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• Which mobile operating system should I code for?

  - by samgoody

  It seems as though mobile computing has fully arrived. I would like to rewrite two of our programs for mobile devices, but am a bit lost as to which platform to target. Complicating this decision: I would need to learn the relevant languages and IDEs - my coding to date has been almost all web based (PHP, JS, Actionscript, etc. Some ASPX). Most users seem to be religious about their mobile decision, so oral conversations leave me more confused then enlightened. I do not yet own a smartphone - will have to buy one once I know which platform to be aiming for. Both of my programs are more for business users, (one is only useful for C.P.A.s). I am a single developer, and cannot develop for more than one platform at a time. Getting it right is important. Based on what I've found on the web, I would've expected RIM to be a shoo-in, and the general order to be as follows: RIM Blackberry - More of them than any other brand. Despite naysayers, they've had double the sales (or perhaps 5X the sales) of any other smartphone, and have continued to grow. And, they have business users. Android - According to Schmidt, they have outsold everyone else except RIM (though I can't find where I read that now), and they are just getting started. According to Comscore, they are already at 8% of the market and expected to hit Shcmidt's claims within six months. Nokia - The largest worldwide. If they would just make up between Maemo or Symbian, I would be far less confused. iPhone - Much more competition by other apps, fewer sales to be had, and a overlord that can delay or cancel my app at any time. Is Cocoa hard to learn? Windows Mobile - Word is that version 7 will not be backwards compatible and losing market share. Palm WebOS - Perhaps this should go first, as it is the only one that offers tools to make my life easy as a web application developer. No competition in marketplace. But not very many users either. However, a search on StackOverflow shows a hugely disproportionate number of iPhone questions versus Blackberry. Likewise, there are clearly more apps on iPhone, so it must be getting developer love. What is the one platform I should develop for? Please back up your answer with the logic.

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• How can a test script inform R CMD check that it should emit a custom message?

  - by mariotomo

  I'm writing a R package (delftfews) here at office. we are using svUnit for unit testing. our process for describing new functionality: we define new unit tests, initially marked as DEACTIVATED; one block of tests at a time we activate them and implement the function described by the tests. almost all the time we have a small amount of DEACTIVATED tests, relative to functions that might be dropped or will be implemented. my problem/question is: can I alter the doSvUnit.R so that R CMD check pkg emits a NOTE (i.e. a custom message "NOTE" instead of "OK") in case there are DEACTIVATED tests? as of now, we see only that the active tests don't give error: . . * checking for unstated dependencies in tests ... OK * checking tests ... Running ‘doSvUnit.R’ OK * checking PDF version of manual ... OK which is all right if all tests succeed, but less all right if there are skipped tests and definitely wrong if there are failing tests. In this case, I'd actually like to see a NOTE or a WARNING like the following: . . * checking for unstated dependencies in tests ... OK * checking tests ... Running ‘doSvUnit.R’ NOTE 6 test(s) were skipped. WARNING 1 test(s) are failing. * checking PDF version of manual ... OK As of now, we have to open the doSvUnit.Rout to check the real test results. I contacted two of the maintainers at r-forge and CRAN and they pointed me to the sources of R, in particular the testing.R script. if I understand it correctly, to answer this question we need patching the tools package: scripts in the tests directory are called using a system call, output (stdout and stderr) go to one single file, there are two possible outcomes: ok or not ok, so I opened a change request on R, proposing something like bit-coding the return status, bit-0 for ERROR (as it is now), bit-1 for WARNING, bit-2 for NOTE. with my modification, it would be easy producing this output: . . * checking for unstated dependencies in tests ... OK * checking tests ... Running ‘doSvUnit.R’ NOTE - please check doSvUnit.Rout. WARNING - please check doSvUnit.Rout. * checking PDF version of manual ... OK Brian Ripley replied "There are however several packages with properly written unit tests that do signal as required. Please do take this discussion elsewhere: R-bugs is not the place to ask questions." and closed the change request. anybody has hints?

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• What are five things you hate about your favorite language?

  - by brian d foy

  There's been a cluster of Perl-hate on Stackoverflow lately, so I thought I'd bring my "Five things you hate about your favorite language" question to StackOverflow. Take your favorite language and tell me five things you hate about it. Those might be things that just annoy you, admitted design flaws, recognized performance problems, or any other category. You just have to hate it, and it has to be your favorite language. Don't compare it to another language, and don't talk about languages that you already hate. Don't talk about the things you like in your favorite language. I just want to hear the things that you hate but tolerate so you can use all of the other stuff, and I want to hear it about the language you wished other people would use. I ask this whenever someone tries to push their favorite language on me, and sometimes as an interview question. If someone can't find five things to hate about his favorite tool, he don't know it well enough to either advocate it or pull in the big dollars using it. He hasn't used it in enough different situations to fully explore it. He's advocating it as a culture or religion, which means that if I don't choose his favorite technology, I'm wrong. I don't care that much which language you use. Don't want to use a particular language? Then don't. You go through due diligence to make an informed choice and still don't use it? Fine. Sometimes the right answer is "You have a strong programming team with good practices and a lot of experience in Bar. Changing to Foo would be stupid." This is a good question for code reviews too. People who really know a codebase will have all sorts of suggestions for it, and those who don't know it so well have non-specific complaints. I ask things like "If you could start over on this project, what would you do differently?" In this fantasy land, users and programmers get to complain about anything and everything they don't like. "I want a better interface", "I want to separate the model from the view", "I'd use this module instead of this other one", "I'd rename this set of methods", or whatever they really don't like about the current situation. That's how I get a handle on how much a particular developer knows about the codebase. It's also a clue about how much of the programmer's ego is tied up in what he's telling me. Hate isn't the only dimension of figuring out how much people know, but I've found it to be a pretty good one. The things that they hate also give me a clue how well they are thinking about the subject.

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• Volunteer for a potential employer?

  - by EoRaptor013

  I've been looking for work since March, and haven't had much luck. Recently, however, I interviewed with a small company near my home for a C#, .NET, SQL development position. I hit it off very well with the hiring manager during the phone screen, and even more so during the face to face. Unfortunately, I failed the practical test: wiring up a web form, creating a couple of SQL stored procedures, saving new data with validation, and creating a minimal search screen. I knew what I was doing, but I was too slow to meet their standards as all the work needed to be done within an hour. Nevertheless, I really liked the place, the environment, the people who I would have been working with, and the boss. (I gave the company an 11 on Joel's 12 point scale.) So, the obvious next step was to scrape the rust off. I've been trying to create little projects for myself, but I don't know that I've been effective in getting any faster. What with all that goes into creating a project, I'm not heads-down coding as much as I think I need. Now, with all that introduction, here's the question. I have been thinking about calling the hiring manager at that place, and asking him to let me volunteer for three or four weeks, with no strings attached. I think it would benefit me, and wouldn't cost him anything (as long as I didn't slow the existing people down!). At the end of that period, he might, or might not, be inclined to hire me, but even if not, I would have had as much as 160 hours of in the trenches development. Maybe not all shiny, but no more rust, I would think. Does this plan make any sense at all? I certainly don't want to sound desperate (although, I'm not far from being there), and I very much need the tuneup, lube, and change the oil. What's the downside, if any, to me doing this? Do any of you see red flags going up—either from the prerspective of the hiring manager, or from the perspective of a developer?

