Frequently Asked Questions: 2011

Friday, December 30, 2011

HTML Printing & Page Breaks

<html>
<head>
<style>
@page { size 8.5in 11in; margin: 2cm }
div.page { page-break-after: always }
</style>
</head>
<body>
<div class="page">Page 1 Here</div>
<div class="page">Page 2 Here</div>
</body>
</html>

Thursday, December 22, 2011

Optimize Your Site With GZIP Compression

In Apache, enabling output compression is fairly straightforward. Add the following to your .htaccess file:


# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

# Or, compress certain file types by extension:
<files *.html>
SetOutputFilter DEFLATE
</files>

Apache actually has two compression options:

mod_deflate is easier to set up and is standard.
mod_gzip seems more powerful: you can pre-compress content.

Deflate is quick and works, so I use it; use mod_gzip if that floats your boat. In either case, Apache checks if the browser sent the "Accept-encoding" header and returns the compressed or regular version of the file. However, some older browsers may have trouble (more below) and there are special directives you can add to correct this.
If you can't change your .htaccess file, you can use PHP to return compressed content. Give your HTML file a .php extension and add this code to the top:

In PHP:
<?php if (substr_count($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip')) ob_start("ob_gzhandler"); else ob_start(); ?>

We check the "Accept-encoding" header and return a gzipped version of the file (otherwise the regular version). This is almost like building your own webserver (what fun!). But really, try to use Apache to compress your output if you can help it. You don't want to monkey with your files.

Verify Your Compression

Once you've configured your server, check to make sure you're actually serving up compressed content.

Online: Use the online gzip test to check whether your page is compressed.
In your browser: Use Web Developer Toolbar > Information > View Document Size (like I did for Yahoo, above) to see whether the page is compressed.
View the headers: Use Live HTTP Headers to examine the response. Look for a line that says "Content-encoding: gzip".

Reference: http://betterexplained.com/articles/how-to-optimize-your-site-with-gzip-compression/

Creating image thumbnails using PHP

Sometimes restricting images size is required. Following function is very useful to create images of certain sizes on the fly

function createThumbs($source, $dest, $requiredWidth, $requiredHeight, $fileType='')
{
    $size = getimagesize($source);
    $givenWidth = $size[0];
    $givenHeight = $size[1];

    if ($givenWidth > 800)
    {
        $requiredRatio = $requiredWidth / $requiredHeight;
        $middleWidth = ceil($givenHeight * $requiredRatio);
        if($middleWidth>$givenWidth){
            $requiredRatio = $requiredHeight / $requiredWidth;
            $middleHeight = ceil($givenWidth * $requiredRatio);
            $middleWidth = $givenWidth;
            $y = ceil(($givenHeight - $middleHeight)/2);
        }
        else{
            $middleHeight = $givenHeight;
            $middleWidth = ceil($givenHeight * $requiredRatio);
            $x = ceil(($givenWidth - $middleWidth)/2);
        }

        $new_im = imagecreatetruecolor($requiredWidth,$requiredHeight);

        $extention = strtolower(substr($source, strlen($source)-3, strlen($source)));
        if ($extention == "jpg" || $extention == "jpeg") { $im = imagecreatefromjpeg($source); }
        elseif ($extention == "gif") { $im = imagecreatefromgif($source); }
        elseif ($extention == "png") { $im = imagecreatefrompng($source); }
        else
        {
            //echo("ERROR: Unknown image source file format");
            return;
        }

        imagecopyresampled($new_im,$im,0,0,$x,$y,$requiredWidth,$requiredHeight,$middleWidth,$middleHeight);
        imagejpeg($new_im,$dest,85);
    }
}

Thursday, November 3, 2011

Redirect to www .htaccess

Create a .htaccess file with the below code, it will ensure that all requests coming in to domain.com will get redirected to www.domain.com
The .htaccess file needs to be placed in the root directory of your old website (i.e the same directory where your index file is placed)

Options +FollowSymlinks
RewriteEngine on
rewritecond %{http_host} ^domain.com [nc]
rewriterule ^(.*)$ http://www.domain.com/$1 [r=301,nc]

Please REPLACE domain.com and www.newdomain.com with your actual domain name.

Note* This .htaccess method of redirection works ONLY on Linux servers having the Apache Mod-Rewrite moduled enabled.

Reference: http://www.webconfs.com/how-to-redirect-a-webpage.php

Tuesday, October 25, 2011

Why ASP.NET appears to be faster than Classic ASP?

Pages with the .aspx extension use compiled ASP.NET (based on Microsoft's .NET Framework), which makes them faster and more robust than server-side scripting in ASP, which is interpreted at run-time; however, ASP.NET pages may still include some ASP scripting

Reference: http://en.wikipedia.org/wiki/Active_Server_Pages

Classic ASP Built-in Objects

ASP 2.0 provided six built-in objects: Application, ASPError, Request, Response, Server, and Session. Session, for example, represents a cookie-based session that maintains the state of variables from page to page. The Active Scripting engine's support of the Component Object Model (COM) enables ASP Websites to access functionality in compiled libraries such as DLLs.

