URI

Utilities for working with URIs.

This module provides functions for working with URIs (for example, parsing URIs or encoding query strings). The functions in this module are implemented according to RFC 3986.

Summary

Types

t()

Functions

char_reserved?(char): Checks if the character is a “reserved” character in a URI
char_unescaped?(char): Checks if the character is allowed unescaped in a URI
char_unreserved?(char): Checks if the character is a “unreserved” character in a URI
decode(uri): Percent-unescapes a URI
decode_query(query, map \\ %{}): Decodes a query string into a map
decode_www_form(string): Decodes a string as “x-www-form-urlencoded”
default_port(scheme): Returns the default port for a given scheme
default_port(scheme, port): Registers the default port for the given scheme
encode(string, predicate \\ &char_unescaped?/1): Percent-escapes all characters that require escaping in a string
encode_query(enumerable): Encodes an enumerable into a query string
encode_www_form(string): Encodes a string as “x-www-form-urlencoded”
merge(uri, rel): Merges two URIs
parse(uri): Parses a well-formed URI reference into its components
query_decoder(query): Returns a stream of two-element tuples representing key-value pairs in the given query
to_string(uri): Returns the string representation of the given URI struct

Types

t()

t() :: %URI{
  authority: nil | binary(),
  fragment: nil | binary(),
  host: nil | binary(),
  path: nil | binary(),
  port: nil | :inet.port_number(),
  query: nil | binary(),
  scheme: nil | binary(),
  userinfo: nil | binary()
}

Functions

char_reserved?(char)

char_reserved?(char()) :: boolean()

Checks if the character is a “reserved” character in a URI.

Reserved characters are specified in RFC 3986, section 2.2.

Examples

iex> URI.char_reserved?(?+)
true

char_unescaped?(char)

char_unescaped?(char()) :: boolean()

Checks if the character is allowed unescaped in a URI.

This is the default used by URI.encode/2 where both reserved and unreserved characters are kept unescaped.

Examples

iex> URI.char_unescaped?(?{)
false

char_unreserved?(char)

char_unreserved?(char()) :: boolean()

Checks if the character is a “unreserved” character in a URI.

Unreserved characters are specified in RFC 3986, section 2.3.

Examples

iex> URI.char_unreserved?(?_)
true

decode(uri)

decode(binary()) :: binary()

Percent-unescapes a URI.

Examples

iex> URI.decode("http%3A%2F%2Felixir-lang.org")
"http://elixir-lang.org"

decode_query(query, map \\ %{})

decode_query(binary(), %{optional(binary()) => binary()}) :: %{
  optional(binary()) => binary()
}

Decodes a query string into a map.

Given a query string of the form of key1=value1&key2=value2..., this function inserts each key-value pair in the query string as one entry in the given map. Keys and values in the resulting map will be binaries. Keys and values will be percent-unescaped.

Use query_decoder/1 if you want to iterate over each value manually.

Examples

iex> URI.decode_query("foo=1&bar=2")
%{"bar" => "2", "foo" => "1"}

iex> URI.decode_query("percent=oh+yes%21", %{"starting" => "map"})
%{"percent" => "oh yes!", "starting" => "map"}

decode_www_form(string)

decode_www_form(binary()) :: binary()

Decodes a string as “x-www-form-urlencoded”.

Examples

iex> URI.decode_www_form("%3Call+in%2F")
"<all in/"

default_port(scheme)

default_port(binary()) :: nil | non_neg_integer()

Returns the default port for a given scheme.

If the scheme is unknown to the URI module, this function returns nil. The default port for any scheme can be configured globally via default_port/2.

Examples

iex> URI.default_port("ftp")
21

iex> URI.default_port("ponzi")
nil

default_port(scheme, port)

default_port(binary(), non_neg_integer()) :: :ok

Registers the default port for the given scheme.

After this function is called, port will be returned by default_port/1 for the given scheme scheme. Note that this function changes the default port for the given scheme globally, meaning for every application.

It is recommended for this function to be invoked in your application’s start callback in case you want to register new URIs.

encode(string, predicate \\ &char_unescaped?/1)

encode(binary(), (byte() -> boolean())) :: binary()

Percent-escapes all characters that require escaping in a string.

This means reserved characters, such as : and /, and the so- called unreserved characters, which have the same meaning both escaped and unescaped, won’t be escaped by default.

