I'm using PHP's function file_get_contents()
to fetch contents of a URL and then I process headers through the variable $http_response_header
.
Now the problem is that some of the URLs need some data to be posted to the URL (for example, login pages).
How do I do that?
I realize using stream_context I may be able to do that but I am not entirely clear.
Thanks.
The file_get_contents() reads a file into a string. This function is the preferred way to read the contents of a file into a string. It will use memory mapping techniques, if this is supported by the server, to enhance performance.
The file_get_contents() function returns Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. An E_WARNING level error is generated if filename cannot be found, maxlength is less than zero, or if seeking the specified offset in the stream fails.
Curl is a much faster alternative to file_get_contents. Using file_get_contents to retrieve http://www.knowledgecornor.com/ took 0.198035001234 seconds. Meanwhile, using curl to retrieve the same file took 0.025691986084 seconds. As you can see, curl is much faster.
readfile("/path/to/file"); This will read the file and send it to the browser in one command. This is essentially the same as: echo file_get_contents("/path/to/file");
Sending an HTTP POST request using file_get_contents
is not that hard, actually : as you guessed, you have to use the $context
parameter.
There's an example given in the PHP manual, at this page : HTTP context options (quoting) :
$postdata = http_build_query( array( 'var1' => 'some content', 'var2' => 'doh' ) ); $opts = array('http' => array( 'method' => 'POST', 'header' => 'Content-Type: application/x-www-form-urlencoded', 'content' => $postdata ) ); $context = stream_context_create($opts); $result = file_get_contents('http://example.com/submit.php', false, $context);
Basically, you have to create a stream, with the right options (there is a full list on that page), and use it as the third parameter to file_get_contents
-- nothing more ;-)
As a sidenote : generally speaking, to send HTTP POST requests, we tend to use curl, which provides a lot of options an all -- but streams are one of the nice things of PHP that nobody knows about... too bad...
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