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• Verify Authenticode signature as being from our company for automatic updater

  - by James Johnston

  I am implementing an automatic update feature and need some advice on how to do this securely using best practices. I would like to use the downloaded file's Authenticode signature to verify that it is safe to run (i.e. originates from our company and hasn't been tampered with). My question is very similar to question #2008519. The bottom-line question: what's the best, most secure way to check Authenticode signatures for an automatic update feature? What fields in the certificate should be checked? Requirements being: (1) check signature is valid, (2) check it's my signature, (3) old clients can still update when my certificate expires and I get a new one. Here's some background information / ideas from my research: I believe this could be broken into two steps: Verify that the signature is valid. I believe this should be easy using WinVerifyTrust as outlined in http://msdn.microsoft.com/en-us/library/aa382384(VS.85).aspx - I don't expect problems here. Verify that the signature corresponds to our company, and not another company. This seems to be a more difficult question to answer: One possibility is to check some of the strings in the signature. Could be obtained via code at MS KB article #323809, but this article doesn't make recommendations on what fields should be checked for this type of application (or any other, for that matter). Question #1072540 also illustrates how to get some certificate info, but again doesn't recommend what fields to actually check. My concern is that the strings might not be the best check: what if another person is able to obtain a certificate with the same name, for example? Or if there's a valid reason for us to change the strings in the future? The person at question #2008519 has a very similar requirement. His need for a "TrustedByUs" function is identical to mine. However, he goes about doing the check by comparing public keys. While this would work in the short-term, it seems like it won't work for an automatic update feature. This is because code signing certificates are only valid for 2 - 3 years max. Therefore, in the future, when we buy a new certificate in 2 years, the old clients wouldn't be able to update any more due to the change in public key.

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• Override variables while testing a standalone Perl script

  - by BrianH

  There is a Perl script in our environment that I now need to maintain. It is full of bad practices, including using (and re-using) global variables throughout the script. Before I start making changes to the script, I was going to try to write some test scripts so I can have a good regression base. To do this, I was going to use a method described on this page. I was starting by writing tests for a single subroutine. I put this line somewhat near the top of the script I am testing: return 1 if ( caller() ); That way, in my test script, I can require 'script_to_test.pl'; and it won't execute the whole script. The first subroutine I was going to test makes a lot of use of global variables that are set throughout the script. My thought was to try to override these variables in my test script, something like this: require_ok('script_to_test.pl'); $var_from_other_script = 'Override Value'; ok( sub_from_other_script() ); Unfortunately (for me), the script I am testing has a massive "my" block at the top, where it declares all variables used in the script. This prevents my test script from seeing/changing the variables in the script I'm running tests against. I've played with Exporter, Test::Mock..., and some other modules, but it looks like if I want to be able to change any variables I am going to have to modify the other script in some fashion. My goal is to not change the other script, but to get some good tests running so when I do start changing the other script, I can make sure I didn't break anything. The script is about 10,000 lines (3,000 of them in the main block), so I'm afraid that if I start changing things, I will affect other parts of the code, so having a good test suite would help. Is this possible? Can a calling script modify variables in another script declared with "my"? And please don't jump in with answers like, "Just re-write the script from scratch", etc. That may be the best solution, but it doesn't answer my question, and we don't have the time/resources for a re-write.

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• Hidden Features of PHP?

  - by George Mauer

  EDIT: This didn't really start as a hidden features of PHP topic, but thats what it ended up as, so go nuts. I know this sounds like a point-whoring question but let me explain where I'm coming from. Out of college I got a job at a PHP shop. I worked there for a year and a half and thought that I had learned all there was to learn about programming. Then I got a job as a one-man internal development shop at a sizable corporation where all the work was in C#. In my commitment to the position I started reading a ton of blogs and books and quickly realized how wrong I was to think I knew everything. I learned about unit testing, dependency injection and decorator patterns, the design principle of loose coupling, the composition over inheritance debate, and so on and on and on - I am still very much absorbing it all. Needless to say my programming style has changed entirely in the last year. Now I find myself picking up a php project doing some coding for a friend's start-up and I feel completely constrained as opposed to programming in C#. It really bothers me that all variables at a class scope have to be referred to by appending '$this-' . It annoys me that none of the IDEs that I've tried have very good intellisense and that my SimpleTest unit tests methods have to start with the word 'test'. It drives me crazy that dynamic typing keeps me from specifying implicitly which parameter type a method expects, and that you have to write a switch statement to do method overloads. I can't stand that you can't have nested namespaces and have to use the :: operator to call the base class's constructor. Now I have no intention of starting a PHP vs C# debate, rather what I mean to say is that I'm sure there are some PHP features that I either don't know about or know about yet fail to use properly. I am set in my C# universe and having trouble seeing outside the glass bowl. So I'm asking, what are your favorite features of PHP? What are things you can do in it that you can't or are more difficult in the .Net languages?

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• get current selected button cell placed inside tableview using cocoa

