Performance Testing in JavaScript

Fast pages and quick load times are key factors to keeping visitors on your site.
If you make them wait, they will leave.

So the speed of your JavaScript applications is crucial.

Fortunately, it turns out that JavaScript applications are ripe for performance optimization.

This requires a strong testing framework... enter JSTR.

String Concatenation Performance

A simple example of the type of benefit available from performance testing can come from testing String concatenation.

Javascript allows the use of "+" to concatenate Strings, but it turns out to be rather inefficient if you are building a very big string, eg: dynamically building HTML from AJAX.

Instead, the use of a Array (wrapped to provide a StringBuffer object) provides a huge boost in performance.

[cc lang="javascript" tab_size="2" lines="40"]
function StringBuffer() {
this.buffer = [];
}

StringBuffer.prototype.append = function append(string) {
this.buffer.push(string);
return this;
};

StringBuffer.prototype.toString = function toString() {
return this.buffer.join("");
};

var buf = new StringBuffer();
buf.append("this is being added");
alert(buf.toString());
[/cc]

To test this against a normal concatenation:
Copy the String below, and then paste it into the IMPORT function in JSTR.

[cc lang="javascript" tab_size="2" lines="40"] jstr_StringBuffer=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 [/cc]

Just to give you an idea...
StringBuffer is just faster for short strings
and about 50 times faster for long strings...!

My thanks to Pavel Simakov for this.

A 'foolish' new tool for Javascript

I have been dying to shout about this...

instead I have been waiting very patiently...

BUT now it is time to SHOUT!

JSTR(Jester) is out of the box!

JSTR is the first 'Browser based' (ie:Cross-browser ):

• Testing


• Benchmarking


• Optimization

tool for javascript.

With both import & export of Test-Sets, as well as auto-generated URLs, JSTR lets you easily share your code with everyone else, so they can try it for themselves.

Now, when you write about your new discovery, put a link to the test-set in your blog and let everyone else actually try it.

Find out about the new funny man for JavaScript.

Watch the video to learn more

Fixing an error building my first carbide.c++ project

I installed the Carbide.C++ IDE today, followed the tutorial instructions but got an error when I went to build the project.

Error: "bldmake returned with exit value = 2"

A little digging later and I found the solution...

Open a CMD prompt to the group folder of my project and run:

"bldmake bldfiles"

It told me that bldmake.pl was unable to be run...

Even though I have perl installed.

So now I know I have a problem with my perl install.

The simple fix was installing ActivePerl as originally suggested.

Now it works.

Secure your phpinfo from the bad people

I use the phpinfo() function a great deal, for basic information to advanced server administration checking, so I like to have it running on all my hosts.

Unfortunately this is a great hole in my security, as this information is a gold mine for the hackers out there.

I could simply remove the file when I am finished, or obfuscate the filename to make it difficult to find. But both of these would rather destroy the ease and simplicity I am looking for.

So, I decided to sort this out today.

The solution I am using is simple. Basic HTTP Auth.

Just enough to deter any would be hackers, as no-one can see how complicated my security is behind this shield. And, this should work on all PHP servers.

Here is the code.

[cc lang="php" tab_size="2" lines="40"]
function authenticate($uid,$pw) {
if (
!isset($_SERVER['PHP_AUTH_USER']) ||
!isset($_SERVER['PHP_AUTH_PW']) ||
$_SERVER['PHP_AUTH_USER'] != $uid ||
$_SERVER['PHP_AUTH_PW'] != $pw
){
header('WWW-Authenticate: Basic realm="Security Check"');
header('HTTP/1.0 401 Unauthorized');
echo "You must enter a valid login ID and password to access this resource\n";
exit;
}
if($pw == "password"){
echo "You must change the 'password' before you can have access to this...";
exit;
}
}
authenticate("admin","password");
phpinfo();
[/cc]

And a zipped version.

If you have a standard file with phpinfo() in it...
I highly suggest you start using this.