MIME Sniffing

This library aims to be a complete implementation of the WHATWG Mime Sniffing specification, along with other features related to MIME types. Presently it does not implement MIME sniffing itself, but it will be expanded in due course once the specification stabilizes.

Features

Parsing

A MIME type string may be parsed into a structured MimeType instance as follows:

$mimeType = \MensBeam\Mime\MimeType::parse("text/HTML; charSet=UTF-8");
echo $mimeType->type;              // prints "text"
echo $mimeType->subtype;           // prints "html"
echo $mimeType->essence;           // prints "text/html"
echo $mimeType->params['charset']; // prints "UTF-8"

Normalizing

Once parsed, a MimeType instance can be serialized to produce a normalized text representation:

$typeString = 'TeXt/HTML;  CHARset="UTF\-8"; charset=iso-8859-1; unset=';
$mimeType = \MensBeam\Mime\MimeType::parse($typeString);
echo (string) $mimeType; // prints "text/html;charset=UTF-8"

Extracting from HTTP headers

A structured MimeType instance may also be produced from one or more HTTP header lines using the extract() method:

/* Assume $response is a PSR-7 HTTP message containing the following
   header fields:

   Content-Type: text/html; charset=UTF-8, invalid
   Content-Type:
   Content-Type: text/html; foo=bar

*/
echo (string) \MensBeam\Mime\MimeType::extract($response->getHeader("Content-Type")); // prints "text/html;foo=bar;charset=UTF-8"
echo (string) \MensBeam\Mime\MimeType::extract($response->getHeaderLine("Content-Type")); // also prints "text/html;foo=bar;charset=UTF-8"

Negotiating a content type

HTTP content type negotiation can be performed using the negotiate static method:

/* Assume $request1 is a PSR-7 HTTP message containing the following
   header fields:

   Accept: application/json;q=0.8, application/xml
   Accept: text/html;q=0.1, text/*;q=0.7

   Assume $request2 is a PSR-7 HTTP message containing the following
   header fields:

   Accept: application/xml
   Accept: application/json

*/
$ourTypes1 = ["application/json", "application/xml"];
$ourTypes2 = ["text/html", "text/xml", "text/plain"];
echo \MensBeam\Mime\MimeType::negotiate($ourTypes1, $request1->getHeader("Accept")); // "application/xml" has higher qvalue, so is returned
echo \MensBeam\Mime\MimeType::negotiate($ourTypes2, $request1->getHeaderLine("Accept")); // "text/html" has lower qvalue and is disqualified; "text/xml" appears first in our array, so is returned
echo \MensBeam\Mime\MimeType::negotiate($ourTypes1, $request2->getHeader("Accept")); // "application/json" appears first in our array, so is returned
echo \MensBeam\Mime\MimeType::negotiate($ourTypes2, $request2->getHeaderLine("Accept")); // no types are acceptable; null is returned

MIME type groups

The MIME Sniffing specification defines a series of MIME type groups; these are exposed via the boolean properties isArchive, isAudioVideo, isFont, isHtml, isImage, isJavascript, isJson, isScriptable, isXml, and isZipBased. For example:

$mimeType = \MensBeam\Mime\MimeType::parse("image/svg+xml");
var_export($mimeType->isImage);      // prints "true"
var_export($mimeType->isXml);        // prints "true"
var_export($mimeType->isScriptable); // prints "true"
var_export($mimeType->isArchive);    // prints "false"