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• What are simple instructions for creating a Python package structure and egg?

  - by froadie

  I just completed my first (minor) Python project, and my boss wants me to package it nicely so that it can be distributed and called from other programs easily. He suggested I look into eggs. I've been googling and reading, but I'm just getting confused. Most of the sites I'm looking at explain how to use Python eggs that were already created, or how to create an egg from a setup.py file (which I don't yet have). All I have now is an Eclipse pydev project with about 4 modules and a settings/configuration file. In easy steps, how do I go about structuring it into folders/packages and compiling it into an egg? And once it's an egg, what do I have to know about deploying/building/using it? I'm really starting from scratch here, so don't assume I know anything; simple step-by-step instructions would be really helpful... These are some of the sites that I've been looking at so far: http://peak.telecommunity.com/DevCenter/PythonEggs http://www.packtpub.com/article/writing-a-package-in-python http://www.ibm.com/developerworks/library/l-cppeak3.html#N10232 I've also browsed a few SO questions but haven't really found what I need. Thanks!

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• Using Python to get a CSV output for the following example.

  - by Az

  Hi there, I'm back again with my ongoing saga of Student-Project Allocation questions. Thanks to Moron (who does not match his namesake) I've got a bit of direction for an evaluation portion of my project. Going with the idea of the Assignment Problem and Hungarian Algorithm I would like to express my data in the form of a .csv file which would end up looking like this in spreadsheet form. This is based on the structure I saw here. | | Project 1 | Project 2 | Project 3 | |----------|-----------|-----------|-----------| |Student1 | | 2 | 1 | |----------|-----------|-----------|-----------| |Student2 | 1 | 2 | 3 | |----------|-----------|-----------|-----------| |Student3 | 1 | 3 | 2 | |----------|-----------|-----------|-----------| To make it less cryptic: the rows are the Students/Agents and the columns represent Projects/Task. Obviously ONE project can be assigned to ONE student. That, in short, is what my project is about. The fields represent the preference weights the students have placed upon the projects (ranging from 1 to 10). If blank, that student does not want that project and there's no chance of him/her being assigned such. Anyway, my data is stored within dictionaries. Specifically the students and projects dictionaries such that: students[student_id] = Student(student_id, student_name, alloc_proj, alloc_proj_rank, preferences) where preferences is in the form of a dictionary such that preferences[rank] = {project_id} and projects[project_id] = Project(project_id, project_name) I'm aware that sorted(students.keys()) will give me a sorted list of all the student IDs which will populate the row labels and sorted(projects.keys()) will give me the list I need to populate the column labels. Thus for each student, I'd go into their preferences dictionary and match the applicable projects to ranks. I can do that much. Where I'm failing is understanding how to create a .csv file. Any help, pointers or good tutorials will be highly appreciated.

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• Persistant Http client connections in java

  - by Akusete

  I am trying to write a simple Http client application in Java and am a bit confused by the seemingly different ways to establish Http client connections, and efficiently re-use the objects. Current I am using the following steps (I have left out exception handling for simplicity) Iterator<URI> uriIterator = someURIs(); HttpClient client = new DefaultHttpClient(); while (uriIterator.hasNext()) { URI uri = uriIterator.next(); HttpGet request = new HttpGet(uri); HttpResponse response = client.execute(request); HttpEntity entity = response.getEntity(); InputStream s = entity.getContent(); processStream (); s.close(); } In regard to the code above, my questions is: Assuming all URI's are pointing to the same host (but different resources on that host). What is the recommended way to use a single http connection for all requests? And how do you close the connection after the last request? --edit: Also what is the difference between using uri.openConnection(), versus HttpClient? Which is preferable, and what other methods exist?

