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  • ~1 second TcpListener Pending()/AcceptTcpClient() lag

    - by cpf
    Probably just watch this video: http://screencast.com/t/OWE1OWVkO As you see, the delay between a connection being initiated (via telnet or firefox) and my program first getting word of it. Here's the code that waits for the connection public IDLServer(System.Net.IPAddress addr,int port) { Listener = new TcpListener(addr, port); Listener.Server.NoDelay = true;//I added this just for testing, it has no impact Listener.Start(); ConnectionThread = new Thread(ConnectionListener); ConnectionThread.Start(); } private void ConnectionListener() { while (Running) { while (Listener.Pending() == false) { System.Threading.Thread.Sleep(1); }//this is the part with the lag Console.WriteLine("Client available");//from this point on everything runs perfectly fast TcpClient cl = Listener.AcceptTcpClient(); Thread proct = new Thread(new ParameterizedThreadStart(InstanceHandler)); proct.Start(cl); } } (I was having some trouble getting the code into a code block) I've tried a couple different things, could it be I'm using TcpClient/Listener instead of a raw Socket object? It's not a mandatory TCP overhead I know, and I've tried running everything in the same thread, etc.

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  • Did I implement clock drift properly?

    - by David Titarenco
    I couldn't find any clock drift RNG code for Windows anywhere so I attempted to implement it myself. I haven't run the numbers through ent or DIEHARD yet, and I'm just wondering if this is even remotely correct... void QueryRDTSC(__int64* tick) { __asm { xor eax, eax cpuid rdtsc mov edi, dword ptr tick mov dword ptr [edi], eax mov dword ptr [edi+4], edx } } __int64 clockDriftRNG() { __int64 CPU_start, CPU_end, OS_start, OS_end; // get CPU ticks -- uses RDTSC on the Processor QueryRDTSC(&CPU_start); Sleep(1); QueryRDTSC(&CPU_end); // get OS ticks -- uses the Motherboard clock QueryPerformanceCounter((LARGE_INTEGER*)&OS_start); Sleep(1); QueryPerformanceCounter((LARGE_INTEGER*)&OS_end); // CPU clock is ~1000x faster than mobo clock // return raw return ((CPU_end - CPU_start)/(OS_end - OS_start)); // or // return a random number from 0 to 9 // return ((CPU_end - CPU_start)/(OS_end - OS_start)%10); } If you're wondering why I Sleep(1), it's because if I don't, OS_end - OS_start returns 0 consistently (because of the bad timer resolution, I presume). Basically, (CPU_end - CPU_start)/(OS_end - OS_start) always returns around 1000 with a slight variation based on the entropy of CPU load, maybe temperature, quartz crystal vibration imperfections, etc. Anyway, the numbers have a pretty decent distribution, but this could be totally wrong. I have no idea.

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  • Php script running as scheduled task hangs - help!

    - by Ali
    Hi guys, I've built a php script that runs from the command line. It opens a connection into a pop3 email account and downloads all the emails and writes them to a database, and deletes them once downloaded. I have this script being called from the commandline by a bat file. in turn I have created a scheduled task which invokes the bat file every 5 minutes. The thing is that I have set the time out to zero for the fact that at times there could be emails with large attachments and the script actually downloads the attachments and stores them as raw files offline and the no timeout is so that the script doesnt die out during downloading. I've found that the program hangs sometimes and its a bit annoying at that - it always hangs are one point i.e. when negotiating the connection and getting connected to the mail server. And because the timeout is set to zero it seems to stay stuck up in taht position. And because of that the task is not run as its technically hung up. I want that the program should not timeout when downloading emails - however at the points where it is negotiating a connection or trying to connect to the mailserver there should be a timeout only at that point itself and not the rest of the program execution. How do I do this :(

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  • Request size limitation when using MultipartHttpServletRequest of Spring 3.0

