) { result = host.RenderTemplate(reader, new string[] { "System.Windows.Forms.dll" }, this.CustomContext); } RenderTemplate() is fairly high level and it handles loading of the runtime, compiling into an assembly and rendering of the template. If you want more control you can use the lower level methods to control each step of the way which is important for the HostContainers I’ll discuss later. Basically for those scenarios you want to separate out loading of the engine, compiling into an assembly and then rendering the template from the assembly. Why? So we can keep assemblies cached. In the code above a new assembly is created for each template rendered which is inefficient and uses up resources. Depending on the size of your templates and how often you fire them you can chew through memory very quickly. This slighter lower level approach is only a couple of extra steps: // we can pass any object as context - here create a custom context var context = new CustomContext() { WinForm = this, FirstName = "Rick", Entered = DateTime.Now.AddDays(-10) }; var engine = new RazorEngine<RazorTemplateBase>(); string assId = null; using (StringReader reader = new StringReader(this.txtSource.Text)) { assId = engine.ParseAndCompileTemplate(new string[] { "System.Windows.Forms.dll" }, reader); } string output = engine.RenderTemplateFromAssembly(assId, context); if (output == null) this.txtResult.Text = "*** ERROR:\r\n" + engine.ErrorMessage; else this.txtResult.Text = output; The difference here is that you can capture the assembly – or rather an Id to it – and potentially hold on to it to render again later assuming the template hasn’t changed. The HostContainers take advantage of this feature to cache the assemblies based on certain criteria like a filename and file time step or a string hash that if not change indicate that an assembly can be reused. Note that ParseAndCompileTemplate returns an assembly Id rather than the assembly itself. This is done so that that the assembly always stays in the host’s AppDomain and is not passed across AppDomain boundaries which would cause load failures. We’ll talk more about this in a minute but for now just realize that assemblies references are stored in a list and are accessible by this ID to allow locating and re-executing of the assembly based on that id. Reuse of the assembly avoids recompilation overhead and creation of yet another assembly that loads into the current AppDomain. You can play around with several different versions of the above code in the main sample form:   Using Hosting Containers for more Control and Caching The above examples simply render templates into assemblies each and every time they are executed. While this works and is even reasonably fast, it’s not terribly efficient. If you render templates more than once it would be nice if you could cache the generated assemblies for example to avoid re-compiling and creating of a new assembly each time. Additionally it would be nice to load template assemblies into a separate AppDomain optionally to be able to be able to unload assembli es and also to protect your host application from scripting attacks with malicious template code. Hosting containers provide also provide a wrapper around the RazorEngine<T> instance, a factory (which allows creation in separate AppDomains) and an easy way to start and stop the container ‘runtime’. The Razor Hosting samples provide two hosting containers: RazorFolderHostContainer and StringHostContainer. The folder host provides a simple runtime environment for a folder structure similar in the way that the ASP.NET runtime handles a virtual directory as it’s ‘application' root. Templates are loaded from disk in relative paths and the resulting assemblies are cached unless the template on disk is changed. The string host also caches templates based on string hashes – if the same string is passed a second time a cached version of the assembly is used. Here’s how HostContainers work. I’ll use the FolderHostContainer because it’s likely the most common way you’d use templates – from disk based templates that can be easily edited and maintained on disk. The first step is to create an instance of it and keep it around somewhere (in the example it’s attached as a property to the Form): RazorFolderHostContainer Host = new RazorFolderHostContainer(); public RazorFolderHostForm() { InitializeComponent(); // The base path for templates - templates are rendered with relative paths // based on this path. Host.TemplatePath = Path.Combine(Environment.CurrentDirectory, TemplateBaseFolder); // Add any assemblies you want reference in your templates Host.ReferencedAssemblies.Add("System.Windows.Forms.dll"); // Start up the host container Host.Start(); } Next anytime you want to render a template you can use simple code like this: private void RenderTemplate(string fileName) { // Pass the template path via the Context var relativePath = Utilities.GetRelativePath(fileName, Host.TemplatePath); if (!Host.RenderTemplate(relativePath, this.Context, Host.RenderingOutputFile)) { MessageBox.Show("Error: " + Host.ErrorMessage); return; } this.webBrowser1.Navigate("file://" + Host.RenderingOutputFile); } You can also render the output to a string instead of to a file: string result = Host.RenderTemplateToString(relativePath,context); Finally if you want to release the engine and shut down the hosting AppDomain you can simply do: Host.Stop(); Stopping the AppDomain and restarting it (ie. calling Stop(); followed by Start()) is also a nice way to release all resources in the AppDomain. The FolderBased domain also supports partial Rendering based on root path based relative paths with the same caching characteristics as the main templates. From within a template you can call out to a partial like this: @RenderPartial(@"partials\PartialRendering.cshtml", Context) where partials\PartialRendering.cshtml is a relative to the template root folder. The folder host example lets you load up templates from disk and display the result in a Web Browser control which demonstrates using Razor HTML output from templates that contain HTML syntax which happens to me my target scenario for Html Help Builder.   The Razor Engine Wrapper Project The project I created to wrap Razor hosting has a fair bit of code and a number of classes associated with it. Most of the components are internally used and as you can see using the final RazorEngine<T> and HostContainer classes is pretty easy. The classes are extensible and I suspect developers will want to build more customized host containers for their applications. Host containers are the key to wrapping up all functionality – Engine, BaseTemplate, AppDomain Hosting, Caching etc in a logical piece that is ready to be plugged into an application. When looking at the code there are a couple of core features provided: Core Razor Engine Hosting This is the core Razor hosting which provides the basics of loading a template, compiling it into an assembly and executing it. This is fairly straightforward, but without a host container that can cache assemblies based on some criteria templates are recompiled and re-created each time which is inefficient (although pretty fast). The base engine wrapper implementation also supports hosting the Razor runtime in a separate AppDomain for security and the ability to unload it on demand. Host Containers The engine hosting itself doesn’t provide any sort of ‘runtime’ service like picking up files from disk, caching assemblies and so forth. So my implementation provides two HostContainers: RazorFolderHostContainer and RazorStringHostContainer. The FolderHost works off a base directory and loads templates based on relative paths (sort of like the ASP.NET runtime does off a virtual). The HostContainers also deal with caching of template assemblies – for the folder host the file date is tracked and checked for updates and unless the template is changed a cached assembly is reused. The StringHostContainer similiarily checks string hashes to figure out whether a particular string template was previously compiled and executed. The HostContainers also act as a simple startup environment and a single reference to easily store and reuse in an application. TemplateBase Classes The template base classes are the base classes that from which the Razor engine generates .NET code. A template is parsed into a class with an Execute() method and the class is based on this template type you can specify. RazorEngine<TBaseTemplate> can receive this type and the HostContainers default to specific templates in their base implementations. Template classes are customizable to allow you to create templates that provide application specific features and interaction from the template to your host application. How does the RazorEngine wrapper work? You can browse the source code in the links above or in the repository or download the source, but I’ll highlight some key features here. Here’s part of the RazorEngine implementation that can be used to host the runtime and that demonstrates the key code required to host the Razor runtime. The RazorEngine class is implemented as a generic class to reflect the Template base class type: public class RazorEngine<TBaseTemplateType> : MarshalByRefObject where TBaseTemplateType : RazorTemplateBase The generic type is used to internally provide easier access to the template type and assignments on it as part of the template processing. The class also inherits MarshalByRefObject to allow execution over AppDomain boundaries – something that all the classes discussed here need to do since there is much interaction between the host and the template. The first two key methods deal with creating a template assembly: /// <summary> /// Creates an instance of the RazorHost with various options applied. /// Applies basic namespace imports and the name of the class to generate /// </summary> /// <param name="generatedNamespace"></param> /// <param name="generatedClass"></param> /// <returns></returns> protected RazorTemplateEngine CreateHost(string generatedNamespace, string generatedClass) { Type baseClassType = typeof(TBaseTemplateType); RazorEngineHost host = new RazorEngineHost(new CSharpRazorCodeLanguage()); host.DefaultBaseClass = baseClassType.FullName; host.DefaultClassName = generatedClass; host.DefaultNamespace = generatedNamespace; host.NamespaceImports.Add("System"); host.NamespaceImports.Add("System.Text"); host.NamespaceImports.Add("System.Collections.Generic"); host.NamespaceImports.Add("System.Linq"); host.NamespaceImports.Add("System.IO"); return new RazorTemplateEngine(host); } /// <summary> /// Parses and compiles a markup template into an assembly and returns /// an assembly name. The name is an ID that can be passed to /// ExecuteTemplateByAssembly which picks up a cached instance of the /// loaded assembly. /// /// </summary> /// <param name="namespaceOfGeneratedClass">The namespace of the class to generate from the template</param> /// <param name="generatedClassName">The name of the class to generate from the template</param> /// <param name="ReferencedAssemblies">Any referenced assemblies by dll name only. Assemblies must be in execution path of host or in GAC.</param> /// <param name="templateSourceReader">Textreader that loads the template</param> /// <remarks> /// The actual assembly isn't returned here to allow for cross-AppDomain /// operation. If the assembly was returned it would fail for cross-AppDomain /// calls. /// </remarks> /// <returns>An assembly Id. The Assembly is cached in memory and can be used with RenderFromAssembly.</returns> public string ParseAndCompileTemplate( string namespaceOfGeneratedClass, string generatedClassName, string[] ReferencedAssemblies, TextReader templateSourceReader) { RazorTemplateEngine engine = CreateHost(namespaceOfGeneratedClass, generatedClassName); // Generate the template class as CodeDom GeneratorResults razorResults = engine.GenerateCode(templateSourceReader); // Create code from the codeDom and compile CSharpCodeProvider codeProvider = new CSharpCodeProvider(); CodeGeneratorOptions options = new CodeGeneratorOptions(); // Capture Code Generated as a string for error info // and debugging LastGeneratedCode = null; using (StringWriter writer = new StringWriter()) { codeProvider.GenerateCodeFromCompileUnit(razorResults.GeneratedCode, writer, options); LastGeneratedCode = writer.ToString(); } CompilerParameters compilerParameters = new CompilerParameters(ReferencedAssemblies); // Standard Assembly References compilerParameters.ReferencedAssemblies.Add("System.dll"); compilerParameters.ReferencedAssemblies.Add("System.Core.dll"); compilerParameters.ReferencedAssemblies.Add("Microsoft.CSharp.dll"); // dynamic support! // Also add the current assembly so RazorTemplateBase is available compilerParameters.ReferencedAssemblies.Add(Assembly.GetExecutingAssembly().CodeBase.Substring(8)); compilerParameters.GenerateInMemory = Configuration.CompileToMemory; if (!Configuration.CompileToMemory) compilerParameters.OutputAssembly = Path.Combine(Configuration.TempAssemblyPath, "_" + Guid.NewGuid().ToString("n") + ".dll"); CompilerResults compilerResults = codeProvider.CompileAssemblyFromDom(compilerParameters, razorResults.GeneratedCode); if (compilerResults.Errors.Count > 0) { var compileErrors = new StringBuilder(); foreach (System.CodeDom.Compiler.CompilerError compileError in compilerResults.Errors) compileErrors.Append(String.Format(Resources.LineX0TColX1TErrorX2RN, compileError.Line, compileError.Column, compileError.ErrorText)); this.SetError(compileErrors.ToString() + "\r\n" + LastGeneratedCode); return null; } AssemblyCache.Add(compilerResults.CompiledAssembly.FullName, compilerResults.CompiledAssembly); return compilerResults.CompiledAssembly.FullName; } Think of the internal CreateHost() method as setting up the assembly generated from each template. Each template compiles into a separate assembly. It sets up namespaces, and assembly references, the base class used and the name and namespace for the generated