  - by Swati

  hi i have a NSTableView i have two columns A and B B contains some data A contains custom button the button is added to column A using this: Below code is placed inside awakeFromNib method NSButtonCell *buttonCell = [[[NSButtonCell alloc] init] autorelease]; [buttonCell setBordered:NO]; [buttonCell setImagePosition:NSImageOnly]; [buttonCell setButtonType:NSMomentaryChangeButton]; [buttonCell setImage:[NSImage imageNamed:@"uncheck.png"]]; [buttonCell setSelectable:TRUE]; [buttonCell setTag:100]; [buttonCell setTarget:self]; [buttonCell setAction:@selector(selectButtonsForDeletion:)]; [[myTable tableColumnWithIdentifier:@"EditIdentifier"] setDataCell:buttonCell]; Some code in display cell of nstableview: -(void)tableView:(NSTableView *)tableView willDisplayCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)rowIndex { if(tableView == myTable) { if([[tableColumn identifier] isEqualToString:@"DataIdentifier"]) { } else if([[tableColumn identifier] isEqualToString:@"EditIdentifier"]) { NSButtonCell *zCell = (NSButtonCell *)cell; [zCell setTag:rowIndex]; [zCell setTitle:@"abc"]; [zCell setTarget:self]; [zCell setAction:@selector(selectButtonsForDeletion:)]; } } } now i want that when i click on the button the image of button cell gets changed as well as i want to do some coding. When button gets clicked then by default the tableView's reference gets passed. How can i get the button cell reference i looked here for similar problem: Cocoa: how to nest a button inside a Table View cell? but i am unable to add button inside column of NSTableView. How i change the image: - (void)tableView:(NSTableView *)tableView setObjectValue:(id)object forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row; { if(tableView == myTable) { if([[tableColumn identifier] isEqualToString:@"EditIdentifier"]) { NSButtonCell *aCell = (NSButtonCell *)[[tableView tableColumnWithIdentifier:@"EditIdentifier"] dataCellForRow:row]; NSInteger index = [[aCell title]intValue]; if([self.selectedIndexesArray count]>0) { if(![self.selectedIndexesArray containsObject:[NSNumber numberWithInt:index]]) { [aCell setImage:[NSImage imageNamed:@"check.png"]]; [self.selectedIndexesArray addObject:[NSNumber numberWithInt:index]]; } else { [aCell setImage:[NSImage imageNamed:@"uncheck.png"]]; [self.selectedIndexesArray removeObjectAtIndex:[selectedIndexesArray indexOfObject:[NSNumber numberWithInt:index]]]; } } else { [aCell setImage:[NSImage imageNamed:@"check.png"]]; [self.selectedIndexesArray addObject:[NSNumber numberWithInt:index]]; } } } } I have debugged the code and found that proper tag and titles are passed but image applies on more than one button cell, this is too very irregular. cant understand how its working!!! Any suggestions what am i doing wrong??

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• Detect Client Computer name when an RDP session is open

  - by Ubiquitous Che

  Hey all, My manager has pointed out to me a few nifty things that one of our accounting applications can do because it can load different settings based on the machine name of the host and the machine name of the client when the package is opened in an RDP session. We want to provide similar functionality in one of my company's applications. I've found out on this site how to detect if I'm in an RDP session, but I'm having trouble finding information anywhere on how to detect the name of the client computer. Any pointers in the right direction would be great. I'm coding in C# for .NET 3.5 EDIT The sample code I cobbled together from the advice below - it should be enough for anyone who has a use for the WTSQuerySessionInformation to get a feel for what's going on. Note that this isn't necessarily the best way of doing it - just a starting point that I've found useful. When I run this locally, I get boring, expected answers. When I run it on our local office server in an RDP session, I see my own computer name in the WTSClientName property. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace TerminalServicesTest { class Program { const int WTS_CURRENT_SESSION = -1; static readonly IntPtr WTS_CURRENT_SERVER_HANDLE = IntPtr.Zero; static void Main(string[] args) { StringBuilder sb = new StringBuilder(); uint byteCount; foreach (WTS_INFO_CLASS item in Enum.GetValues(typeof(WTS_INFO_CLASS))) { Program.WTSQuerySessionInformation( WTS_CURRENT_SERVER_HANDLE, WTS_CURRENT_SESSION, item, out sb, out byteCount); Console.WriteLine("{0}({1}): {2}", item.ToString(), byteCount, sb); } Console.WriteLine(); Console.WriteLine("Press any key to exit..."); Console.ReadKey(); } [DllImport("Wtsapi32.dll")] public static extern bool WTSQuerySessionInformation( IntPtr hServer, int sessionId, WTS_INFO_CLASS wtsInfoClass, out StringBuilder ppBuffer, out uint pBytesReturned); } enum WTS_INFO_CLASS { WTSInitialProgram = 0, WTSApplicationName = 1, WTSWorkingDirectory = 2, WTSOEMId = 3, WTSSessionId = 4, WTSUserName = 5, WTSWinStationName = 6, WTSDomainName = 7, WTSConnectState = 8, WTSClientBuildNumber = 9, WTSClientName = 10, WTSClientDirectory = 11, WTSClientProductId = 12, WTSClientHardwareId = 13, WTSClientAddress = 14, WTSClientDisplay = 15, WTSClientProtocolType = 16, WTSIdleTime = 17, WTSLogonTime = 18, WTSIncomingBytes = 19, WTSOutgoingBytes = 20, WTSIncomingFrames = 21, WTSOutgoingFrames = 22, WTSClientInfo = 23, WTSSessionInfo = 24, WTSSessionInfoEx = 25, WTSConfigInfo = 26, WTSValidationInfo = 27, WTSSessionAddressV4 = 28, WTSIsRemoteSession = 29 } }

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• one page over 9 different urls

  - by Ali Demirtas

  Hi I am using prestashop as the cart for my website. I have a problem; the website used to be in dynamic urls. I enabled friendly url writing. The problem is that one page has more than one url. You can access a same page from the dynamic url and static url. In fact a single page has 9 different urls. This obviously creates problems for seo as search engines penalize my website for this. Here are examples of a page with more than 2 urls (http://www.turkishfootballstore.com/lang-nl/product.php?id_product=515) (http://www.turkishfootballstore.com/fenerbahce/515-fenerbahce-thuisshirt-20092010.html) (http://www.turkishfootballstore.com/lang-nl/fenerbahce/515-fenerbahce-thuisshirt-20092010.html) you can see even the static url's have 2 one with language defined and the other without. out fo the three urls above the correct one is the one at the bottom. What can I do to solve this problem? I have no knowledge of programming. Here is the htaccess for the website. Any sample code or help is really appreciated. There is 550 pages and every page is published in 17 different languages I want to use a 301 auto redirect. What is the simplest way to do it? I have no idea of coding. # URL rewriting module activation RewriteEngine on # URL rewriting rules RewriteRule ^([a-z0-9]+)\-([a-z0-9]+)(\-[_a-zA-Z0-9-]*)/([_a-zA-Z0-9-]*)\.jpg$ /img/p/$1-$2$3.jpg [L,E] RewriteRule ^([0-9]+)\-([0-9]+)/([_a-zA-Z0-9-]*)\.jpg$ /img/p/$1-$2.jpg [L,E] RewriteRule ^([0-9]+)(\-[_a-zA-Z0-9-]*)/([_a-zA-Z0-9-]*)\.jpg$ /img/c/$1$2.jpg [L,E] RewriteRule ^lang-([a-z]{2})/([a-zA-Z0-9-]*)/([0-9]+)\-([a-zA-Z0-9-]*)\.html(.*)$ /product.php?id_product=$3&isolang=$1$5 [L,E] RewriteRule ^lang-([a-z]{2})/([0-9]+)\-([a-zA-Z0-9-]*)\.html(.*)$ /product.php?id_product=$2&isolang=$1$4 [L,E] RewriteRule ^lang-([a-z]{2})/([0-9]+)\-([a-zA-Z0-9-]*)(.*)$ /category.php?id_category=$2&isolang=$1 [QSA,L,E] RewriteRule ^([a-zA-Z0-9-]*)/([0-9]+)\-([a-zA-Z0-9-]*)\.html(.*)$ /product.php?id_product=$2$4 [L,E] RewriteRule ^([0-9]+)\-([a-zA-Z0-9-]*)\.html(.*)$ /product.php?id_product=$1$3 [L,E] RewriteRule ^([0-9]+)\-([a-zA-Z0-9-]*)(.*)$ /category.php?id_category=$1 [QSA,L,E] RewriteRule ^content/([0-9]+)\-([a-zA-Z0-9-]*)(.*)$ /cms.php?id_cms=$1 [QSA,L,E] RewriteRule ^([0-9]+)__([a-zA-Z0-9-]*)(.*)$ /supplier.php?id_supplier=$1$3 [QSA,L,E] RewriteRule ^([0-9]+)_([a-zA-Z0-9-]*)(.*)$ /manufacturer.php?id_manufacturer=$1$3 [QSA,L,E] RewriteRule ^lang-([a-z]{2})/(.*)$ /$2?isolang=$1 [QSA,L,E] # Catch 404 errors ErrorDocument 404 /404.php Options +FollowSymLinks RewriteEngine on RewriteCond %{HTTP_HOST} ^***.com [NC] RewriteRule ^(.*)$ http://www.***.com/$1 [L,R=301] Options +FollowSymLinks RewriteEngine on # index.php to / RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*index\.php\ HTTP/ RewriteRule ^(.*)index\.php$ /$1 [R=301,L] Header set Cache-Control: "no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0"