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• coredata using old file version on device

  - by Martin KS

  This is a follow on from my previous problems here. Resetting the simulator solved all my troubles before, and I've gone on to complete my App. I now have the exact same problem when installing the app onto my iPhone device. It picks up an old version of my database, which doesn't have the second entity in it, and crashes when I try to access the second entity: 2010-04-22 23:52:18.860 albumCloud[135:207] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '+entityForName: could not locate an NSManagedObjectModel for entity name 'Image'' 2010-04-22 23:52:18.874 albumCloud[135:207] Stack: ( 843263261, 825818644, 820669213, 20277, 844154820, 16985, 14633, 844473760, 844851728, 862896011, 843011267, 843009055, 860901832, 843738160, 843731504, 11547, 11500 ) terminate called after throwing an instance of 'NSException' I have two questions: 1) How on earth do I delete my app thoroughly enough from my phone that it removes the old data? (I've so far tried regular app deletion, deleting and then holding home and power for a reboot, cursing at and threatening the app while running it... everything) 2) How do I prevent this happening when my application is in the App store, and I for some reason decide that I want to add another entity to the store, or another attribute to the existing entities? is there an "if x doesn't exist then create it" method?

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• When downloading a file using FileStream, why does page error message refers to aspx page name, not

  - by StuperUser

  After building a filepath (path, below) in a string (I am aware of Path in System.IO, but am using someone else's code and do not have the opportunity to refactor it to use Path). I am using a FileStream to deliver the file to the user (see below): FileStream myStream = new FileStream(path, FileMode.Open, FileAccess.Read); long fileSize = myStream.Length; byte[] Buffer = new byte[(int)fileSize + 1]; myStream.Read(Buffer, 0, (int)myStream.Length); myStream.Close(); Response.ContentType = "application/csv"; Response.AddHeader("content-disposition", "attachment; filename=" + filename); Response.BinaryWrite(Buffer); Response.Flush(); Response.End(); I have seen from: http://stackoverflow.com/questions/736301/asp-net-how-to-stream-file-to-user reasons to avoid use of Response.End() and Response.Close(). I have also seen several articles about different ways to transmit files and have diagnosed and found a solution to the problem (https and http headers) with a colleague. However, the error message that was being displayed was not about access to the file at path, but the aspx file. Edit: Error message is: Internet Explorer cannot download MyPage.aspx from server.domain.tld Internet Explorer was not able to open this Internet site. The requested site is either unavailable or cannot be found. Please try again later. (page name and address anonymised) Why is this? Is it due to the contents of the file coming from the HTTP response .Flush() method rather than a file being accessed at its address?

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• binding a command inside a listbox item to a property on the viewmodel parent

  - by giddy

  I've been working on this for about an hour and looked at all related SO questions. My problem is very simple: I have HomePageVieModel: HomePageVieModel +IList<NewsItem> AllNewsItems +ICommand OpenNewsItem My markup: <Window DataContext="{Binding HomePageViewModel../> <ListBox ItemsSource="{Binding Path=AllNewsItems}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <TextBlock> <Hyperlink Command="{Binding Path=OpenNews}"> <TextBlock Text="{Binding Path=NewsContent}" /> </Hyperlink> </TextBlock> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> The list shows fine with all the items, but for the life of me whatever I try for the Command won't work: <Hyperlink Command="{Binding Path=OpenNewsItem, RelativeSource={RelativeSource AncestorType=vm:HomePageViewModel, AncestorLevel=1}}"> <Hyperlink Command="{Binding Path=OpenNewsItem, RelativeSource={RelativeSource AncestorType=vm:HomePageViewModel,**Mode=FindAncestor}**}"> <Hyperlink Command="{Binding Path=OpenNewsItem, RelativeSource={RelativeSource AncestorType=vm:HomePageViewModel,**Mode=TemplatedParent}**}"> I just always get : System.Windows.Data Error: 4 : Cannot find source for binding with reference .....

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• Releasing Excel after using Interop

