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• how to commit 'commit log' itself in same svn version?

  - by understack

  It might sound unnecessary, but let me explain my problem first. Probably then it would make sense. Few artists keep updating images based on clients' change requests. An artist makes changes accordingly and commits with proper 'commit messages'. Just before actual commit, I want to create a text file with image properties like size and all the 'commit messages'. And then this file would be committed itself. So basically some sort of pre-commit processing is required. Even though most of the artists are not very comfortable with svn, they can always see what changes were made last time to the image via simple text file. So artists only do update and commit with svn. How this could be done? Are there any better alternatives?

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• What are the pros and cons of using an in memeory DB rather than a ThreadLocal

  - by Pangea

  we have been using ThreadLocal so far to carry some data so as to not clutter the API. However below are some of issues of using thread local that which I dont like 1) over the years the data items being carried in thread local has increased 2) Since we started using threads (for some light weight processing), we have also migrating these data to the threads in the pool and copying them back again I am thinking of using an in memory DB for these (we doesnt want to add this to the API). I wondering if this approach is good. What r the pros and cons. thx in advance.

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• Performance Tricks for C# Logging

  - by Charles

  I am looking into C# logging and I do not want my log messages to spend any time processing if the message is below the logging threshold. The best I can see log4net does is a threshold check AFTER evaluating the log parameters. Example: _logger.Debug( "My complicated log message " + thisFunctionTakesALongTime() + " will take a long time" ) Even if the threshold is above Debug, thisFunctionTakesALongTime will still be evaluated. In log4net you are supposed to use _logger.isDebugEnabled so you end up with if( _logger.isDebugEnabled ) _logger.Debug( "Much faster" ) I want to know if there is a better solution for .net logging that does not involve a check each time I want to log. In C++ I am allowed to do LOG_DEBUG( "My complicated log message " + thisFunctionTakesALongTime() + " will take no time" ) since my LOG_DEBUG macro does the log level check itself. This frees me to have a 1 line log message throughout my app which I greatly prefer. Anyone know of a way to replicate this behavior in C#?

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• Multiple Socket Connections

  - by BSchlinker

  I need to write a server which accepts connections from multiple client machines, maintains track of connected clients and sends individual clients data as necessary. Sometimes, all clients may be contacted at once with the same message, other times, it may be one individual client or a group of clients. Since I need confirmation that the clients received the information and don't want to build an ACK structure for a UDP connection, I decided to use a TCP streaming method. However, I've been struggling to understand how to maintain multiple connections and keep them idle. I seem to have three options. Use a fork for each incoming connection to create a separate child process, use pthread_create to create an entire new thread for each process, or use select() to wait on all open socket IDs for a connection. Recommendations as to how to attack this? I've begun working with pthreads but since performance will likely not be an issue, multicore processing is not necessary and perhaps there is a simpler way.

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• Problem updating a database field from my controller

  - by ben

  I have an update method in my users controller that I call from a HTTPService in Flex 4. The update method is as follows: def updateName @user = User.find_by_email(params[:email]) @user.name = params[:nameNew] render :nothing => true end This is console output: Processing UsersController#updateName (for 127.0.0.1 at 2010-05-24 14:12:49) [POST] Parameters: {"action"="updateName", "nameNew"="ben", "controller"="users", "email"="[email protected]"} User Load (0.6ms) SELECT * FROM "users" WHERE ("users"."email" = '[email protected]') LIMIT 1 Completed in 20ms (View: 1, DB: 1) | 200 OK [http://localhost/users/updateName] But when I check my database, the name field is never updated. What am I doing wrong? Thanks for reading.

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• Stop applet execution on load, pause/resume using javascript?

  - by Zane

  I'm making something of a java applet gallery for my website (processing applets, if you're interested) and I'd like to keep the applets from running when the sit first loads. Then, when the appropriate button is clicked, a piece of javascript would tell the applet to continue execution until another button is pressed to stop it. I know that I can use appletName.start() and appletName.stop(), but it doesn't seem to work on load, at least not well. I'm using element.getElementsById( "applet" ) to get the applets to use the start and stop methods on. It slows Firefox to a crawl for some reason.

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• How to properly close a socket after an exception is caught?