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• What does N years of experience with a language really mean?

  - by marcgg

  I've been looking at jobs descriptions since I'm graduating soon and looking for a job and what's always coming back - I'm not teaching you anything - is the "N years of experience in this language". It has been discussed in this question that if you work professionally with let's say Ruby for 2 years, but during these two years you also did some C# and PHP and were actually coding in Ruby 50% of the time. Do you say you have 1 year of experience in Ruby? 2 years? Another issue that hasn't been reviewed in the other post is for "non-professional experience". I'll give you a personal example: I've been working with Ruby on Rails since 2004 while at school. I did a lot of personal projects and school projects using this technology. I also used Rails in 2 6-month internships. Do I have 5 years of Rails experience (2004-now)? Do I have 1 year(2 internships)? Do I have nothing? I feel like I don't deserve the credit for 5 years, because the first years I wasn't working a lot with rails, but since last year I launched some websites and invested myself a lot in this technology and just saying 1 year doesn't really reflect how much I know the technology... Another example: I Learned C++ at school and did 1 big project with it (2-3 month of work and a semester of classes). I never used it in a company but I'd be able to be productive fairly quickly if I had to work on a C++ project and I have a good grasp of the concepts. Do I have no experience? 3 months? 6 months? ... something else? What I'm really trying to do is to find a way to present my skill set in a way that is compliant to what recruiters expect. I also don't want to end up at an interview that would go something like this... Recruiter (finding out the horrible truth): Oh but you said that you had 2 years of experience with this when you have none! / slaps me in the face / Me (in pain): Oh! The irony! Recruiter (yelling): Get out of my office / calls security, punches me in the throat /

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• A couple questions using fwrite/fread with data structures

  - by Nazgulled

  Hi, I'm using fwrite() and fread() for the first time to write some data structures to disk and I have a couple of questions about best practices and proper ways of doing things. What I'm writing to disk (so I can later read it back) is all user profiles inserted in a Graph structure. Each graph vertex is of the following type: typedef struct sUserProfile { char name[NAME_SZ]; char address[ADDRESS_SZ]; int socialNumber; char password[PASSWORD_SZ]; HashTable *mailbox; short msgCount; } UserProfile; And this is how I'm currently writing all the profiles to disk: void ioWriteNetworkState(SocialNetwork *social) { Vertex *currPtr = social->usersNetwork->vertices; UserProfile *user; FILE *fp = fopen("save/profiles.dat", "w"); if(!fp) { perror("fopen"); exit(EXIT_FAILURE); } fwrite(&(social->usersCount), sizeof(int), 1, fp); while(currPtr) { user = (UserProfile*)currPtr->value; fwrite(&(user->socialNumber), sizeof(int), 1, fp); fwrite(user->name, sizeof(char)*strlen(user->name), 1, fp); fwrite(user->address, sizeof(char)*strlen(user->address), 1, fp); fwrite(user->password, sizeof(char)*strlen(user->password), 1, fp); fwrite(&(user->msgCount), sizeof(short), 1, fp); break; currPtr = currPtr->next; } fclose(fp); } Notes: The first fwrite() you see will write the total user count in the graph so I know how much data I need to read back. The break is there for testing purposes. There's thousands of users and I'm still experimenting with the code. My questions: After reading this I decided to use fwrite() on each element instead of writing the whole structure. I also avoid writing the pointer to to the mailbox as I don't need to save that pointer. So, is this the way to go? Multiple fwrite()'s instead of a global one for the whole structure? Isn't that slower? How do I read back this content? I know I have to use fread() but I don't know the size of the strings, cause I used strlen() to write them. I could write the output of strlen() before writing the string, but is there any better way without extra writes?

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• Rendering javascript at the server side level. A good or bad idea?

  - by davidhong

  I want to make it clear first: This isn't a question in relation to server-side Javascript or running Javascript server side. This is a question regarding rendering of Javascript code (which will be executed on the client-side) from server-side code. Having said that, take a look at below ASP.net code for example: hlRemoveCategory.Attributes.Add("onclick", "return confirm('Are you sure you want to delete this?');") This is prescribing the client-side onclick event on the server-side. As oppose to: $('a[rel=remove]').bind('click', function(event) { return confirm('Are you sure you want to delete this?'); } Now the question I want to ask is: What is the benefit of rendering javascript from the server-side code? Or the vice-versa? I personally prefer the second way of hooking up client-side UI/behaviour to HTML elements for the following reasons: Server-side does what ever it needs to already, including data-validation, event delegation and etc; and What server-side sees as an event is not necessarily the same process on the client-side. i.e., there are plenty more events on client-side (just look at custom events); and What happens on client-side and on server-side, during an event, could be completely irrelevant and decoupled; and What ever happens on client-side happens on client-side, there is no need for the server to know. Server should process and run what is given to them, how the process comes to life is not really up to them to decide in the event of the client-side events; and so and so forth. These are my thoughts obviously. I want to know what others think and if there has been any discussions on this topic. Topics branching from this argument can reach: Code management: is it easier to render everything from server-side? Separation of concern: is it easier if client-side logic is separated to server-side logic? Efficiency: which is more efficient both in terms of coding and running? At the end of the day, I am trying to move my team to go towards the second approach. There are lot of old guys in this team who are afraid of this change. I just wish to convince them with the right facts and stats. Let me know your thoughts.

