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  • boost::filesystem - how to create a boost path from a windows path string on posix plattforms?

    - by VolkA
    I'm reading path names from a database which are stored as relative paths in Windows format, and try to create a boost::filesystem::path from them on a Unix system. What happens is that the constructor call interprets the whole string as the filename. I need the path to be converted to a correct Posix path as it will be used locally. I didn't find any conversion functions in the boost::filesystem reference, nor through google. Am I just blind, is there an obvious solution? If not, how would you do this? Example: std::string win_path("foo\\bar\\asdf.xml"); std::string posix_path("foo/bar/asdf.xml"); // loops just once, as part is the whole win_path interpreted as a filename boost::filesystem::path boost_path(win_path); BOOST_FOREACH(boost::filesystem::path part, boost_path) { std::cout << part << std::endl; } // prints each path component separately boost::filesystem::path boost_path_posix(posix_path); BOOST_FOREACH(boost::filesystem::path part, boost_path_posix) { std::cout << part << std::endl; }

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  • How do you prove a function works?

    - by glenn I.
    I've recently gotten the testing religion and have started primarily with unit testing. I code unit tests which illustrate that a function works under certain cases, specifically using the exact inputs I'm using. I may do a number of unit tests to exercise the function. Still, I haven't actually proved anything other than the function does what I expect it to do under the scenarios I've tested. There may be other inputs and scenarios I haven't thought of and thinking of edge cases is expensive, particularly on the margins. This is all not very satisfying to do me. When I start to think of having to come up with tests to satisfy branch and path coverage and then integration testing, the prospective permutations can become a little maddening. So, my question is, how can one prove (in the same vein of proving a theorem in mathematics) that a function works (and, in a perfect world, compose these 'proofs' into a proof that a system works)? Is there a certain area of testing that covers an approach where you seek to prove a system works by proving that all of its functions work? Does anybody outside of academia bother with an approach like this? Are there tools and techniques to help? I realize that my use of the word 'work' is not precise. I guess I mean that a function works when it does what some spec (written or implied) states that it should do and does nothing other than that. Note, I'm not a mathematician, just a programmer.

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  • How to easily map c++ enums to strings

    - by Roddy
    I have a bunch of enum types in some library header files that I'm using, and I want to have a way of converting enum values to user strings - and vice-versa. RTTI won't do it for me, because the 'user strings' need to be a bit more readable than the enumerations. A brute force solution would be a bunch of functions like this, but I feel that's a bit too C-like. enum MyEnum {VAL1, VAL2,VAL3}; String getStringFromEnum(MyEnum e) { switch e { case VAL1: return "Value 1"; case VAL2: return "Value 2"; case VAL1: return "Value 3"; default: throw Exception("Bad MyEnum"); } } I have a gut feeling that there's an elegant solution using templates, but I can't quite get my head round it yet. UPDATE: Thanks for suggestions - I should have made clear that the enums are defined in a third-party library header, so I don't want to have to change the definition of them. My gut feeling now is to avoid templates and do something like this: char * MyGetValue(int v, char *tmp); // implementation is trivial #define ENUM_MAP(type, strings) char * getStringValue(const type &T) \ { \ return MyGetValue((int)T, strings); \ } ; enum eee {AA,BB,CC}; - exists in library header file ; enum fff {DD,GG,HH}; ENUM_MAP(eee,"AA|BB|CC") ENUM_MAP(fff,"DD|GG|HH") // To use... eee e; fff f; std::cout<< getStringValue(e); std::cout<< getStringValue(f);

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  • How to update GUI thread/class from worker thread/class?

    - by user315182
    First question here so hello everyone. The requirement I'm working on is a small test application that communicates with an external device over a serial port. The communication can take a long time, and the device can return all sorts of errors. The device is nicely abstracted in its own class that the GUI thread starts to run in its own thread and has the usual open/close/read data/write data basic functions. The GUI is also pretty simple - choose COM port, open, close, show data read or errors from device, allow modification and write back etc. The question is simply how to update the GUI from the device class? There are several distinct types of data the device deals with so I need a relatively generic bridge between the GUI form/thread class and the working device class/thread. In the GUI to device direction everything works fine with [Begin]Invoke calls for open/close/read/write etc. on various GUI generated events. I've read the thread here (How to update GUI from another thread in C#?) where the assumption is made that the GUI and worker thread are in the same class. Google searches throw up how to create a delegate or how to create the classic background worker but that's not at all what I need, although they may be part of the solution. So, is there a simple but generic structure that can be used? My level of C# is moderate and I've been programming all my working life, given a clue I'll figure it out (and post back)... Thanks in advance for any help.