    - by Spiderman
    I'd like to know what is the size limitation if I upload list of files in one client's form submition using HTTP multipart content type. On the server side I am using Spring's MultipartHttpServletRequest to handle the request. mM questions: Is there should be different file size limitation and total request size limitation or file size is the only limitation and the request is capable of uploading 100s of files as lonng as they are not too large. Doest the Spring request wrapper read the complete request and store it in the JAVA heap memory or it store temporaray files of it to be able to use big quota. Is the use of reading the httpservlet request in streaming would change the size limitation than using complete http request read at-once by the application server. What is the bottleneck of this process - Java heap size, the quota of the filesystem on which my web-server runs, the maximum allowed BLOB size that the DataBase in which I am gonna save the file alows? or Spring internal limitations? Related threads that still don't have exact answer to this: does-spring-framework-support-streaming-mode-in-mutlipart-requests is-there-a-way-to-get-raw-http-request-stream-from-java-servlet-handler how-to- drop-body-of-a-request-after-checking-headers-in-servlet apache-commons-fileupload-throws-malformedstreamexception

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  • Graphing the pitch (frequency) of a sound

    - by Coronatus
    I want to plot the pitch of a sound into a graph. Currently I can plot the amplitude. The graph below is created by the data returned by getUnscaledAmplitude(): AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(new BufferedInputStream(new FileInputStream(file))); byte[] bytes = new byte[(int) (audioInputStream.getFrameLength()) * (audioInputStream.getFormat().getFrameSize())]; audioInputStream.read(bytes); // Get amplitude values for each audio channel in an array. graphData = type.getUnscaledAmplitude(bytes, this); public int[][] getUnscaledAmplitude(byte[] eightBitByteArray, AudioInfo audioInfo) { int[][] toReturn = new int[audioInfo.getNumberOfChannels()][eightBitByteArray.length / (2 * audioInfo. getNumberOfChannels())]; int index = 0; for (int audioByte = 0; audioByte < eightBitByteArray.length;) { for (int channel = 0; channel < audioInfo.getNumberOfChannels(); channel++) { // Do the byte to sample conversion. int low = (int) eightBitByteArray[audioByte]; audioByte++; int high = (int) eightBitByteArray[audioByte]; audioByte++; int sample = (high << 8) + (low & 0x00ff); if (sample < audioInfo.sampleMin) { audioInfo.sampleMin = sample; } else if (sample > audioInfo.sampleMax) { audioInfo.sampleMax = sample; } toReturn[channel][index] = sample; } index++; } return toReturn; } But I need to show the audio's pitch, not amplitude. Fast Fourier transform appears to get the pitch, but it needs to know more variables than the raw bytes I have, and is very complex and mathematical. Is there a way I can do this?

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  • Need a workaround to filter on related model and aggregated fields in Django

    - by parxier
    I opened a ticket for this problem. In a nutshell here is my model: class Plan(models.Model): cap = models.IntegerField() class Phone(models.Model): plan = models.ForeignKey(Plan, related_name='phones') class Call(models.Model): phone = models.ForeignKey(Phone, related_name='calls') cost = models.IntegerField() I want to run a query like this one: Phone.objects.annotate(total_cost=Sum('calls__cost')).filter(total_cost__gte=0.5*F('plan__cap')) Unfortunately Django generates bad SQL: SELECT "app_phone"."id", "app_phone"."plan_id", SUM("app_call"."cost") AS "total_cost" FROM "app_phone" INNER JOIN "app_plan" ON ("app_phone"."plan_id" = "app_plan"."id") LEFT OUTER JOIN "app_call" ON ("app_phone"."id" = "app_call"."phone_id") GROUP BY "app_phone"."id", "app_phone"."plan_id" HAVING SUM("app_call"."cost") >= 0.5 * "app_plan"."cap" and errors with: ProgrammingError: column "app_plan.cap" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: ...."plan_id" HAVING SUM("app_call"."cost") >= 0.5 * "app_plan".... Is there any workaround apart from running raw SQL?

