cowboy_req:binding(3)

Name

cowboy_req:binding - Access a value bound from the route

Description

binding(Name, Req)          -> binding(Name, Req, undefined)
binding(Name, Req, Default) -> any() | Default

Name    :: atom()
Req     :: cowboy_req:req()
Default :: any()

Return the value for the given binding.

Arguments

Name

Desired binding name as an atom.

Req

The Req object.

Default

Default value returned when the binding is missing.

Return value

By default the value is a case sensitive binary string, however constraints may change the type of this value (for example automatically converting numbers to integer).

Changelog

• 2.0: Only the value is returned, it is no longer wrapped in a tuple.
• 1.0: Function introduced.

Examples

%% Route is "/users/:user"
Username = cowboy_req:binding(user, Req).

%% Route is "/log[/:branch]"
Branch = cowboy_req:binding(branch, Req, <<"master">>)

See also

cowboy_req(3), cowboy_req:bindings(3), cowboy_req:host_info(3), cowboy_req:path_info(3), cowboy_router(3)