Initial commit

5 files changed, 459 insertions, 0 deletions

diff --git a/lib/boltex.ex b/lib/boltex.ex
new file mode 100644
index 0000000..9de7d3b
--- /dev/null
+++ b/lib/boltex.ex
@@ -0,0 +1,13 @@
+defmodule Boltex do
+  alias Boltex.Bolt
+
+  def test(host, port, query) do
+    {:ok, p}   = :gen_tcp.connect host, port, [active: false, mode: :binary, packet: :raw]
+
+    :ok        = Bolt.handshake :gen_tcp, p
+    :ok        = Bolt.init :gen_tcp, p
+
+    Enum.map Bolt.run_statement(:gen_tcp, p, query), &IO.inspect/1
+  end
+
+end
diff --git a/lib/boltex/bolt.ex b/lib/boltex/bolt.ex
new file mode 100644
index 0000000..dc0c04d
--- /dev/null
+++ b/lib/boltex/bolt.ex
@@ -0,0 +1,209 @@
+defmodule Boltex.Bolt do
+  alias Boltex.{Utils, PackStream}
+  require Logger
+
+  @recv_timeout    1_000
+  @max_chunk_size  65_535
+
+  @user_agent      "Boltex/1.0"
+  @hs_magic        << 0x60, 0x60, 0xB0, 0x17 >>
+  @hs_version      << 1 :: 32, 0 :: 32, 0 :: 32, 0 :: 32 >>
+
+  @zero_chunk      << 0, 0 >>
+
+  @sig_init        0x01
+  @sig_ack_failure 0x0E
+  @sig_reset       0x0F
+  @sig_run         0x10
+  @sig_discard_all 0x2F
+  @sig_pull_all    0x3F
+  @sig_success     0x70
+  @sig_record      0x71
+  @sig_ignored     0x7E
+  @sig_failure     0x7F
+
+  @summary         ~w(success ignored failure)a
+
+  @moduledoc """
+  The Boltex.Bolt module handles the Bolt protocol specific steps (i.e.
+  handshake, init) as well as sending and receiving messages and wrapping
+  them in chunks.
+
+  It abstracts transportation, expecing the transport layer to define
+  send/2 and recv/3 analogous to :gen_tcp.
+  """
+
+  @doc "Does the handshake"
+  def handshake(transport, port) do
+    transport.send port, @hs_magic <> @hs_version
+    case transport.recv(port, 4, @recv_timeout) do
+      {:ok, << 1 :: 32 >>} ->
+        :ok
+
+      response ->
+        Logger.error "Handshake failed. Received: #{Utils.hex_encode response})"
+        {:error, :handshake_failed}
+    end
+  end
+
+  @doc """
+  Initialises the connection.
+  """
+  def init(transport, port, params \\ %{}) do
+    send_messages transport, port, [{[@user_agent, params], @sig_init}]
+
+    case receive_data(transport, port) do
+      {:success, %{}} ->
+        :ok
+
+      response ->
+        Logger.error "Init failed. Received: #{Utils.hex_encode response})"
+        {:error, :init_failed}
+    end
+  end
+
+  @doc """
+  Sends a list of messages using the Bolt protocol and PackStream encoding.
+
+  Messages have to be in the form of {[messages], signature}.
+  """
+  def send_messages(transport, port, messages) do
+    Enum.map(messages, &generate_binary_message/1)
+    |> generate_chunks
+    |> Enum.each(&(transport.send(port, &1)))
+  end
+
+  defp generate_binary_message({messages, signature}) do
+    messages    = List.wrap messages
+    struct_size = length messages
+
+    << 0xB :: 4, struct_size :: 4, signature >> <>
+    Utils.reduce_to_binary(messages, &PackStream.encode/1)
+  end
+
+  defp generate_chunks(messages, chunks \\ [], current_chunk \\ <<>>)
+  defp generate_chunks([], chunks, current_chunk) do
+    [current_chunk | chunks]
+    |> Enum.reverse
+  end
+  defp generate_chunks([message | messages], chunks, current_chunk)
+  when byte_size(current_chunk <> message) <= @max_chunk_size do
+    message_size  = byte_size message
+    current_chunk =
+      current_chunk <>
+      << message_size :: 16 >> <>
+      message <>
+      @zero_chunk
+
+    generate_chunks messages, chunks, current_chunk
+  end
+  defp generate_chunks([chunk | chunks], chunks, current_chunk) do
+    oversized_chunk = current_chunk <> chunk
+    {first, rest}   = binary_part oversized_chunk, 0, @max_chunk_size
+    first_size      = byte_size first
+    rest_size       = byte_size rest
+    current_chunk   = current_chunk <> << first_size :: 16 >> <> first
+    new_chunk       = << rest_size :: 16 >> <> rest
+
+    generate_chunks chunks, [current_chunk | chunks], new_chunk
+  end
+
+  @doc """
+  Runs a statement (most like Cypher statement) and returns a list of the
+  records and a summary.
+
+  Records are represented using PackStream's record data type. Their Elixir
+  representation is a Keyword with the indexse `:sig` and `:fields`.
