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cowboy/examples/rest_hello_world/src/toppage_h.erl

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Add a REST Hello World example
2012-07-22 04:46:05 +02:00
%% Feel free to use, reuse and abuse the code in this file.
%% @doc Hello world handler.
Rename handler modules to _h
2018-09-07 13:48:43 -04:00
-module(toppage_h).
Add a REST Hello World example
2012-07-22 04:46:05 +02:00
Unify the init and terminate callbacks This set of changes is the first step to simplify the writing of handlers, by removing some extraneous callbacks and making others optional. init/3 is now init/2, its first argument being removed. rest_init/2 and rest_terminate/2 have been removed. websocket_init/3 and websocket_terminate/3 have been removed. terminate/3 is now optional. It is called regardless of the type of handler, including rest and websocket. The return value of init/2 changed. It now returns {Mod, Req, Opts} with Mod being either one of the four handler type or a custom module. It can also return extra timeout and hibernate options. The signature for sub protocols has changed, they now receive these extra timeout and hibernate options. Loop handlers are now implemented in cowboy_long_polling, and will be renamed throughout the project in a future commit.
2014-09-26 15:58:44 +03:00
-export([init/2]).
Add a REST Hello World example
2012-07-22 04:46:05 +02:00
-export([content_types_provided/2]).
-export([hello_to_html/2]).
-export([hello_to_json/2]).
-export([hello_to_text/2]).
Unify the init and terminate callbacks This set of changes is the first step to simplify the writing of handlers, by removing some extraneous callbacks and making others optional. init/3 is now init/2, its first argument being removed. rest_init/2 and rest_terminate/2 have been removed. websocket_init/3 and websocket_terminate/3 have been removed. terminate/3 is now optional. It is called regardless of the type of handler, including rest and websocket. The return value of init/2 changed. It now returns {Mod, Req, Opts} with Mod being either one of the four handler type or a custom module. It can also return extra timeout and hibernate options. The signature for sub protocols has changed, they now receive these extra timeout and hibernate options. Loop handlers are now implemented in cowboy_long_polling, and will be renamed throughout the project in a future commit.
2014-09-26 15:58:44 +03:00
init(Req, Opts) ->
Improve handler interface and documentation This change simplifies a little more the sub protocols mechanism. Aliases have been removed. The renaming of loop handlers as long polling handlers has been reverted. Plain HTTP handlers now simply do their work in the init/2 callback. There is no specific code for them. Loop handlers now follow the same return value as Websocket, they use ok to continue and shutdown to stop. Terminate reasons for all handler types have been documented. The terminate callback is now appropriately called in all cases (or should be). Behaviors for all handler types have been moved in the module that implement them. This means that cowboy_handler replaces the cowboy_http_handler behavior, and similarly cowboy_loop replaces cowboy_loop_handler, cowboy_websocket replaces cowboy_websocket_handler. Finally cowboy_rest now has the start of a behavior in it and will have the full list of optional callbacks defined once Erlang 18.0 gets released. The guide has been reorganized and should be easier to follow.
2014-09-30 20:12:13 +03:00
{cowboy_rest, Req, Opts}.
Add a REST Hello World example
2012-07-22 04:46:05 +02:00
content_types_provided(Req, State) ->
{[
{<<"text/html">>, hello_to_html},
{<<"application/json">>, hello_to_json},
{<<"text/plain">>, hello_to_text}
], Req, State}.
hello_to_html(Req, State) ->
Body = <<"<html>
<head>
<meta charset=\"utf-8\">
<title>REST Hello World!</title>
</head>
<body>
<p>REST Hello World as HTML!</p>
</body>
</html>">>,
{Body, Req, State}.
hello_to_json(Req, State) ->
Body = <<"{\"rest\": \"Hello World!\"}">>,
{Body, Req, State}.
hello_to_text(Req, State) ->
{<<"REST Hello World as text!">>, Req, State}.
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