Permalink
783 lines (615 sloc) 23 KB
defmodule Phoenix.Router do
defmodule NoRouteError do
@moduledoc """
Exception raised when no route is found.
"""
defexception plug_status: 404, message: "no route found", conn: nil, router: nil
def exception(opts) do
conn = Keyword.fetch!(opts, :conn)
router = Keyword.fetch!(opts, :router)
path = "/" <> Enum.join(conn.path_info, "/")
%NoRouteError{message: "no route found for #{conn.method} #{path} (#{inspect router})",
conn: conn, router: router}
end
end
@moduledoc """
Defines a Phoenix router.
The router provides a set of macros for generating routes
that dispatch to specific controllers and actions. Those
macros are named after HTTP verbs. For example:
defmodule MyAppWeb.Router do
use Phoenix.Router
get "/pages/:page", PageController, :show
end
The `get/3` macro above accepts a request of format `"/pages/VALUE"` and
dispatches it to the show action in the `PageController`.
Routes can also match glob-like patterns, routing any path with a common
base to the same controller. For example:
get "/dynamic*anything", DynamicController, :show
Phoenix's router is extremely efficient, as it relies on Elixir
pattern matching for matching routes and serving requests.
## Helpers
Phoenix automatically generates a module `Helpers` inside your router
which contains named helpers to help developers generate and keep
their routes up to date.
Helpers are automatically generated based on the controller name.
For example, the route:
get "/pages/:page", PageController, :show
will generate the following named helper:
MyAppWeb.Router.Helpers.page_path(conn_or_endpoint, :show, "hello")
"/pages/hello"
MyAppWeb.Router.Helpers.page_path(conn_or_endpoint, :show, "hello", some: "query")
"/pages/hello?some=query"
MyAppWeb.Router.Helpers.page_url(conn_or_endpoint, :show, "hello")
"http://example.com/pages/hello"
MyAppWeb.Router.Helpers.page_url(conn_or_endpoint, :show, "hello", some: "query")
"http://example.com/pages/hello?some=query"
If the route contains glob-like patterns, parameters for those have to be given as
list:
MyAppWeb.Router.Helpers.dynamic_path(conn_or_endpoint, :show, ["dynamic", "something"])
"/dynamic/something"
The URL generated in the named URL helpers is based on the configuration for
`:url`, `:http` and `:https`. However, if for some reason you need to manually
control the URL generation, the url helpers also allow you to pass in a `URI`
struct:
uri = %URI{scheme: "https", host: "other.example.com"}
MyAppWeb.Router.Helpers.page_url(uri, :show, "hello")
"https://other.example.com/pages/hello"
The named helper can also be customized with the `:as` option. Given
the route:
get "/pages/:page", PageController, :show, as: :special_page
the named helper will be:
MyAppWeb.Router.Helpers.special_page_path(conn, :show, "hello")
"/pages/hello"
## Scopes and Resources
It is very common in Phoenix applications to namespace all of your
routes under the application scope:
scope "/", MyAppWeb do
get "/pages/:id", PageController, :show
end
The route above will dispatch to `MyAppWeb.PageController`. This syntax
is not only convenient for developers, since we don't have to repeat
the `MyAppWeb.` prefix on all routes, but it also allows Phoenix to put
less pressure on the Elixir compiler. If instead we had written:
get "/pages/:id", MyAppWeb.PageController, :show
The Elixir compiler would infer that the router depends directly on
`MyAppWeb.PageController`, which is not true. By using scopes, Phoenix
can properly hint to the Elixir compiler the controller is not an
actual dependency of the router. This provides more efficient
compilation times.
Scopes allow us to scope on any path or even on the helper name:
scope "/api/v1", MyAppWeb, as: :api_v1 do
get "/pages/:id", PageController, :show
end
For example, the route above will match on the path `"/api/v1/pages/:id"`
and the named route will be `api_v1_page_path`, as expected from the
values given to `scope/2` option.