class. ParseAndCompileTemplate() then calls the CreateHost() method to receive the template engine generator which effectively generates a CodeDom from the template – the template is turned into .NET code. The code generated from our earlier example looks something like this: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.1 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace RazorTest { using System; using System.Text; using System.Collections.Generic; using System.Linq; using System.IO; using System.Reflection; public class RazorTemplate : RazorHosting.RazorTemplateBase { #line hidden public RazorTemplate() { } public override void Execute() { WriteLiteral("Hello "); Write(Context.FirstName); WriteLiteral("! Your entry was entered on: "); Write(Context.Entered); WriteLiteral("\r\n\r\n"); // Code block: Update the host Windows Form passed in through the context Context.WinForm.Text = "Hello World from Razor at " + DateTime.Now.ToString(); WriteLiteral("\r\nAppDomain Id:\r\n "); Write(AppDomain.CurrentDomain.FriendlyName); WriteLiteral("\r\n \r\nAssembly:\r\n "); Write(Assembly.GetExecutingAssembly().FullName); WriteLiteral("\r\n\r\nCode based output: \r\n"); // Write output with Response object from code string output = string.Empty; for (int i = 0; i < 10; i++) { output += i.ToString() + " "; } } } } Basically the template’s body is turned into code in an Execute method that is called. Internally the template’s Write method is fired to actually generate the output. Note that the class inherits from RazorTemplateBase which is the generic parameter I used to specify the base class when creating an instance in my RazorEngine host: var engine = new RazorEngine<RazorTemplateBase>(); This template class must be provided and it must implement an Execute() and Write() method. Beyond that you can create any class you chose and attach your own properties. My RazorTemplateBase class implementation is very simple: public class RazorTemplateBase : MarshalByRefObject, IDisposable { /// <summary> /// You can pass in a generic context object /// to use in your template code /// </summary> public dynamic Context { get; set; } /// <summary> /// Class that generates output. Currently ultra simple /// with only Response.Write() implementation. /// </summary> public RazorResponse Response { get; set; } public object HostContainer {get; set; } public object Engine { get; set; } public RazorTemplateBase() { Response = new RazorResponse(); } public virtual void Write(object value) { Response.Write(value); } public virtual void WriteLiteral(object value) { Response.Write(value); } /// <summary> /// Razor Parser implements this method /// </summary> public virtual void Execute() {} public virtual void Dispose() { if (Response != null) { Response.Dispose(); Response = null; } } } Razor fills in the Execute method when it generates its subclass and uses the Write() method to output content. As you can see I use a RazorResponse() class here to generate output. This isn’t necessary really, as you could use a StringBuilder or StringWriter() directly, but I prefer using Response object so I can extend the Response behavior as needed. The RazorResponse class is also very simple and merely acts as a wrapper around a TextWriter: public class RazorResponse : IDisposable { /// <summary> /// Internal text writer - default to StringWriter() /// </summary> public TextWriter Writer = new StringWriter(); public virtual void Write(object value) { Writer.Write(value); } public virtual void WriteLine(object value) { Write(value); Write("\r\n"); } public virtual void WriteFormat(string format, params object[] args) { Write(string.Format(format, args)); } public override string ToString() { return Writer.ToString(); } public virtual void Dispose() { Writer.Close(); } public virtual void SetTextWriter(TextWriter writer) { // Close original writer if (Writer != null) Writer.Close(); Writer = writer; } } The Rendering Methods of RazorEngine At this point I’ve talked about the assembly generation logic and the template implementation itself. What’s left is that once you’ve generated the assembly is to execute it. The code to do this is handled in the various RenderXXX methods of the RazorEngine class. Let’s look at the lowest level one of these which is RenderTemplateFromAssembly() and a couple of internal support methods that handle instantiating and invoking of the generated template method: public string RenderTemplateFromAssembly( string assemblyId, string generatedNamespace, string generatedClass, object context, TextWriter outputWriter) { this.SetError(); Assembly generatedAssembly = AssemblyCache[assemblyId]; if (generatedAssembly == null) { this.SetError(Resources.PreviouslyCompiledAssemblyNotFound); return null; } string className = generatedNamespace + "." + generatedClass; Type type; try { type = generatedAssembly.GetType(className); } catch (Exception ex) { this.SetError(Resources.UnableToCreateType + className + ": " + ex.Message); return null; } // Start with empty non-error response (if we use a writer) string result = string.Empty; using(TBaseTemplateType instance = InstantiateTemplateClass(type)) { if (instance == null) return null; if (outputWriter != null) instance.Response.SetTextWriter(outputWriter); if (!InvokeTemplateInstance(instance, context)) return null; // Capture string output if implemented and return // otherwise null is returned if (outputWriter == null) result = instance.Response.ToString(); } return result; } protected virtual TBaseTemplateType InstantiateTemplateClass(Type type) { TBaseTemplateType instance = Activator.CreateInstance(type) as TBaseTemplateType; if (instance == null) { SetError(Resources.CouldnTActivateTypeInstance + type.FullName); return null; } instance.Engine = this; // If a HostContainer was set pass that to the template too instance.HostContainer = this.HostContainer; return instance; } /// <summary> /// Internally executes an instance of the template, /// captures errors on execution and returns true or false /// </summary> /// <param name="instance">An instance of the generated template</param> /// <returns>true or false - check ErrorMessage for errors</returns> protected virtual bool InvokeTemplateInstance(TBaseTemplateType instance, object context) { try { instance.Context = context; instance.Execute(); } catch (Exception ex) { this.SetError(Resources.TemplateExecutionError + ex.Message); return false; } finally { // Must make sure Response is closed instance.Response.Dispose(); } return true; } The RenderTemplateFromAssembly method basically requires the namespace and class to instantate and creates an instance of the class using InstantiateTemplateClass(). It then invokes the method with InvokeTemplateInstance(). These two methods are broken out because they are re-used by various other rendering methods and also to allow subclassing and providing additional configuration tasks to set properties and pass values to templates at execution time. In the default mode instantiation sets the Engine and HostContainer (discussed later) so the template can call back into the template engine, and the context is set when the template method is invoked. The various RenderXXX methods use similar code although they create the assemblies first. If you’re after potentially cashing assemblies the method is the one to call and that’s exactly what the two HostContainer classes do. More on that in a minute, but before we get into HostContainers let’s talk about AppDomain hosting and the like. Running Templates in their own AppDomain With the RazorEngine class above, when a template is parsed into an assembly and executed the assembly is created (in memory or on disk – you can configure that) and cached in the current AppDomain. In .NET once an assembly has been loaded it can never be unloaded so if you’re loading lots of templates and at some time you want to release them there’s no way to do so. If however you load the assemblies in a separate AppDomain that new AppDomain can be unloaded and the assemblies loaded in it with it. In order to host the templates in a separate AppDomain the easiest thing to do is to run the entire RazorEngine in a separate AppDomain. Then all interaction occurs in the other AppDomain and no further changes have to be made. To facilitate this there is a RazorEngineFactory which has methods that can instantiate the RazorHost in a separate AppDomain as well as in the local AppDomain. The host creates the remote instance and then hangs on to it to keep it alive as well as providing methods to shut down the AppDomain and reload the engine. Sounds complicated but cross-AppDomain invocation is actually fairly easy to implement. Here’s some of the relevant code from the RazorEngineFactory class. Like the RazorEngine this class is generic and requires a template base type in the generic class name: public class RazorEngineFactory<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase Here are the key methods of interest: /// <summary> /// Creates an instance of the RazorHost in a new AppDomain. This /// version creates a static singleton that that is cached and you /// can call UnloadRazorHostInAppDomain to unload it. /// </summary> /// <returns></returns> public static RazorEngine<TBaseTemplateType> CreateRazorHostInAppDomain() { if (Current == null) Current = new RazorEngineFactory<TBaseTemplateType>(); return Current.GetRazorHostInAppDomain(); } public static void UnloadRazorHostInAppDomain() { if (Current != null) Current.UnloadHost(); Current = null; } /// <summary> /// Instance method that creates a RazorHost in a new AppDomain. /// This method requires that you keep the Factory around in /// order to keep the AppDomain alive and be able to unload it. /// </summary> /// <returns></returns> public RazorEngine<TBaseTemplateType> GetRazorHostInAppDomain() { LocalAppDomain = CreateAppDomain(null); if (LocalAppDomain == null) return null; /// Create the instance inside of the new AppDomain /// Note: remote domain uses local EXE's AppBasePath!!! RazorEngine<TBaseTemplateType> host = null; try { Assembly ass = Assembly.GetExecutingAssembly(); string AssemblyPath = ass.Location; host = (RazorEngine<TBaseTemplateType>) LocalAppDomain.CreateInstanceFrom(AssemblyPath, typeof(RazorEngine<TBaseTemplateType>).FullName).Unwrap(); } catch (Exception ex) { ErrorMessage = ex.Message; return null; } return host; } /// <summary> /// Internally creates a new AppDomain in which Razor templates can /// be run. /// </summary> /// <param name="appDomainName"></param> /// <returns></returns> private AppDomain CreateAppDomain(string appDomainName) { if (appDomainName == null) appDomainName = "RazorHost_" + Guid.NewGuid().ToString("n"); AppDomainSetup setup = new AppDomainSetup(); // *** Point at current directory setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory; AppDomain localDomain = AppDomain.CreateDomain(appDomainName, null, setup); return localDomain; } /// <summary> /// Allow unloading of the created AppDomain to release resources /// All internal resources in the AppDomain are released including /// in memory compiled Razor assemblies. /// </summary> public void UnloadHost() { if (this.LocalAppDomain != null) { AppDomain.Unload(this.LocalAppDomain); this.LocalAppDomain = null; } } The static CreateRazorHostInAppDomain() is the key method that startup code usually calls. It uses a Current singleton instance to an instance of itself that is created cross AppDomain and is kept alive because it’s static. GetRazorHostInAppDomain actually creates a cross-AppDomain instance which first creates a new AppDomain and then loads the RazorEngine into it. The remote Proxy instance is returned as a result to the method and can be used the same as a local instance. The code to run with a remote AppDomain is simple: private RazorEngine<RazorTemplateBase> CreateHost() { if (this.Host != null) return this.Host; // Use Static Methods - no error message if host doesn't load this.Host = RazorEngineFactory<RazorTemplateBase>.CreateRazorHostInAppDomain(); if (this.Host == null) { MessageBox.Show("Unable to load Razor Template Host", "Razor Hosting", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); } return this.Host; } This code relies on a local reference of the Host which is kept around for the duration of the app (in this case a form reference). To use this you’d simply do: this.Host = CreateHost(); if (host == null) return; string result = host.RenderTemplate( this.txtSource.Text, new string[] { "System.Windows.Forms.dll", "Westwind.Utilities.dll" }, this.CustomContext); if (result == null) { MessageBox.Show(host.ErrorMessage, "Template Execution Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); return; } this.txtResult.Text = result; Now all templates run in a remote AppDomain and can be unloaded with simple code like this: RazorEngineFactory<RazorTemplateBase>.UnloadRazorHostInAppDomain(); this.Host = null; One Step further – Providing a caching ‘Runtime’ Once we can load templates in a remote AppDomain we can add some additional functionality like assembly caching based on application specific features. One of my typical scenarios is to render templates out of a scripts folder. So all templates live in a folder and they change infrequently. So a Folder based host that can compile these templates once and then only recompile them if something changes would be ideal. Enter host containers which are basically wrappers around the RazorEngine<t> and RazorEngineFactory<t>. They provide additional logic for things like file caching based on changes on disk or string hashes for string based template inputs. The folder host also provides for partial rendering logic through a custom template base implementation. There’s a base implementation in RazorBaseHostContainer, which provides the basics for hosting a RazorEngine, which includes the ability to start and stop the engine, cache assemblies and add references: public abstract class RazorBaseHostContainer<TBaseTemplateType> : MarshalByRefObject where TBaseTemplateType : RazorTemplateBase, new() { public RazorBaseHostContainer() { UseAppDomain = true; GeneratedNamespace = "__RazorHost"; } /// <summary> /// Determines whether the Container hosts Razor /// in a separate AppDomain. Seperate AppDomain /// hosting allows unloading and releasing of /// resources. /// </summary> public bool UseAppDomain { get; set; } /// <summary> /// Base folder location where the AppDomain /// is hosted. By default uses the same folder /// as the host application. /// /// Determines where binary dependencies are /// found for assembly references. /// </summary> public string BaseBinaryFolder { get; set; } /// <summary> /// List of referenced assemblies as string values. /// Must be in GAC or in the current folder of the host app/ /// base BinaryFolder /// </summary> public List<string> ReferencedAssemblies = new List<string>(); /// <summary> /// Name of the generated namespace for template classes /// </summary> public string GeneratedNamespace {get; set; } /// <summary> /// Any error messages /// </summary> public string ErrorMessage { get; set; } /// <summary> /// Cached instance of the Host. Required to keep the /// reference to the host alive for multiple uses. /// </summary> public RazorEngine<TBaseTemplateType> Engine; /// <summary> /// Cached instance of the Host Factory - so we can unload /// the host and its associated AppDomain. /// </summary> protected RazorEngineFactory<TBaseTemplateType> EngineFactory; /// <summary> /// Keep track of each compiled assembly /// and when it was compiled. /// /// Use a hash of the string to identify string /// changes. /// </summary> protected Dictionary<int, CompiledAssemblyItem> LoadedAssemblies = new Dictionary<int, CompiledAssemblyItem>(); /// <summary> /// Call to start the Host running. Follow by a calls to RenderTemplate to /// render individual templates. Call Stop when done. /// </summary> /// <returns>true or false - check ErrorMessage on false </returns> public virtual bool Start() { if (Engine == null) { if (UseAppDomain) Engine = RazorEngineFactory<TBaseTemplateType>.CreateRazorHostInAppDomain(); else Engine = RazorEngineFactory<TBaseTemplateType>.CreateRazorHost(); Engine.Configuration.CompileToMemory = true; Engine.HostContainer = this; if (Engine == null) { this.ErrorMessage = EngineFactory.ErrorMessage; return false; } } return true; } /// <summary> /// Stops the Host and releases the host AppDomain and cached /// assemblies. /// </summary> /// <returns>true or false</returns> public bool Stop() { this.LoadedAssemblies.Clear(); RazorEngineFactory<RazorTemplateBase>.UnloadRazorHostInAppDomain(); this.Engine = null; return true; } … } This base class provides most of the mechanics to host the runtime, but no application specific implementation for rendering. There are rendering functions but they just call the engine directly and provide no caching – there’s no context to decide how to cache and reuse templates. The key methods are Start and Stop and their main purpose is to start a new AppDomain (optionally) and shut it down when requested. The RazorFolderHostContainer – Folder Based Runtime Hosting Let’s look at the more application specific RazorFolderHostContainer implementation which is defined like this: public class RazorFolderHostContainer : RazorBaseHostContainer<RazorTemplateFolderHost> Note that a customized RazorTemplateFolderHost class template is used for this implementation that supports partial rendering in form of a RenderPartial() method that’s available to templates. The folder host’s features are: Render templates based on a Template Base Path (a ‘virtual’ if you will) Cache compiled assemblies based on the relative path and file time stamp File changes on templates cause templates to be recompiled into new assemblies Support for partial rendering using base folder relative pathing As shown in the startup examples earlier host containers require some startup code with a HostContainer tied to a persistent property (like a Form property): // The base path for templates - templates are rendered with relative paths // based on this path. HostContainer.TemplatePath = Path.Combine(Environment.CurrentDirectory, TemplateBaseFolder); // Default output rendering disk location HostContainer.RenderingOutputFile = Path.Combine(HostContainer.TemplatePath, "__Preview.htm"); // Add any assemblies you want reference in your templates HostContainer.ReferencedAssemblies.Add("System.Windows.Forms.dll"); // Start up the host container HostContainer.Start(); Once that’s done, you can render templates with the host container: // Pass the template path for full filename seleted with OpenFile Dialog // relativepath is: subdir\file.cshtml or file.cshtml or ..\file.cshtml var relativePath = Utilities.GetRelativePath(fileName, HostContainer.TemplatePath); if (!HostContainer.RenderTemplate(relativePath, Context, HostContainer.RenderingOutputFile)) { MessageBox.Show("Error: " + HostContainer.ErrorMessage); return; } webBrowser1.Navigate("file://" + HostContainer.RenderingOutputFile); The most critical task of the RazorFolderHostContainer implementation is to retrieve a template from disk, compile and cache it and then deal with deciding whether subsequent requests need to re-compile the template or simply use a cached version. Internally the GetAssemblyFromFileAndCache() handles this task: /// <summary> /// Internally checks if a cached assembly exists and if it does uses it /// else creates and compiles one. Returns an assembly Id to be /// used with the LoadedAssembly list. /// </summary> /// <param name="relativePath"></param> /// <param name="context"></param> /// <returns></returns> protected virtual CompiledAssemblyItem GetAssemblyFromFileAndCache(string relativePath) { string fileName = Path.Combine(TemplatePath, relativePath).ToLower(); int fileNameHash = fileName.GetHashCode(); if (!File.Exists(fileName)) { this.SetError(Resources.TemplateFileDoesnTExist + fileName); return null; } CompiledAssemblyItem item = null; this.LoadedAssemblies.TryGetValue(fileNameHash, out item); string assemblyId = null; // Check for cached instance if (item != null) { var fileTime = File.GetLastWriteTimeUtc(fileName); if (fileTime <= item.CompileTimeUtc) assemblyId = item.AssemblyId; } else item = new CompiledAssemblyItem(); // No cached instance - create assembly and cache if (assemblyId == null) { string safeClassName = GetSafeClassName(fileName); StreamReader reader = null; try { reader = new StreamReader(fileName, true); } catch (Exception ex) { this.SetError(Resources.ErrorReadingTemplateFile + fileName); return null; } assemblyId = Engine.ParseAndCompileTemplate(this.ReferencedAssemblies.ToArray(), reader); // need to ensure reader is closed if (reader != null) reader.Close(); if (assemblyId == null) { this.SetError(Engine.ErrorMessage); return null; } item.AssemblyId = assemblyId; item.CompileTimeUtc = DateTime.UtcNow; item.FileName = fileName; item.SafeClassName = safeClassName; this.LoadedAssemblies[fileNameHash] = item; } return item; } This code uses a LoadedAssembly dictionary which is comprised of a structure that holds a reference to a compiled assembly, a full filename and file timestamp and an assembly id. LoadedAssemblies (defined on the base class shown earlier) is essentially a cache for compiled assemblies and they are identified by a hash id. In the case of files the hash is a GetHashCode() from the full filename of the template. The template is checked for in the cache and if not found the file stamp is checked. If that’s newer than the cache’s compilation date the template is recompiled otherwise the version in the cache is used. All the core work defers to a RazorEngine<T> instance to ParseAndCompileTemplate(). The three rendering specific methods then are rather simple implementations with just a few lines of code dealing with parameter and return value parsing: /// <summary> /// Renders a template to a TextWriter. Useful to write output into a stream or /// the Response object. Used for partial rendering. /// </summary> /// <param name="relativePath">Relative path to the file in the folder structure</param> /// <param name="context">Optional context object or null</param> /// <param name="writer">The textwriter to write output into</param> /// <returns></returns> public bool RenderTemplate(string relativePath, object context, TextWriter writer) { // Set configuration data that is to be passed to the template (any object) Engine.TemplatePerRequestConfigurationData = new RazorFolderHostTemplateConfiguration() { TemplatePath = Path.Combine(this.TemplatePath, relativePath), TemplateRelativePath = relativePath, }; CompiledAssemblyItem item = GetAssemblyFromFileAndCache(relativePath); if (item == null) { writer.Close(); return false; } try { // String result will be empty as output will be rendered into the // Response object's stream output. However a null result denotes // an error string result = Engine.RenderTemplateFromAssembly(item.AssemblyId, context, writer); if (result == null) { this.SetError(Engine.ErrorMessage); return false; } } catch (Exception ex) { this.SetError(ex.Message); return false; } finally { writer.Close(); } return true; } /// <summary> /// Render a template from a source file on disk to a specified outputfile. /// </summary> /// <param name="relativePath">Relative path off the template root folder. Format: path/filename.cshtml</param> /// <param name="context">Any object that will be available in the template as a dynamic of this.Context</param> /// <param name="outputFile">Optional - output file where output is written to. If not specified the /// RenderingOutputFile property is used instead /// </param> /// <returns>true if rendering succeeds, false on failure - check ErrorMessage</returns> public bool RenderTemplate(string relativePath, object context, string outputFile) { if (outputFile == null) outputFile = RenderingOutputFile; try { using (StreamWriter writer = new StreamWriter(outputFile, false, Engine.Configuration.OutputEncoding, Engine.Configuration.StreamBufferSize)) { return RenderTemplate(relativePath, context, writer); } } catch (Exception ex) { this.SetError(ex.Message); return false; } return true; } /// <summary> /// Renders a template to string. Useful for RenderTemplate /// </summary> /// <param name="relativePath"></param> /// <param name="context"></param> /// <returns></returns> public string RenderTemplateToString(string relativePath, object context) { string result = string.Empty; try { using (StringWriter writer = new StringWriter()) { // String result will be empty as output will be rendered into the // Response object's stream output. However a null result denotes // an error if (!RenderTemplate(relativePath, context, writer)) { this.SetError(Engine.ErrorMessage); return null; } result = writer.ToString(); } } catch (Exception ex) { this.SetError(ex.Message); return null; } return result; } The idea is that you can create custom host container implementations that do exactly what you want fairly easily. Take a look at both the RazorFolderHostContainer and RazorStringHostContainer classes for the basic concepts you can use to create custom implementations. Notice also that you can set the engine’s PerRequestConfigurationData() from the host container: // Set configuration data that is to be passed to the template (any object) Engine.TemplatePerRequestConfigurationData = new RazorFolderHostTemplateConfiguration() { TemplatePath = Path.Combine(this.TemplatePath, relativePath), TemplateRelativePath = relativePath, }; which when set to a non-null value is passed to the Template’s InitializeTemplate() method. This method receives an object parameter which you can cast as needed: public override void InitializeTemplate(object configurationData) { // Pick up configuration data and stuff into Request object RazorFolderHostTemplateConfiguration config = configurationData as RazorFolderHostTemplateConfiguration; this.Request.TemplatePath = config.TemplatePath; this.Request.TemplateRelativePath = config.TemplateRelativePath; } With this data you can then configure any custom properties or objects on your main template class. It’s an easy way to pass data from the HostContainer all the way down into the template. The type you use is of type object so you have to cast it yourself, and it must be serializable since it will likely run in a separate AppDomain. This might seem like an ugly way to pass data around – normally I’d use an event delegate to call back from the engine to the host, but since this is running over AppDomain boundaries events get really tricky and passing a template instance back up into the host over AppDomain boundaries doesn’t work due to serialization issues. So it’s easier to pass the data from the host down into the template using this rather clumsy approach of set and forward. It’s ugly, but it’s something that can be hidden in the host container implementation as I’ve done here. It’s also not something you have to do in every implementation so this is kind of an edge case, but I know I’ll need to pass a bunch of data in some of my applications and this will be the easiest way to do so. Summing Up Hosting the Razor runtime is something I got jazzed up about quite a bit because I have an immediate need for this type of templating/merging/scripting capability in an application I’m working on. I’ve also been using templating in many apps and it’s always been a pain to deal with. The Razor engine makes this whole experience a lot cleaner and more light weight and with these wrappers I can now plug .NET based templating into my code literally with a few lines of code. That’s something to cheer about… I hope some of you will find this useful as well… Resources The examples and code require that you download the Razor runtimes. Projects are for Visual Studio 2010 running on .NET 4.0 Platform Installer 3.0 (install WebMatrix or MVC 3 for Razor Runtimes) Latest Code in Subversion Repository Download Snapshot of the Code Documentation (CHM Help File) © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  .NET  