  - by marco

  Hello, after my last project I had the problem that the client was expecting an object from the server, but while processing the clients input an exception that forces the server to close the socket for security reasons is caught. This causes the client to terminate in a very unpleasant way, the way I decided to deal with this was sending the client a Input status message after each recieved input so that he knows if his input was processed properly or if he needs to throw an exception. So my question: Is there a better/cleaner way to close the socket after an exception is caught?? thanks,

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• Cannot easy_install readline for Python 2.7.3 on Mac Os Lion

  - by user11170

  I am trying to install readline for python 2.7.3 installed via homebrew. If I type easy_install readline I get Downloading http://pypi.python.org/packages/source/r/readline/readline-6.2.2.tar.gz#md5=ad9d4a5a3af37d31daf36ea917b08c77 Processing readline-6.2.2.tar.gz Writing /var/folders/44/dhrdb5sx53s243j4w03063vh0000gn/T/easy_install-64FbG8/readline-6.2.2/setup.cfg Running readline-6.2.2/setup.py -q bdist_egg --dist-dir /var/folders/44/dhrdb5sx53s243j4w03063vh0000gn/T/easy_install-64FbG8/readline-6.2.2/egg-dist-tmp-NOmStB clang: error: no such file or directory: 'readline/libreadline.a' clang: error: no such file or directory: 'readline/libhistory.a' error: Setup script exited with error: command '/usr/bin/clang' failed with exit status 1 Any ideas about how I could fix this ? Thanks

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• How to pre-process CSV data for FasterCSV?

  - by Katherine Chalmers

  We're having a significant number of problems creating a bulk upload function for our little app. We're using the FasterCSV gem to upload data to a MySQL database but he Faster CSV is so twitchy and precise in its requirements that it constantly breaks with malformed CSV errors and time out errors. The csv files are generally created by users' pasting text from their web sites or from Microsoft Word docs so it is not reasonable to expect that there will never be odd characters like smart quotes or accents in the data. Also users aren't going to be readily able to identify whether their data is perfect enough for FasterCSV or not. We need to find a way to fix it for them automatically. Is there a good way or a reliable tool for pre-processing CSV data to fix any nits in the data before having the FasterCSV gem process it?

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• Converting raw bytes into audio sound

  - by Afro Genius

  In my application I inherit a javastreamingaudio class from the freeTTS package then bypass the write method which sends an array of bytes to the SourceDataLine for audio processing. Instead of writing to the data line, I write this and subsequent byte arrays into a buffer which I then bring into my class and try to process into sound. My application processes sound as arrays of floats so I convert to float and try to process but always get static sound back. I am sure this is the way to go but am missing something along the way. I know that sound is processed as frames and each frame is a group of bytes so in my application I have to process the bytes into frames somehow. Am I looking at this the right way? Thanx in advance for any help.

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• paperclip callbacks or simple processor?

  - by holden

  I wanted to run the callback after_post_process but it doesn't seem to work in Rails 3.0.1 using Paperclip 2.3.8. It gives an error: undefined method `_post_process_callbacks' for #<Class:0x102d55ea0> I want to call the Panda API after the file has been uploaded. I would have created my own processor for this, but as Panda handles the processing, and it can upload the files as well, and queue itself for an undetermined duration I thought a callback would do fine. But the callbacks don't seem to work in Rails3. after_post_process :panda_create def panda_create video = Panda::Video.create(:source_url => mp3.url.gsub(/[?]\d*/,''), :profiles => "f4475446032025d7216226ad8987f8e9", :path_format => "blah/1234") end I tried require and include for paperclip in my model but it didn't seem to matter. Anyideas?

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• Tarballing without git metadata

  - by zaf

  My source tree contains several directories which are using git source control and I need to tarball the whole tree excluding any references to the git metadata or custom log files. I thought I'd have a go using a combo of find/egrep/xargs/tar but somehow the tar file contains the .git directories and the *.log files. This is what I have: find -type f . | egrep -v '\.git|\.log' | xargs tar rvf ~/app.tar Can someone explain my misunderstanding here? Why is tar processing the files that find and egrep are filtering? I'm open to other techniques as well.

