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/HTTP

Trailer

The Trailer response header allows the sender to include additional fields at the end of chunked messages in order to supply metadata that might be dynamically generated while the message body is sent, such as a message integrity check, digital signature, or post-processing status.

The TE request header needs to be set to "trailers" to allow trailer fields.

Syntax

Trailer: header-names

Directives

header-names
HTTP header fields which will be present in the trailer part of chunked messages. These header fields are disallowed:

Examples

Chunked transfer encoding using a trailing header

In this example, the Expires header is used at the end of the chunked message and serves as a trailing header.

HTTP/1.1 200 OK 
Content-Type: text/plain 
Transfer-Encoding: chunked
Trailer: Expires

7\r\n 
Mozilla\r\n 
9\r\n 
Developer\r\n 
7\r\n 
Network\r\n 
0\r\n 
Expires: Wed, 21 Oct 2015 07:28:00 GMT\r\n
\r\n

Specifications

Specification Title
RFC 7230, section 4.4: Trailer Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing
RFC 7230, section 4.1.2: Chunked trailer part Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing

Browser compatibility

Feature Chrome Firefox Edge Internet Explorer Opera Safari
Basic Support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Edge mobile Firefox for Android IE mobile Opera Android iOS Safari
Basic Support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Trailer