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  • Where can these be posted besides the Python Cookbook?

    - by Noctis Skytower
    Whitespace Assembler #! /usr/bin/env python """Assembler.py Compiles a program from "Assembly" folder into "Program" folder. Can be executed directly by double-click or on the command line. Give name of *.WSA file without extension (example: stack_calc).""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 3 $' ################################################################################ import string from Interpreter import INS, MNEMONIC ################################################################################ def parse(code): program = [] process_virtual(program, code) process_control(program) return tuple(program) def process_virtual(program, code): for line, text in enumerate(code.split('\n')): if not text or text[0] == '#': continue if text.startswith('part '): parse_part(program, line, text[5:]) elif text.startswith(' '): parse_code(program, line, text[5:]) else: syntax_error(line) def syntax_error(line): raise SyntaxError('Line ' + str(line + 1)) ################################################################################ def process_control(program): parts = get_parts(program) names = dict(pair for pair in zip(parts, generate_index())) correct_control(program, names) def get_parts(program): parts = [] for ins in program: if isinstance(ins, tuple): ins, arg = ins if ins == INS.PART: if arg in parts: raise NameError('Part definition was found twice: ' + arg) parts.append(arg) return parts def generate_index(): index = 1 while True: yield index index *= -1 if index > 0: index += 1 def correct_control(program, names): for index, ins in enumerate(program): if isinstance(ins, tuple): ins, arg = ins if ins in HAS_LABEL: if arg not in names: raise NameError('Part definition was never found: ' + arg) program[index] = (ins, names[arg]) ################################################################################ def parse_part(program, line, text): if not valid_label(text): syntax_error(line) program.append((INS.PART, text)) def valid_label(text): if not between_quotes(text): return False label = text[1:-1] if not valid_name(label): return False return True def between_quotes(text): if len(text) < 3: return False if text.count('"') != 2: return False if text[0] != '"' or text[-1] != '"': return False return True def valid_name(label): valid_characters = string.ascii_letters + string.digits + '_' valid_set = frozenset(valid_characters) label_set = frozenset(label) if len(label_set - valid_set) != 0: return False return True ################################################################################ from Interpreter import HAS_LABEL, Program NO_ARGS = Program.NO_ARGS HAS_ARG = Program.HAS_ARG TWO_WAY = tuple(set(NO_ARGS) & set(HAS_ARG)) ################################################################################ def parse_code(program, line, text): for ins, word in enumerate(MNEMONIC): if text.startswith(word): check_code(program, line, text[len(word):], ins) break else: syntax_error(line) def check_code(program, line, text, ins): if ins in TWO_WAY: if text: number = parse_number(line, text) program.append((ins, number)) else: program.append(ins) elif ins in HAS_LABEL: text = parse_label(line, text) program.append((ins, text)) elif ins in HAS_ARG: number = parse_number(line, text) program.append((ins, number)) elif ins in NO_ARGS: if text: syntax_error(line) program.append(ins) else: syntax_error(line) def parse_label(line, text): if not text or text[0] != ' ': syntax_error(line) text = text[1:] if not valid_label(text): syntax_error(line) return text ################################################################################ def parse_number(line, text): if not valid_number(text): syntax_error(line) return int(text) def valid_number(text): if len(text) < 2: return False if text[0] != ' ': return False text = text[1:] if '+' in text and '-' in text: return False if '+' in text: if text.count('+') != 1: return False if text[0] != '+': return False text = text[1:] if not text: return False if '-' in text: if text.count('-') != 1: return False if text[0] != '-': return False text = text[1:] if not text: return False valid_set = frozenset(string.digits) value_set = frozenset(text) if len(value_set - valid_set) != 0: return False return True ################################################################################ ################################################################################ from Interpreter import partition_number VMC_2_TRI = { (INS.PUSH, True): (0, 0), (INS.COPY, False): (0, 2, 0), (INS.COPY, True): (0, 1, 0), (INS.SWAP, False): (0, 2, 1), (INS.AWAY, False): (0, 2, 2), (INS.AWAY, True): (0, 1, 2), (INS.ADD, False): (1, 0, 0, 0), (INS.SUB, False): (1, 0, 0, 1), (INS.MUL, False): (1, 0, 0, 2), (INS.DIV, False): (1, 0, 1, 0), (INS.MOD, False): (1, 0, 1, 1), (INS.SET, False): (1, 1, 0), (INS.GET, False): (1, 1, 1), (INS.PART, True): (2, 0, 0), (INS.CALL, True): (2, 0, 1), (INS.GOTO, True): (2, 0, 2), (INS.ZERO, True): (2, 1, 0), (INS.LESS, True): (2, 1, 1), (INS.BACK, False): (2, 1, 2), (INS.EXIT, False): (2, 2, 2), (INS.OCHR, False): (1, 2, 0, 0), (INS.OINT, False): (1, 2, 0, 1), (INS.ICHR, False): (1, 2, 1, 0), (INS.IINT, False): (1, 2, 1, 1) } ################################################################################ def to_trinary(program): trinary_code = [] for ins in program: if isinstance(ins, tuple): ins, arg = ins trinary_code.extend(VMC_2_TRI[(ins, True)]) trinary_code.extend(from_number(arg)) else: trinary_code.extend(VMC_2_TRI[(ins, False)]) return tuple(trinary_code) def from_number(arg): code = [int(arg < 0)] if arg: for bit in reversed(list(partition_number(abs(arg), 2))): code.append(bit) return code + [2] return code + [0, 2] to_ws = lambda trinary: ''.join(' \t\n'[index] for index in trinary) def compile_wsa(source): program = parse(source) trinary = to_trinary(program) ws_code = to_ws(trinary) return ws_code ################################################################################ ################################################################################ import os import sys import time import traceback def main(): name, source, command_line, error = get_source() if not error: start = time.clock() try: ws_code = compile_wsa(source) except: print('ERROR: File could not be compiled.\n') traceback.print_exc() error = True else: path = os.path.join('Programs', name + '.ws') try: open(path, 'w').write(ws_code) except IOError as err: print(err) error = True else: div, mod = divmod((time.clock() - start) * 1000, 1) args = int(div), '{:.3}'.format(mod)[1:] print('DONE: Comipled in {}{} ms'.format(*args)) handle_close(error, command_line) def get_source(): if len(sys.argv) > 1: command_line = True name = sys.argv[1] else: command_line = False try: name = input('Source File: ') except: return None, None, False, True print() path = os.path.join('Assembly', name + '.wsa') try: return name, open(path).read(), command_line, False except IOError as err: print(err) return None, None, command_line, True def handle_close(error, command_line): if error: usage = 'Usage: {} <assembly>'.format(os.path.basename(sys.argv[0])) print('\n{}\n{}'.format('-' * len(usage), usage)) if not command_line: time.sleep(10) ################################################################################ if __name__ == '__main__': main() Whitespace Helpers #! /usr/bin/env python """Helpers.py Includes a function to encode Python strings into my WSA format. Has a "PRINT_LINE" function that can be copied to a WSA program. Contains a "PRINT" function and documentation as an explanation.""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 1 $' ################################################################################ def encode_string(string, addr): print(' push', addr) print(' push', len(string)) print(' set') addr += 1 for offset, character in enumerate(string): print(' push', addr + offset) print(' push', ord(character)) print(' set') ################################################################################ # Prints a string with newline. # push addr # call "PRINT_LINE" """ part "PRINT_LINE" call "PRINT" push 10 ochr back """ ################################################################################ # def print(array): # if len(array) <= 0: # return # offset = 1 # while len(array) - offset >= 0: # ptr = array.ptr + offset # putch(array[ptr]) # offset += 1 """ part "PRINT" # Line 1-2 copy get less "__PRINT_RET_1" copy get zero "__PRINT_RET_1" # Line 3 push 1 # Line 4 part "__PRINT_LOOP" copy copy 2 get swap sub less "__PRINT_RET_2" # Line 5 copy 1 copy 1 add # Line 6 get ochr # Line 7 push 1 add goto "__PRINT_LOOP" part "__PRINT_RET_2" away part "__PRINT_RET_1" away back """ Whitespace Interpreter #! /usr/bin/env python """Interpreter.py Runs programs in "Programs" and creates *.WSO files when needed. Can be executed directly by double-click or on the command line. If run on command line, add "ASM" flag to dump program assembly.""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 4 $' ################################################################################ def test_file(path): disassemble(parse(trinary(load(path))), True) ################################################################################ load = lambda ws: ''.join(c for r in open(ws) for c in r if c in ' \t\n') trinary = lambda ws: tuple(' \t\n'.index(c) for c in ws) ################################################################################ def enum(names): names = names.replace(',', ' ').split() space = dict((reversed(pair) for pair in enumerate(names)), __slots__=()) return type('enum', (object,), space)() INS = enum('''\ PUSH, COPY, SWAP, AWAY, \ ADD, SUB, MUL, DIV, MOD, \ SET, GET, \ PART, CALL, GOTO, ZERO, LESS, BACK, EXIT, \ OCHR, OINT, ICHR, IINT''') ################################################################################ def parse(code): ins = iter(code).