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• Current state of client-side XSLT

  - by Casey

  Last I heard, Blizzard was one of the few companies to put client-side XSLT into practice (2008). Is this still the case in 2011, or are more people now exploring this technique in production?  It seems that modern browsers (IE9, FF4, Chrome) and client processing power are primed to exploit this standard for tangible savings in server CPU power and bandwidth on large scale properties. Am I missing something? The negative aspects I'm aware of include * additional rendering time * additional assets required on uncached page load * additional layer of complexity * noticably less developer experience than server-side template techniques The benefits I perceive include * distributed template composition (offloaded on the client) * caching of common template fragments offloaded on the client * logical separation of document structure and data * well-documented web standard supported by all modern browsers Finally, although I know it's impossible to predict the future, I am curious to know opinions on whether or not client-side XSLT's day will come. With interest in HTML5 driving users to upgrade their browsers and developers to explore new techniques, I would say yes. How about you? Thanks in advance, Casey

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• BackgroundWorker vs background Thread

  - by freddy smith

  I have a stylistic question about the choice of background thread implementation I should use on a windows form app. Currently I have a BackgroundWorker on a form that has an infinite (while(true)) loop. In this loop I use WaitHandle.WaitAny to keep the thread snoozing until something of interest happens. One of the event handles I wait on is a "stopthread" event so that I can break out of the loop. This event is signaled when from my overridden Form.Dispose(). I read somewhere that BackgroundWorker is really intended for operations that you dont want to tie up the UI with and have an finite end - like downloading a file, or processing a sequence of items. In this case the "end" is unknown and only when the window is closed. Therefore would it be more appropriate for me to use a background Thread instead of BackgroundWorker for this purpose?

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• Object tree navigation language in Java

  - by lewap

  In the system which I'm currently developing I often have to navigate an object tree and based on its state and values take actions. In normal Java this results in tedious for loops, if statements etc... Are there alternative ways to achieve tree navigation, similar to XPath for XML? I know there is JXPath and OGNL, but do you know any other libraries for such purpose? Do you know any libraries which generate bytecodes for specific tree navigation expressions to make the processing as fast as Java native fors and ifs?

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• Verify my form workflow

  - by Shackrock

  I have a form, with some sensitive info (CC numbers). My work flow is: One page to take all form items Upon submission, values are validated. If all is well, all data is stored in a session variable, and the page reloads and displays this info from the session variable. If everything is ok on the review page, the user clicks submit and the session variable is sent to another form for processing (sending payment). Upon success, the session is destroyed. Upon failure (bad CC number, for example) - the user is sent back to the form, with all of the fields filled in just like before, so that they can check for errors and try again (session is NOT destroyed). Does anyone see anything wrong with this, from a security or best practices stand point? UPDATE I'm thinking I can get rid of a step - storing the info in a session EVER. Just have a one page checkout, no review page... makes sense.

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• Fast single thread comet server, possible?

  - by Pepijn

  I recently encountered a few cases where a server would distribute an event stream that contains the exact same data for all listeners, such as a 'recent activity' box. It occurred to me that it is quite strange and inefficient to have a server like Apache run a thread processing and querying the database for every single comet stream containing the same data. What I would do for those global(not per user) streams is run a single thread that continuously emits data, and a new (green)thread for every new request that outputs the headers and then 'merges' into the main thread. Is it possible for one thread to serve multiple sockets, or for multiple clients to listen to the same socket? An example o = event # threads received | a b # 3 o / / # 3 - |/_/ | # 1 o c # 2 a, b | / o/ # 2 a, b o # 1 a, b, c | # connection b closed o # 1 a, c Does something like this exist? Would it work? Is it possible to do? Disclaimer: I'm not a server expert.

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• Using Windows media foundation

  - by Martin Beckett

  Ok so my new gig is high performance video (think Google streetview but movies) - the hard work is all embedded capture and image processing but: I was looking at the new MS video offerings to display content = Windows Media Foundation. Is anyone actually using this ? There are no books on the topic. The only documentation is a developer team blog with a single entry 9 months old. I thought we had got past having to learn an MS api by spying on the com control messages! Is it just another wrapper around the same old activeX control?

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• Multiple merchant accounts with Activemerchant gem.

  - by sosborn

  I am developing a rails site that will allow a group of merchants (5 - 10) to accept credit card orders online. I plan on using the Activemerchant gem to handle the processing. In this case, each merchant will have their own merchant accounts to handle the payments. Storing banking information like that is not something I am a fan of. This could be solved by queing orders and allowing the merchant to log in to the site, input their credentials and process the order. However, if I go that route then it seems to me that I would have to store the customers' credit card information temporarily until the merchant has the opportunity to log in and process the order, which to me is the greater evil. Has anyone dealt with this situation? If so, what are the options available and what pitfalls should I look out for? In my mind, security customer credit card information is priority number one with the merchant account information a close second.