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• i don't understand how...

  - by Hristo

  how can something print 3 times when it only goes the printing code twice? I'm coding in C and the code is in a SIGCHLD signal handler I created. void chld_signalHandler() { int pidadf = (int) getpid(); printf("pidafdfaddf: %d\n", pidadf); while (1) { int termChildPID = waitpid(-1, NULL, WNOHANG); if (termChildPID == 0 || termChildPID == -1) { break; } dll_node_t *temp = head; while (temp != NULL) { printf("stuff\n"); if (temp-pid == termChildPID && temp-type == WORK) { printf("inside if\n"); // read memory mapped file b/w WORKER and MAIN // get statistics and write results to pipe char resultString[256]; // printing TIME int i; for (i = 0; i < 24; i++) { sprintf(resultString, "TIME; %d ; %d ; %d ; %s\n",i,1,2,temp->stats->mboxFileName); fwrite(resultString, strlen(resultString), 1, pipeFD); } remove_node(temp); break; } temp = temp-next; } printf("done printing from sigchld \n"); } return; } the output for my MAIN process is this: MAIN PROCESS 16214 created WORKER PROCESS 16220 for file class.sp10.cs241.mbox pidafdfaddf: 16214 stuff stuff inside if done printing from sigchld MAIN PROCESS 16214 created WORKER PROCESS 16221 for file class.sp10.cs225.mbox pidafdfaddf: 16214 stuff stuff inside if done printing from sigchld and the output for the MONITOR process is this: MONITOR: pipe is open for reading MONITOR PIPE: TIME; 0 ; 1 ; 2 ; class.sp10.cs225.mbox MONITOR PIPE: TIME; 0 ; 1 ; 2 ; class.sp10.cs225.mbox MONITOR PIPE: TIME; 0 ; 1 ; 2 ; class.sp10.cs241.mbox MONITOR: end of readpipe ( I've taken out repeating lines so I don't take up so much space ) Thanks, Hristo

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• Using JUnit as an acceptance test framework

  - by Chris Knight

  OK, so I work for a company who has openly adopted agile practices for development in recent years. Our unit tests and code quality are improving. One area we still are working on is to find what works best for us in the automated acceptance test arena. We want to take our well formed user stories and use these to drive the code in a test driven manner. This will also give us acceptance level tests for each user story which we can then automate. To date, we've tried Fit, Fitnesse and Selenium. Each have their advantages, but we've also had real issues with them as well. With Fit and Fitnesse, we can't help but feel they overcomplicate things and we've had many technical issues using them. The business haven't fully bought in these tools and aren't particularly keen on maintaining the scripts all the time (and aren't big fans of the table style). Selenium is really good, but slow and relies on real time data and resources. One approach we are now considering is the use of the JUnit framework to provide similiar functionality. Rather than testing just a small unit of work using JUnit, why not use it to write a test (using the JUnit framework) to cover an acceptance level swath of the application? I.e. take a new story ("As a user I would like to see basic details of my policy...") and write a test in JUnit which starts executing application code at the point of entry for the policy details link but covers all code and logic down to the stubbed data access layer and back to the point of forwarding to the next page in the application, asserting on what data the user should see on that page. This seems to me to have the following advantages: Simplicity (no additional frameworks required) Zero effort to integrate with our Continuous Integration build server (since it already handles our JUnit tests) Full skillset already present in the team (its just a JUnit test after all) And the downsides being: Less customer involvement (though they are heavily involved in writing the user stories in the first place from which the acceptance tests will be written) Perhaps more difficult to understand (or make understood) the user story and acceptance criteria in a JUnit class verses a freetext specification ala Fit or Fitnesse So, my question is really, have you ever tried this method? Ever considered it? What are your thoughts? What do you like and dislike about this approach? Finally, please only mention alternative frameworks if you can say why you like or dislike them more than this approach.

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• Set maven to use archiva repositories WITHOUT using activeByDefault?

  - by Sam Levin

  I am very close to finally having a working setup with archiva and maven. The last thing that's really boggling me, is how to set up my internal and snapshot repositories - without using a profile which contains activeByDefault set to true. I am using a SUPER super pom - a company-wide pom which contains distributionManagement information for releases. I was thinking that I could specify the repositories in this pom, and configure the authentication settings in settings.xml? Can I use repositories tag without a profile? There should be no "profile" for my internal and snapshot repositories, as they will never change... What I'm trying to steer clear from, is using a "default" profile, which is active all the time. I hear activeByDefault is NOT a best practice and I don't intend to use it. With that said, how should I go about doing this? My internal repo is a mirror of the maven central repo, so I would like to lock down my developers to ONLY use our internal artifact server. Remember - I do NOT want a profile with activeByDefault set to true. I cannot stress this enough! Should I use Maven mirrors? Should I "add" additional repositories? If I take the repositories tag instead of the mirrors tag, will maven force builds to use ONLY my archiva settings, instead of the default maven central? Or is what I seek to accomplish able to be done using only the mirrors tag in maven? I know how to configure repo credentials when using repositories tag, but not with mirrors. How is this done? Is providing credentials for anything in mirrors tags the same as for anything in repositories tags? Am I missing something obvious? I've had it up to here with getting things up and running using maven. I know it will be worthwhile in the end, but it is surely causing me a ton of aggravation and resources seem to be sparse. Either that, or people are content using it however they please without regard to best-practices. Thank you

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• What are the benefits of using ORM over XML Serialization/Deserialization?