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  • Xlib.h and Xutil.h not found in Eclipse, how can I fix this?

    - by eclipseNoob
    Hi, I'm a newbie to Eclipse IDE for C/C++ development. I just installed MingW and set it up as my system's environment variable. I am trying to make an application that uses the X library but eclipse cant seem to find it. Eclipse works with any other simple standard library functions but it cant find the X library. Please Help! Here's a sample code snippet that's failing: #include <stdio.h> #include <X11/Xlib.h> // Can't find this #include <X11/Xutil.h> // Or this... int main() { printf("Hello"); return 0; } Do I have to download the X library from somewhere? If so then from where and where do I paste it to? Please tell me what to do in order for me to start coding using the Xlib in Eclipse. If you find any useful links, please dont hesitate to post. Thanks.

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  • Socket Read In Multi-Threaded Application Returns Zero Bytes or EINTR (-1)

    - by user309670
    Hi. Am a c-coder for a while now - neither a newbie nor an expert. Now, I have a certain daemoned application in C on a PPC Linux. I use PHP's socket_connect as a client to connect to this service locally. The server uses epoll for concurrent connections via a Unix socket. A user submitted string is parsed for certain characters/words using strstr() and if found, spawns 4 joinable threads to different websites simultaneously. I use socket, connect, write and read, to interact with the said webservers via TCP on port 80 in each thread. All connections and writes seems successful. Reads to the webserver sockets fail however, with either (A) all 3 threads seem to hang, and only one thread returns -1 and errno is set to 104. The responding thread takes like 10 minutes - an eternity long:-(. *I read somewhere that the 104 (is EINTR) suggests that ...'the connection was reset by peer', or (B) 0 bytes from 3 threads, and only 1 of the 4 threads actually returns some data. Isn't the socket read/write thread-safe? Otherwise, use thread-safe (and reentrant) libc functions such as strtok_r, gethostbyname_r, etc. *I doubt that the said webhosts are actually resetting the connection, because when I run a single-threaded standalone (everything else equal) all things works perfectly right. There's a second problem too (oops), I can't write back to the client who connect to my epoll-ed Unix socket. My daemon application will hang and hog CPU 100% for ever. Yet nothing is written to the clients end. Am sure the client (a very typical PHP socket application) hasn't closed the connection whenever this is happening - no error(s) detected either. I cannot figure-out whatever is wrong even with Valgrind or GDB

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  • How to re-prompt after a trap return in bash?

    - by verbose
    I have a script that is supposed to trap SIGTERM and SIGTSTP. This is what I have in the main block: trap 'killHandling' TERM And in the function: killHandling () { echo received kill signal, ignoring return } ... and similar for SIGINT. The problem is one of user interface. The script prompts the user for some input, and if the SIGTERM or SIGINT occurs when the script is waiting for input, it's confusing. Here is the output in that case: Enter something: # SIGTERM received received kill signal, ignoring # shell waits at blank line for user input, user gets confused # user hits "return", which then gets read as blank input from the user # bad things happen because of the blank input I have definitely seen scripts which handle this more elegantly, like so: Enter something: # SIGTERM received received kill signal, ignoring Enter something: # re-prompts user for user input, user is not confused What is the mechanism used to accomplish the latter? Unfortunately I can't simply change my trap code to do the re-prompt as the script prompts the user for several things and what the prompt says is context-dependent. And there has to be a better way than writing context-dependent trap functions. I'd be very grateful for any pointers. Thanks!

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  • Where to store site settings: DB? XML? CONFIG? CLASS FILES?

