(PECL pecl_http >= 0.19.0)
http_negotiate_content_type — Negotiate client's preferred content type
$supported
[, array &$result
] )This function negotiates the clients preferred content type based on its Accept HTTP header. The qualifier is recognized and content types without qualifier are rated highest.
supported
array containing the supported content types as values
result
will be filled with an array containing the negotiation results
Returns the negotiated content type or the default content type (i.e. first array entry) if none match.
Example #1 Using http_negotiate_content_type()
<?php
$content_types = array('application/xhtml+xml', 'text/html');
http_send_content_type(http_negotiate_content_type($content_types));
?>
Vasil Rangelov (2007-09-21 05:18:19)
Newer versions of this extension fix the bug from the previous note.
Still, if you want to ensure there's no match, you can use the array, as the array will remain empty.
I used this fact in the following technique to ensure good content negotiation between application/xhtml+xml and text/html, since IE sends only "*/*" and thus receives application/xhtml+xml if you use the current sample from the documentation.
<?php
$bestContentType = http_negotiate_content_type(array('application/xhtml+xml', 'text/html'),
$contentTypes);
$contentType = (empty($contentTypes) ? 'text/html' : $bestContentType);
http_send_content_type($contentType);
?>
Note that at the time of writing, Opera accepts text/html with this approach, because it places application/xhtml+xml with a lower qualifier.
Pieter van Beek (2007-07-03 09:38:37)
The documentation says:
Returns the negotiated content type or the default content type (i.e. first array entry) if none match.
It would seem that in fact, this method returns the empty string or NULL if none match.