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  • WPF data-bound ComboBox only shows first item of ItemsSource list

    - by Mark
    Hi all, I'm sure I'm doing something stupid but for the life of me I can't think of right now. I have a ComboBox that is data-bound to a list of Layout objects. The list is initially empty but things are added over time. When the list is updated by the model the first time, this update reflects properly in the ComboBox. However, subsequent updates never show up in the ComboBox even though I can see that the list itself contains these items. Since the first update works, I know the data-binding is OK - so what am I doing wrong here? Here's the XAML (abridged): <Grid HorizontalAlignment="Stretch"> <ComboBox ItemsSource="{Binding Path=SavedLayouts, diagnostics:PresentationTraceSources.TraceLevel=High}" DisplayMemberPath="Name" SelectedValuePath="Name" SelectedItem="{Binding LoadLayout}" Height="25" Grid.Row="1" Grid.Column="0"></ComboBox> </Grid> And the related part of the model: public IList<Layout> SavedLayouts { get { return _layouts; } } public Layout SaveLayout( String data_ ) { Layout theLayout = new Layout( SaveLayoutName ); _layouts.Add( theLayout ); try { return theLayout; } finally { PropertyChangedEventHandler handler = PropertyChanged; if( handler != null ) { handler( this, new PropertyChangedEventArgs( "SavedLayouts" ) ); } } } And finally, the layout class (abridged): public class Layout { public String Name { get; private set; } } In the output window, I can see the update occurring: System.Windows.Data Warning: 91 : BindingExpression (hash=64564967): Got PropertyChanged event from TickerzModel (hash=43624632) System.Windows.Data Warning: 97 : BindingExpression (hash=64564967): GetValue at level 0 from TickerzModel (hash=43624632) using RuntimePropertyInfo(SavedLayouts): List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 76 : BindingExpression (hash=64564967): TransferValue - got raw value List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 85 : BindingExpression (hash=64564967): TransferValue - using final value List`1 (hash=16951421 Count=11) But I get do not get this 11th item in the ComboBox. Any ideas?

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  • Tool to detect use/abuse of String.Concat (where StringBuilder should be used)

    - by Mark Rushakoff
    It's common knowledge that you shouldn't use a StringBuilder in place of a small number of concatenations: string s = "Hello"; if (greetingWorld) { s += " World"; } s += "!"; However, in loops of a significant size, StringBuilder is the obvious choice: string s = ""; foreach (var i in Enumerable.Range(1,5000)) { s += i.ToString(); } Console.WriteLine(s); Is there a tool that I can run on either raw C# source or a compiled assembly to identify where in the source code that String.Concat is being called? (If you're not familiar, s += "foo" is mapped to String.Concat in the IL output.) Obviously, I can't realistically search through an entire project and evaluate every += to identify whether the lvalue is a string. Ideally, it would only point out calls inside a for/foreach loop, but I would even put up with all the false positives of noting every String.Concat. Also, I'm aware that there are some refactoring tools that will automatically refactor my code to use StringBuilder, but I am only interested in identifying the Concat usage at this point. I routinely run Gendarme and FxCop on my code, and neither of those tools identify what I've described.

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  • What's the recommended implementation for hashing OLE Variants?