  - by figus

  Hi everyone I've read many post looking for my answer, but all are similar to this: http://stackoverflow.com/questions/1610743/reading-excel-files-in-vb-net-leaves-excel-process-hanging My problem is that I don't quit the app... The idea is this: If a User has Excel Open, if he has the file I'm interested in open... get that Excel instance and do whatever I want to do... But I don't to close his File after I'm done... I want him to keep working on it, the problem is that when he closes Excel... The process keeps running... and running... and running after the user closes Excel with the X button... this is how I try to do it This piece is used to know if he has Excel open, and in the For I check for the file name I'm interested in. Try oApp = GetObject(, "Excel.Application") libroAbierto = True For Each libro As Microsoft.Office.Interop.Excel.Workbook In oApp.Workbooks If libro.Name = EquipoASeccionIdSeccion.Text & ".xlsm" Then Exit Try End If Next libroAbierto = False Catch ex As Exception oApp = New Microsoft.Office.Interop.Excel.Application End Try here would be my code... if he hasn't Excel open, I create a new instance, open the file and everything else. My code ends with this: If Not libroAbierto Then libroSeccion.Close(SaveChanges:=True) oApp.Quit() Else oApp.UserControl = True libroSeccion.Save() End If System.Runtime.InteropServices.Marshal.FinalReleaseComObject(libroOriginal) System.Runtime.InteropServices.Marshal.FinalReleaseComObject(libroSeccion) System.Runtime.InteropServices.Marshal.FinalReleaseComObject(origen) System.Runtime.InteropServices.Marshal.FinalReleaseComObject(copiada) System.Runtime.InteropServices.Marshal.FinalReleaseComObject(oApp) libroOriginal = Nothing libroSeccion = Nothing oApp = Nothing origen = Nothing copiada = Nothing nuevosGuardados = True So you can see that, if I opened the file, I call oApp.Quit() and everything else and the Excel Process ends after a few seconds (maybe 5 aprox.) BUT if I mean the user to keep the file open (not calling Quit()), Excel process keeps running after the user closes Excel with the X button. Is there any way to do what I try to do?? Control a open instance of excel and releasing everything so when the user closes it with the X button, the Excel Process dies normally??? Thanks!!!

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• How to create platform independent 3D video on 3D TV via HDMI 1.4?

  - by artif

  I am writing a real-time, interactive 3D visualization program and at each point in the program, I can compute 2 images (bitmaps) that are meant to look 3D together by means of stereoscopy. How do I get my program to display the image pairs such that they look 3D on a 3D TV? Is there a platform independent way of accomplishing it? (By platform I mean independent of GPU brand, operating system, 3D TV vendor, etc.) If not, which is preferable-- to lock in by GPU, OS, or 3D TV? I suppose I need to be using an HDMI 1.4 cable with the 3D TV? HDMI 1.4 can encode stereoscopy via side-by-side method. But how do I send such an encoded signal to the monitor? What kind of libraries do I use for this sort of thing? Windows DirectShow? If DirectShow is correct, is there a cross platform equivalent available? If anyone asks, yes I have seen this question: http://stackoverflow.com/questions/2811350/generating-3d-tv-stereoscopic-output-programmatically. However, correct me if I am wrong, it does not appear to be what I'm looking for. I do not have an OpenGL or Direct3D program that generates polygons, for which a Nvidia card can do ad-hoc impromptu stereoscopy simply by rendering the scene from 2 slightly offset points of view and then displaying those 2 images on the monitor-- my program already has those image pairs and needs to display them (and they are not the result of rendering polygons). Btw, I have never done any major multimedia programming before and know very little about HDMI, Direct Show, 3D TVs, etc so pardon me if any parts of this question did not make any sense at all.

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• HTML entity encoding (convert '<' to '&lt;') on iPhone in objective-c

  - by Markus

  I'm developing an application for the iPhone that has inApp-mail sending capabilities. So far so good, but now I want to avoid html-injections as some parts of the mail are user-generated texts. Basically I search for something like this: // inits NSString *sourceString = [NSString stringWithString:@"Hello world! Grüße dich Welt <-- This is in German."]; // ----- THAT'S WHAT I'M LOOKING FOR // pseudo-code | // V NSString *htmlEncodedString = [sourceString htmlEncode]; // log NSLog(@"source string: %@", sourceString); NSLog(@"encoded string: %@", htmlEncodedString); Expected output source string: Hello world! Grüße dich Welt <-- This is in German. encoded string: Hello world! Gr&#252;&#223;e dich Welt &lt;-- This is in German. I already googled and looked through several of SO's questions and answers, but all of them seem to be related to URL-encoding and that's not what I really need (I tried stringByAddingPercentEscapesUsingEncoding with no luck - it creates %C3%BC out of an 'ü' that should be an ü). A code sample would be really great (correcting mine?)... -- Thanks in advance, Markus

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• How to get pixel information inside a fragment shader?