Phoenix also provides a `resources/4` macro that allows developers
to generate "RESTful" routes to a given resource:
defmodule MyAppWeb.Router do
use Phoenix.Router
resources "/pages", PageController, only: [:show]
resources "/users", UserController, except: [:delete]
end
Finally, Phoenix ships with a `mix phx.routes` task that nicely
formats all routes in a given router. We can use it to verify all
routes included in the router above:
$ mix phx.routes
page_path GET /pages/:id PageController.show/2
user_path GET /users UserController.index/2
user_path GET /users/:id/edit UserController.edit/2
user_path GET /users/new UserController.new/2
user_path GET /users/:id UserController.show/2
user_path POST /users UserController.create/2
user_path PATCH /users/:id UserController.update/2
PUT /users/:id UserController.update/2
One can also pass a router explicitly as an argument to the task:
$ mix phx.routes MyAppWeb.Router
Check `scope/2` and `resources/4` for more information.
## Pipelines and plugs
Once a request arrives at the Phoenix router, it performs
a series of transformations through pipelines until the
request is dispatched to a desired end-point.
Such transformations are defined via plugs, as defined
in the [Plug](http://github.com/elixir-lang/plug) specification.
Once a pipeline is defined, it can be piped through per scope.
For example:
defmodule MyAppWeb.Router do
use Phoenix.Router
pipeline :browser do
plug :fetch_session
plug :accepts, ["html"]
end
scope "/" do
pipe_through :browser
# browser related routes and resources
end
end
`Phoenix.Router` imports functions from both `Plug.Conn` and `Phoenix.Controller`
to help define plugs. In the example above, `fetch_session/2`
comes from `Plug.Conn` while `accepts/2` comes from `Phoenix.Controller`.
Note that router pipelines are only invoked after a route is found.
No plug is invoked in case no matches were found.
"""
alias Phoenix.Router.{Resource, Scope, Route, Helpers}
@http_methods [:get, :post, :put, :patch, :delete, :options, :connect, :trace, :head]
@doc false
defmacro __using__(_) do
quote do
unquote(prelude())
unquote(defs())
unquote(match_dispatch())
end
end
defp prelude() do
quote do
Module.register_attribute __MODULE__, :phoenix_routes, accumulate: true
@phoenix_forwards %{}
import Phoenix.Router
# TODO v2: No longer automatically import dependencies
import Plug.Conn
import Phoenix.Controller
# Set up initial scope
@phoenix_pipeline nil
Phoenix.Router.Scope.init(__MODULE__)
@before_compile unquote(__MODULE__)
end
end
# Because those macros are executed multiple times,
# we end-up generating a huge scope that drastically
# affects compilation. We work around it by defining
# those functions only once and calling it over and
# over again.
defp defs() do
quote unquote: false do
var!(add_resources, Phoenix.Router) = fn resource ->
path = resource.path
ctrl = resource.controller
opts = resource.route
if resource.singleton do
Enum.each resource.actions, fn
:show -> get path, ctrl, :show, opts
:new -> get path <> "/new", ctrl, :new, opts
:edit -> get path <> "/edit", ctrl, :edit, opts
:create -> post path, ctrl, :create, opts
:delete -> delete path, ctrl, :delete, opts
:update ->
patch path, ctrl, :update, opts
put path, ctrl, :update, Keyword.put(opts, :as, nil)
end
else
param = resource.param
Enum.each resource.actions, fn
:index -> get path, ctrl, :index, opts
:show -> get path <> "/:" <> param, ctrl, :show, opts
:new -> get path <> "/new", ctrl, :new, opts
:edit -> get path <> "/:" <> param <> "/edit", ctrl, :edit, opts
:create -> post path, ctrl, :create, opts
:delete -> delete path <> "/:" <> param, ctrl, :delete, opts
:update ->
patch path <> "/:" <> param, ctrl, :update, opts
put path <> "/:" <> param, ctrl, :update, Keyword.put(opts, :as, nil)
end
end
end
end
end
@doc false
def __call__({%Plug.Conn{private: %{phoenix_router: router, phoenix_bypass: {router, pipes}}} = conn, _pipeline, _dispatch}) do
Enum.reduce(pipes, conn, fn pipe, acc -> apply(router, pipe, [acc, []]) end)
end
def __call__({%Plug.Conn{private: %{phoenix_bypass: :all}} = conn, _pipeline, _dispatch}) do
conn
end
def __call__({conn, pipeline, {plug, opts}}) do
case pipeline.(conn) do
%Plug.Conn{halted: true} = halted_conn ->
halted_conn
%Plug.Conn{} = piped_conn ->
try do
plug.call(piped_conn, plug.init(opts))
rescue
e in Plug.Conn.WrapperError ->
Plug.Conn.WrapperError.reraise(e)
catch
:error, reason ->
Plug.Conn.WrapperError.reraise(piped_conn, :error, reason, System.stacktrace())
end
end
end
defp match_dispatch() do
quote location: :keep do
@behaviour Plug
@doc """
Callback required by Plug that initializes the router
for serving web requests.
