README

Strict RFC-compliant HTTP content negotiator.

Implements HTTP negotiation semantics defined in RFC 9110 and language matching defined in RFC 4647.

• Negotiation for Accept, Accept-Language, Accept-Encoding, and Accept-Charset headers
• Deterministic tie-breaking and stable selection
• Basic and extended language filtering
• Strict token and quoted-string parsing with correct handling of quoted parameters and escaped characters
• Quality (q) weighting and wildcard handling
• Media range specificity precedence (text/plain;charset=utf-8 > text/plain > text/* > */*)

Installation

composer require oasys/negotiator

Quick start

<?php declare(strict_types=1);

use Oasys\Http\Negotiator;

$result = Negotiator::content(
    header: 'application/json, text/html;q=0.8',
    supported: ['text/html', 'application/json']
);

'application/json'

Matching

Selection is determined by:

1. quality
2. match specificity
3. header order
4. supported list order

Accept header

$result = Negotiator::content(
    'text/*;q=0.3, text/plain;q=0.7, text/plain;format=flowed, */*;q=0.5',
    ['text/plain', 'text/plain;format=flowed', 'text/html']
);

'text/plain;format=flowed'

Accept-Language header

Extended language filtering

$result = Negotiator::language(
    'de-*-DE, fr;q=0.5',
    ['de-Latn-DE', 'fr-FR']
);

'de-Latn-DE'

Basic language filtering

$result = Negotiator::language(
    'en, fr;q=0.5',
    ['en-US', 'fr-FR'],
    extendedFiltering: false
);

'en-US'

Accept-Encoding header

$result = Negotiator::encoding(
    'gzip, br',
    ['7z']
);

'identity'

If your application does not support unencoded content, you can disable it by setting identity: false.

$result = Negotiator::encoding(
    'gzip, br',
    ['7z'],
    identity: false
);

null

Accept-Charset header

$result = Negotiator::charset(
    'utf-8, windows-1250;q=0.5, *;q=0.1',
    ['windows-1250', 'utf-8']
);

'utf-8'

Design notes

• Matching is case-insensitive
• Whitespace around members and separators is ignored
• Invalid header members are dropped; invalid supported values throw an exception
• Duplicate header members are evaluated individually; members with duplicate parameters are dropped
• Best match is formatted exactly as listed in supported values
• No match returns null