= cowboy(3)

== Name

cowboy - HTTP server

== Description

The module `cowboy` provides convenience functions for
manipulating Ranch listeners.

== Exports

* link:man:cowboy:start_clear(3)[cowboy:start_clear(3)] - Listen for connections using plain TCP
* link:man:cowboy:start_tls(3)[cowboy:start_tls(3)] - Listen for connections using TLS
* link:man:cowboy:stop_listener(3)[cowboy:stop_listener(3)] - Stop the given listener
* link:man:cowboy:get_env(3)[cowboy:get_env(3)] - Retrieve a listener's environment value
* link:man:cowboy:set_env(3)[cowboy:set_env(3)] - Update a listener's environment value

== Types

=== fields()

[source,erlang]
----
fields() :: [Name
           | {Name, Constraints}
           | {Name, Constraints, Default}]

Name        :: atom()
Constraints :: Constraint | [Constraint]
Constraint  :: cowboy_constraints:constraint()
Default     :: any()
----

Fields description for match operations.

This type is used in link:man:cowboy_router(3)[cowboy_router(3)]
for matching bindings and in the match functions found in
link:man:cowboy_req(3)[cowboy_req(3)].

=== http_headers()

[source,erlang]
----
http_headers() :: #{binary() => iodata()}
----

HTTP headers.

=== http_status()

[source,erlang]
----
http_status() :: non_neg_integer() | binary()
----

HTTP response status.

A binary status can be used to set a reason phrase. Note
however that HTTP/2 only sends the status code and drops
the reason phrase entirely.

=== http_version()

[source,erlang]
----
http_version() :: 'HTTP/2' | 'HTTP/1.1' | 'HTTP/1.0'
----

HTTP version.

Note that semantically, HTTP/1.1 and HTTP/2 are equivalent.

=== opts()

[source,erlang]
----
opts() :: map()
----

Options for the HTTP/1.1, HTTP/2 and Websocket protocols.

The protocol options are in a map containing all the options for
the different protocols that may be involved when connecting
to the listener, including HTTP/1.1 and HTTP/2.

The HTTP/1.1 options are documented in the
link:man:cowboy_http(3)[cowboy_http(3)] manual
and the HTTP/2 options in
link:man:cowboy_http2(3)[cowboy_http2(3)].

== See also

link:man:cowboy(7)[cowboy(7)],
link:man:ranch(3)[ranch(3)]