    - by Barry Kelly
    OLE Variants, as used by older versions of Visual Basic and pervasively in COM Automation, can store lots of different types: basic types like integers and floats, more complicated types like strings and arrays, and all the way up to IDispatch implementations and pointers in the form of ByRef variants. Variants are also weakly typed: they convert the value to another type without warning depending on which operator you apply and what the current types are of the values passed to the operator. For example, comparing two variants, one containing the integer 1 and another containing the string "1", for equality will return True. So assuming that I'm working with variants at the underlying data level (e.g. VARIANT in C++ or TVarData in Delphi - i.e. the big union of different possible values), how should I hash variants consistently so that they obey the right rules? Rules: Variants that hash unequally should compare as unequal, both in sorting and direct equality Variants that compare as equal for both sorting and direct equality should hash as equal It's OK if I have to use different sorting and direct comparison rules in order to make the hashing fit. The way I'm currently working is I'm normalizing the variants to strings (if they fit), and treating them as strings, otherwise I'm working with the variant data as if it was an opaque blob, and hashing and comparing its raw bytes. That has some limitations, of course: numbers 1..10 sort as [1, 10, 2, ... 9] etc. This is mildly annoying, but it is consistent and it is very little work. However, I do wonder if there is an accepted practice for this problem.

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  • Find all CSS rules that apply to an element

    - by Carl Byström
    Many tools/APIs provide ways of selecting elements of specific classes or IDs. There's also possible to inspect the raw stylesheets loaded by the browser. However, for browsers to render an element, they'll compile all CSS rules (possibly from different stylesheet files) and apply it to the element. This is what you see with Firebug or the WebKit Inspector - the full CSS inheritance tree for an element. How can I reproduce this feature in pure JavaScript without requiring additional browser plugins? Perhaps an example can provide some clarification for what I'm looking for: <style type="text/css"> p { color :red; } #description { font-size: 20px; } </style> <p id="description">Lorem ipsum</p> Here the p#description element have two CSS rules applied: a red color and a font size of 20 px. I would like to find the source from where these computed CSS rules originate from (color comes the p rule and so on).

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  • How to enforce users to create objects of class derived from mine with "new" only?

    - by sharptooth
    To implement reference counting we use an IUnknown-like interface and a smart pointer template class. The interface has implementation for all the reference-count methods, including Release(): void IUnknownLike::Release() { if( --refCount == 0 ) { delete this; } } The smart pointer template class has a copy constructor and an assignment operator both accepting raw pointers. So users can do the following: class Class : public IUnknownLike { }; void someFunction( CSmartPointer<Class> object ); //whatever function Class object; someFunction( &object ); and the program runs into undefined behavior - the object is created with reference count zero, the smart pointer is constructed and bumps it to one, then the function returns, smart pointer is destroyed, calls Release() which leads to delete of a stack-allocated variable. Users can as well do the following: struct COuter { //whatever else; Class inner;// IUnknownLike descendant }; COuter object; somefunction( &object.Inner ); and again an object not created with new is deleted. Undefined behavior at its best. Is there any way to change the IUnknownLike interface so that the user is forced to use new for creating all objects derived from IUnknownLike - both directly derived and indirectly derived (with classes in between the most derived and the base)?

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  • Play Multiple iPod Library Songs On iPhone At The Same Time With Pitch Bending & Other Effects

    - by Dino
    Hi, I have been going at this for the past two weeks and it is driving me crazy. I asked this question a couple of days ago (Extract iPod Library raw PCM samples and play with sound effects) and whilst the answer got me half way there I am still stuck. Basically what I am trying to achieve is load up multiple songs from the iPod library for playback with effects such as pitch bend, eq effects etc... I have gone down the route of AVPlayer and AVAudioPlayer which are too simple. The only framework I've seen that can play audio with these effects is OpenAL. I have tried a few objective c wrappers (Finch and ObjectAL) Finch does not play compressed audio whilst ObjectAL will only convert it for me if I pass in a URL for the file (which is something I cannot do because I only have an incompatible iPod library URL). An example of an app that does what I want beautifilly is Tap DJ. It can load up songs from the iPod library fast (unlike TouchDJ and it plays them with all sorts of effects. Any help would be much appreciated.