    - by Emin
    I am re-building a news portal of which already have a large number of visits every day. One of the major concerns when re-building this site was to maximize performance and speed. Having said this, we have done many things from caching, to all sort of other measures to ensure speed. Now towards the end of the project, I am having a dilemma of where to store my site settings that would least affect performance. The site settings will include things such as: Domain, DefaultImgPath, Google Analytics code, default emails of editors as well as more dynamic design/display feature settings such as the background color of specific DIVs and default color for links etc.. As far as I know, I have 4 choices in storing all these info. Database: Storing general settings in the DB and caching them may be a solution however, I want to limit the access to the database for only necessary and essential functions of the project which generally are insert/update/delete news items, author articles etc.. XML: I can store these settings in an XML file but I have not done this sort of thing before so I don't know what kind of problems -if any- I might face in the future. CONFIG: I can also store these settings in web.config CLASS FILE: I can hard code all these settings in a SiteSettings class, but since the site admin himself will be able to edit these settings, It may not be the best solution. Currently, I am more close to choosing web.config but letting people fiddle with it too often is something I do not want. E.g. if somehow, I miss out a validation for something and it breaks the web.config, the whole site will go down. My concern basically is that, I cannot forsee any possible consequences of using any of the methods above (or is there any other?), I was hoping to get this question over to more experienced people out here who hopefully help make my decision.

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  • Matab - Trace contour line between two different points

    - by Graham
    Hi, I have a set of points represented as a 2 row by n column matrix. These points make up a connected boundary or edge. I require a function that traces this contour from a start point P1 and stop at an end point P2. It also needs to be able trace the contour in a clockwise or anti-clockwise direction. I was wondering if this can be achieved by using some of matlabs functions. I have tried to write my own function but this was riddled with bugs and I have also tried using bwtraceboundary and indexing however this has problematic results as the points within the matrix are not in the order that create the contour. Thank you in advance for any help. Btw, I have included a link to a plot of the set of points. It is half the outline of a hand. The function would ideally trace the contour from ether the red star to the green triangle. Returning the points in order of traversal.

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  • Extracting function declarations from a PHP file

    - by byronh
    I'm looking to create an on-site API reference for my framework and application. Basically, say I have a class file model.class.php: class Model extends Object { ... code here ... // Separates results into pages. // Returns Paginator object. final public function paginate($perpage = 10) { ... more code here ... } } and I want to be able to generate a reference that my developers can refer to quickly in order to know which functions are available to be called. They only need to see the comments directly above each function and the declaration line. Something like this (similar to a C++ header file): // Separates results into pages. // Returns Paginator object. final public function paginate($perpage = 10); I've done some research and this answer looked pretty good (using Reflection classes), however, I'm not sure how I can keep the comments in. Any ideas? EDIT: Sorry, but I want to keep the current comment formatting. Myself and the people who are working on the code hate the verbosity associated with PHPDocumentor. Not to mention a comment-rewrite of the entire project would take years, so I want to preserve just the // comments in plaintext.

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  • Setting objct literal property value via asynchronous callback.

    - by typeof
    I'm creating a self-contained javascript utility object that detects advanced browser features. Ideally, my object would look something like this: Support = { borderRadius : false, // values returned by functions gradient : false, // i am defining dataURI : true }; My current problem deals with some code I'm adapting from Weston Ruter's site which detects dataURI support. It attempts to use javascript to create an image with a dataURI source, and uses onload/onerror callbacks to check the width/height. Since onload is asynchronous, I lose my scope and returning true/false does not assign true/false to my object. Here is my attempt: Support = { ... dataURI : function(prop) { prop = prop; // keeps in closure for callback var data = new Image(); data.onload = data.onerror = function(){ if(this.width != 1 || this.height != 1) { that = false; } that = true; } data.src = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw=="; return -1; }(this) }; I'm executing the anonymous function immediately, passing this (which I hoped was a reference to Support.dataURI), but unfortunately references the window object -- so the value is always -1. I can get it to work by using an externally defined function to assign the value after the Support object is created... but I don't think it's very clean that way. Is there a way for it to be self-contained? Can the object literal's function reference the property it's assigned to?

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  • Are there any libraries for parsing "number expressions" like 1,2-9,33- in Java

    - by mihi
    Hi, I don't think it is hard, just tedious to write: Some small free (as in beer) library where I can put in a String like 1,2-9,33- and it can tell me whether a given number matches that expression. Just like most programs have in their print range dialogs. Special functions for matching odd or even numbers only, or matching every number that is 2 mod 5 (or something like that) would be nice, but not needed. The only operation I have to perform on this list is whether the range contains a given (nonnegative) integer value; more operations like max/min value (if they exist) or an iterator would be nice, of course. What would be needed that it does not occupy lots of RAM if anyone enters 1-10000000 but the only number I will ever query is 12345 :-) (To implement it, I would parse a list into several (min/max/value/mod) pairs, like 1,10,0,1 for 1-10 or 11,33,1,2 for 1-33odd, or 12,62,2,10 for 12-62/10 (i. e. 12, 22, 32, ..., 62) and then check each number for all the intervals. Open intervals by using Integer.MaxValue etc. If there are no libs, any ideas to do it better/more efficient?)

