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diff --git a/guide/handlers.md b/guide/handlers.md deleted file mode 100644 index 5ffe401..0000000 --- a/guide/handlers.md +++ /dev/null @@ -1,56 +0,0 @@ -Handlers -======== - -Purpose -------- - -Handlers are Erlang modules that represent a resource. - -Handlers must process the request and send a reply. The nature of the -reply will vary between handlers. - -Different kinds of handlers can be combined in a single module. This -allows a module to handle both websocket and long-polling code in a -single place, for example. - -Protocol upgrades ------------------ - -Cowboy features many different handlers: HTTP handlers, loop handlers, -websocket handlers, REST handlers and static handlers. All of them -have a common entry point: the `init/3` function. - -By default, Cowboy considers your handler to be an HTTP handler. - -To switch to a different protocol, like, for example, Websocket, -you must perform a protocol upgrade. This is done by returning -a protocol upgrade tuple at the end of `init/3`. - -The following snippet upgrades the handler to `my_protocol`. - -``` erlang -init(_Any, _Req, _Opts) -> - {upgrade, protocol, my_protocol}. -``` - -Cowboy comes with two protocol upgrades: `cowboy_rest` and -`cowboy_websocket`. Use these values in place of `my_protocol` -to use them. - -Custom protocol upgrades ------------------------- - -The `my_protocol` module above will be used for further processing -of the request. It should use the `cowboy_sub_protocol` behaviour, -which requires only one callback, `upgrade/4`. - -It receives the request object, the middleware environment, and -the handler this request has been routed to along with its options. - -``` erlang -upgrade(Req, Env, Handler, HandlerOpts) -> - %% ... -``` - -This callback is expected to behave like any middleware. Please -see the corresponding chapter for more information. |