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  • Generating a canonical path

    - by Joel
    Does any one know of any Java libraries I could use to generate canonical paths (basically remove back-references). I need something that will do the following: Raw Path - Canonical Path /../foo/ -> /foo /foo/ -> /foo /../../../ -> / /./foo/./ -> /foo //foo//bar -> /foo/bar //foo/../bar -> /bar etc... At the moment I lazily rely on using: new File("/", path).getCanonicalPath(); But this resolves the path against the actual file system, and is synchronised. java.lang.Thread.State: BLOCKED (on object monitor) at java.io.ExpiringCache.get(ExpiringCache.java:55) - waiting to lock <0x93a0d180> (a java.io.ExpiringCache) at java.io.UnixFileSystem.canonicalize(UnixFileSystem.java:137) at java.io.File.getCanonicalPath(File.java:559) The paths that I am canonicalising do not exist on my file system, so just the logic of the method will do me fine, thus not requiring any synchronisation. I'm hoping for a well tested library rather than having to write my own.

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  • How do I detect proximity of the mouse pointer to a line in Flex?

    - by Hanno Fietz
    I'm working on a charting UI in Flex. One of the features I want to implement is "snapping" of the mousepointer to the data points in the diagram. I. e., if the user hovers the mouse pointer over a line diagram and gets close to the data point, I want the pointer to move to the exact coordinates and show a marker, like this: Currently, the lines are drawn on a Shape, using the Graphics API. The Shape is a child DisplayObject of a custom UIComponent subclass with the exact same dimensions. This means, I already get mouseOver events on the parent of the diagram's canvas. Now I need a way to detect if the pointer is close to one of the data points. I. e. I need an answer to the question "Which data points lie within a radius of x pixels from my current position and which of them is closest?" upon each move of the mouse. I can think of the following possibilities: draw the lines not as simple lines in the graphics API, but as more advanced objects that can have their own mouseOver events. However, I want the snapping to trigger before the mouse is actually over the line. check the original data for possible candidates upon each mouse movement. Using binary search, I might be able to reduce the number of items I have to compare sufficently. prepare some kind of new data structure from the raw data that makes the above search more efficient. I don't know how that would look like. I'm guessing this is a pretty standard problem for a number of applications, but probably the actual code usually is inside of some framework. Is there anything I can read about this topic?

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  • MSSQL 2005 FOR XML

    - by Lima
    Hi, I am wanting to export data from a table to a specifically formated XML file. I am fairly new to XML files, so what I am after may be quite obvious but I just cant find what I am looking for on the net. The format of the XML results I need are: <data> <event start="May 28 2006 09:00:00 GMT" end="Jun 15 2006 09:00:00 GMT" isDuration="true" title="Writing Timeline documentation" image="http://simile.mit.edu/images/csail-logo.gif"> A few days to write some documentation </event> </data> My table structure is: name VARCHAR(50), description VARCHAR(255), startDate DATETIME, endDate DATETIME (I am not too interested in the XML fields image or isDuration at this point in time). I have tried: SELECT [name] ,[description] ,[startDate] ,[endTime] FROM [testing].[dbo].[time_timeline] FOR XML RAW('event'), ROOT('data'), type Which gives me: <data> <event name="Test1" description="Test 1 Description...." startDate="1900-01-01T00:00:00" endTime="1900-01-01T00:00:00" /> <event name="Test2" description="Test 2 Description...." startDate="1900-01-01T00:00:00" endTime="1900-01-01T00:00:00" /> </data> What I am missing, is the description needs to be outside of the event attributes, and there needs to be a tag. Is anyone able to point me in the correct direction, or point me to a tutorial or similar on how to accomplish this? Thanks, Matt

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  • problem with joomla, php and json

