defmodule Ankh.HTTP do
@moduledoc """
HTTP public interface
This module implements `Ankh` public APIs and provides protocol negotiation.
"""
alias Ankh.{HTTP, HTTP1, HTTP2, Protocol, TCP, TLS, Transport}
alias HTTP.{Request, Response}
alias HTTP2.Error
@typedoc "HTTP body"
@type body :: iodata()
@typedoc "HTTP Header name"
@type header_name :: String.t()
@typedoc "HTTP Header value"
@type header_value :: String.t()
@typedoc "HTTP Header"
@type header :: {header_name(), header_value()}
@typedoc "HTTP Headers"
@type headers :: [header()]
@type complete :: boolean()
@type response ::
{:data, reference(), iodata(), complete()}
| {:headers | :push_promise, reference(), headers(), complete()}
| {:error, reference, Error.t(), complete()}
@doc """
Accepts an HTTP connection
After accepting the connection, `stream` will receive requests from the client and `respond`
can be used to send replies.
"""
@spec accept(URI.t(), Transport.socket(), Transport.options()) ::
{:ok, Protocol.t()} | {:error, any()}
def accept(uri, socket, options \\ [])
def accept(%URI{scheme: "http"} = uri, socket, options),
do: Protocol.accept(%HTTP1{}, uri, %TCP{}, socket, options)
def accept(%URI{scheme: "https"} = uri, socket, options) do
with {:ok, negotiated_protocol} <- Transport.negotiated_protocol(%TLS{socket: socket}),
{:ok, protocol} <- protocol_for_id(negotiated_protocol),
{:ok, protocol} <- Protocol.accept(protocol, uri, %TLS{}, socket, options),
do: {:ok, protocol}
end
def accept(_uri, _socket, _options), do: {:error, :unsupported_uri_scheme}
@doc """
Establishes an HTTP connection to a server
After establishing the connection, `request` can be user to send request to the server and
`stream` can be used to receive receive responses.
"""
@spec connect(URI.t(), Transport.options()) ::
{:ok, Protocol.t()} | {:error, any()}
def connect(uri, options \\ [])
def connect(%URI{scheme: "http"} = uri, options) do
{timeout, options} = Keyword.pop(options, :timeout, 5_000)
with {:ok, transport} <- Transport.connect(%TCP{}, uri, timeout, options),
{:ok, protocol} <- Protocol.connect(%HTTP1{}, uri, transport, options),
do: {:ok, protocol}
end
def connect(%URI{scheme: "https"} = uri, options) do
{:ok, tls_options} = Plug.SSL.configure(cipher_suite: :strong, key: nil, cert: nil)
tls_options =
tls_options
|> Keyword.take([:versions, :ciphers, :eccs])
|> Keyword.merge(alpn_advertised_protocols: ["h2", "http/1.1"])
{timeout, options} =
options
|> Keyword.merge(tls_options)
|> Keyword.pop(:timeout, 5_000)
with {:ok, transport} <- Transport.connect(%TLS{}, uri, timeout, options),
{:ok, negotiated_protocol} <- Transport.negotiated_protocol(transport),
{:ok, protocol} <- protocol_for_id(negotiated_protocol),
{:ok, protocol} <- Protocol.connect(protocol, uri, transport, options),
do: {:ok, protocol}
end
def connect(_uri, _options), do: {:error, :unsupported_uri_scheme}
defp protocol_for_id("http/1.1"), do: {:ok, %HTTP1{}}
defp protocol_for_id("h2"), do: {:ok, %HTTP2{}}
defp protocol_for_id(_id), do: {:error, :unsupported_protocol_identifier}
@doc """
Sends a request to a server
Needs a connection to be established via `connect` beforehand.
"""
@spec request(Protocol.t(), Request.t()) ::
{:ok, Protocol.t(), Protocol.request_ref()} | {:error, any()}
def request(protocol, request), do: Protocol.request(protocol, request)
@doc """
Sends a response to a client request
Needs a connection to be accepted via `accept` beforehand.