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  • Socket isn't listed by netstat unless using certain ports

    - by illuzive
    I'm a computer science student with a few years of programming experience. Yesterday, while working on a project (Mac OS X, BSD sockets) at school, I encountered a strange problem. I was adding several modules to a very basic "server" (mostly a bunch of functions to set up and manage an UDP socket on a certain port). While doing this, I started the server from time to time in order to see that everything worked like it should. I've been using port 32000 during the development of the server. When I start the server and run netstat, the socket is listed as expected. > netstat -p UDP | grep 32000 udp46 0 0 *.32000 *.* However, when I run the server on other ports (random (10000 - 50000)), it's not listed by netstat. My thought was that I had somehow hard coded the port somewhere in the code, but that's not the case. The thing is - I can connect to the socket on any of the tested ports, and it reads data sent to it without any problem at all. It just doesn't get listed by netstat. What I wonder, is if anyone of you have any idea of why this happens? Note: Although this is a project at school, it's not homework. This is just something I want to understand for my own benefit.

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  • Is it possible to filter data used by pivot table based on filtering the rows in a source table in Excel?

    - by Geoffrey Stoel
    I have developed a dashboard in Excel 2007 that uses one source table in a sheet (being filled with a query on our data warehouse) and multiple pivot tables making different cross sections on this data. I use the GETPIVOTDATA in almost a hundred formulas to give me the right value for a specific indicator in my dashboard. This all works fine. However I now have received the question to make the dashboard for 5 different segments. As you can imagine I don't want to create 5 different workbooks for this and need to maintain the dashboard logic on all of them. So my question is the following. Is it possible to automatically (through VBA or any other means) filter the results in my source table which is the source for my pivot tables and thus for my dashboard values. So schematically: DATABASE_VIEW -- SOURCE_TABLE -- 12 pivot tables -- 100 GETPIVOTDATA functions Preferably I would like to load all the segments in the source_table (one view on my database) and then filter the data in the source table, which results in filterd source_dat for my pivots. This way I can (without requerying the db) quickly change between segments in the dashboards (refreshing pivots only). Data in the source table has the column: CUSTOMER_SEGMENT available to filter upon. Any help is appreciated. Geoffrey

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  • Visual Studio project remains "stuck" when stopped

    - by Traveling Tech Guy
    Hi, Currently developing a connector DLL to HP's Quality Center. I'm using their (insert expelative) COM API to connect to the server. An Interop wrapper gets created automatically by VStudio. My solution has 2 projects: the DLL and a tester application - essentially a form with buttons that call functions in the DLL. Everything works well - I can create defects, update them and delete them. When I close the main form, the application stops nicely. But when I call a function that returns a list of all available projects (to fill a combo box), if I close the main form, VStudio still shows the solution as running and I have to stop it. I've managed to pinpoint a single function in my code that when I call, the solution remains "hung" and if I don't, it closes well. It's a call to a property in the TDC object get_VisibleProjects that returns a List (not the .Net one, but a type in the COM library) - I just iterate over it and return a proper list (that I later use to fill the combo box): public List<string> GetAvailableProjects() { List<string> projects = new List<string>(); foreach (string project in this.tdc.get_VisibleProjects(qcDomain)) { projects.Add(project); } return projects; } My assumption is that something gets retained in memory. If I run the EXE outside of VStudio it closes - but who knows what gets left behind in memory? My question is - how do I get rid of whatever calling this property returns? Shouldn't the GC handle this? Do I need to delve into pointers? Things I've tried: getting the list into a variable and setting it to null at the end of the function Adding a destructor to the class and nulling the tdc object Stepping through the tester function application all the way out, whne the form closes and the Main function ends - it closes, but VStudio still shows I'm running. Thanks for your assistance!

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  • question about jQuery droppable/draggable.