  - by Tequila Jinx

  I've been reading about NHibernate and Microsoft's Entity Framework to perform Object Relational Mapping against my data access layer. I'm interested in the benefits of having an established framework to perform ORM, but I'm curious as to the performance costs of using it against standard XML Serialization and Deserialization. Right now, I develop stored procedures in Oracle and SQL Server that use XML Types for either input or output parameters and return or shred XML depending on need. I use a custom database command object that uses generics to deserialize the XML results into a specified serializable class. By using a combination of generics, xml (de)serialization and Microsoft's DAAB, I've got a process that's fairly simple to develop against regardless of the data source. Moreover, since I exclusively use Stored Procedures to perform database operations, I'm mostly protected from changes in the data structure. Here's an over-simplified example of what I've been doing. static void main() { testXmlClass test = new test(1); test.Name = "Foo"; test.Save(); } // Example Serializable Class ------------------------------------------------ [XmlRootAttribute("test")] class testXmlClass() { [XmlElement(Name="id")] public int ID {set; get;} [XmlElement(Name="name")] public string Name {set; get;} //create an instance of the class loaded with data. public testXmlClass(int id) { GenericDBProvider db = new GenericDBProvider(); this = db.ExecuteSerializable("myGetByIDProcedure"); } //save the class to the database... public Save() { GenericDBProvider db = new GenericDBProvider(); db.AddInParameter("myInputParameter", DbType.XML, this); db.ExecuteSerializableNonQuery("mySaveProcedure"); } } // Database Handler ---------------------------------------------------------- class GenericDBProvider { public T ExecuteSerializable<T>(string commandText) where T : class { XmlSerializer xml = new XmlSerializer(typeof(T)); // connection and command code is assumed for the purposes of this example. // the final results basically just come down to... return xml.Deserialize(commandResults) as T; } public void ExecuteSerializableNonQuery(string commandText) { // once again, connection and command code is assumed... // basically, just execute the command along with the specified // parameters which have been serialized. } public void AddInParameter(string name, DbType type, object value) { StringWriter w = new StringWriter(); XmlSerializer x = new XmlSerializer(value.GetType()); //handle serialization for serializable classes. if (type == DbType.Xml && (value.GetType() != typeof(System.String))) { x.Serialize(w, value); w.Close(); // store serialized object in a DbParameterCollection accessible // to my other methods. } else { //handle all other parameter types } } } I'm starting a new project which will rely heavily on database operations. I'm very curious to know whether my current practices will be sustainable in a high-traffic situation and whether or not I should consider switching to NHibernate or Microsoft's Entity Framework to perform what essentially seems to boil down to the same thing I'm currently doing. I appreciate any advice you may have.

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• Observer pattern used with decorator pattern

  - by icelated

  I want to make a program that does an order entry system for beverages. ( i will probably do description, cost) I want to use the Decorator pattern and the observer pattern. I made a UML drawing and saved it as a pic for easy viewing. This site wont let me upload as a word doc so i have to upload a pic - i hope its easily viewable.... I need to know if i am doing the UML / design patterns correctly before moving on to the coding part. Beverage is my abstract component class. Espresso, houseblend, darkroast are my concrete subject classes.. I also have a condiment decorator class milk,mocha,soy,whip. would be my observer? because they would be interested in data changes to cost? Now, would the espresso,houseblend etc, be my SUBJECT and the condiments be my observer? My theory is that Cost is a changes and that the condiments need to know the changes? So, subject = esspresso,houseblend,darkroast,etc.. // they hold cost() Observer = milk,mocha,soy,whip? // they hold cost() would be the concrete components and the milk,mocha,soy,whip? would be the decorator! So, following good software engineering practices "design to an interface and not implementation" or "identify things that change from those that dont" would i need a costbehavior interface? If you look at the UML you will see where i am going with this and see if i am implementing observer + Decorator pattern correctly? I think the decorator is correct. since, the pic is not very viewable i will detail the classes here: Beverage class(register observer, remove observer, notify observer, description) these classes are the concrete beverage classes espresso, houseblend,darkroast, decaf(cost,getdescription,setcost,costchanged) interface observer class(update) // cost? interface costbehavior class(cost) // since this changes? condiment decorator class( getdescription) concrete classes that are linked to the 2 interface s and decorator are: milk,mocha,soy,whip(cost,getdescription,update) these are my decorator/ wrapper classes. Thank you.. Is there a way to make this picture bigger?

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• Printing gives unhandled exception. Access Denied

  - by Smoka

  Im newish to coding, currently on a Windows Forms App using CLI in VS10 Everything seems to work, my document shows fine in the Preview dialog but then crash's. Heres only the code that seems relevant private: System::Drawing::Printing::PrintDocument^ docPrint; private: System::Windows::Forms::PrintDialog^ dlgPrint; private: System::Windows::Forms::PrintPreviewDialog^ dlgPrintPreview; this->button2 = (gcnew System::Windows::Forms::Button()); this->docPrint = (gcnew System::Drawing::Printing::PrintDocument()); this->dlgPrint = (gcnew System::Windows::Forms::PrintDialog()); this->dlgPrintPreview = (gcnew System::Windows::Forms::PrintPreviewDialog()); this->button2->Location = System::Drawing::Point(152, 355); this->button2->Name = L"button2"; this->button2->Size = System::Drawing::Size(75, 23); this->button2->TabIndex = 53; this->button2->Text = L"Print"; this->button2->UseVisualStyleBackColor = true; this->button2->Click += gcnew System::EventHandler(this, &Form1::button2_Click_1); // // docPrint // this->docPrint->DocumentName = L"ResultsPage"; this->docPrint->PrintPage += gcnew System::Drawing::Printing::PrintPageEventHandler(this, &Form1::docPrint_PrintPage); // // dlgPrint // this->dlgPrint->Document = this->docPrint; this->dlgPrint->UseEXDialog = true; // // dlgPrintPreview // this->dlgPrintPreview->AutoScrollMargin = System::Drawing::Size(0, 0); this->dlgPrintPreview->AutoScrollMinSize = System::Drawing::Size(0, 0); this->dlgPrintPreview->ClientSize = System::Drawing::Size(400, 300); this->dlgPrintPreview->Document = this->docPrint; this->dlgPrintPreview->Enabled = true; this->dlgPrintPreview->Icon = (cli::safe_cast<System::Drawing::Icon^ >(resources->GetObject(L"dlgPrintPreview.Icon"))); this->dlgPrintPreview->Name = L"dlgPrintPreview"; this->dlgPrintPreview->Visible = false; this->dlgPrintPreview->Load += gcnew System::EventHandler(this, &Form1::dlgPrintPreview_Load); private: System::Void docPrint_PrintPage(System::Object^ sender, System::Drawing::Printing::PrintPageEventArgs^ e) { String ^ strDisplay = L"A Axis Rotations"; String ^ strDisplay2 = L"Centerline of Y" + CL_Y->Text + " + Z" + CL_Z->Text; String ^ strDisplay3 = L"Initial Position Y" + G54_Y->Text + " + Z" + G54_Z->Text; System::Drawing::Font ^ fntString = gcnew System::Drawing::Font(L"Times New Roman", 38, FontStyle::Bold); e->Graphics->DrawString(strDisplay, fntString, Brushes::Black, 200,20); e->Graphics->DrawString(strDisplay2, fntString, Brushes::Black, 80,150); e->Graphics->DrawString(strDisplay3, fntString, Brushes::Black, 80,220); e->Graphics->DrawString(Results->Text, fntString,Brushes::Black, 50,400); } private: System::Void button2_Click_1(System::Object^ sender, System::EventArgs^ e) { // docPrint->Print; dlgPrintPreview->ShowDialog(); } private: System::Void dlgPrintPreview_Load(System::Object^ sender, System::EventArgs^ e) { } Sorry if the formatting is ugly here.

