Cowboy routes on steroids!
If you find any bugs or have a problem while using this library, please open an issue in this repo (or a pull request 😄).
And you can check out all of our open-source projects at inaka.github.io.
Cowboy-Trails enables you to:
- add information to
cowboyroutes, which can later be used to interact with the server in a higher abstraction level, - define the server routes directly within the module that implements them.
The most common use case for cowboy_trails is to compile cowboy routes.
Normally with cowboy you compile routes in the following way:
Routes = [{'_',
[ {"/resource1", resource1_handler, []}
, {"/resource2/[:id]", resource2_handler, []}
]
}
],
cowboy_router:compile(Routes),Trails is fully compatible with cowboy routes, so you can pass the same
routes in order to be processed by Trails:
trails:compile(Routes),So far it seems like there's no difference, right? But most of the time,
with cowboy, you usually work with only a single host, but you're
required to keep defining the host parameter within the routes ([{'_', [...]}]).
Well, with Trails you have another useful function to compile single host routes:
%% You only define the routes/paths
Routes = [ {"/resource1", resource1_handler, []}
, {"/resource2/[:id]", resource2_handler, []}
],
trails:single_host_compile(Routes),Now, let's suppose you want to add metadata to
cowboy routes related with the semantics of each HTTP method.
You'd do something like:
Metadata = #{put => #{description => "PUT method"},
post => #{description => "POST method"},
get => #{description => "GET method"}},
Trail = trails:trail("/",
cowboy_static,
{private_file, "index2.html"},
Metadata,
[]),
%% You can later retrieve the metadata:
Metadata = trails:metadata(Trail),This can then be used to generate documentation related to each endpoint.
Also, when you work with cowboy, you have to define all routes in one place:
Routes =
[{'_',
[ {"/", cowboy_static, {file, "www/index.html"}}
, {"/favicon.ico", cowboy_static, {file, "www/assets/favicon.ico"}}
, {"/assets/[...]", cowboy_static, {dir, "www/assets"}}
, {"/game/:game_id", cowboy_static, {file, "www/game.html"}}
, {"/api/status", spts_status_handler, []}
, {"/api/games", spts_games_handler, []}
, {"/api/games/:game_id", spts_single_game_handler, []}
, {"/api/games/:game_id/serpents", spts_serpents_handler, []}
, { "/api/games/:game_id/serpents/:token"
, spts_single_serpent_handler, []
}
, {"/api/games/:game_id/news", lasse_handler, [spts_news_handler]}
]
}
],
Dispatch = cowboy_router:compile(Routes),But now, with trails, you're able to define the routes on each of your resource handlers,
separately.
These handlers must implement callback c:trails_handler:trails/0 or c:trails_handler:trails/1
and return the specific
routes that define them. For a better understanding, you can check out the
examples in the test folder (trails_test_handler).
Once you have implemented the c:trails_handler:trails/0 or c:trails_handler:trails/1 callback
on your handlers, you can do
something like this:
Handlers =
[ spts_status_handler
, spts_games_handler
, spts_single_game_handler
, spts_serpents_handler
, spts_single_serpent_handler
, spts_news_handler
, {support_params_handler, #{key => value}}
],
Trails =
[ {"/", cowboy_static, {file, "www/index.html"}}
, {"/favicon.ico", cowboy_static, {file, "www/assets/favicon.ico"}}
, {"/assets/[...]", cowboy_static, {dir, "www/assets"}}
, {"/game/:game_id", cowboy_static, {file, "www/game.html"}}
| trails:trails(Handlers)
],
trails:single_host_compile(Trails),This way each handler maintains their own routes, as it should be, and you can merge them easily.
For more information about cowboy_trails, how to use it and the different
functions that it exposes, please check this example.