+
+  ## Examples
+
+      iex> Boltex.Bolt.run_statement("MATCH (n) RETURN n")
+      [
+        {:record, [sig: 1, fields: [1, "Exmaple", "Labels", %{"some_attribute" => "some_value"},
+        {:success, %{"type" => "r"}}
+      ]
+  """
+  def run_statement(transport, port, statement, params \\ %{}) do
+    send_messages transport, port, [
+      {[statement, params], @sig_run},
+      {[nil], @sig_pull_all}
+    ]
+
+    with {:success, %{}} <- receive_data(transport, port),
+    do:  receive_data transport, port
+  end
+
+  @doc """
+  Receives data.
+
+  This function is supposed to be called after a request to the server has been
+  made. It receives data chunks, mends them (if they were split between frames)
+  and decodes them using PackStream.
+
+  When just a single message is received (i.e. to acknowledge a command), this
+  function returns a tuple with two items, the first being the signature and the
+  second being the message(s) itself. If a list of messages is received it will
+  return a list of the former.
+
+  The same goes for the messages: If there was a single data point in a message
+  said data point will be returned by itself. If there were multiple data points,
+  the list will be returned.
+
+  The signature is represented as one of the following:
+
+  * `:success`
+  * `:record`
+  * `:ignored`
+  * `:failure`
+  """
+  def receive_data(transport, port, previous \\ []) do
+    case do_receive_data(transport, port) |> unpack do
+      {:record, _} = data ->
+        receive_data transport, port, [data | previous]
+
+      {status, _} = data when status in @summary and previous == [] ->
+        data
+
+      {status, _} = data when status in @summary ->
+        Enum.reverse [data | previous]
+    end
+  end
+
+  defp do_receive_data(transport, port) do
+    with {:ok, <<chunk_size :: 16>>} <- transport.recv(port, 2, @recv_timeout),
+    do:  do_receive_data(transport, port, chunk_size)
+  end
+  defp do_receive_data(transport, port, chunk_size) do
+    with {:ok, data} <- transport.recv(port, chunk_size, @recv_timeout)
+    do
+      case transport.recv(port, 2, @recv_timeout) do
+        {:ok, @zero_chunk} ->
+          data
+        {:ok, <<chunk_size :: 16>>} ->
+          data <> do_receive_data(transport, port, chunk_size)
+      end
+    else
+      {:error, :timeout} ->
+        {:error, :no_more_data_received}
+      other ->
+        IO.inspect Utils.hex_encode other
+        raise "receive failed"
+    end
+  end
+
+  @doc """
+  Unpacks (or in other words parses) a message.
+  """
+  def unpack(<< 0x0B :: 4, packages :: 4, status, message :: binary >>) do
+    response = PackStream.decode(message)
+    response = if packages == 1, do: List.first(response), else: response
+
+    case status do
+      @sig_success -> {:success, response}
+      @sig_record  -> {:record,  response}
+      @sig_ignored -> {:ignored, response}
+      @sig_failure -> {:failure, response}
+      other        -> raise "Couldn't decode #{Utils.hex_encode << other >>}"
+    end
+  end
+end
diff --git a/lib/boltex/pack_stream.ex b/lib/boltex/pack_stream.ex
new file mode 100644
index 0000000..ada9667
--- /dev/null
+++ b/lib/boltex/pack_stream.ex
@@ -0,0 +1,113 @@
+defmodule Boltex.PackStream do
+  @moduledoc """
+  The PackStream implementation for Bolt.
+
+  This module defines a decode function, that will take a binary stream of data
+  and recursively turn it into a list of Elixir data types.
+
+  It further defines a function for encoding Elixir data types into a binary
+  stream, using the Boltex.PackStream.Encoder protocol.
+  """
+
+  @doc """
+  Encodes a list of items into their binary representation.
+
+  As developers tend to be lazy, single objects may be passed.
+
+  ## Examples
+
+      iex> Boltex.PackStream.encode "hello world"
+      <<0x8B, 0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x20, 0x77, 0x6F, 0x72, 0x6C, 0x64>>
+  """
+  def encode(item), do: Boltex.PackStream.Encoder.encode(item)
+
+  ##
+  # Decode
+  @doc "Decodes a binary stream recursively into Elixir data types"
+  # Null
+  def decode(<< 0xC0, rest :: binary >>), do: [nil| decode(rest)]
+
+  # Boolean
+  def decode(<< 0xC3, rest :: binary >>), do: [true  | decode(rest)]
+  def decode(<< 0xC2, rest :: binary >>), do: [false | decode(rest)]
+
+  # Float
+  def decode(<< 0xC1, number :: float, rest :: binary >>) do
+    [number | decode(rest)]
+  end
+
+  # Strings
+  def decode(<< 0x8 :: 4, str_length :: 4, rest :: bytes >>) do
+    decode_text rest, str_length
+  end
+  def decode(<< 0xD0, str_length, rest :: bytes >>) do
+    decode_text rest, str_length
+  end
+  def decode(<< 0xD1, str_length :: 16, rest :: bytes >>) do
+    decode_text rest, str_length
+  end
+  def decode(<< 0xD2, str_length :: 32, rest :: binary >>) do
+    decode_text rest, str_length
+  end
+
+  # Lists
+  # FIXME: Make sure list size is correct, only collect items within list-size.