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• How can I reuse my javascript code between client and server?

  - by Chris Farmer

  I have some javascript code that includes an ANTLR-generated lexer and parser, and some associated syntax tree evaluation functionality. This code runs in the browser in my web app to support users who author code snippets which process scientific data. Now I'd like to do some additional background processing on the server using the same generated parser. I would prefer not to have to re-implement this stuff in C# and have multiple bits of code that did the exact same thing. Performance isn't as critical to me as eliminating duplication, since this is a background process. So, how can I call into my javascript code from C#? And how can I format my script so that it plays nicely with my .NET web app?

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• Performance logging tips

  - by Germstorm

  I am developing large data collecting ASP.Net/Windows service application-pair that uses Microsoft SQL Server 2005 through LINQ2Sql. Performance is always the issue. Currently the application is divided into multiple larger processing parts, each logging the duration of their work. This is not detailed and does not help us with anything. It would be nice to have some database tables that contain statistics that the application itself collected from its own behavior. What logging tips and data structures do you recommend to spot the parts that cause performance problems?

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• How do I do an AJAX post to a url within a class library but not the same IIS Web Application?

  - by Mark Adesina

  I have been working with ajax and there has been no problems below is how my ajax post code look like: $.ajax({ type: "POST", url: '<%=ResolveUrl("TodoService.asmx/CreateNewToDo")%>', data: jsonData, contentType: "application/json; charset=utf-8", datatype: "json", success: function () { //if (msg.d) { $('#ContentPlaceHolder1_useridHiddenField').val(""); $('#ContentPlaceHolder1_titleTextBox').val(""); $('#ContentPlaceHolder1_destTextBox').val(""); $('#ContentPlaceHolder1_duedateTextBox').val(""); alert('Your todo has been saved'); // } }, error: function (msg) { alert('There was an error processing your request'); } }); However, the problem came up when I try to get the url to a webservice that is located in a class library within the same solution.

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• Dealing with external processes