__next__ program = [] while True: try: imp = ins() except StopIteration: return tuple(program) if imp == 0: # [Space] parse_stack(ins, program) elif imp == 1: # [Tab] imp = ins() if imp == 0: # [Tab][Space] parse_math(ins, program) elif imp == 1: # [Tab][Tab] parse_heap(ins, program) else: # [Tab][Line] parse_io(ins, program) else: # [Line] parse_flow(ins, program) def parse_number(ins): sign = ins() if sign == 2: raise StopIteration() buffer = '' code = ins() if code == 2: raise StopIteration() while code != 2: buffer += str(code) code = ins() if sign == 1: return int(buffer, 2) * -1 return int(buffer, 2) ################################################################################ def parse_stack(ins, program): code = ins() if code == 0: # [Space] number = parse_number(ins) program.append((INS.PUSH, number)) elif code == 1: # [Tab] code = ins() number = parse_number(ins) if code == 0: # [Tab][Space] program.append((INS.COPY, number)) elif code == 1: # [Tab][Tab] raise StopIteration() else: # [Tab][Line] program.append((INS.AWAY, number)) else: # [Line] code = ins() if code == 0: # [Line][Space] program.append(INS.COPY) elif code == 1: # [Line][Tab] program.append(INS.SWAP) else: # [Line][Line] program.append(INS.AWAY) def parse_math(ins, program): code = ins() if code == 0: # [Space] code = ins() if code == 0: # [Space][Space] program.append(INS.ADD) elif code == 1: # [Space][Tab] program.append(INS.SUB) else: # [Space][Line] program.append(INS.MUL) elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] program.append(INS.DIV) elif code == 1: # [Tab][Tab] program.append(INS.MOD) else: # [Tab][Line] raise StopIteration() else: # [Line] raise StopIteration() def parse_heap(ins, program): code = ins() if code == 0: # [Space] program.append(INS.SET) elif code == 1: # [Tab] program.append(INS.GET) else: # [Line] raise StopIteration() def parse_io(ins, program): code = ins() if code == 0: # [Space] code = ins() if code == 0: # [Space][Space] program.append(INS.OCHR) elif code == 1: # [Space][Tab] program.append(INS.OINT) else: # [Space][Line] raise StopIteration() elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] program.append(INS.ICHR) elif code == 1: # [Tab][Tab] program.append(INS.IINT) else: # [Tab][Line] raise StopIteration() else: # [Line] raise StopIteration() def parse_flow(ins, program): code = ins() if code == 0: # [Space] code = ins() label = parse_number(ins) if code == 0: # [Space][Space] program.append((INS.PART, label)) elif code == 1: # [Space][Tab] program.append((INS.CALL, label)) else: # [Space][Line] program.append((INS.GOTO, label)) elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] label = parse_number(ins) program.append((INS.ZERO, label)) elif code == 1: # [Tab][Tab] label = parse_number(ins) program.append((INS.LESS, label)) else: # [Tab][Line] program.append(INS.BACK) else: # [Line] code = ins() if code == 2: # [Line][Line] program.append(INS.EXIT) else: # [Line][Space] or [Line][Tab] raise StopIteration() ################################################################################ MNEMONIC = '\ push copy swap away add sub mul div mod set get part \ call goto zero less back exit ochr oint ichr iint'.split() HAS_ARG = [getattr(INS, name) for name in 'PUSH COPY AWAY PART CALL GOTO ZERO LESS'.split()] HAS_LABEL = [getattr(INS, name) for name in 'PART CALL GOTO ZERO LESS'.split()] def disassemble(program, names=False): if names: names = create_names(program) for ins in program: if isinstance(ins, tuple): ins, arg = ins assert ins in HAS_ARG has_arg = True else: assert INS.PUSH <= ins <= INS.IINT has_arg = False if ins == INS.PART: if names: print(MNEMONIC[ins], '"' + names[arg] + '"') else: print(MNEMONIC[ins], arg) elif has_arg and ins in HAS_ARG: if ins in HAS_LABEL and names: assert arg in names print(' ' + MNEMONIC[ins], '"' + names[arg] + '"') else: print(' ' + MNEMONIC[ins], arg) else: print(' ' + MNEMONIC[ins]) ################################################################################ def create_names(program): names = {} number = 1 for ins in program: if isinstance(ins, tuple) and ins[0] == INS.PART: label = ins[1] assert label not in names names[label] = number_to_name(number) number += 1 return names def number_to_name(number): name = '' for offset in reversed(list(partition_number(number, 27))): if offset: name += chr(ord('A') + offset - 1) else: name += '_' return name def partition_number(number, base): div, mod = divmod(number, base) yield mod while div: div, mod = divmod(div, base) yield mod ################################################################################ CODE = (' \t\n', ' \n ', ' \t \t\n', ' \n\t', ' \n\n', ' \t\n \t\n', '\t ', '\t \t', '\t \n', '\t \t ', '\t \t\t', '\t\t ', '\t\t\t', '\n \t\n', '\n \t \t\n', '\n \n \t\n', '\n\t \t\n', '\n\t\t \t\n', '\n\t\n', '\n\n\n', '\t\n ', '\t\n \t', '\t\n\t ', '\t\n\t\t') EXAMPLE = ''.join(CODE) ################################################################################ NOTES = '''\ STACK ===== push number copy copy number swap away away number MATH ==== add sub mul div mod HEAP ==== set get FLOW ==== part label call label goto label zero label less label back exit I/O === ochr oint ichr iint''' ################################################################################ ################################################################################ class Stack: def __init__(self): self.__data = [] # Stack Operators def push(self, number): self.__data.append(number) def copy(self, number=None): if number is None: self.__data.append(self.__data[-1]) else: size = len(self.__data) index = size - number - 1 assert 0 <= index < size self.__data.append(self.__data[index]) def swap(self): self.__data[-2], self.__data[-1] = self.__data[-1], self.__data[-2] def away(self, number=None): if number is None: self.__data.pop() else: size = len(self.__data) index = size - number - 1 assert 0 <= index < size del self.__data[index:-1] # Math Operators def add(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix + suffix) def sub(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix - suffix) def mul(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix * suffix) def div(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix // suffix) def mod(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix % suffix) # Program Operator def pop(self): return self.__data.pop() ################################################################################ class Heap: def __init__(self): self.__data = {} def set_(self, addr, item): if item: self.__data[addr] = item elif addr in self.__data: del self.__data[addr] def get_(self, addr): return self.__data.get(addr, 0) ################################################################################ import os import zlib import msvcrt import pickle import string class CleanExit(Exception): pass NOP = lambda arg: None DEBUG_WHITESPACE = False ################################################################################ class Program: NO_ARGS = INS.COPY, INS.SWAP, INS.AWAY, INS.ADD, \ INS.SUB, INS.MUL, INS.DIV, INS.MOD, \ INS.SET, INS.GET, INS.BACK, INS.EXIT, \ INS.OCHR, INS.OINT, INS.ICHR, INS.IINT HAS_ARG = INS.PUSH, INS.COPY, INS.AWAY, INS.PART, \ INS.CALL, INS.GOTO, INS.ZERO, INS.LESS def __init__(self, code): self.__data = code self.__validate() self.__build_jump() self.__check_jump() self.__setup_exec() def __setup_exec(self): self.__iptr = 0 self.__stck = stack = Stack() self.__heap = Heap() self.__cast = [] self.__meth = (stack.push, stack.copy, stack.swap, stack.away, stack.add, stack.sub, stack.mul, stack.div, stack.mod, self.__set, self.__get, NOP, self.__call, self.__goto, self.__zero, self.__less, self.__back, self.__exit, self.__ochr, self.__oint, self.__ichr, self.__iint) def step(self): ins = self.__data[self.__iptr] self.__iptr += 1 if isinstance(ins, tuple): self.__meth[ins[0]](ins[1]) else: self.__meth[ins]() def run(self): while True: ins = self.__data[self.__iptr] self.__iptr += 1 if isinstance(ins, tuple): self.__meth[ins[0]](ins[1]) else: self.__meth[ins]() def __oint(self): for digit in str(self.__stck.pop()): msvcrt.putwch(digit) def __ichr(self): addr = self.__stck.pop() # Input Routine while msvcrt.kbhit(): msvcrt.getwch() while True: char = msvcrt.getwch() if char in '\x00\xE0': msvcrt.getwch() elif char in string.printable: char = char.replace('\r', '\n') msvcrt.putwch(char) break item = ord(char) # Storing Number self.__heap.set_(addr, item) def __iint(self): addr = self.__stck.pop() # Input Routine while msvcrt.kbhit(): msvcrt.getwch() buff = '' char = msvcrt.getwch() while char != '\r' or not buff: if char in '\x00\xE0': msvcrt.getwch() elif char in '+-' and not buff: msvcrt.putwch(char) buff += char elif '0' <= char <= '9': msvcrt.putwch(char) buff += char elif char == '\b': if buff: buff = buff[:-1] msvcrt.putwch(char) msvcrt.putwch(' ') msvcrt.putwch(char) char = msvcrt.getwch() msvcrt.putwch(char) msvcrt.putwch('\n') item = int(buff) # Storing Number self.__heap.set_(addr, item) def __goto(self, label): self.__iptr = self.__jump[label] def __zero(self, label): if self.__stck.pop() == 0: self.__iptr = self.__jump[label] def __less(self, label): if self.__stck.pop() < 0: self.__iptr = self.__jump[label] def __exit(self): self.__setup_exec() raise CleanExit() def __set(self): item = self.__stck.pop() addr = self.__stck.po