  - by user697111

  In my fragment shader I can load a texture, then do this: uniform sampler2D tex; void main(void) { vec4 color = texture2D(tex, gl_TexCoord[0].st); gl_FragColor = color; } That sets the current pixel to color value of texture. I can modify these, etc and it works well. But a few questions. How do I tell "which" pixel I am? For example, say I want to set pixel 100,100 (x,y) to red. Everything else to black. How do I do a : "if currentSelf.Position() == (100,100); then color=red; else color=black?" ? I know how to set colors, but how do I get "my" location? Secondly, how do I get values from a neighbor pixel? I tried this: vec4 nextColor = texture2D(tex, gl_TexCoord[1].st); But not clear what it is returning? if I'm pixel 100,100; how do I get the values from 101,100 or 100,101?

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• How can I use JSONP to download client-side javascript objects?

  - by Alex Mcp

  I'm trying to get client-side javascript objects saved as a file locally. I'm not sure if this is possible. The basic architecture is this: Ping an external API to get back a JSON object Work client-side with that object, and eventually have a "download me" link This link sends the data to my server, which processes it and sends it back with a mime type application/json, which (should) prompt the user to download the file locally. Right now here are my pieces: Server Side Code <?php $data = array('zero', 'one', 'two', 'testing the encoding'); $json = json_encode($data); //$json = json_encode($_GET['']); //eventually I'll encode their data, but I'm testing header("Content-type: application/json"); header('Content-Disposition: attachment; filename="backup.json"'); echo $_GET['callback'] . ' (' . $json . ');'; ?> Relevant Client Side Code $("#download").click(function(){ var json = JSON.stringify(collection); //serializes their object $.ajax({ type: "GET", url: "http://www.myURL.com/api.php?callback=?", //this is the above script dataType: "jsonp", contentType: 'jsonp', data: json, success: function(data){ console.log( "Data Received: " + data[3] ); } }); return false; }); Right now when I visit the api.php site with Firefox, it prompts a download of download.json and that results in this text file, as expected: (["zero","one","two","testing the encoding"]); And when I click #download to run the AJAX call, it logs in Firebug Data Received: testing the encoding which is almost what I'd expect. I'm receiving the JSON string and serializing it, which is great. I'm missing two things: The Actual Questions What do I need to do to get the same prompt-to-download behavior that I get when I visit the page in a browser (much simpler) How do I access, server-side, the json object being sent to the server to serialize it? I don't know what index it is in the GET array (silly, I know, but I've tried almost everything)

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• How to scale a PHP application (servers, mysql, memcache)

  - by Stéphane Goetz

  Hi, I'm currently creating a website for a social project in switzerland. And before there is an overflow of user, I want to prepare the application to scale. I answered by myself many questions but some are left. I explain what I want to do. First at the beginnning, the Application will have only one server (short time) with DNS, PHP, Mysql, Data, and memcache. Second Then I will split them in two DNS, Mysql, memcache Data, PHP Third Here is the problem, I don't know how to do it exactly here to keep the application running well. I could do : Front : Load Balancer, memcache, DNS Web 1 : PHP, DATA Web 2 : PHP, DATA Mysql This would be the scheme, all PHP sessions are kept in the DB. BUT, how do I sync the data? do I run a Rsync to keep them up to date. do I put them on a separate disk (network disk) to be sure ? but in this case, how can I do in case of user uploads ? and if the website gets more success and we have to go on greater structures, would'nt it create some latency on updates ? or would it be a good thing to go directly to amazon's web services ? some infos I use codeigniter as Framework. I use linux as webserver (distribution not chosen now, but should be Debian) Thanks in advance for your answers.