  - by Jesse Aldridge

  I've been working on a gui app that needs to manage external processes. Working with external processes leads to a lot of issues that can make a programmer's life difficult. I feel like maintenence on this app is taking an unacceptably long time. I've been trying to list the things that make working with external processes difficult so that I can come up with ways of mitigating the pain. This kind of turned into a rant which I thought I'd post here in order to get some feedback and to provide some guidance to anybody thinking about sailing into these very murky waters. Here's what I've got so far: Output from the child can get mixed up with output from the parent. This can make both outputs misleading and hard to read. It can be hard to tell what came from where. It becomes harder to figure out what's going on when things are asynchronous. Here's a contrived example: import textwrap, os, time from subprocess import Popen test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) proc = Popen('python -B "%s"' % test_path) for i in range(3): print 'Hello %i' % i time.sleep(1) os.remove(test_path) I guess I could have the child process write its output to a file. But it can be annoying to have to open up a file every time I want to see the result of a print statement. If I have code for the child process I could add a label, something like print 'child: Hello %i', but it can be annoying to do that for every print. And it adds some noise to the output. And of course I can't do it if I don't have access to the code. I could manually manage the process output. But then you open up a huge can of worms with threads and polling and stuff like that. A simple solution is to treat processes like synchronous functions, that is, no further code executes until the process completes. In other words, make the process block. But that doesn't work if you're building a gui app. Which brings me to the next problem... Blocking processes cause the gui to become unresponsive. import textwrap, sys, os from subprocess import Popen from PyQt4.QtGui import * from PyQt4.QtCore import * test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) app = QApplication(sys.argv) button = QPushButton('Launch process') def launch_proc(): # Can't move the window until process completes proc = Popen('python -B "%s"' % test_path) proc.communicate() button.connect(button, SIGNAL('clicked()'), launch_proc) button.show() app.exec_() os.remove(test_path) Qt provides a process wrapper of its own called QProcess which can help with this. You can connect functions to signals to capture output relatively easily. This is what I'm currently using. But I'm finding that all these signals behave suspiciously like goto statements and can lead to spaghetti code. I think I want to get sort-of blocking behavior by having the 'finished' signal from QProcess call a function containing all the code that comes after the process call. I think that should work but I'm still a bit fuzzy on the details... Stack traces get interrupted when you go from the child process back to the parent process. If a normal function screws up, you get a nice complete stack trace with filenames and line numbers. If a subprocess screws up, you'll be lucky if you get any output at all. You end up having to do a lot more detective work everytime something goes wrong. Speaking of which, output has a way of disappearing when dealing external processes. Like if you run something via the windows 'cmd' command, the console will pop up, execute the code, and then disappear before you have a chance to see the output. You have to pass the /k flag to make it stick around. Similar issues seem to crop up all the time. I suppose both problems 3 and 4 have the same root cause: no exception handling. Exception handling is meant to be used with functions, it doesn't work with processes. Maybe there's some way to get something like exception handling for processes? I guess that's what stderr is for? But dealing with two different streams can be annoying in itself. Maybe I should look into this more... Processes can hang and stick around in the background without you realizing it. So you end up yelling at your computer cuz it's going so slow until you finally bring up your task manager and see 30 instances of the same process hanging out in the background. Also, hanging background processes can interefere with other instances of the process in various fun ways, such as causing permissions errors by holding a handle to a file or someting like that. It seems like an easy solution to this would be to have the parent process kill the child process on exit if the child process didn't close itself. But if the parent process crashes, cleanup code might not get called and the child can be left hanging. Also, if the parent waits for the child to complete, and the child is in an infinite loop or something, you can end up with two hanging processes. This problem can tie in to problem 2 for extra fun, causing your gui to stop responding entirely and force you to kill everything with the task manager. F***ing quotes Parameters often need to be passed to processes. This is a headache in itself. Especially if you're dealing with file paths. Say... 'C:/My Documents/whatever/'. If you don't have quotes, the string will often be split at the space and interpreted as two arguments. If you need nested quotes you can use ' and ". But if you need to use more than two layers of quotes, you have to do some nasty escaping, for example: "cmd /k 'python \'path 1\' \'path 2\''". A good solution to this problem is passing parameters as a list rather than as a single string. Subprocess allows you to do this. Can't easily return data from a subprocess. You can use stdout of course. But what if you want to throw a print in there for debugging purposes? That's gonna screw up the parent if it's expecting output formatted a certain way. In functions you can print one string and return another and everything works just fine. Obscure command-line flags and a crappy terminal based help system. These are problems I often run into when using os level apps. Like the /k flag I mentioned, for holding a cmd window open, who's idea was that? Unix apps don't tend to be much friendlier in this regard. Hopefully you can use google or StackOverflow to find the answer you need. But if not, you've got a lot of boring reading and frusterating trial and error to do. External factors. This one's kind of fuzzy. But when you leave the relatively sheltered harbor of your own scripts to deal with external processes you find yourself having to deal with the "outside world" to a much greater extent. And that's a scary place. All sorts of things can go wrong. Just to give a random example: the cwd in which a process is run can modify it's behavior. There are probably other issues, but those are the ones I've written down so far. Any other snags you'd like to add? Any suggestions for dealing with these problems?

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• telling java to accept self-signed ssl certificate

  - by Nikita Rybak

  It looks like a standard question, but I couldn't find clear directions anywhere. I have java code trying to connect server with probably self-signed (or expired) certificate. It gives something like this [HttpMethodDirector] I/O exception (javax.net.ssl.SSLHandshakeException) caught when processing request: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target As I understand, I have to play around with keytool and tell java that it's ok to allow this connection. But all comments I've found assume I'm fully proficient with keytool, like "generate private key for server and import it into keystore". And I'm not. Is there anybody who could post detailed instructions? I'm running unix, so bash script would be best. Not sure if it's important, but code executed in jboss. Thanks a lot!

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• Recordset manipulation in SSIS

  - by JSacksteder

  In my SSIS job, I have a need to accumulate a set of rows and commit them all transitionally when processing has completed successfully. If this was pure SQL, I would use a temp table inside a transaction. In SSIS there are a number of issues complicating this. It's difficult to have multiple components share the same transaction and having temp tables that do not exist at design time is a pain. If I use Recordsets inside SSIS for this purpose, there are other issues. My understanding is that an 'Execute SQL' component will re-initialize the Recordset when it runs, so I can't use that to append an additional row. Is there a way to create an OLE DB connection that references an in-memory Recordset? Is there a better way to achieve this result?

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