README

Provides frequently-used HTTP protocol constants for PHP applications. This library includes commonly-used status codes, request methods, headers, media types, and cache control directives that are typically referenced in PHP application code.

Example

use Koriym\HttpConstants\HttpStatusCode;
use Koriym\HttpConstants\RequestHeader;
use Koriym\HttpConstants\ResponseHeader;
use Koriym\HttpConstants\MediaType;
use Koriym\HttpConstants\Method;

http_response_code(StatusCode::BAD_REQUEST);
header(ResponseHeader::CONTENT_TYPE . ': ' . MediaType::APPLICATION_JSON_API);
// Content-Type: application/vnd.api+json
header(ResponseHeader::CACHE_CONTROL . ': max-age=3600');
// Cache-Control: max-age=3600

Install

$ composer require koriym/http-constants

Scope and Philosophy

This library focuses on HTTP constants frequently used in PHP application code, rather than providing comprehensive coverage of all HTTP specifications.

For example:

CORS headers are included because they are commonly set in API endpoints
Rate limiting status codes (429) are included for API development
Security headers typically configured at the web server level are not included
Basic image media types (image/png, etc.) are not included as they are rarely referenced in application code

HTTP Constants Coverage

The following tables show commonly-used HTTP constants and whether they are included in this library (✓) or not (✗).

HTTP Status Codes

Code	Name	Included	Reason if excluded
100	Continue	✓
101	Switching Protocols	✓
102	Processing	✓
103	Early Hints	✗	Rarely used in PHP code
200	OK	✓
201	Created	✓
202	Accepted	✓
203	Non-Authoritative Information	✓
204	No Content	✓
205	Reset Content	✓
206	Partial Content	✓
207	Multi-Status	✗	WebDAV-specific
208	Already Reported	✗	WebDAV-specific
226	IM Used	✗	Rarely used
300	Multiple Choices	✓
301	Moved Permanently	✓
302	Found	✓
303	See Other	✓
304	Not Modified	✓
305	Use Proxy	✓
307	Temporary Redirect	✓
308	Permanent Redirect	✓
400	Bad Request	✓
401	Unauthorized	✓
402	Payment Required	✓
403	Forbidden	✓
404	Not Found	✓
405	Method Not Allowed	✓
406	Not Acceptable	✓
407	Proxy Authentication Required	✓
408	Request Timeout	✓
409	Conflict	✓
410	Gone	✓
411	Length Required	✓
412	Precondition Failed	✓
413	Request Entity Too Large	✓
414	Request-URI Too Long	✓
415	Unsupported Media Type	✓
416	Requested Range Not Satisfiable	✓
417	Expectation Failed	✓
418	I'm a teapot	✓
421	Misdirected Request	✗	HTTP/2 specific, rarely used
422	Unprocessable Entity	✗	In statusText only
423	Locked	✗	WebDAV-specific
424	Failed Dependency	✗	WebDAV-specific
425	Too Early	✗	Rarely used
426	Upgrade Required	✗	Rarely used in PHP code
428	Precondition Required	✓
429	Too Many Requests	✓
431	Request Header Fields Too Large	✓
451	Unavailable For Legal Reasons	✗	Rarely used in PHP code
500	Internal Server Error	✓
501	Not Implemented	✓
502	Bad Gateway	✓
503	Service Unavailable	✓
504	Gateway Timeout	✓
505	HTTP Version Not Supported	✓
506	Variant Also Negotiates	✗	Rarely used
507	Insufficient Storage	✗	WebDAV-specific
508	Loop Detected	✗	WebDAV-specific
510	Not Extended	✗	Rarely used
511	Network Authentication Required	✗	Captive portal specific

IANA Registry: HTTP Status Code Registry

HTTP Methods

Method	Included	Reason if excluded
GET	✓
POST	✓
PUT	✓
DELETE	✓
HEAD	✓
OPTIONS	✓
PATCH	✓
CONNECT	✓
TRACE	✓
LINK	✓
UNLINK	✓
PROPFIND	✗	WebDAV-specific
PROPPATCH	✗	WebDAV-specific
MKCOL	✗	WebDAV-specific
COPY	✗	WebDAV-specific
MOVE	✗	WebDAV-specific
LOCK	✗	WebDAV-specific
UNLOCK	✗	WebDAV-specific