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  • Save output and exit code of command to files on windows

    - by poncha
    I want to run a command and save its output and its exit code, in different files. Here's what i am doing: cmd.exe /C command 1> %TEMP%\output.log 2> %TEMP%\error.log && echo %ERRORLEVEL% > %TEMP%\status || echo %ERRORLEVEL% > %TEMP%\status If i don't do output redirection (into %TEMP%\output.log and/or %TEMP%\error.log), then exit code is saved just fine. However, when i run the line as shown above more than once (just get back to previous line in command prompt and rerun it), i get 0 in %TEMP%\status regardless of the real exit code. What am i missing? Or maybe there's a better way of doing this?

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  • How does java permgen relate to code size

    - by brad
    I've been reading a lot about java memory management, garbage collecting et al and I'm trying to find the best settings for my limited memory (1.7g on a small ec2 instance) I'm wondering if there is a direct correlation between my code size and the permgen setting. According to sun: The permanent generation is special because it holds data needed by the virtual machine to describe objects that do not have an equivalence at the Java language level. For example objects describing classes and methods are stored in the permanent generation. To me this means that it's literally storing my class def'ns etc... Does this mean there is a direct correlation between my compiled code size and the permgen I should be setting? My whole app is about 40mb and i noticed we're using 256mb permgen. I'm thinking maybe we're using memory that could be better allocated to dynamic code like object instances etc...