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• How can I model the data in a multi-language data editor in WPF with MVVM?

  - by Patrick Szalapski

  Are there any good practices to follow when designing a model/ViewModel to represent data in an app that will view/edit that data in multiple languages? Our top-level class--let's call it Course--contains several collection properties, say Books and TopicsCovered, which each might have a collection property among its data. For example, the data needs to represent course1.Books.First().Title in different languages, and course1.TopicsCovered.First().Name in different languages. We want a app that can edit any of the data for one given course in any of the available languages--as well as edit non-language-specific data, perhaps the Author of a Book (i.e. course1.Books.First().Author). We are having trouble figuring out how best to set up the model to enable binding in the XAML view. For example, do we replace (in the single-language model) each String with a collection of LanguageSpecificString instances? So to get the author in the current language: course1.Books.First().Author.Where(Function(a) a.Language = CurrentLanguage).SingleOrDefault If we do that, we cannot easily bind to any value in one given language, only to the collection of language values such as in an ItemsControl. <TextBox Text={Binding Author.???} /> <!-- no way to bind to the current language author --> Do we replace the top-level Course class with a collection of language-specific Courses? So to get the author in the current language: course1.GetLanguage(CurrentLanguage).Books.First.Author If we do that, we can only easily work with one language at a time; we might want a view to show one language and let the user edit the other. <TextBox Text={Binding Author} /> <!-- good --> <TextBlock Text={Binding ??? } /> <!-- no way to bind to the other language author --> Also, that has the disadvantage of not representing language-neutral data as such; every property (such as Author) would seem to be in multiple languages. Even non-string properties would be in multiple languages. Is there an option in between those two? Is there another way that we aren't thinking of? I realize this is somewhat vague, but it would seem to be a somewhat common problem to design for. Note: This is not a question about providing a multilingual UI, but rather about actually editing multi-language data in a flexible way.

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• How do I correct "Commit Failed. File xxx is out of date. xxx path not found."

  - by Ryan Taylor

  I have recently run into a particularly sticky issue regarding committing the result of a merge in subversion. Our Subversion server is @ 1.5.0 and my TortoiseSVN client is now @ 1.6.1. I am trying to merge a feature branch back into my trunk. The merge appears to work okay; however, the commit fails with the following error message. Commit failed (details follow): File 'flex/src/com/penbay/invision/portal/services/http/soap/ReportServices/GetAllBldgsParamsByRegionBySiteResultEvent.as' is out of date '/svn/ibis/!svn/wrk/531d459d-80fa-ea46-bfb4-940d79ee6d2e/visualization/trunk/source/flex/src/com/penbay/invision/portal/services/http/soap/ReportServices/GetAllBldgsParamsByRegionBySiteResultEvent.as' path not found You have to update your working copy first. My working trunk is up to date. I have even checked out a new one into a different folder to make sure there wasn't any local cruft messing with the merge. I have done some more research into this and I think part of the problem is user error. I think our problems are: We had some developers committing work with a subversion client before 1.5 and some after. I believe this has the potential to corrupt the merge info. In other branches we have performed partial merges. That is, we did not always perform merges at the root of the branch. This was to facilitate updating Flex and .NET efforts within the same branch. We performed cyclic (reflexive) merges on our branch. This was done because we had multiple parallel branches and we wanted to periodically update our branch with the latest code in trunk. All of these things are explicitly not recommended by the Subversion book/team. We have learned our lesson and now know the best practices. However, we first need to merge and commit our latest branch. What it the best way to correct the problems we are encountering? Would deleting all the merge info in the trunk and branch be a viable solution? No. I have done this but it does not resolve the error that I am getting above.

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• How to force VS 2010 to skip "builds" of projects which haven't changed?

  - by Ladislav Mrnka

  Our product's solution has more than 100+ projects (500+ksloc of production code). Most of them are C# projects but we also have few using C++/CLI to bridge communication with native code. Rebuilding the whole solution takes several minutes. That's fine. If I want to rebuilt the solution I expect that it will really take some time. What is not fine is time needed to build solution after full rebuild. Imagine I used full rebuild and know without doing any changes to to the solution I press Build (F6 or Ctrl+Shift+B). Why it takes 35s if there was no change? In output I see that it started "building" of each project - it doesn't perform real build but it does something which consumes significant amount of time. That 35s delay is pain in the ass. Yes I can improve the time by not using build solution but only build project (Shift+F6). If I run build project on particular test project I'm currently working on it will take "only" 8+s. It requires me to run project build on correct project (the test project to ensure dependent tested code is build as well). At least ReSharper test runner correctly recognizes that only this single project must be build and rerunning test usually contains only 8+s compilation. My current coding Kata is: don't touch Ctrl+Shift+B. The test project build will take 8s even if I don't do any changes. The reason why it takes 8s is because it also "builds" dependencies = in my case it "builds" more than 20 projects but I made changes only to unit test or single dependency! I don't want it to touch other projects. Is there a way to simply tell VS to build only projects where some changes were done and projects which are dependent on changed ones (preferably this part as another build option)? I worry you will tell me that it is exactly what VS is doing but in MS way ... I want to improve my TDD experience and reduce the time of compilation (in TDD the compilation can happen twice per minute). To make this even more frustrated I'm working in a team where most of developers used to work on Java projects prior to joining this one. So you can imagine how they are pissed off when they must use VS in contrast to full incremental compilation in Java. I don't require incremental compilation of classes. I expect working incremental compilation of solutions. Especially in product like VS 2010 Ultimate which costs several thousands dollars. I really don't want to get answers like: Make a separate solution Unload projects you don't need etc. I can read those answers here. Those are not acceptable solutions. We're not paying for VS to do such compromises.