    - by sebastian
    hi, i have a problem with a joomla component. i'm, unsing php and json for some dynamic drop down boxes. here is the code:` jQuery( function () { //jQuery.ajaxSetup({error : function (a,b) {console.dir(a); console.dir(b);}}); jQuery("#util, #loc").change( function() { var locatie = jQuery("#loc").val(); var utilitate = jQuery("#util").val(); if ( (locatie!= '---') && (utilitate!='---') ) jQuery.getJSON( "index.php?option=com_calculator&opt=json_contor&format=raw", { locatie: locatie, utilitate: utilitate }, function (data) { var html = ""; if ( data.success == 'ok' ) for (var i in data.val) html += "<option name=den_contor value ='"+ i+"' >" + data.val[i]+ " </option>"; jQuery("#den_contor").html( html ) } ) }) }); the query works, but only on one PC. we have exactly the same xampp server, exactly the same files. on one pc it works, and on a online server and on my pc it doesn't. EDIT: i have three drop down boxes, the first is populated directly from the database, the second has 4 predefined values. and the third is populated depending on combination of the first two. i have a test site online. http://contor.redxart.com must be logged in to use Calculator in the menu. you can make an new account :) "Adaugare Index" is the part that isn't working any ideas? thanks, sebastian

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  • Radio buttons being reset in FF on cache-refresh

    - by Andrew Song
    (This is technically an addendum to an earlier StackOverflow question I had posted, but my original post asked a different question which doesn't really cover this topic -- I don't want to edit my older question as I feel this is different enough to merit its own page) While browsing my website in Firefox 3.5 (and only FF3.5), I come across a page with two radio buttons that have the following HTML code: <input id="check1" type="radio" value="True" name="check" checked="checked"/> <input id="check2" type="radio" value="False" name="check"/> This page renders as expected, with 'check1' checked and 'check2' unchecked. When I then go to refresh the page by pressing Control + R, the two radio buttons render, but they are both unchecked even though the raw HTML code is the same (as above). If I do a cache-miss refresh (via Control + F5 or Control + Shift + R), the page returns back to the way you'd expect it. This is not a problem in any other browser I've tried except FF3.5. What is causing these radio buttons to be reset on a normal refresh? How can I avoid this?

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  • making html table columns optionally sortable

    - by jdamae
    I have an html table that is populated from a text file, formatted and semi colon separated. I would like the user to have the option of sorting alphabetically with either of the columns when clicking on the column name (header). How do I do this in php?? Or is there another way of doing this? Thanks for your help. Sample raw data/input looks like this: TYPE=abc;PART=georgetown;FILE=goog_abc.dat.2010122211.gz TYPE=xyz;PART=ucny;FILE=aol_xyz.dat.2010122209.gz Php code for table: $lines = preg_split('~\s*[\r\n]+\s*~', file_get_contents('/temp/tab.txt')); foreach($lines as $i => $line) { $pairs = explode(';', $line); foreach($pairs as $pair) { list($column, $value) = explode('=', $pair, 2); $columns[$column] = true; $rows[$i][$column] = $value; } } $columns = array_keys($columns); echo '<table><thead><tr>'; foreach($columns as $column) { echo '<th>'.$column.'</th>'; } echo '</tr></thead><tbody>'; foreach ($rows as $row) { echo '<tr>'; foreach($columns as $column){ echo '<td>'.$row[$column].'</td>'; } echo '</tr>'; } echo '</tbody></table>';

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  • How to handle 'this' pointer in constructor?

    - by Kyle
    I have objects which create other child objects within their constructors, passing 'this' so the child can save a pointer back to its parent. I use boost::shared_ptr extensively in my programming as a safer alternative to std::auto_ptr or raw pointers. So the child would have code such as shared_ptr<Parent>, and boost provides the shared_from_this() method which the parent can give to the child. My problem is that shared_from_this() cannot be used in a constructor, which isn't really a crime because 'this' should not be used in a constructor anyways unless you know what you're doing and don't mind the limitations. Google's C++ Style Guide states that constructors should merely set member variables to their initial values. Any complex initialization should go in an explicit Init() method. This solves the 'this-in-constructor' problem as well as a few others as well. What bothers me is that people using your code now must remember to call Init() every time they construct one of your objects. The only way I can think of to enforce this is by having an assertion that Init() has already been called at the top of every member function, but this is tedious to write and cumbersome to execute. Are there any idioms out there that solve this problem at any step along the way?