IANA Registry: HTTP Method Registry

HTTP Request Headers

Header	Included	Reason if excluded
Accept	✓
Accept-Charset	✓
Accept-Datetime	✓
Accept-Encoding	✓
Accept-Language	✓
Access-Control-Request-Headers	✓
Access-Control-Request-Method	✓
Authorization	✓
Cache-Control	✓
Connection	✓
Content-Encoding	✓
Content-Length	✓
Content-MD5	✓
Content-Range	✓
Content-Type	✓
Cookie	✓
Date	✓
DNT	✓
Expect	✓
Forwarded	✗	Less common than X-Forwarded-*
From	✓
Front-End-Https	✓
Host	✓
If-Match	✓
If-Modified-Since	✓
If-None-Match	✓
If-Range	✓
If-Unmodified-Since	✓
Max-Forwards	✓
Origin	✓
Pragma	✓
Proxy-Authorization	✓
Proxy-Connection	✓
Range	✓
Referer	✓
Sec-Fetch-Dest	✗	Browser-set, not in PHP code
Sec-Fetch-Mode	✗	Browser-set, not in PHP code
Sec-Fetch-Site	✗	Browser-set, not in PHP code
TE	✓
Upgrade	✓
Upgrade-Insecure-Requests	✗	Browser-set, not in PHP code
User-Agent	✓
Via	✓
Warning	✓
X-Csrf-Token	✓
X-Forwarded-For	✓
X-Forwarded-Proto	✓
X-Http-Method-Override	✓
X-Requested-With	✓
X-Wap-Profile	✓

IANA Registry: Message Headers Registry

HTTP Response Headers

Header	Included	Reason if excluded
Accept-Patch	✓
Accept-Ranges	✓
Access-Control-Allow-Credentials	✓
Access-Control-Allow-Headers	✓
Access-Control-Allow-Methods	✓
Access-Control-Allow-Origin	✓
Access-Control-Expose-Headers	✓
Access-Control-Max-Age	✓
Age	✓
Allow	✓
Cache-Control	✓
Connection	✓
Content-Disposition	✓
Content-Encoding	✓
Content-Language	✓
Content-Length	✓
Content-Location	✓
Content-MD5	✓
Content-Range	✓
Content-Security-Policy	✓
Content-Type	✓
Cross-Origin-Embedder-Policy	✗	Usually set in web server config
Cross-Origin-Opener-Policy	✗	Usually set in web server config
Cross-Origin-Resource-Policy	✗	Usually set in web server config
Date	✓
ETag	✓
Expires	✓
Last-Modified	✓
Location	✓
P3P	✓
Permissions-Policy	✗	Usually set in web server config
Proxy-Authenticate	✓
Public-Key-Pins	✓
Referrer-Policy	✗	Usually set in web server config
Refresh	✓
Retry-After	✓
Server	✓
Set-Cookie	✓
Status	✓
Strict-Transport-Security	✓
Trailer	✓
Transfer-Encoding	✓
Upgrade	✓
Vary	✓
Warning	✓
WWW-Authenticate	✓
X-Content-Duration	✓
X-Content-Type-Options	✓
X-Frame-Options	✗	Usually set in web server config
X-Powered-By	✓
X-UA-Compatible	✓
X-XSS-Protection	✓

IANA Registry: Message Headers Registry

Media Types

Media Type	Included	Reason if excluded
/	✓
application/atom+xml	✓
application/graphql+json	✗	Could be added if requested
application/gzip	✗	Rarely referenced in PHP code
application/hal+json	✓
application/json	✓
application/ld+json	✓
application/octet-stream	✓
application/pdf	✗	Rarely referenced in PHP code
application/problem+json	✗	Could be added if requested
application/rdf+xml	✓
application/svg+xml	✓
application/vnd.api+json	✓
application/vnd.collection+json	✓
application/vnd.siren+json	✓
application/vnd.uber+json	✓
application/x-www-form-urlencoded	✓
application/xhtml+xml	✓
application/xml	✓
application/zip	✗	Rarely referenced in PHP code
image/gif	✗	Rarely referenced in PHP code
image/jpeg	✗	Rarely referenced in PHP code
image/png	✗	Rarely referenced in PHP code
image/svg+xml	✗	Rarely referenced in PHP code
image/webp	✗	Rarely referenced in PHP code
multipart/form-data	✓
text/css	✗	Rarely referenced in PHP code
text/csv	✗	Rarely referenced in PHP code
text/html	✓
text/javascript	✗	Rarely referenced in PHP code
text/plain	✓
text/xml	✓

IANA Registry: Media Types Registry

Cache-Control Directives

Directive	Included	Reason if excluded
public	✓
private	✓
no-cache	✓
no-store	✓
max-age	✓
s-maxage	✓
must-revalidate	✓
proxy-revalidate	✓
immutable	✓
stale-while-revalidate	✓
stale-if-error	✓
no-transform	✗	Less commonly used
only-if-cached	✗	Client directive, less common
max-stale	✗	Client directive, less common
min-fresh	✗	Client directive, less common

RFC 9111: HTTP Caching

koriym / http-constants

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