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  • bash code in rc.local not excuting after bootup

    - by mrTomahawk
    Does anyone know why a system would not execute the script code within rc.local on bootup? I have a post configuration bash script that I want to run after the initial install of VMware ESX (Red Hat), and for some reason it doesn't seem to execute. I have the setup to log its start of execution and even its progress so that I can see how far it gets in case it fails at some point, but even when I look at that log, I am finding that didn't even started the execution of the script code. I already checked to see that script has execution permissions (755), what else should I be looking at? Here is the first few lines of my code: #!/bin/sh echo >> /tmp/configLog "" echo >> /tmp/configLog "Entering maintenance mode"

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  • libvirt + ESX (HTTP response code 400 for call to 'Login')

    - by Coops
    I'm trying to connect to a vSphere cluster using the information from the libvirt documentation. $ virsh -c "vpx://[email protected]/dc1/dc1-cluster-e01/dc1-vsphere-e04/?no_verify=1" Enter root's password for 10.51.4.11: error: internal error HTTP response code 400 for call to 'Login' error: failed to connect to the hypervisor I seem to be able to establish a connection, but it fails with a "HTTP code 400". If I provide the incorrect password it fails with a 'login credentials' error, so it looks like I am getting a connection, but it's failing for another reason. Wireshark is no help as it's all done over SSL/TLS. Any thoughts folks? UPDATE: 15:21 28/02/11 FYI - I'm running libvirt-0.8.3 (the Ubuntu package recompiled with the ESX flag enabled). When I put virsh into debug mode it returns this: [snip] Enter root's password for 10.51.4.11: 15:19:09.011: debug : do_open:1249 : driver 3 ESX returned ERROR 15:19:09.011: debug : virUnrefConnect:294 : unref connection 0x98aa8f8 1 15:19:09.011: debug : virReleaseConnect:249 : release connection 0x98aa8f8 error: internal error HTTP response code 400 for call to 'Login' error: failed to connect to the hypervisor

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  • HOw to secure whm/cpanel centos server from javascript malacious code virus

    - by Master
    Recently my sites index.php code was replaced some malacious javascript virus code. I really don't know how did that entered into that page. Today when i tried to download that file via ftp then antivirus gave me the warning. So it means it was not entered from my computer. Is there any way to install some antivirus on VPS server with centos 5 , cpanel/whm so that those code should not be allowed to add. also what is mod_security . will it be helpful.

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  • Where do you find the Bash source files of programs in Linux/Mac OSX?

    - by AndrewKS
    I am currently writing some convenience methods for my terminal in my bash_profile and am sure if what I am writing is "the best way". I figure a good way to verify whether what I'm doing is right or not would be to find some source code of more established programs and see how they do it. My question then is, where can I find this code on my Mac? An example is, with Macports installed, where is the source code that opens the port interactive console when I type nothing but "port" in my shell? (I added Linux in the title even though I am on a Mac because I assume the answer would be the same for both) Edit: The answer I am looking for is in terms of which directory relative to the programs will I find their unix scripts.

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  • MySQL query works in Workbench but gives error code 63 from PHP

    - by smund3
    I am making a poll system with PHP/MySQL and have made created a MySQL user for the system to use. However, whenever I try to run a query from PHP as that user, I get error code 63, which after some Googleing I found out means: OS error code 63: Out of streams resources If I make the PHP script use an almighty user instead, everything works fine, so it looks like it has something to do with permissions. I am using a non-persistent connection. I have Googled a lot but I haven't found anything even slightly relevant to this issue. What could cause this error? EDIT: Now it actually started giving me a different error: OS error code 65: Package not installed ...all I did was revert the script to using the poll user instead of the almighty one.

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  • Run single php code using multiple domains

    - by Acharya
    Hi all, I have a php code/site at xyz.com. Now I want to run the same site using multiple domains means when somebody open domain1.com, domain2.com ,domain4.com, so on urls, it should run the code/side that is at xyz.com I know one way to do this. I can host all these domains to the server where xyz.com is hosted so all domains will point to same peace of code/site. n above solution i need to hosted the domains manually. Is there any other way to do this as I want to add domains dynamically? Thanks in advance!

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  • Domain provider for all Country Code TLDs?

    - by 8k_of_power
    I find it very disturbing to buy some domains from one domain provider than when I have to buy a Country Code TLD that is not supported, I have to buy from another domain provider, and thus ending up having multiple domain providers for all my domains. I have looked at Gandi and GoDaddy. They both lack some Country Code TLDs the other one has. Is there domain providers that has all (or almost all) Country Code TLDs? If not, how do you guys do to get all (or almost all) domains under in one place? Also, it would be good if someone could suggest some of the big players of domain providing besides Gandi and GoDaddy, cause I'm new to the international domain market (have only used a couple in Sweden).

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  • Why have minimal user/handwritten code and do everything in XAML?

    - by Mrk Mnl
    I feel the MVVM community has become overzealous like the OO programmers in the 90's - it is a misnomer MVVM is synonymous with no code. From my closed StackOverflow question: Many times I come across posts here about someone trying to do the equivalent in XAML instead of code behind. Their only reason being they want to keep their code behind 'clean'. Correct me if I am wrong, but is not the case that: XAML is compiled too - into BAML - then at runtime has to be parsed into code anyway. XAML can potentially have more runtime bugs as they will not be picked up by the compiler at compile time - from incorrect spellings - these bugs are also harder to debug. There already is code behind - like it or not InitializeComponent(); has to be run and the .g.i.cs file it is in contains a bunch of code though it may be hidden. Is it purely psychological? I suspect it is developers who come from a web background and like markup as opposed to code. EDIT: I don't propose code behind instead of XAML - use both - I prefer to do my binding in XAML too - I am just against making every effort to avoid writing code behind esp in a WPF app - it should be a fusion of both to get the most out of it. UPDATE: Its not even Microsoft's idea, every example on MSDN shows how you can do it in both.

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  • Can too much abstraction be bad?

    - by m3th0dman
    As programmers I feel that our goal is to provide good abstractions on the given domain model and business logic. But where should this abstraction stop? How to make the trade-off between abstraction and all it's benefits (flexibility, ease of changing etc.) and ease of understanding the code and all it's benefits. I believe I tend to write code overly abstracted and I don't know how good is it; I often tend to write it like it is some kind of a micro-framework, which consists of two parts: Micro-Modules which are hooked up in the micro-framework: these modules are easy to be understood, developed and maintained as single units. This code basically represents the code that actually does the functional stuff, described in requirements. Connecting code; now here I believe stands the problem. This code tends to be complicated because it is sometimes very abstracted and is hard to be understood at the beginning; this arises due to the fact that it is only pure abstraction, the base in reality and business logic being performed in the code presented 1; from this reason this code is not expected to be changed once tested. Is this a good approach at programming? That it, having changing code very fragmented in many modules and very easy to be understood and non-changing code very complex from the abstraction POV? Should all the code be uniformly complex (that is code 1 more complex and interlinked and code 2 more simple) so that anybody looking through it can understand it in a reasonable amount of time but change is expensive or the solution presented above is good, where "changing code" is very easy to be understood, debugged, changed and "linking code" is kind of difficult. Note: this is not about code readability! Both code at 1 and 2 is readable, but code at 2 comes with more complex abstractions while code 1 comes with simple abstractions.