"""
def init(opts) do
opts
end
@doc """
Callback invoked by Plug on every request.
"""
def call(conn, _opts) do
conn
|> prepare()
|> __match_route__(conn.method, Enum.map(conn.path_info, &URI.decode/1), conn.host)
|> Phoenix.Router.__call__()
end
defoverridable [init: 1, call: 2]
end
end
@anno (if :erlang.system_info(:otp_release) >= '19' do
[generated: true]
else
[line: -1]
end)
@doc false
defmacro __before_compile__(env) do
routes = env.module |> Module.get_attribute(:phoenix_routes) |> Enum.reverse
routes_with_exprs = Enum.map(routes, &{&1, Route.exprs(&1)})
Helpers.define(env, routes_with_exprs)
{matches, _} = Enum.map_reduce(routes_with_exprs, %{}, &build_match/2)
# @anno is used here to avoid warnings if forwarding to root path
match_404 =
quote @anno do
def __match_route__(conn, _method, _path_info, _host) do
raise NoRouteError, conn: conn, router: __MODULE__
end
end
quote do
@doc false
def __routes__, do: unquote(Macro.escape(routes))
@doc false
def __helpers__, do: __MODULE__.Helpers
defp prepare(conn) do
update_in conn.private,
&(&1
|> Map.put(:phoenix_router, __MODULE__)
|> Map.put(__MODULE__, {conn.script_name, @phoenix_forwards}))
end
unquote(matches)
unquote(match_404)
end
end
defp build_match({route, exprs}, known_pipelines) do
%{pipe_through: pipe_through} = route
%{
prepare: prepare,
dispatch: dispatch,
verb_match: verb_match,
path: path,
host: host
} = exprs
{pipe_name, pipe_definition, known_pipelines} =
case known_pipelines do
%{^pipe_through => name} ->
{name, :ok, known_pipelines}
%{} ->
name = :"__pipe_through#{map_size(known_pipelines)}__"
{name, build_pipes(name, pipe_through), Map.put(known_pipelines, pipe_through, name)}
end
quoted =
quote line: route.line do
unquote(pipe_definition)
@doc false
def __match_route__(var!(conn), unquote(verb_match), unquote(path), unquote(host)) do
{unquote(prepare), &unquote(Macro.var(pipe_name, __MODULE__))/1, unquote(dispatch)}
end
end
{quoted, known_pipelines}
end
defp build_pipes(name, []) do
quote do
defp unquote(name)(conn) do
Plug.Conn.put_private(conn, :phoenix_pipelines, [])
end
end
end
defp build_pipes(name, pipe_through) do
plugs = pipe_through |> Enum.reverse |> Enum.map(&{&1, [], true})
{conn, body} = Plug.Builder.compile(__ENV__, plugs, init_mode: Phoenix.plug_init_mode())
quote do
defp unquote(name)(unquote(conn)) do
unquote(conn) = Plug.Conn.put_private(unquote(conn), :phoenix_pipelines, unquote(pipe_through))
unquote(body)
end
end
end
@doc """
Generates a route match based on an arbitrary HTTP method.
Useful for defining routes not included in the builtin macros:
#{Enum.map_join(@http_methods, ", ", &"`#{&1}`")}
The catch-all verb, `:*`, may also be used to match all HTTP methods.
## Examples
match(:move, "/events/:id", EventController, :move)
match(:*, "/any", SomeController, :any)
"""
defmacro match(verb, path, plug, plug_opts, options \\ []) do
add_route(:match, verb, path, plug, plug_opts, options)
end
for verb <- @http_methods do
@doc """
Generates a route to handle a #{verb} request to the given path.