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• Calling delegate methods and calling selectors

  - by Crystal

  I'm new to the concept of delegates and selectors when used with notifications. So my first question is, 1) Let's say you have a button that has a delegate that implements some doWork method. If you want the same functionality that's in the method, is it 'ok' to just call that method? I didn't know if that was considered good coding practices and/or if you should do that, or do something different in getting that type of functionality. Like if that is ok architecture? 2) Similarly, with NSNotificationCenter, I see some code that posts a notification. Then there's a HandleSegmentedControl:(NSNotification *)notification method. If I want to manually have that functionality, but without pressing the segment control, is it 'ok' to just take that functionality out of that method and put it in a new method so it would look like this: Original: - (void)HandleSegmentedControl:(NSNotification *)notification { NSDictionary *dict = [userInfo notification]; // do stuff with the dictionary } New: - (void)HandleSegmentedControl:(NSNotification *)notification { NSDictionary *dict = [userInfo notification]; [self newMethod:dict]; } - (void)newMethod:(NSDictionary *)dict { // do stuff with the dictionary } - (void)myOtherMethodThatNeedsTheSameFunctionality { NSDictionary *dict = // create some dictionary [self newMethod:dict]; } Sorry if these are basic questions. I'm not sure what the best practices are for things like this and wanted to start the right way. Thanks.

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• binding a command inside a listbox item to a property on the viewmodel parent

  - by gideon

  I've been working on this for about an hour and looked at all related SO questions. My problem is very simple: I have HomePageVieModel: HomePageVieModel +IList<NewsItem> AllNewsItems +ICommand OpenNews My markup: <Window DataContext="{Binding HomePageViewModel../> <ListBox ItemsSource="{Binding Path=AllNewsItems}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <TextBlock> <Hyperlink Command="{Binding Path=OpenNews}"> <TextBlock Text="{Binding Path=NewsContent}" /> </Hyperlink> </TextBlock> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> The list shows fine with all the items, but for the life of me whatever I try for the Command won't work: <Hyperlink Command="{Binding Path=OpenNewsItem, RelativeSource={RelativeSource AncestorType=vm:HomePageViewModel, AncestorLevel=1}}"> <Hyperlink Command="{Binding Path=OpenNewsItem, RelativeSource={RelativeSource AncestorType=vm:HomePageViewModel,**Mode=FindAncestor}**}"> <Hyperlink Command="{Binding Path=OpenNewsItem, RelativeSource={RelativeSource AncestorType=vm:HomePageViewModel,**Mode=TemplatedParent}**}"> I just always get : System.Windows.Data Error: 4 : Cannot find source for binding with reference ..... Update I am setting my ViewModel like this? Didn't think this would matter: <Window.DataContext> <Binding Path="HomePage" Source="{StaticResource Locator}"/> </Window.DataContext> I use the ViewModelLocator class from the MVVMLight toolkit which does the magic.

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• Passing arguments and values from HTML to jQuery (events)

  - by Jaroslav Moravec

  What is the practice to pass arguments from HTML to jQuery events function. For example getting id of row from db: <tr class="jq_killMe" id="thisItemId-id"> ... </tr> and jQuery: $(".jq_killMe").click(function () { var tmp = $(this).attr('id).split("-"); var id = tmp[0] // ... } What's the best practise, if I want to pass more than one argument? Is it better not to use jQuery? For example: <tr onclick="killMe('id')"> ... </tr> I didn't find the answer on my question, I will be glad even for links. Thanks. Edit (pre solution) So you suggested two methods to do that: Add custom attributes to element (XHTML) Use attribute ID and parse it by regex Attribute data-* attributes in HTML5 Use hidden children elements I like first solution, but... I would like to (I have to (employer)) produce valid code. Here is a nice question and answers: http://stackoverflow.com/questions/994856/so-what-if-custom-html-attributes-arent-valid-xhtml And the second is not so pretty as the first, but valid. So the compromise is... The third is the solution for future, but here is a lot of CMS where we have to use XHTML or HTML4. (And HTML5 is the long process)

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• Python - Things one MUST avoid