"""
@spec respond(Protocol.t(), Protocol.request_ref(), Response.t()) ::
{:ok, Protocol.t()} | {:error, any()}
def respond(protocol, reference, response),
do: Protocol.respond(protocol, reference, response)
@doc """
Receives data form the the peer and returns responses
"""
@spec stream(Protocol.t(), any()) :: {:ok, Protocol.t(), any()} | {:error, any()}
def stream(protocol, msg), do: Protocol.stream(protocol, msg)
@doc """
Closes the underlying connection
"""
@spec close(Protocol.t()) :: :ok | {:error, any()}
def close(%{transport: transport} = protocol) do
with {:ok, transport} <- Transport.close(transport),
do: {:ok, %{protocol | transport: transport}}
end
@doc """
Reports a connection error
"""
@spec error(Protocol.t()) :: :ok | {:error, any()}
def error(protocol), do: Protocol.error(protocol)
@doc false
@spec put_header(Request.t() | Response.t(), HTTP.header_name(), HTTP.header_value()) ::
Request.t() | Response.t()
def put_header(%{headers: headers} = response, name, value),
do: %{response | headers: [{String.downcase(name), value} | headers]}
@doc false
@spec put_headers(Request.t() | Response.t(), HTTP.headers()) :: Request.t() | Response.t()
def put_headers(response, headers),
do:
Enum.reduce(headers, response, fn {header, value}, acc ->
put_header(acc, header, value)
end)
@doc false
@spec put_trailer(Request.t() | Response.t(), HTTP.header_name(), HTTP.header_value()) ::
Request.t() | Response.t()
def put_trailer(%{trailers: trailers} = response, name, value),
do: %{response | trailers: [{String.downcase(name), value} | trailers]}
@doc false
@spec put_trailers(Request.t() | Response.t(), HTTP.headers()) :: Request.t() | Response.t()
def put_trailers(response, trailers) do
Enum.reduce(trailers, response, fn {header, value}, acc ->
put_trailer(acc, header, value)
end)
end
@doc false
@spec validate_body(Request.t() | Response.t()) :: {:ok, Request.t() | Response.t()} | :error
def validate_body(%{body: body} = request) do
with content_length when not is_nil(content_length) <-
request
|> fetch_header_values("content-length")
|> List.first(),
data_length when data_length != content_length <-
body
|> IO.iodata_length()
|> Integer.to_string() do
:error
else
_ ->
{:ok, request}
end
end
@doc false
@spec fetch_header_values(Request.t() | Response.t(), HTTP.header_name()) :: [
HTTP.header_value()
]
def fetch_header_values(%{headers: headers}, name), do: fetch_values(headers, name)
@doc false
@spec fetch_trailer_values(Request.t() | Response.t(), HTTP.header_name()) :: [
HTTP.header_value()
]
def fetch_trailer_values(%{trailers: trailers}, name), do: fetch_values(trailers, name)
defp fetch_values(headers, name) do
headers
|> Enum.reduce([], fn
{^name, value}, acc ->
[value | acc]
_, acc ->
acc
end)
|> Enum.reverse()
end
@spec validate_trailers(headers(), boolean()) :: :ok | {:error, :protocol_error}
def validate_trailers([], _strict), do: :ok
def validate_trailers([{":" <> _trailer, _value} | _rest], _strict),
do: {:error, :protocol_error}
def validate_trailers([{name, _value} | rest], strict) do
if header_name_valid?(name, strict) do
validate_trailers(rest, strict)
else
{:error, :protocol_error}
end
end
@spec header_name_valid?(header_name(), boolean()) :: boolean()
def header_name_valid?(name, false = _strict) do
name
|> String.downcase()
|> header_name_valid?(true)
end
def header_name_valid?(name, true = _strict),
do: name =~ ~r(^[[:lower:][:digit:]\!\#\$\%\&\'\*\+\-\.\^\_\`\|\~]+$)
end