Reference: http://en.wikipedia.org/wiki/Active_Server_Pages

Implementing Cookieless Session in ASP.NET

Cookies are basically text data which a web site may store of the user's machine. Cookies are not considered as safe medium to store data as they could be dangerous in some scenario. Also there might be the case that user has cookies turned off on his machine or the browser doesn't supports the cookies. Our application might get failed if it is depended on cookies support on client side. Most of the time session id is stored at client side in cookies. Therefore we won't be able to retrieve session's data in the case when cookies are not enable.

ASP.NET Cookieless Support

ASP.NET support cookieless execution of the application when the client doens't have cookies support. When to chose cookieless, the session id is transferred via the request url. Each and every request of the application page contains the session id embedded in its url. So the web application need not to request the session from the cookies.

To set Cookieless session in an ASP.NET application set following value in web.config file

<sessionstate cookieless="true" />

When you have cookieless session then the url may look like this

http://www.dailycoding.com/Posts/(_entv9gVODTzHuenph6KAlK07..)/test.aspx

Issue

Session IDs can be hijacked which is a security issue if above mentioned approach is used

Reference: http://www.dailycoding.com/Posts/implementing_cookieless_session_aspnet.aspx

Tuesday, September 13, 2011

How to find trigger assosiated with a table ?

select 'alter table '+quotename(s.name)+'.'+quotename(object_name(o.parent_obj))+ ' disable trigger '+quotename(o.name)

from sys.sql_modules m

join sys.sysobjects o on m.object_id=o.id

join sys.schemas s on s.schema_id = o.uid

where o.type='tr'

and definition like '%TABLENAME%'

Friday, August 19, 2011

Difference between varchar(max) and varchar(8000)

Varchar(8000) stores a maximum of 8000 characters

Varchar(max) stores a maximum of 2 147 483 647 characters

Works in SQL Server 2005 or above

Thursday, July 21, 2011

Zip Files or Folder On The Fly Using PHP

Zip Files
<?php
include_once 'CreateZipFile.inc.php';
$createZip = new CreateZipFile;
$createZip->addDirectory('/');
$filecontent1 = file_get_contents('fileone.txt');
$filecontent2 = file_get_contents('filetwo.txt');
$createZip->addFile($filecontent1, '/fileone.txt');
$createZip->addFile($filecontent2, '/filetwo.txt');
$zipFileName = 'myzip.zip';
$handle       = fopen($zipFileName, 'wb');
$out           = fwrite($handle, $createZip->getZippedFile());
fclose($handle);
$createZip->forceDownload($zipFileName);
@unlink($zipFileName);
?>
Zip Folder


<?php
include_once 'CreateZipFile.inc.php';
$createZip = new CreateZipFile;
$createZip->zipDirectory('/testdir', '');
$zipFileName = 'myzip.zip';
$handle       = fopen($zipFileName, 'wb');
$out           = fwrite($handle, $createZip->getZippedFile());
fclose($handle);
$createZip->forceDownload($zipFileName);
@unlink($zipFileName);
?>
Reference: http://www.londatiga.net/it/programming/how-to-zip-files-or-folder-on-the-fly-using-php/

Tuesday, July 5, 2011

Displaying iFrame content in a DIV

if your images are outside of your iFrame, of course your dropdown menu will not show up since you are trying to tell the dropdown menu to go out of its windows. iframe is a different window inside your html, therefore any overflow of the window will never go out, elements inside the iframe is not affected with the z-index.

what you could do is, if your http://website.com/dropdown.html has the dropdown content only, you can call it by jQuery

<div id="myDropDown">
</div>

<script type="text/javascript">
    $(document).ready(function() {
        $("#myDropDown").load("http://website.com/dropdown.html");
    });
</script>

this will append the content of your dropdown.html into the div

Saturday, March 12, 2011

PHP function for checking http in a URL

function check_url($url)
{
    if(!strstr($url, "http://"))
    {
        $url = "http://".$url;
    }
    return $url;
}

Monday, February 7, 2011

Check website for http 404

function is_404($url) {
    $handle = curl_init($url);
    curl_setopt($handle,  CURLOPT_RETURNTRANSFER, TRUE);

    /* Get the HTML or whatever is linked in $url. */
    $response = curl_exec($handle);

    /* Check for 404 (file not found). */
    $httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
    curl_close($handle);

    /* If the document has loaded successfully without any redirection or error */
    if ($httpCode >= 200 && $httpCode < 300) {
        return false;
    } else {
        return true;
    }
}