  - by Anurag Uniyal

  Today I was bitten again by "Mutable default arguments" after many years. I usually don't use mutable default arguments unless needed but I think with time I forgot about that, and today in the application I added tocElements=[] in a pdf generation function's argument list and now 'Table of Content' gets longer and longer after each invocation of "generate pdf" :) My question is what other things should I add to my list of things to MUST avoid? 1 Mutable default arguments 2 import modules always same way e.g. 'from y import x' and 'import x' are totally different things actually they are treated as different modules see http://stackoverflow.com/questions/1459236/module-reimported-if-imported-from-different-path 3 Do not use range in place of lists because range() will become an iterator anyway, so things like this will fail, so wrap it by list myIndexList = [0,1,3] isListSorted = myIndexList == range(3) # will fail in 3.0 isListSorted = myIndexList == list(range(3)) # will not same thing can be mistakenly done with xrange e.g myIndexList == xrange(3). 4 Catching multiple exceptions try: raise KeyError("hmm bug") except KeyError,TypeError: print TypeError It prints "hmm bug", though it is not a bug, it looks like we are catching exceptions of type KeyError,TypeError but instead we are catching KeyError only as variable TypeError, instead use try: raise KeyError("hmm bug") except (KeyError,TypeError): print TypeError

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• retrieving multiple versions through API through hbase

  - by sammy

  hello , this is a continuation of my previous question where id used hbase shell.. http://stackoverflow.com/questions/3024417/facing-problems-while-updating-rows-in-hbase i tried the same with API.. im not able to figure out how to retrieve all versions , iterate and print their values for a specific row... i've spending hours reading... please help me out... Scan s = new Scan(Bytes.toBytes("row1")); s.addColumn(Bytes.toBytes("column"),Bytes.toBytes("address")); SETTING RANGE FOR THE VERSIONS s.setTimeRange(0L,6L); ResultScanner scanner = table.getScanner(s); for (Result r : scanner) { for(KeyValue kv : r.sorted()) { System.out.println("To"+kv.getTimestamp()); System.out.println("from "+Bytes.toString(kv.getKey())); System.out.println("To "+Bytes.toString(kv.getValue())); } scanner.close(); } here im intending to print all versions of the column..... but it gives the most recent one... im stuck here...

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• Using ZLib unit to compress files vs using ZipForge

  - by user193655

  There are many questions on zipping in Delphi, anyway this is not a duplicate. I am using ZipForge for zip/unzip capability in my application. Currently I use 2 features of ZipForge: 1) zip and unzip (!) 2) password protect the archives Now I am removing the password from all the archives so I need only to zip and unzip files. I zip them just for minimizing bandwith when uploading/downloading files from the server. So my idea is to process all files once for unzipping them (with password) and rezipping them without password. I have nothing against ZipForge, anyway it is an extra component, every time I upgrade to a newest Delphi version I have to wait for the new IDE support and moreover the more components the more problems during the installation. So since what I do is very simple I'd like to replace ZipForge with 2 simple functinos using the ZLib unit. I found (and tested) the functions here on Torry's. What do you think of using Zlib unit? Do you see any potential problem that I would not have with ZipForge? Can you comment on speed?

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• ASP MVC - Routing Required?

  - by evo_9

  I've been reading up on MVC2 which came in VS2010 and it sounds pretty interesting. I'm actually in the middle of a large multi-tenant application project, and have just started coding the UI. I'm considering changing to MVC as I'm not that far along at this point. I have some questions about the Routing capabilities, namely are they required to use MVC or can I more or less ignore Routing? Or do I have to setup a default routing record that will make things work like standard ASPX (as far as routing alone is concerned)? The reason why I don't want to use Routing is because I've already defined a custom URL 'rewrite' mechanism of my own (which fires on session_start). In addition, I'm using jquery and opens-standards for the entire UI, and MVC's aspx overhead-free approach seems like a better fit based on how I've already started to build the application (I am not using viewstate at all, for example). I guess my big concern is whether the routing can be ignored, of if I will have to re-implement my custom URL rewriting to work with MVC, and if that's the case, how would I do that? As a new Routing routine, or stick with the session_start (if that's even possible?). Lastly, I don't want to use anything even remotely 'intelligent/readable' for the url - for a site like StackOverflow, the readability of the URL is a positive, but the opposite is true if it's not a public website like this one. In fact, it would seem to me that the more friendly MVC routing URL (which indirectly show method names) could pose a security risk on a private, non-public website app like I'm developing. For all these reasons I would love to use the lightweight aspects of MVC but skip the Routing entirely - is this possible?