"""
defmacro unquote(verb)(path, plug, plug_opts, options \\ []) do
add_route(:match, unquote(verb), path, plug, plug_opts, options)
end
end
defp add_route(kind, verb, path, plug, plug_opts, options) do
quote do
@phoenix_routes Scope.route(
__ENV__.line,
__ENV__.module,
unquote(kind),
unquote(verb),
unquote(path),
unquote(plug),
unquote(plug_opts),
unquote(options)
)
end
end
@doc """
Defines a plug pipeline.
Pipelines are defined at the router root and can be used
from any scope.
## Examples
pipeline :api do
plug :token_authentication
plug :dispatch
end
A scope may then use this pipeline as:
scope "/" do
pipe_through :api
end
Every time `pipe_through/1` is called, the new pipelines
are appended to the ones previously given.
"""
defmacro pipeline(plug, do: block) do
block =
quote do
plug = unquote(plug)
@phoenix_pipeline []
unquote(block)
end
compiler =
quote unquote: false do
Scope.pipeline(__MODULE__, plug)
{conn, body} = Plug.Builder.compile(__ENV__, @phoenix_pipeline,
init_mode: Phoenix.plug_init_mode())
def unquote(plug)(unquote(conn), _) do
try do
unquote(body)
rescue
e in Plug.Conn.WrapperError ->
Plug.Conn.WrapperError.reraise(e)
catch
:error, reason ->
Plug.Conn.WrapperError.reraise(unquote(conn), :error, reason, System.stacktrace())
end
end
@phoenix_pipeline nil
end
quote do
try do
unquote(block)
unquote(compiler)
after
:ok
end
end
end
@doc """
Defines a plug inside a pipeline.
See `pipeline/2` for more information.
"""
defmacro plug(plug, opts \\ []) do
quote do
if pipeline = @phoenix_pipeline do
@phoenix_pipeline [{unquote(plug), unquote(opts), true}|pipeline]
else
raise "cannot define plug at the router level, plug must be defined inside a pipeline"
end
end
end
@doc """
Defines a pipeline to send the connection through.
See `pipeline/2` for more information.
"""
defmacro pipe_through(pipes) do
quote do
if pipeline = @phoenix_pipeline do
raise "cannot pipe_through inside a pipeline"
else
Scope.pipe_through(__MODULE__, unquote(pipes))
end
end
end
@doc """
Defines "RESTful" routes for a resource.
The given definition:
resources "/users", UserController
will include routes to the following actions:
* `GET /users` => `:index`
* `GET /users/new` => `:new`
* `POST /users` => `:create`
* `GET /users/:id` => `:show`
* `GET /users/:id/edit` => `:edit`
* `PATCH /users/:id` => `:update`
* `PUT /users/:id` => `:update`
* `DELETE /users/:id` => `:delete`
## Options
This macro accepts a set of options:
* `:only` - a list of actions to generate routes for, for example: `[:show, :edit]`
* `:except` - a list of actions to exclude generated routes from, for example: `[:delete]`
* `:param` - the name of the parameter for this resource, defaults to `"id"`
* `:name` - the prefix for this resource. This is used for the named helper
and as the prefix for the parameter in nested resources. The default value
is automatically derived from the controller name, i.e. `UserController` will
have name `"user"`
* `:as` - configures the named helper exclusively
* `:singleton` - defines routes for a singleton resource that is looked up by
the client without referencing an ID. Read below for more information
## Singleton resources
When a resource needs to be looked up without referencing an ID, because
it contains only a single entry in the given context, the `:singleton`
option can be used to generate a set of routes that are specific to
such single resource:
* `GET /user` => `:show`
* `GET /user/new` => `:new`
* `POST /user` => `:create`
* `GET /user/edit` => `:edit`
* `PATCH /user` => `:update`
* `PUT /user` => `:update`
* `DELETE /user` => `:delete`
Usage example:
resources "/account", AccountController, only: [:show], singleton: true
## Nested Resources
This macro also supports passing a nested block of route definitions.
This is helpful for nesting children resources within their parents to
generate nested routes.
