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lib/phoenix/router/helpers.ex

defmodule Phoenix.Router.Helpers do
# Module that generates the routing helpers.
@moduledoc false
alias Phoenix.Router.Route
@doc """
Generates the router module for the given environment and routes.
"""
def define(env, routes) do
ast = for route <- routes, do: defhelper(route)
# It is in general bad practice to generate large chunks of code
# inside quoted expressions. However, we can get away with this
# here for two reasons:
#
# * Helper modules are quite uncommon, typically one per project.
#
# * We inline most of the code for performance, so it is specific
# per helper module anyway.
#
code = quote do
@moduledoc """
Module with named helpers generated from #{inspect unquote(env.module)}.
"""
unquote(ast)
@doc """
Generates a URL for the given path.
"""
def url(path) do
Phoenix.Config.cache(unquote(env.module),
:__phoenix_url_helper__,
&Phoenix.Router.Helpers.url/1) <> path
end
@doc """
Generates a URL for the given path considering the connection data.
"""
def url(%Plug.Conn{}, path), do: url(path)
# Functions used by generated helpers
defp to_path(segments, [], _reserved) do
segments
end
defp to_path(segments, query, reserved) do
dict = for {k, v} <- query,
not (k = to_string(k)) in reserved,
do: {k, v}
case Plug.Conn.Query.encode dict do
"" -> segments
o -> segments <> "?" <> o
end
end
end
Module.create(Module.concat(env.module, Helpers), code,
line: env.line, file: env.file)
end
@doc """
Builds the url from the router configuration.
"""
def url(router) do
{scheme, port} =
cond do
config = router.config(:https) ->
{"https", config[:port]}
config = router.config(:http) ->
{"http", config[:port]}
true ->
{"http", "80"}
end
url = router.config(:url)
scheme = url[:scheme] || scheme
host = url[:host]
port = to_string(url[:port] || port)
case {scheme, port} do
{"https", "443"} -> "https://" <> host
{"http", "80"} -> "http://" <> host
{_, _} -> scheme <> "://" <> host <> ":" <> port
end
end
@doc """
Receives a route and returns the quoted definition for its helper function.
In case a helper name was not given, returns nil.
"""
def defhelper(%Route{helper: nil}), do: nil
def defhelper(%Route{} = route) do
helper = route.helper
action = route.action
{bins, vars} = :lists.unzip(route.binding)
segs = optimize_segments(route.path_segments)
# We are using -1 to avoid warnings in case a path has already been defined.
quote line: -1 do
def unquote(:"#{helper}_path")(unquote(action), unquote_splicing(vars)) do
unquote(:"#{helper}_path")(unquote(action), unquote_splicing(vars), [])
end
def unquote(:"#{helper}_path")(unquote(action), unquote_splicing(vars), params) do
to_path(unquote(segs), params, unquote(bins))
end
end
end
defp optimize_segments([]), do: "/"
defp optimize_segments(segments) when is_list(segments),
do: optimize_segments(segments, "")
defp optimize_segments(segments),
do: quote(do: "/" <> Enum.join(unquote(segments), "/"))
defp optimize_segments([{:|, _, [h, t]}], acc),
do: quote(do: unquote(optimize_segments([h], acc)) <> "/" <> Enum.join(unquote(t), "/"))
defp optimize_segments([h|t], acc) when is_binary(h),
do: optimize_segments(t, quote(do: unquote(acc) <> unquote("/" <> h)))
defp optimize_segments([h|t], acc),
do: optimize_segments(t, quote(do: unquote(acc) <> "/" <> to_string(unquote(h))))
defp optimize_segments([], acc),
do: acc
end