See encode_www_form if you are interested in escaping reserved characters too.

This function also accepts a predicate function as an optional argument. If passed, this function will be called with each byte in string as its argument and should return true if the given byte should be left as is.

Examples

iex> URI.encode("ftp://s-ite.tld/?value=put it+й")
"ftp://s-ite.tld/?value=put%20it+%D0%B9"

iex> URI.encode("a string", &(&1 != ?i))
"a str%69ng"

encode_query(enumerable)

encode_query(term()) :: binary()

Encodes an enumerable into a query string.

Takes an enumerable that enumerates as a list of two-element tuples (e.g., a map or a keyword list) and returns a string in the form of key1=value1&key2=value2... where keys and values are URL encoded as per encode_www_form/1.

Keys and values can be any term that implements the String.Chars protocol, except lists which are explicitly forbidden.

Examples

iex> hd = %{"foo" => 1, "bar" => 2}
iex> URI.encode_query(hd)
"bar=2&foo=1"

iex> query = %{"key" => "value with spaces"}
iex> URI.encode_query(query)
"key=value+with+spaces"

iex> URI.encode_query(%{key: [:a, :list]})
** (ArgumentError) encode_query/1 values cannot be lists, got: [:a, :list]

encode_www_form(string)

encode_www_form(binary()) :: binary()

Encodes a string as “x-www-form-urlencoded”.

Example

iex> URI.encode_www_form("put: it+й")
"put%3A+it%2B%D0%B9"

merge(uri, rel)

merge(t() | binary(), t() | binary()) :: t()

Merges two URIs.

This function merges two URIs as per RFC 3986, section 5.2.

Examples

iex> URI.merge(URI.parse("http://google.com"), "/query") |> to_string
"http://google.com/query"

iex> URI.merge("http://example.com", "http://google.com") |> to_string
"http://google.com"

parse(uri)

parse(t() | binary()) :: t()

Parses a well-formed URI reference into its components.

Note this function expects a well-formed URI and does not perform any validation. See the “Examples” section below for examples of how URI.parse/1 can be used to parse a wide range of URIs.

This function uses the parsing regular expression as defined in RFC 3986, Appendix B.

When a URI is given without a port, the value returned by URI.default_port/1 for the URI’s scheme is used for the :port field.

If a %URI{} struct is given to this function, this function returns it unmodified.

Examples

iex> URI.parse("http://elixir-lang.org/")
%URI{scheme: "http", path: "/", query: nil, fragment: nil,
     authority: "elixir-lang.org", userinfo: nil,
     host: "elixir-lang.org", port: 80}

iex> URI.parse("//elixir-lang.org/")
%URI{authority: "elixir-lang.org", fragment: nil, host: "elixir-lang.org",
     path: "/", port: nil, query: nil, scheme: nil, userinfo: nil}

iex> URI.parse("/foo/bar")
%URI{authority: nil, fragment: nil, host: nil, path: "/foo/bar",
     port: nil, query: nil, scheme: nil, userinfo: nil}

iex> URI.parse("foo/bar")
%URI{authority: nil, fragment: nil, host: nil, path: "foo/bar",
     port: nil, query: nil, scheme: nil, userinfo: nil}

query_decoder(query)

query_decoder(binary()) :: Enumerable.t()

Returns a stream of two-element tuples representing key-value pairs in the given query.

Key and value in each tuple will be binaries and will be percent-unescaped.

Examples

iex> URI.query_decoder("foo=1&bar=2") |> Enum.to_list()
[{"foo", "1"}, {"bar", "2"}]

to_string(uri)

to_string(t()) :: binary()

Returns the string representation of the given URI struct.

Examples

iex> URI.to_string(URI.parse("http://google.com"))
"http://google.com"

iex> URI.to_string(%URI{scheme: "foo", host: "bar.baz"})
"foo://bar.baz"

Note that when creating this string representation, the authority will be used if the host is nil. Otherwise, the userinfo, host, and port will be used.

iex> URI.to_string(%URI{authority: "[email protected]:80"})
"//[email protected]:80"

iex> URI.to_string(%URI{userinfo: "bar", host: "example.org", port: 81})
"//[email protected]:81"

iex> URI.to_string(%URI{authority: "[email protected]:80",
...>                    userinfo: "bar", host: "example.org", port: 81})
"//[email protected]:81"