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.
Note: The
TE request header needs to be set to "trailers" to allow
trailer fields.
| Header type | Request header, Response header, Payload header |
|---|---|
| Forbidden header name | yes |
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:
-
message framing headers (e.g.,
Transfer-EncodingandContent-Length), - routing headers (e.g.,
Host), -
request modifiers (e.g., controls and conditionals, like
Cache-Control,Max-Forwards, orTE), -
authentication headers (e.g.,
AuthorizationorSet-Cookie), -
or
Content-Encoding,Content-Type,Content-Range, andTraileritself.
-
message framing headers (e.g.,
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 |
|---|
| Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing # header.trailer |
| Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing # chunked.trailer.part |
Browser compatibility
Report problems with this compatibility data on GitHubChrome | Edge | Firefox | Internet Explorer | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on iOS | Samsung Internet | WebView Android | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Legend
Full support