Supernifty - nifty stuff » hack

JavaScript Task Queue – Hack it #9

peter — Sun, 17 Jul 2011 04:28:37 +0000

Suppose you have a lot of tasks with completion callbacks to complete in the browser, but you want to do them sequentially. For instance, you might have a list of AJAX requests to make to your server.

This JavaScript demonstrates a simple solution:

If you can’t see the source code, look here.

Ultra Simple PHP Profiling – Hack it #8

peter — Tue, 09 Nov 2010 07:25:08 +0000

We wanted to profile a few PHP scripts, so we tried xdebug, but there were a few issues:

Not suitable for a production server
Difficult to turn on/off for specific scripts and requests
Difficult to profile MySQL queries, without also attracting a mass of other data

xdebug is better for offline application profiling.

If you just want to track down a bottleneck, or see what your script is spending all its time doing, here’s a simple alternative.

To profile your SQL, replace mysql_query with mysql_queryx.

This generates a CSV file at /tmp/profile.1 for easy analysis.

Now create the file profile.php:

Too easy!

To stop profiling a page, set $profile = false.

If you’re concerned about performance, do something like $profile = rand(0, 100) > 99.

py2exe, python 2.6 and wxPython – hack it #7

peter — Tue, 06 Jul 2010 09:20:25 +0000

If you’ve tried to build a client application with Python 2.6 and wxPython, you might hit a problem.

Python 2.6 no longer includes the Visual Studio dependencies required by wxPython. These dependencies may not be present, either on your build machine, or the target user’s machine.

When building with py2exe, you may encounter an error similar to:

error: MSVCP90.dll: No such file or directory

The solution!

To successfully build your executable, you need the Visual Studio 2008 redistributable package, which can be obtained from Microsoft. Run this on your build machine to install the appropriate DLLs.

If your build still fails, you may need to copy the DLLs into your build directory. Locate msvcp90.dll, msvcm90.dll and msvcr90.dll on your machine and copy them to the build directory.

Once you have a successful Python build, you also want your executable to run on the target machine. To do this, your install script needs to install the vcredist package as part of the installation.

The command you need to run as part of your client installation is:

vcredist_x86.exe /q:a

If you are using NSIS as your installer, the appropriate code is:

File /r vcredist_x86.exe ;to copy the file
ExecWait ‘”$INSTDIR\vcredist_x86.exe” /q:a”‘ ;to install

With the Visual Studio redistributable installed, it will now execute successfully on the target machine. Hurrah!