mirror of
https://github.com/ninenines/cowboy.git
synced 2025-07-15 20:50:24 +00:00
75 lines
1.5 KiB
Text
75 lines
1.5 KiB
Text
|
= cowboy_req:header(3)
|
||
|
|
|
||
|
|
== Name
|
||
|
|
|
||
|
|
cowboy_req:header - HTTP header
|
||
|
|
|
||
|
|
== Description
|
||
|
|
|
||
|
|
[source,erlang]
|
||
|
|
----
|
||
|
|
header(Name :: binary(), Req) -> header(Name, Req, undefined)
|
||
|
|
header(Name :: binary(), Req, Default) -> binary() | Default
|
||
|
|
|
||
|
|
Req :: cowboy_req:req()
|
||
|
|
----
|
||
|
|
|
||
|
|
Return the value for the given HTTP header.
|
||
|
|
|
||
|
|
The header name must be given as a lowercase binary string.
|
||
|
|
While header names are case insensitive, Cowboy requires them
|
||
|
|
to be given as lowercase to function properly.
|
||
|
|
|
||
|
|
Headers can also be obtained using pattern matching:
|
||
|
|
|
||
|
|
[source,erlang]
|
||
|
|
----
|
||
|
|
#{headers := #{Name := Value}} = Req.
|
||
|
|
----
|
||
|
|
|
||
|
|
Note that this snippet will crash if the header is missing.
|
||
|
|
|
||
|
|
== Arguments
|
||
|
|
|
||
|
|
Name::
|
||
|
|
|
||
|
|
Desired HTTP header name as a binary string.
|
||
|
|
|
||
|
|
Req::
|
||
|
|
|
||
|
|
The Req object.
|
||
|
|
|
||
|
|
Default::
|
||
|
|
|
||
|
|
Default value returned when the header is missing.
|
||
|
|
|
||
|
|
== Return value
|
||
|
|
|
||
|
|
The header value is returned as a binary string. When the
|
||
|
|
header is missing, the default argument is returned.
|
||
|
|
|
||
|
|
== Changelog
|
||
|
|
|
||
|
|
* *2.0*: Only the header value is returned, it is no longer wrapped in a tuple.
|
||
|
|
* *1.0*: Function introduced.
|
||
|
|
|
||
|
|
== Examples
|
||
|
|
|
||
|
|
.Get the accept header
|
||
|
|
[source,erlang]
|
||
|
|
----
|
||
|
|
Accept = cowboy_req:header(<<"accept">>, Req).
|
||
|
|
----
|
||
|
|
|
||
|
|
.Get the content-length header with a default value
|
||
|
|
[source,erlang]
|
||
|
|
----
|
||
|
|
Length = cowboy_req:header(<<"content-length">>, Req, <<"0">>).
|
||
|
|
----
|
||
|
|
|
||
|
|
== See also
|
||
|
|
|
||
|
|
link:man:cowboy_req(3)[cowboy_req(3)],
|
||
|
|
link:man:cowboy_req:headers(3)[cowboy_req:headers(3)],
|
||
|
|
link:man:cowboy_req:parse_header(3)[cowboy_req:parse_header(3)]
|