    - by FALCONSEYE
    I modified a sample photo manager application. photo manager application Instead of photos, I have employee records coming from a query. My version will let managers mark employees as on vacation, or at work. One of the things I did is to include employee ids like <a href="123">. I get the ids from event.target. This works for the click function but not for the "droppable" function. This is what I have for the click function: $('ul.gallery > li').click(function(ev) { var $item = $(this); var $unid = ev.target; var $target = $(ev.target); if ($target.is('a.ui-icon-suitcase')) { deleteImage($item,$unid); } else if ($target.is('a.ui-icon-arrowreturnthick-1-w')) { recycleImage($item,$unid); } return false; }); ev.target correctly gives the employee id. when i try the same in one of the droppable functions: $gallery.droppable({ accept: '#suitcase li', activeClass: 'custom-state-active', drop: function(ev, ui) { var $unid = ev.target; alert($unid); recycleImage(ui.draggable,$unid); } }); the alert(ui) gives me [object]. What's in this object? How do i get the href out of this? thanks

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  • AJAX Post Not Sending Data?

    - by Jascha
    I can't for the life of me figure out why this is happening. This is kind of a repost, so forgive me, but I have new data. I am running a javascript log out function called logOut() that has make a jQuery ajax call to a php script... function logOut(){ var data = new Object; data.log_out = true; $.ajax({ type: 'POST', url: 'http://www.mydomain.com/functions.php', data: data, success: function() { alert('done'); } }); } the php function it calls is here: if(isset($_POST['log_out'])){ $query = "INSERT INTO `token_manager` (`ip_address`) VALUES('logOutSuccess')"; $connection->runQuery($query); // <-- my own database class... // omitted code that clears session etc... die(); } Now, 18 hours out of the day this works, but for some reason, every once in a while, the POST data will not trigger my query. (this will last about an hour or so). I figured out the post data is not being set by adding this at the end of my script... $query = "INSERT INTO `token_manager` (`ip_address`) VALUES('POST FAIL')"; $connection->runQuery($query); So, now I know for certain my log out function is being skipped because in my database is the following data: if it were NOT being skipped, my data would show up like this: I know it is being skipped for two reasons, one the die() at the end of my first function, and two, if it were a success a "logOutSuccess" would be registered in the table. Any thoughts? One friend says it's a janky hosting company (hostgator.com). I personally like them because they are cheap and I'm a fan of cpanel. But, if that's the case??? Thanks in advance. -J

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  • TicTacToe strategic reduction

    - by NickLarsen
    I decided to write a small program that solves TicTacToe in order to try out the effect of some pruning techniques on a trivial game. The full game tree using minimax to solve it only ends up with 549,946 possible games. With alpha-beta pruning, the number of states required to evaluate was reduced to 18,297. Then I applied a transposition table that brings the number down to 2,592. Now I want to see how low that number can go. The next enhancement I want to apply is a strategic reduction. The basic idea is to combine states that have equivalent strategic value. For instance, on the first move, if X plays first, there is nothing strategically different (assuming your opponent plays optimally) about choosing one corner instead of another. In the same situation, the same is true of the center of the walls of the board, and the center is also significant. By reducing to significant states only, you end up with only 3 states for evaluation on the first move instead of 9. This technique should be very useful since it prunes states near the top of the game tree. This idea came from the GameShrink method created by a group at CMU, only I am trying to avoid writing the general form, and just doing what is needed to apply the technique to TicTacToe. In order to achieve this, I modified my hash function (for the transposition table) to enumerate all strategically equivalent positions (using rotation and flipping functions), and to only return the lowest of the values for each board. Unfortunately now my program thinks X can force a win in 5 moves from an empty board when going first. After a long debugging session, it became apparent to me the program was always returning the move for the lowest strategically significant move (I store the last move in the transposition table as part of my state). Is there a better way I can go about adding this feature, or a simple method for determining the correct move applicable to the current situation with what I have already done?

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  • Should my validator have access to my entire model?

