Packages
plug
0.9.0
1.20.3
1.20.2
1.20.1
retired
1.20.0
retired
1.19.5
1.19.4
1.19.3
1.19.2
1.19.1
1.19.0
1.18.5
1.18.4
1.18.3
1.18.2
1.18.1
1.18.0
1.17.4
1.17.3
1.17.2
1.17.1
1.17.0
1.16.6
1.16.5
1.16.4
1.16.3
1.16.2
1.16.1
1.16.0
1.15.6
1.15.5
1.15.4
1.15.3
1.15.2
1.15.1
1.15.0
1.14.2
1.14.1
1.14.0
1.13.6
1.13.5
1.13.4
1.13.3
1.13.2
1.13.1
retired
1.13.0
retired
1.12.1
1.12.0
1.11.1
1.11.0
1.10.4
1.10.3
1.10.2
1.10.1
1.10.0
1.9.0
1.8.3
1.8.2
1.8.1
1.8.0
1.7.2
1.7.1
1.7.0
1.6.4
1.6.3
1.6.2
1.6.1
1.6.0
1.5.1
1.5.0
1.5.0-rc.2
1.5.0-rc.1
1.5.0-rc.0
1.4.5
1.4.4
1.4.3
1.4.2
1.4.1
1.4.0
1.4.0-rc.0
1.3.6
1.3.5
1.3.4
1.3.3
1.3.2
1.3.1
1.3.0
1.2.6
1.2.5
1.2.4
1.2.3
1.2.2
1.2.1
1.2.0
1.2.0-rc.0
1.1.9
1.1.8
1.1.7
1.1.6
1.1.5
1.1.4
1.1.3
1.1.2
1.1.1
1.1.0
1.0.6
1.0.5
1.0.4
1.0.3
1.0.2
1.0.1
1.0.0
0.14.0
0.13.1
0.13.0
0.12.2
0.12.1
0.12.0
0.11.3
0.11.2
0.11.1
0.11.0
0.10.0
0.9.0
0.8.4
0.8.3
0.8.2
0.8.1
0.8.0
0.7.0
0.6.0
0.5.3
0.5.2
0.5.1
0.5.0
0.4.4
0.4.3
0.4.2
0.4.1
Compose web applications with functions
Security advisory:
This version has known vulnerabilities.
View advisories
Current section
Files
Jump to
Current section
Files
lib/plug/conn/query.ex
defmodule Plug.Conn.Query do
@moduledoc """
Conveniences for decoding and encoding url encoded queries
Plug allows a developer to build query strings
that maps to Elixir structures in order to make
manipulation of such structures easier on the server
side. Here are some examples:
iex> decode("foo=bar")["foo"]
"bar"
If a value is given more than once, the last value wins:
iex> decode("foo=bar&foo=baz")["foo"]
"baz"
Nested structures can be created via `[key]`:
iex> decode("foo[bar]=baz")["foo"]["bar"]
"baz"
Lists are created with `[]`:
iex> decode("foo[]=bar&foo[]=baz")["foo"]
["bar", "baz"]
Encoding Dicts:
iex> encode(%{foo: "bar", baz: "bat"})
"baz=bat&foo=bar"
Encoding keyword lists preserves field order:
iex> encode([foo: "bar", baz: "bat"])
"foo=bar&baz=bat"
Encoding keyword lists with duplicate keys, first one wins:
iex> encode([foo: "bar", foo: "bat"])
"foo=bar"
Encoding named lists:
iex> encode(%{foo: ["bar", "baz"]})
"foo[]=bar&foo[]=baz"
Encoding nested structures:
iex> encode(%{foo: %{bar: "baz"}})
"foo[bar]=baz"
"""
@doc """
Decodes the given binary.
"""
def decode(query, initial \\ %{})
def decode("", initial) do
initial
end
def decode(query, initial) do
decoder = URI.query_decoder(query)
Enum.reduce(Enum.reverse(decoder), initial, &decode_pair(&1, &2))
end
@doc """
Decodes the given tuple and store it in the accumulator.
It parses the key and stores the value into te current
accumulator.
Parameters lists are added to the accumulator in reverse
order, so be sure to pass the parameters in reverse order.
"""
def decode_pair({key, value}, acc) do
parts =
if key != "" and :binary.last(key) == ?] do
# Remove trailing ]
subkey = :binary.part(key, 0, byte_size(key) - 1)
# Split the first [ then split remaining ][.
#
# users[address][street #=> [ "users", "address][street" ]
#
case :binary.split(subkey, "[") do
[key, subpart] ->
[key|:binary.split(subpart, "][", [:global])]
_ ->
[key]
end
else
[key]
end
assign_parts parts, value, acc
end
# We always assign the value in the last segment.
# `age=17` would match here.
defp assign_parts([key], value, acc) do
Map.put_new(acc, key, value)
end
# The current segment is a list. We simply prepend
# the item to the list or create a new one if it does
# not yet. This assumes that items are iterated in
# reverse order.
defp assign_parts([key,""|t], value, acc) do
case Map.fetch(acc, key) do
{:ok, current} when is_list(current) ->
Map.put(acc, key, assign_list(t, current, value))
:error ->
Map.put(acc, key, assign_list(t, [], value))
_ ->
acc
end
end
# The current segment is a parent segment of a
# map. We need to create a map and then
# continue looping.
defp assign_parts([key|t], value, acc) do
case Map.fetch(acc, key) do
{:ok, %{} = current} ->
Map.put(acc, key, assign_parts(t, value, current))
:error ->
Map.put(acc, key, assign_parts(t, value, %{}))
_ ->
acc
end
end
defp assign_list(t, current, value) do
if value = assign_list(t, value), do: [value|current], else: current
end
defp assign_list([], value), do: value
defp assign_list(t, value), do: assign_parts(t, value, %{})
@doc """
Encodes the given dict.
"""
def encode(dict) do
encode_pair(nil, dict)
end
# covers maps
defp encode_pair(parent_field, dict) when is_map(dict) do
encode_dict(dict, parent_field)
end
# covers keyword lists
defp encode_pair(parent_field, list) when is_list(list) and is_tuple(hd(list)) do
encode_dict(Enum.uniq(list, &elem(&1, 0)), parent_field)
end
# covers non-keyword lists
defp encode_pair(parent_field, list) when is_list(list) do
Enum.map_join list, "&", &encode_pair("#{parent_field}[]", &1)
end
defp encode_pair(field, value) do
field <> "=" <> encode_www_form(value)
end
defp encode_dict(dict, parent_field) do
Enum.map_join(dict, "&", fn {field, value} ->
field = if parent_field do
"#{parent_field}[#{encode_www_form(field)}]"
else
encode_www_form(field)
end
encode_pair(field, value)
end)
end
defp encode_www_form(item) do
item |> to_string |> URI.encode_www_form
end
end