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  • How to get acts on taggable working

    - by Schipperius
    I am new to ruby on rails (and programming) and this is probably a really stupid question. I am using Rails 3.2 and trying to use acts_as_taggable_on to generate tags on articles and to have those tags show on article index and show pages as a clickable links. I have tags clickable on both the article show and index pages, but the links just go back to the index page and don't sort according to the tag name. I have scoured the Internet and pieced together the code below from various sources, but I am clearly missing something. Any help is greatly appreciated, as I have exhausted my seemingly limited knowledge! Thanks. Here is what I have: class ArticlesController < ApplicationController def tagged @articles = Article.all(:order => 'created_at DESC') @tags = Article.tag_counts_on(:tags) @tagged_articles = Article.tagged_with(params[:tags]) respond_to do |format| format.html # index.html.erb format.json { render :json => @articles } end end def index @article = Article.new @articles = Article.paginate :page => params[:page], :per_page => 3 @tags = Article.tag_counts_on(:tags) respond_to do |format| format.html # index.html.erb format.json { render json: @articles } end end module ArticlesHelper include ActsAsTaggableOn::TagsHelper end class Article < ActiveRecord::Base acts_as_ordered_taggable acts_as_ordered_taggable_on :tags, :location, :about attr_accessible :tag_list scope :by_join_date, order("created_at DESC") end article/index.html.erb <% tag_cloud(@tags, %w(tag1 tag2 tag3 tag4)) do |tag| %> <%= link_to tag.name, articles_path(:id => tag.name) %> <% end %> article/show.html.erb <%= raw @article.tags.map { |tag| link_to tag.name, articles_path(:tag_id => tag) }.join(" | ") %>

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  • Is there a term for this concept, and does it exist in a static-typed language?

    - by Strilanc
    Recently I started noticing a repetition in some of my code. Of course, once you notice a repetition, it becomes grating. Which is why I'm asking this question. The idea is this: sometimes you write different versions of the same class: a raw version, a locked version, a read-only facade version, etc. These are common things to do to a class, but the translations are highly mechanical. Surround all the methods with lock acquires/releases, etc. In a dynamic language, you could write a function which did this to an instance of a class (eg. iterate over all the functions, replacing them with a version which acquires/releases a lock.). I think a good term for what I mean is 'reflected class'. You create a transformation which takes a class, and returns a modified-in-a-desired-way class. Synchronization is the easiest case, but there are others: make a class immutable [wrap methods so they clone, mutate the clone, and include it in the result], make a class readonly [assuming you can identify mutating methods], make a class appear to work with type A instead of type B, etc. The important part is that, in theory, these transformations make sense at compile-time. Even though an ActorModel<T> has methods which change depending on T, they depend on T in a specific way knowable at compile-time (ActorModel<T> methods would return a future of the original result type). I'm just wondering if this has been implemented in a language, and what it's called.

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  • What exactly is the GNU tar ././@LongLink "trick"?

    - by Cheeso
    I read that a tar entry type of 'L' (76) is used by gnu tar and gnu-compliant tar utilities to indicate that the next entry in the archive has a "long" name. In this case the header block with the entry type of 'L' usually encodes the name ././@LongLink . My question is: where is the format of the next block described? The format of a tar archive is very simple: it is just a series of 512-byte blocks. In the normal case, each file in a tar archive is represented as a series of blocks. The first block is a header block, containing the file name, entry type, modified time, and other metadata. Then the raw file data follows, using as many 512-byte blocks as required. Then the next entry. If the filename is longer than will fit in the space allocated in the header block, gnu tar apparently uses what's known as "the ././@LongLink trick". I can't find a precise description for it. When the entry type is 'L', how do I know how long the "long" filename is? Is the long name limited to 512 bytes, in other words, whatever fits in one block? Most importantly: where is this documented?