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• python getelementbyid from string

  - by matthewgall

  Hey, I have the following program, that is trying to upload a file (or files) to an image upload site, however I am struggling to find out how to parse the returned HTML to grab the direct link (contained in a ). I have the code below: #!/usr/bin/python # -*- coding: utf-8 -*- import pycurl import urllib import urlparse import xml.dom.minidom import StringIO import sys import gtk import os import imghdr import locale import gettext try: import pynotify except: print "Please install pynotify." APP="Uploadir Uploader" DIR="locale" locale.setlocale(locale.LC_ALL, '') gettext.bindtextdomain(APP, DIR) gettext.textdomain(APP) _ = gettext.gettext ##STRINGS uploading = _("Uploading image to Uploadir.") oneimage = _("1 image has been successfully uploaded.") multimages = _("images have been successfully uploaded.") uploadfailed = _("Unable to upload to Uploadir.") class Uploadir: def __init__(self, args): self.images = [] self.urls = [] self.broadcasts = [] self.username="" self.password="" if len(args) == 1: return else: for file in args: if file == args[0] or file == "": continue if file.startswith("-u"): self.username = file.split("-u")[1] #print self.username continue if file.startswith("-p"): self.password = file.split("-p")[1] #print self.password continue self.type = imghdr.what(file) self.images.append(file) for file in self.images: self.upload(file) self.setClipBoard() self.broadcast(self.broadcasts) def broadcast(self, l): try: str = '\n'.join(l) n = pynotify.Notification(str) n.set_urgency(pynotify.URGENCY_LOW) n.show() except: for line in l: print line def upload(self, file): #Try to login cookie_file_name = "/tmp/uploadircookie" if ( self.username!="" and self.password!=""): print "Uploadir authentication in progress" l=pycurl.Curl() loginData = [ ("username",self.username),("password", self.password), ("login", "Login") ] l.setopt(l.URL, "http://uploadir.com/user/login") l.setopt(l.HTTPPOST, loginData) l.setopt(l.USERAGENT,"User-Agent: Uploadir (Python Image Uploader)") l.setopt(l.FOLLOWLOCATION,1) l.setopt(l.COOKIEFILE,cookie_file_name) l.setopt(l.COOKIEJAR,cookie_file_name) l.setopt(l.HEADER,1) loginDataReturnedBuffer = StringIO.StringIO() l.setopt( l.WRITEFUNCTION, loginDataReturnedBuffer.write ) if l.perform(): self.broadcasts.append("Login failed. Please check connection.") l.close() return loginDataReturned = loginDataReturnedBuffer.getvalue() l.close() #print loginDataReturned if loginDataReturned.find("<li>Your supplied username or password is invalid.</li>")!=-1: self.broadcasts.append("Uploadir authentication failed. Username/password invalid.") return else: self.broadcasts.append("Uploadir authentication successful.") #cookie = loginDataReturned.split("Set-Cookie: ")[1] #cookie = cookie.split(";",0) #print cookie c = pycurl.Curl() values = [ ("file", (c.FORM_FILE, file)) ] buf = StringIO.StringIO() c.setopt(c.URL, "http://uploadir.com/file/upload") c.setopt(c.HTTPPOST, values) c.setopt(c.COOKIEFILE, cookie_file_name) c.setopt(c.COOKIEJAR, cookie_file_name) c.setopt(c.WRITEFUNCTION, buf.write) if c.perform(): self.broadcasts.append(uploadfailed+" "+file+".") c.close() return self.result = buf.getvalue() #print self.result c.close() doc = urlparse.urlparse(self.result) self.urls.append(doc.getElementsByTagName("download")[0].childNodes[0].nodeValue) def setClipBoard(self): c = gtk.Clipboard() c.set_text('\n'.join(self.urls)) c.store() if len(self.urls) == 1: self.broadcasts.append(oneimage) elif len(self.urls) != 0: self.broadcasts.append(str(len(self.urls))+" "+multimages) if __name__ == '__main__': uploadir = Uploadir(sys.argv) Any help would be gratefully appreciated. Warm regards,

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• Opinion on "loop invariants", and are these frequently used in the industry?

  - by Michael Aaron Safyan

  I was thinking back to my freshman year at college (five years ago) when I took an exam to place-out of intro-level computer science. There was a question about loop invariants, and I was wondering if loop invariants are really necessary in this case or if the question was simply a bad example... the question was to write an iterative definition for a factorial function, and then to prove that the function was correct. The code that I provided for the factorial function was as follows: public static int factorial(int x) { if ( x < 0 ){ throw new IllegalArgumentException("Parameter must be = 0"); }else if ( x == 0 ){ return 1; }else{ int result = 1; for ( int i = 1; i <= x; i++ ){ result*=i; } return result; } } My own proof of correctness was a proof by cases, and in each I asserted that it was correct by definition (x! is undefined for negative values, 0! is 1, and x! is 1*2*3...*x for a positive value of x). The professor wanted me to prove the loop using a loop invariant; however, my argument was that it was correct "by definition", because the definition of "x!" for a positive integer x is "the product of the integers from 1... x", and the for-loop in the else clause is simply a literal translation of this definition. Is a loop invariant really needed as a proof of correctness in this case? How complicated must a loop be before a loop invariant (and proper initialization and termination conditions) become necessary for a proof of correctness? Additionally, I was wondering... how often are such formal proofs used in the industry? I have found that about half of my courses are very theoretical and proof-heavy and about half are very implementation and coding-heavy, without any formal or theoretical material. How much do these overlap in practice? If you do use proofs in the industry, when do you apply them (always, only if it's complicated, rarely, never)?

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• Browser displays page without styles for a short moment (visual glitch)

  - by Pierre

  I have observed that, very infrequently, Internet Explorer (7 or 8, it does not matter) displays our web pages (www.epsitec.ch) a short time without applying the CSS. The layout appears completely broken, with everything displayed sequentially from top to bottom. When the page has finished loading, everything finally gets displayed properly. Our web pages do not use any fancy scripting, just two javascript inclusions for QuantCast and Google Analytics, done at the end of the page. By the way, we already had the issue before adding the QuantCast script. The CSS gets linked in the <head> section: <head> <title>Crésus Comptabilité</title> <link rel="icon" href="/favicon.ico" type="image/x-icon" /> <link rel="shortcut icon" href="http://www.epsitec.ch/favicon.ico" /> <link href="../../style.css" rel="stylesheet" type="text/css" /> ... </head> and then follows static HTML up to the final chunk which includes the JavaScript: ... <div id="account"> <a class="deselect" href="/account/login">Identifiez-vous</a> <script type="text/javascript"> _qoptions={qacct:"..."}; </script> <script type="text/javascript" src="http://edge.quantserve.com/quant.js"> </script> <noscript> <img src="..." style="display: none;" border="0" height="1" width="1"/> </noscript> </div> <div id="contact"> <a href="/support/contact">Contactez-nous</a> </div> <div id="ending"><!-- --></div> </div> <script type="text/javascript"> ... </script> <script type="text/javascript"> var pageTracker = _gat._getTracker("..."); pageTracker._initData(); pageTracker._trackPageview(); </script> </body> As this is a very short visual glitch, I have no idea what provokes it. Worse, I cannot reproduce it and it appears only on seldom occasions. How can I further investigate the cause of the glitch? Are there any best practices I should be aware of?

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