    - by wb
    As the title states I'm wondering if it's a good idea for my validation class to have access to all properties from my model. Ideally, I would like to do that because some fields require 10+ other fields to verify whether it is valid or not. I could but would rather not have functions with 10+ parameters. Or would that make the model and validator too coupled with one another? Here is a little example of what I mean. This code however does not work because it give an infinite loop! Class User Private m_UserID Private m_Validator Public Sub Class_Initialize() End Sub Public Property Let Validator(value) Set m_Validator = value m_Validator.Initialize(Me) End Property Public Property Get Validator() Validator = m_Validator End Property Public Property Let UserID(value) m_UserID = value End property Public Property Get UserID() UserID = m_Validator.IsUserIDValid() End property End Class Class Validator Private m_User Public Sub Class_Initialize() End Sub Public Sub Initialize(value) Set m_User = value End Sub Public Function IsUserIDValid() IsUserIDValid = m_User.UserID > 13 End Function End Class Dim mike : Set mike = New User mike.UserID = 123456 mike.Validator = New Validator Response.Write mike.UserID If I'm right and it is a good idea, how can I go a head and fix the infinite loop with the get property UserID? Thank you.

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  • Are there Windows API binaries for Subversion or do I have to build SVN to call the API from Windows

    - by JeffH
    I want to call a Subversion API from a Visual Studio 2003 C++ project. I know there are threads here, here, here, and here that tell how to get started with C#.NET on Windows (the consensus seems to be SharpSvn, which I've used easily and successfully on another project) but that's not what I want. I've read the chapter on using APIs in the red-bean book which says: Subversion is primarily a set of C libraries, with header (.h) files that live in the subversion/include directory of the source tree. These headers are copied into your system locations (e.g., /usr/local/include) when you build and install Subversion itself from source. These headers represent the entirety of the functions and types meant to be accessible by users of the Subversion libraries. I'd like to use CollabNet Subversion but there doesn't seem to be API binary downloads, and I'd just as soon not build the whole thing if I can avoid it. Considering another approach, I found RapidSVN's C++ API, but it doesn't appear to offer Windows API binaries either and seems to require building SVN (which I would be willing to do as a last choice if RapidSVN's API is higher-level than the stock SVN offering.) Does calling the API from C++ in Windows have to be this much more work compared to using SharpSvn under .NET, or is there something I haven't found that would help me achieve my goal?

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  • File streaming in PHP - How to replicate this C#.net code in PHP?

    - by openid_kenja
    I'm writing an interface to a web service where we need to upload configuration files. The documentation only provides a sample in C#.net which I am not familiar with. I'm trying to implement this in PHP. Can someone familiar with both languages point me in the right direction? I can figure out all the basics, but I'm trying to figure out suitable PHP replacements for the FileStream, ReadBytes, and UploadDataFile functions. I believe that the RecService object contains the URL for the web service. Thanks for your help! private void UploadFiles() { clientAlias = “<yourClientAlias>”; string filePath = “<pathToYourDataFiles>”; string[] fileList = {"Config.txt", "ProductDetails.txt", "BrandNames.txt", "CategoryNames.txt", "ProductsSoldOut.txt", "Sales.txt"}; RecommendClient RecService = new RecommendClient(); for (int i = 0; i < fileList.Length; i++) { bool lastFile = (i == fileList.Length - 1); //start generator after last file try { string fileName = filePath + fileList[i]; if (!File.Exists(fileName)) continue; // file not found } // set up a file stream and binary reader for the selected file and convert to byte array FileStream fStream = new FileStream(fileName, FileMode.Open, FileAccess.Read); BinaryReader br = new BinaryReader(fStream); byte[] data = br.ReadBytes((int)numBytes); br.Close(); // pass byte array to the web service string result = RecService.UploadDataFile(clientAlias, fileList[i], data, lastFile); fStream.Close(); fStream.Dispose(); } catch (Exception ex) { // log an error message } } }

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  • OnConnect event not firing when using TClientSocket inside a TThread on non-blocking mode

    - by mathematician1975
    I am trying to make use of Borlands TClientSocket component in non-blocking mode inside a multithreaded C++ Windows application. I am creating multiple threads (classes derived from TThread), each of which creates its own TClientSocket object. I then assign member functions of the thread class to act as event handlers for the OnConnect, OnDisconnect and OnSocketError events of the socket. The problem I am having here is that whenever I call the TClientSocket::Open() function from within the TThread::Execute() function, the OnConnect event never fires. However, When I call the Open() function from the VCL thread prior to the TThread::Execute() function getting called, all of the events fire and I can use the thread-socket combination as I would like. Now I have not read anything in documentation that says that TClientSocket should not be used in non-blocking mode when used inside a thread, but it appears to me that there is perhaps something wrong conceptually in the way I am trying to use this class. Borland documentation is quite poor on the subject and these components have now been deprecated so reliable information is hard to come by. Despite being deprecated I have to use them as there is no alternative in the Builder 6 package I have. Can anyone please advise me if there is a right/wrong way to use TThread and a non-blocking TClientSocket in combination. I have never had problems using it as part of the VCL thread and never had problems using TServerSocket before and I really cannot understand why some events are not firing.