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  • Database abstraction/adapters for ruby

    - by Stiivi
    What are the database abstractions/adapters you are using in Ruby? I am mainly interested in data oriented features, not in those with object mapping (like active record or data mapper). I am currently using Sequel. Are there any other options? I am mostly interested in: simple, clean and non-ambiguous API data selection (obviously), filtering and aggregation raw value selection without field mapping: SELECT col1, col2, col3 = [val1, val2, val3] not hash of { :col1 = val1 ...} API takes into account table schemas 'some_schema.some_table' in a consistent (and working) way; also reflection for this (get schema from table) database reflection: get list of table columns, their database storage types and perhaps adaptor's abstracted types table creation, deletion be able to work with other tables (insert, update) in a loop enumerating selection from another table without requiring to fetch all records from table being enumerated Purpose is to manipulate data with unknown structure at the time of writing code, which is the opposite to object mapping where structure or most of the structure is usually well known. I do not need the object mapping overhead. What are the options, including back-ends for object-mapping libraries?

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  • Why are Facebook Likes Insisting on using Wrong Product Image...?

    - by Joan Kent
    Firstly, I'm not a web developer so please be patient. I have read the other posts but I think i have everything covered. My website http://www.joaniesgifts.co.uk includes the like button on the product pages. However, I've found that certain product pages are using the incorrect image when a user likes the page. For example - http://www.joaniesgifts.co.uk/terramundi-money-pots/terramundi-money-pot-holiday-fund I think this may have been down to an original incorrect setup which is now corrected. However, the problem remains... The only thing I have to go on :- if i use the facebook url linter (developers.facebook.com/tools/debug) on the above product page, I receive the following error :- Object at URL 'http://www.joaniesgifts.co.uk/terramundi-money-pot-holiday-fund' of type '213689662010141:product' is invalid because the domain 'www.joaniesgifts.co.uk' is not allowed for the application id '213689662010141' which owns the specified object type. If you are the owner of this application, you can verify your configured 'Site Domain' at developers.facebook.com/apps/213689662010141. (I have verified my site's domain) Everything else appears fine except it is also showing the wrong image!! However, under Raw Open Graph Document Information it has the correct link! If I then click graph api - graph.facebook.com/10150450766583352 it again shows the wrong image was linked! I've no idea what else to do - can you help me? Kind Regards, Joan PS Graph API shows the incorrect image after a scrape only minutes ago { "url": "http://www.joaniesgifts.co.uk/terramundi-money-pot-holiday-fund", "type": "website", "title": "Terramundi Money Pot - Holiday Fund", "image": [ { "url": "http://www.joaniesgifts.co.uk/index.php?route=product\u00252Fproduct\u00252Fcaptcha" } ], "updated_time": "2011-11-11T18:54:38+0000", "id": "10150450766583352" }

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  • How to get multiple html() strings in jQuery

    - by Bryan
    I'm pretty new to jQuery... so far I'm impressed. But I encountered a situation today that is giving me trouble. I want to use .html() to get some raw text and use that in a selector, but that function only returns the first element. In the following structure, how can I get ALL of the "toggle_containerLG" divs to show when I click on the trigger "Some Header"? <h6 class="trigger active">Some Header</h6> <ul> <li><a href="#" class="trigger">Title One</a></li> <li><a href="#" class="trigger">Title Two</a></li> <li><a href="#" class="trigger">Title Three</a></li> </ul> <div class="toggle_containerLG" id='Title_One'></div> <!-- show these! --> <div class="toggle_containerLG" id='Title_Two'></div> <div class="toggle_containerLG" id='Title_Three'></div> <div class="toggle_containerLG" id='Title_Four'></div> <!-- not this one! --> I can't use $(".toggle_containerLG") because there are others I don't want to expand... I just want the ones listed under "Some Header". Seems like there should be an easy way to do it... and I'm just missing it because I don't know jQuery very well.

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