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  • How to embed multiple jQuery line of code in custom HtmlHelpers ASP.NET MVC

    - by embarus
    I 've tried to create my own HTML Helper which work fine for my need but I can't embed many lines of jQuery code in my extension HtmlHelpers class. I've tried @ literal for jQuery code I doesn't work or I need to escape every line of code that I thing I not good for multiple line of code. I don't know if there is another way to achieve this problem like << Therefore, I need to include jQuery plugin file and put implement script after HTML tag. I find it would be convenience if I could put every in HTML helper and put a single line of code in aspx page for example <%= Html.ParentChildSelectList(string parentName, string childName, IEnumerable parentViewData, IEnumerable childViewData, int parentSize, in childSize) % The following code is the way that I used now. the .aspx page Category model.CategoryID)% , new { size = 10 })% model.SubcategoryID,"subcategory") % model.SubcategoryID)% , new { size = 10 })% <script type="text/javascript"> jQuery.sarapadchang.parentChildSelectList( { parentId : "CategoryID" , childId : "SubcategoryID", actionName : "GetSubcategoryList", controllerName : "Json" } ); </script> I put in head tag to include ParentChildSelectList.js the following code for ParentChildSelectList.js (function($) { $.sarapadchang = { parentChildSelectList: function(options) { // $("#CategoryID option").click(function() $("#" + options.parentId).find("option").click(function() { $("#" + options.childId).empty(); //clear data $("#" + options.childId).append('<option>loading...</option>'); $.post("/" + options.controllerName + "/" + options.actionName + "/" + $(this).attr('value'), "", function(data) { var html = ""; $.each(data, function(index, entry) { html += '<option value="' + entry['Value'] + '">' + entry['Text'] + '</option>'; } ); $("#" + options.childId).empty() $("#" + options.childId).append(html); }, "json"); //end getJson }); })(jQuery); To illustrate you, I've attached simple solution, please follow this link. http://www.thaileaguefc.net/ParentChildSelectList.rar Please accept my apologies if my English is difficult to understand. I am looking forward to hearing from you. Your faithfully, Theeranit

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  • Ruby: what is the pitfall in this simple code excerpt that tests variable existence

    - by zipizap
    I'm starting with Ruby, and while making some test samples, I've stumbled against an error in the code that I don't understand why it happens. The code pretends to tests if a variable finn is defined?() and if it is defined, then it increments it. If it isn't defined, then it will define it with value 0 (zero). As the code threw an error, I started to decompose it in small pieces and run it, to better trace where the error was comming from. The code was run in IRB irb 0.9.5(05/04/13), using ruby 1.9.1p378 First I certify that the variable finn is not yet defined, and all is ok: ?> finn NameError: undefined local variable or method `finn' for main:Object from (irb):134 from /home/paulo/.rvm/rubies/ruby-1.9.1-p378/bin/irb:15:in `<main>' >> Then I certify that the following inline-condition executes as expected, and all is ok: ?> ((defined?(finn)) ? (finn+1):(0)) => 0 And now comes the code that throws the error: ?> finn=((defined?(finn)) ? (finn+1):(0)) NoMethodError: undefined method `+' for nil:NilClass from (irb):143 from /home/paulo/.rvm/rubies/ruby-1.9.1-p378/bin/irb:15:in `<main>' I was expecting that the code would not throw any error, and that after executing the variable finn would be defined with a first value of 0 (zero). But instead, the code thows the error, and finn get defined but with a value of nil. >> finn => nil Where might the error come from?!? Why does the inline-condition work alone, but not when used for the finn assignment? Any help apreciated :)

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  • searching for a programming platform with hot code swap

    - by Andreas
    I'm currently brainstorming over the idea how to upgrade a program while it is running. (Not while debugging, a "production" system.) But one thing that is required for it, is to actually submit the changed source code or compiled byte code into the running process. Pseudo Code var method = typeof(MyClass).GetMethod("Method1"); var content = //get it from a database (bytecode or source code) SELECT content FROM methods WHERE id=? AND version=? method.SetContent(content); At first, I want to achieve the system to work without the complexity of object-orientation. That leads to the following requirements: change source code or byte code of function drop functions add new functions change the signature of a function With .NET (and others) I could inject a class via an IoC and could thus change the source code. But the loading would be cumbersome, because everything has to be in an Assembly or created via Emit. Maybe with Java this would be easier? The whole ClassLoader is replacable, I think. With JavaScript I could achieve many of the goals. Simply eval a new function (MyMethod_V25) and assign it to MyClass.prototype.MyMethod. I think one can also drop functions somehow with "del" Which general-purpose platform can handle such things?

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  • (x86) Assembler Optimization

    - by Pindatjuh
    I'm building a compiler/assembler/linker in Java for the x86-32 (IA32) processor targeting Windows. High-level concepts of a "language" (in essential a Java API for creating executables) are translated into opcodes, which then are wrapped and outputted to a file. The translation process has several phases, one is the translation between languages: the highest-level code is translated into the medium-level code which is then translated into the lowest-level code (probably more than 3 levels). My problem is the following; if I have higher-level code (X and Y) translated to lower-level code (x, y, U and V), then an example of such a translation is, in pseudo-code: x + U(f) // generated by X + V(f) + y // generated by Y (An easy example) where V is the opposite of U (compare with a stack push as U and a pop as V). This needs to be 'optimized' into: x + y (essentially removing the "useless" code) My idea was to use regular expressions. For the above case, it'll be a regular expression looking like this: x:(U(x)+V(x)):null, meaning for all x find U(x) followed by V(x) and replace by null. Imagine more complex regular expressions, for more complex optimizations. This should work on all levels. What do you suggest? What would be a good approach to optimize in these situations?

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  • How do I protect the trunk from hapless newbies?

    - by Michael Haren
    A coworker relayed the following problem, let's say it's fictional to protect the guilty: A team of 5-10 works on a project which is issue-driven. That is, the typical flow goes like this: a chunk of work (bug, enhancement, etc.) is created as an issue in the issue tracker The issue is assigned to a developer The developer resolves the issue and commits their code changes to the trunk At release time, the frozen, and heavily tested trunk or release branch or whatever is built in release mode and released The problem he's having is that a couple newbies made several bad commits that weren't caught due to an unfortunate chain of events. This was followed by a bad release with a rollback or flurry of hot fixes. One idea we're toying with: Revoke commit access to the trunk for newbies and make them develop on a per-developer branch (we're using SVN): Good: newbies are isolated and can't hurt others Good: committers merge newbie branches with the trunk frequently Good: this enforces rigid code reviews Bad: this is burdensome on the committers (but there's probably no way around it since the code needs reviewed!) Bad: it might make traceability of trunk changes a little tougher since the reviewer would be doing the commit--not too sure on this. Update: Thank you, everyone, for your valuable input. I have concluded that this is far less a code/coder problem than I first presented. The root of the issue is that the release procedure failed to capture and test some poor quality changes to the trunk. Plugging that hole is most important. Relying on the false assumption that code in the trunk is "good" is not the solution. Once that hole--testing--is plugged, mistakes by everyone--newbie or senior--will be caught properly and dealt with accordingly. Next, a greater emphasis on code reviews and mentorship (probably driven by some systematic changes to encourage it) will go a long way toward improving code quality. With those two fixes in place, I don't think something as rigid or draconian as what I proposed above is necessary. Thanks!

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  • Alternative way of implementation of a code

    - by vikramjb
    The title is not exactly meaningful, but I am not share what else to name it. I wrote a TOC Generation code sometime later. Based on this I was writing code to check for duplicates also. The code is as follows curNumber = getTOCReference(selItem.SNo, IsParent); CheckForDuplicates(curNumber, IsParent,out realTOCRef); curNumber = realTOCRef; And the code for CheckForDuplicates is ListViewItem curItem = this.tlvItems.FindItemWithText(curNumber); if (curItem != null) { curNumber = this.getTOCReference(curNumber, !IsParent); CheckForDuplicates(curNumber, IsParent,out realTOCRef); } else { realTOCRef= curNumber; } What this code does, it gets a TOC and tries it find if it already exists in the ObjectListView and gets a new TOC if there is a existing TOC. Once it determines that the generated TOC is not there in the list it stores it in realTOCRef and sends it back to the main calling code. I have used "out" to return the last generated TOC, which is something I did not want to do. The reason why I did it was after the non duplicate TOC was generated the return was not going back to the calling code instead it looped through the previous instances then it returned back. When the looping back happened the TOC that was to be returned also got reset. I would appreciate any help on this.

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  • P/Invoke declarations should not be safe-critical

    - by Bobrovsky
    My code imports following native methods: DeleteObject, GetFontData and SelectObject from gdi32.dll GetDC and ReleaseDC from user32.dll I want to run the code in full trust and medium trust environments (I am fine with exceptions being thrown when these imported methods are indirectly used in medium trust environments). When I run Code Analysis on the code I get warnings like: CA5122 P/Invoke declarations should not be safe-critical. P/Invoke method 'GdiFont.DeleteObject(IntPtr)' is marked safe-critical. Since P/Invokes may only be called by critical code, this declaration should either be marked as security critical, or have its annotation removed entirely to avoid being misleading. Could someone explain me (in layman terms) what does this warning really mean? I tried putting these imports in static SafeNativeMethods class as internal static methods but this doesn't make the warnings go away. I didn't try to put them in NativeMethods because after reading this article I am unsure that it's the right way to go because I don't want my code to be completely unusable in medium trust environments (I think this will be the consequence of moving imports to NativeMethods). Honestly, I am pretty much confused about the real meaning of the warning and consequences of different options to suppressing it. Could someone shed some light on all this? EDIT: My code target .NET 2.0 framework. Assembly is marked with [assembly: AllowPartiallyTrustedCallers] Methods are declared like this: [DllImport("gdi32")] internal static extern int DeleteObject(HANDLE hObject);

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