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• ruby on rails one-to-many relationship

  - by fenec

  I would like to model a betting system relationship using the power of rails. so lets start with doing something very simple modelling the relationship from a user to a bet.i would like to have a model bet with 2 primary keys. here are my migrations enter code here class CreateBets < ActiveRecord::Migration def self.up create_table :bets do |t| t.integer :user_1_id t.integer :user_2_id t.integer :amount t.timestamps end end def self.down drop_table :bets end end class CreateUsers < ActiveRecord::Migration def self.up create_table :users do |t| t.string :name t.timestamps end end def self.down drop_table :users end end the models enter code here class Bet < ActiveRecord::Base belongs_to :user_1,:class_name=:User belongs_to :user_2,:class_name=:User end class User < ActiveRecord::Base has_many :bets, :foreign_key =:user_1) has_many :bets, :foreign_key =:user_2) end when i test here in the console my relationships I got an error enter code here u1=User.create :name="aa" = # u2=User.create :name="bb" = # b=Bet.create(:user_1=u1,:user_2=u2) *****error***** QUESTIONS: 1 How do I define the relationships between these tables correctly? 2 are there any conventions to name the attributes (ex:user_1_id...) thank you for your help

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• Java try finally variations

  - by Petr Gladkikh

  This question nags me for a while but I did not found complete answer to it yet (e.g. this one is for C# http://stackoverflow.com/questions/463029/initializing-disposable-resources-outside-or-inside-try-finally). Consider two following Java code fragments: Closeable in = new FileInputStream("data.txt"); try { doSomething(in); } finally { in.close(); } and second variation Closeable in = null; try { in = new FileInputStream("data.txt"); doSomething(in); } finally { if (null != in) in.close(); } The part that worries me is that the thread might be somewhat interrupted between the moment resource is acquired (e.g. file is opened) but resulting value is not assigned to respective local variable. Is there any other scenarios the thread might be interrupted in the point above other than: InterruptedException (e.g. via Thread#interrupt()) or OutOfMemoryError exception is thrown JVM exits (e.g. via kill, System.exit()) Hardware fail (or bug in JVM for complete list :) I have read that second approach is somewhat more "idiomatic" but IMO in the scenario above there's no difference and in all other scenarios they are equal. So the question: What are the differences between the two? Which should I prefer if I do concerned about freeing resources (especially in heavily multi-threading applications)? Why? I would appreciate if anyone points me to parts of Java/JVM specs that support the answers.

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• How do I mock a method with an open array parameter in PascalMock?

  - by Oliver Giesen

  I'm currently in the process of getting started with unit testing and mocking for good and I stumbled over the following method that I can't seem to fabricate a working mock implementation for: function GetInstance(const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID = CID_DEFAULT): Boolean; (TImplContextID is just an alias for Integer) I thought it would have to look something like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; begin Result := AddCall('GetInstance') .WithParams([@AIID, AContextID]) .ReturnsOutParams([AInstance]) .ReturnValue; end; But the compiler complains about the .ReturnsOutParams([AInstance]) saying "Bad argument type in variable type array constructor.". Also I haven't found a way to specify the open array parameter AArgs at all. Also, is using the @-notation for the TGUID-typed parameter the right way to go? Is it possible to mock this method with the current version of PascalMock at all? Update: I now realize I got the purpose of ReturnsOutParams completely wrong: It's intended to be used for populating the values to be returned when defining the expectations rather than for mocking the call itself. I now think the correct syntax for mocking the out parameter would probably have to look more like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; var lCall: TMockMethod; begin lCall := AddCall('GetInstance').WithParams([@AIID, AContextID]); Pointer(AInstance) := lCall.OutParams[0]; Result := lCall.ReturnValue; end; The questions that remain are how to mock the open array parameter AArgs and whether passing the TGUID argument (i.e. a value type) by address will work out...

