HTTP Caching header fields.

HTTP content negotiation header fields.

HTTP representation data and metadata header fields.

Returns an array of content encodings accepted by the request, in order of preference. If there are no encoding supplied in the request, then ["*"] is returned, implying any encoding is accepted.

Whether the input is Iterable or not.

Whether the input is null or not.

Parses the media type and any optional parameters, per RFC 1521. Media types are the values in Content-Type and Content-Disposition headers. On success the function returns a tuple where the first element is the media type and the second element is the optional parameters or undefined if there are none.

Mark that a request is varied on a header field.

HTTP handler API.

HTTP middleware API.