hi sabari,
Good explanation for the file handling techniques in PHP
Here i have given here some more info on CURL functions in PHP to get a web page using CURL

The CURL functions are a standard extension for PHP 4.0.2 and later. They are included in most PHP installations. You can check your installation by calling phpinfo() and looking for --with-curl in the Configure Command section at the start of its output. The CURL library manual has more installation information.

The CURL functions are built atop libcurl, a cross-platform library also available for Perl, Python, Ruby, C/C++, Java, and other languages. The PHP documentation is an abbreviated form of that available at the libcurl web site.

Getting a web page using CURL always includes these steps:

1. Create a CURL handle using curl_init().
2. Set up the request using curl_setopt() or curl_setopt_array().
3. Request the page using curl_exec().
4. Check if an error occurred using curl_errno().
5. Get the HTTP header using curl_getinfo().
6. Close the CURL handle using curl_close().

curl_init()

The curl_init() function creates a CURL handle to manage the web page request. The only function argument is a URL, which is saved until a later curl_exec() call executes the request.

curl_setopt() or curl_setopt_array()

The curl_setopt() and curl_setopt_array() functions configure the page request by setting options and their values. These two PHP functions are equivalent: curl_setopt() sets one option at a time, while curl_setopt_array() sets a list of options all at once.

Here are the basics options for different uses of CURL for getting a web page:

Essential options:

* CURLOPT_RETURNTRANSFER. When true, CURL returns the web page content from curl_exec(). When false, CURL prints the page to the screen (which is hardly ever useful).
* CURLOPT_HEADER. When true, CURL includes the web server’s HTTP response header in the page. When false, it is excluded, making the returned page easier to parse later. The header is still available by calling curl_getinfo().

Important options:

* CURLOPT_FOLLOWLOCATION. When true, CURL follows web page redirects automatically. When false, it stops on the first redirect and returns an error.
* CURLOPT_ENCODING. When empty, CURL handles uncompressed and compressed transfers. Compressed pages are automatically decompressed before they’re returned by curl_exec().

Web etiquette options:

* CURLOPT_USERAGENT. The user agent is the name of the application making the request (such as a web browser). If left empty, some web servers will reject the request.
* CURLOPT_AUTOREFERER. The referer is a URL for the web page that linked to the requested web page. When following redirects, set this to true and CURL automatically fills in the URL of the page being redirected away from.

Error handling options:

* CURLOPT_CONNECTTIMEOUT. Fail if a web server doesn’t respond to a connection within a time limit (seconds).
* CURLOPT_TIMEOUT. Fail if a web server doesn’t return the web page within a time limit (seconds).
* CURLOPT_MAXREDIRS. If a web page redirect leads to another redirect, and another, stop after a maximum number of redirects.

curl_exec()

The curl_exec() function issues the request and returns the web page (HTML, XHTML, XML, image, etc.).
curl_errno() and curl_error()

There are two kinds of errors:

* System errors result from a bad URL, bad protocol, unknown host, connect timeout, response timeout, or redirect loop. On a system error, curl_errno() returns a non-zero error code (see the CURL error code list) and curl_error() returns a short error message suitable for debugging output.
* Site errors result from an unknown web page, insufficient permissions, or a web server that is down for maintenance. On a site error or success, curl_errno() returns zero and the web server’s HTTP status code is available in the server header returned by curl_getinfo() (see below).

curl_getinfo()

The curl_getinfo() function returns values from the server header, such as web page’s content type and the HTTP status code. See the manual for a list of header fields returned. Highlights include:

"url" the final web page URL after redirects
"content_type" the content type (e.g. "text/html; charset=utf-8")
"http_code" the web page status code (e.g. "200" on success)
"filetime" the date stamp on the remote file

The "http_code" entry has the HTTP status code (see Wikipedia’s List of HTTP status codes). On success, the status is 200. The code is 404 if the web page is not found, 401 if authentication is required, 503 if the web site is down, etc.

curl_close()

The curl_close() function destroys the CURL handle, freeing memory.

Here sample code
/**
* Get a web file (HTML, XHTML, XML, image, etc.) from a URL. Return an
* array containing the HTTP server response header fields and content.
*/
function get_web_page( $url )
{
$options = array(
CURLOPT_RETURNTRANSFER => true, // return web page
CURLOPT_HEADER => false, // don't return headers
CURLOPT_FOLLOWLOCATION => true, // follow redirects
CURLOPT_ENCODING => "", // handle all encodings
CURLOPT_USERAGENT => "spider", // who am i
CURLOPT_AUTOREFERER => true, // set referer on redirect
CURLOPT_CONNECTTIMEOUT => 120, // timeout on connect
CURLOPT_TIMEOUT => 120, // timeout on response
CURLOPT_MAXREDIRS => 10, // stop after 10 redirects
);

$ch = curl_init( $url );
curl_setopt_array( $ch, $options );
$content = curl_exec( $ch );
$err = curl_errno( $ch );
$errmsg = curl_error( $ch );
$header = curl_getinfo( $ch );
curl_close( $ch );

$header['errno'] = $err;
$header['errmsg'] = $errmsg;
$header['content'] = $content;
return $header;
}

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J. Jeyaseelan
Everything Possible