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• Web Shop Schema - Document Db

  - by Maxem

  I'd like to evaluate a document db, probably mongo db in an ASP.Net MVC web shop. A little reasoning at the beginning: There are about 2 million products. The product model would be pretty bad for rdbms as there'd be many different kinds of products with unique attributes. For example, there'd be books which have isbn, authors, title, pages etc as well as dvds with play time, directors, artists etc and quite a few more types. In the end, I'd have about 9 different products with a combined column count (counting common columns like title only once) of about 70 to 100 whereas each individual product has 15 columns at most. The three commonly used ways in RDBMS would be: EAV model which would have pretty bad performance characteristics and would make it either impractical or perform even worse if I'd like to display the author of a book in a list of different products (think start page, recommended products etc.). Ignore the column count and put it all in the product table: Although I deal with somewhat bigger databases (row wise), I don't have any experience with tables with more than 20 columns as far as performance is concered but I guess 100 columns would have some implications. Create a table for each product type: I personally don't like this approach as it complicates everything else. C# Driver / Classes: I'd like to use the NoRM driver and so far I think i'll try to create a product dto that contains all properties (grouped within detail classes like book details, except for those properties that should be displayed on list views etc.). In the app I'll use BookBehavior / DvdBehaviour which are wrappers around a product dto but only expose the revelent Properties. My questions now: Are my performance concerns with the many columns approach valid? Did I overlook something and there is a much better way to do it in an RDBMS? Is MongoDb on Windows stable enough? Does my approach with different behaviour wrappers make sense?

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• PHP 5.2 Function needed for GENERIC sorting FOLLOWUP

  - by donbriggs

  OK, you guys gave me a great solution for sorting a recordset array last Friday. (http://stackoverflow.com/questions/2884325/php-5-2-function-needed-for-generic-sorting-of-a-recordset-array) But now when I implement it, I end up with an extra element in the recordset array. I won't wast space reposting the same info, as the link is above. But the bottom line is that when I sort an array of 5 records, the resulting array has 6 records. The last element in the array is not a record array, but rather just a element containing an integer value of 1. I presume that it is somehow getting the output value of the "strnatcasecmp" function, but I have no idea how it is happening. Here is the function that you fine folks provided last week: function getSortCommand($field, $sortfunc) { return create_function('$var1, $var2', 'return '.$sortfunc.'($var1["'.$field.'"], $var2["' .$field .'"]);'); } And here is the line I am calling to sort the array: $trek[] = usort($trek, getSortCommand('name', 'strnatcasecmp')); This produces the following output, with an extra element tacked on to the end. Array ( [0] = Array ( [name] = Kirk [shirt] = Gold [assign] = Bridge ) [1] => Array ( [name] => McCoy [shirt] => Blue [assign] => Sick Bay ) [2] => Array ( [name] => Scotty [shirt] => Red [assign] => Engineering ) [3] => Array ( [name] => Spock [shirt] => Blue [assign] => Bridge ) [4] => Array ( [name] => Uhura [shirt] => Red [assign] => Bridge ) [5] => 1 )

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• ObjectDisposedException when .Show()'ing a form that shouldn't be disposed.

  - by user320781

  ive checked out some of the other questions and obviously the best solution is to prevent the behavior that causes this issue in the first place, but the problem is very intermittent, and very un-reproduceable. I basically have a main form, with sub forms. The sub forms are shown from menus and/or buttons from the main form like so: private void myToolStripMenuItem_Click(object sender, EventArgs e) { try { xDataForm.Show(); xDataForm.Activate(); } catch (ObjectDisposedException) { MessageBox.Show("ERROR 10103"); ErrorLogging newLogger = new ErrorLogging("10103"); Thread errorThread = new Thread(ErrorLogging.writeErrorToLog); errorThread.Start(); } } and the sub forms are actually in the main form(for better or worse. i would actually like to change this but would be a considerable amount of time to do so): public partial class FormMainScreen : Form { Form xDataForm = new xData(); ...(lots more here) public FormMainScreen(int pCount, string pName) { InitializeComponent(); ... } ... } The Dispose function for the sub form is modified so that, the 'close' and 'X' buttons actually hide the form so we dont have to re-create it every time. When the main screen closes, it sets a "flag" to 2, so the other forms know that it is actually ok to close; protected override void Dispose(bool disposing) { if (FormMainScreen.isExiting == 2) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } else { if (xData.ActiveForm != null) { xData.ActiveForm.Hide(); } } } So, the question is, why would this work over and over and over again flawlessly, but, literally, about every 1/1000 of the time, cause an exception, or rather, why is my form being disposed? I had a suspicion that the garbage collector was getting confused, because it occurs slightly more frequently after it has been running for many hours.

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