The given definition:
resources "/users", UserController do
resources "/posts", PostController
end
will include the following routes:
user_post_path GET /users/:user_id/posts PostController :index
user_post_path GET /users/:user_id/posts/:id/edit PostController :edit
user_post_path GET /users/:user_id/posts/new PostController :new
user_post_path GET /users/:user_id/posts/:id PostController :show
user_post_path POST /users/:user_id/posts PostController :create
user_post_path PATCH /users/:user_id/posts/:id PostController :update
PUT /users/:user_id/posts/:id PostController :update
user_post_path DELETE /users/:user_id/posts/:id PostController :delete
"""
defmacro resources(path, controller, opts, do: nested_context) do
add_resources path, controller, opts, do: nested_context
end
@doc """
See `resources/4`.
"""
defmacro resources(path, controller, do: nested_context) do
add_resources path, controller, [], do: nested_context
end
defmacro resources(path, controller, opts) do
add_resources path, controller, opts, do: nil
end
@doc """
See `resources/4`.
"""
defmacro resources(path, controller) do
add_resources path, controller, [], do: nil
end
defp add_resources(path, controller, options, do: context) do
scope =
if context do
quote do
scope resource.member, do: unquote(context)
end
end
quote do
resource = Resource.build(unquote(path), unquote(controller), unquote(options))
var!(add_resources, Phoenix.Router).(resource)
unquote(scope)
end
end
@doc """
Defines a scope in which routes can be nested.
## Examples
scope path: "/api/v1", as: :api_v1, alias: API.V1 do
get "/pages/:id", PageController, :show
end
The generated route above will match on the path `"/api/v1/pages/:id"`
and will dispatch to `:show` action in `API.V1.PageController`. A named
helper `api_v1_page_path` will also be generated.
## Options
The supported options are:
* `:path` - a string containing the path scope
* `:as` - a string or atom containing the named helper scope
* `:alias` - an alias (atom) containing the controller scope
* `:host` - a string containing the host scope, or prefix host scope,
ie `"foo.bar.com"`, `"foo."`
* `:private` - a map of private data to merge into the connection when a route matches
* `:assigns` - a map of data to merge into the connection when a route matches
"""
defmacro scope(options, do: context) do
do_scope(options, context)
end
@doc """
Define a scope with the given path.
This function is a shortcut for:
scope path: path do
...
end
## Examples
scope "/api/v1", as: :api_v1, alias: API.V1 do
get "/pages/:id", PageController, :show
end
"""
defmacro scope(path, options, do: context) do
options = quote do
path = unquote(path)
case unquote(options) do
alias when is_atom(alias) -> [path: path, alias: alias]
options when is_list(options) -> Keyword.put(options, :path, path)
end
end
do_scope(options, context)
end
@doc """
Defines a scope with the given path and alias.
This function is a shortcut for:
scope path: path, alias: alias do
...
end
## Examples
scope "/api/v1", API.V1, as: :api_v1 do
get "/pages/:id", PageController, :show
end
"""
defmacro scope(path, alias, options, do: context) do
options = quote do
unquote(options)
|> Keyword.put(:path, unquote(path))
|> Keyword.put(:alias, unquote(alias))
end
do_scope(options, context)
end
defp do_scope(options, context) do
quote do
Scope.push(__MODULE__, unquote(options))
try do
unquote(context)
after
Scope.pop(__MODULE__)
end
end
end
@doc """
Forwards a request at the given path to a plug.
All paths that match the forwarded prefix will be sent to
the forwarded plug. This is useful for sharing a router between
applications or even breaking a big router into smaller ones.
The router pipelines will be invoked prior to forwarding the
connection.
The forwarded plug will be initialized at compile time.
Note, however, that we don't advise forwarding to another
endpoint. The reason is that plugs defined by your app
and the forwarded endpoint would be invoked twice, which
may lead to errors.
## Examples
scope "/", MyApp do
pipe_through [:browser, :admin]
forward "/admin", SomeLib.AdminDashboard
forward "/api", ApiRouter
end
"""
defmacro forward(path, plug, plug_opts \\ [], router_opts \\ []) do
router_opts = Keyword.put(router_opts, :as, nil)
quote unquote: true, bind_quoted: [path: path, plug: plug] do
plug = Scope.register_forwards(__MODULE__, path, plug)
unquote(add_route(:forward, :*, path, plug, plug_opts, router_opts))
end
end
end