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  • Exporting de-aggregated data

    - by Ben
    I'm currently working on a data export feature for a survey application. We are using SQL2k8. We store data in a normalized format: QuestionId, RespondentId, Answer. We have a couple other tables that define what the question text is for the QuestionId and demographics for the RespondentId... Currently I'm using some dynamic SQL to generate a pivot that joins the question table to the answer table and creates an export, its working... The problem is that it seems slow and we don't have that much data (less than 50k respondents). Right now I'm thinking "why am I 'paying' to de-aggregate the data for each query? Why don't I cache that?" The data being exported is based on dynamic criteria. It could be "give me respondents that completed on x date (or range)" or "people that like blue", etc. Because of that, I think I have to cache at the respondent level, find out what respondents are being exported and then select their combined cached de-aggregated data. To me the quick and dirty fix is a totally flat table, RespondentId, Question1, Question2, etc. The problem is, we have multiple clients and that doesn't scale AND I don't want to have to maintain the flattened table as the survey changes. So I'm thinking about putting an XML column on the respondent table and caching the results of a SELECT * FROM Data FOR XML AUTO WHERE RespondentId = x. With that in place, I would then be able to get my export with filtering and XML calls into the XML column. What are you doing to export aggregated data in a flattened format (CSV, Excel, etc)? Does this approach seem ok? I worry about the cost of XML functions on larger result sets (think SELECT RespondentId, XmlCol.value('//data/question_1', 'nvarchar(50)') AS [Why is there air?], XmlCol.RinseAndRepeat)... Is there a better technology/approach for this? Thanks!

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  • Object equality in context of hibernate / webapp

    - by bert
    How do you handle object equality for java objects managed by hibernate? In the 'hibernate in action' book they say that one should favor business keys over surrogate keys. Most of the time, i do not have a business key. Think of addresses mapped to a person. The addresses are keeped in a Set and displayed in a Wicket RefreshingView (with a ReuseIfEquals strategy). I could either use the surrogate id or use all fields in the equals() and hashCode() functions. The problem is that those fields change during the lifetime ob the object. Either because the user entered some data or the id changes due to JPA merge() being called inside the OSIV (Open Session in View) filter. My understanding of the equals() and hashCode() contract is that those should not change during the lifetime of an object. What i have tried so far: equals() based on hashCode() which uses the database id (or super.hashCode() if id is null). Problem: new addresses start with an null id but get an id when attached to a person and this person gets merged() (re-attached) in the osiv-filter. lazy compute the hashcode when hashCode() is first called and make that hashcode @Transitional. Does not work, as merge() returns a new object and the hashcode does not get copied over. What i would need is an ID that gets assigned during object creation I think. What would be my options here? I don't want to introduce some additional persistent property. Is there a way to explicitly tell JPA to assign an ID to an object? Regards

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  • IE 7 activex object (or xmlhttprequest?) open method using POST takes 20-30 seconds to return

    - by Toddeman
    i have a problem that only shows itself in IE7. its a simple ajax call. i got my object (accounting for the browser) so in 7 i SHOULD have an ActiveXObject. when i call open with POST, it takes 20-30 seconds to return. i am using a TON of GET calls to populate information and all of these work (finally, after some bug fixing), but i am NOT a web developer so much like the other bugs i had to fix, i figured i was just missing another IE anomaly. this is not a consistent bug either, which makes it harder to find for me. most times the POST functions like it does in Firefox or Chrome, but maybe 1 out of 4 or 5 will take 20-30 seconds to return. it DOES return correctly when it returns, it just takes a long time. am i missing something simple? or is there a smarter way for me to find out exactly what is going on (like the equivalent of the firebug 'net' tab for windows?).

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