+  def decode(<< 0x9 :: 4, _list_size :: 4, list :: binary >>), do: [decode list]
+  def decode(<< 0xD4, _list_size :: 8, list :: binary >>),     do: [decode list]
+  def decode(<< 0xD5, _list_size :: 16, list :: binary >>),    do: [decode list]
+  def decode(<< 0xD6, _list_size :: 32, list :: binary >>),    do: [decode list]
+  def decode(<< 0xD7, list :: binary >>) do
+    position =
+      for(<<byte <- list>>, do: byte)
+      |> Enum.find_index(&(&1 == 0xDF))
+
+    << list :: binary-size(position), 0xDF, rest :: binary >> = list
+
+    [decode(list) | decode(rest)]
+  end
+
+  # Maps
+  # FIXME: Make sure map size is correct, only collect items within map-size.
+  def decode(<< 0xA :: 4, _entries :: 4, map :: binary>>), do: decode_map(map)
+  def decode(<< 0xD8, _entries, map :: binary >>),          do: decode_map(map)
+  def decode(<< 0xD9, _entries :: 16, map :: binary >>),    do: decode_map(map)
+  def decode(<< 0xDA, _entries :: 32, map :: binary >>),    do: decode_map(map)
+  def decode(<< 0xDB, map :: binary >>) do
+    position =
+      for(<<byte <- map>>, do: byte)
+      |> Enum.find_index(&(&1 == 0xDF))
+
+    << map:: binary-size(position), 0xDF, rest :: binary >> = map
+
+    decode_map(map) ++ decode(rest)
+  end
+
+  # Struct
+  def decode(<< 0xB :: 4, _struct_size :: 4, sig :: 8>> <> struct) do
+    [sig: sig, fields: decode(struct)]
+  end
+
+  def decode(<<0, 0>>), do: []
+  def decode(""), do: []
+
+  # Integers
+  def decode(<< 0xC8, int, rest :: binary >>),       do: [int | decode(rest)]
+  def decode(<< 0xC9, int :: 16, rest :: binary >>), do: [int | decode(rest)]
+  def decode(<< 0xCA, int :: 32, rest :: binary >>), do: [int | decode(rest)]
+  def decode(<< 0xCB, int :: 64, rest :: binary >>), do: [int | decode(rest)]
+  def decode(<< int, rest :: binary >>),             do: [int | decode(rest)]
+
+  defp decode_text(bytes, str_length) do
+    << string :: binary-size(str_length), rest :: binary >> = bytes
+
+    [string | decode(rest)]
+  end
+
+  defp decode_map(map) do
+    decode(map)
+    |> Enum.chunk(2)
+    |> Enum.map(&List.to_tuple/1)
+    |> Enum.into(%{})
+    |> List.wrap
+  end
+end
diff --git a/lib/boltex/pack_stream/encoder.ex b/lib/boltex/pack_stream/encoder.ex
new file mode 100644
index 0000000..bd7dc6e
--- /dev/null
+++ b/lib/boltex/pack_stream/encoder.ex
@@ -0,0 +1,110 @@
+defprotocol Boltex.PackStream.Encoder do
+  @doc "Encodes an item to its binary PackStream Representation"
+  def encode(entitiy)
+end
+
+defimpl Boltex.PackStream.Encoder, for: Atom do
+  def encode(nil),   do: << 0xC0 >>
+  def encode(true),  do: << 0xC3 >>
+  def encode(false), do: << 0xC2 >>
+  def encode(other) when is_atom(other) do
+    other
+    |> Atom.to_string
+    |> Boltex.PackStream.Encoder.encode
+  end
+end
+
+defimpl Boltex.PackStream.Encoder, for: Integer do
+  @int8 -127..-17
+  @int16_low  -32_768..-129
+  @int16_high 128..32_767
+  @int32_low  -2_147_483_648..-32_769
+  @int32_high 32_768..2_147_483_647
+  @int64_low  -9_223_372_036_854_775_808..-2_147_483_649
+  @int64_high 2_147_483_648..9_223_372_036_854_775_807
+
+  def encode(integer) when integer in -16..127 do
+    <<integer>>
+  end
+  def encode(integer) when integer in @int8 do
+    << 0xC8, integer >>
+  end
+  def encode(integer) when integer in @int16_low  or integer in @int16_high do
+    << 0xC9, integer >>
+  end
+  def encode(integer) when integer in @int32_low  or integer in @int32_high do
+    << 0xCA, integer >>
+  end
+  def encode(integer) when integer in @int64_low  or integer in @int64_high do
+    << 0xCB, integer >>
+  end
+end
+
+defimpl Boltex.PackStream.Encoder, for: BitString do
+  def encode(string), do: do_encode(string, byte_size(string))
+
+  defp do_encode(string, size) when size <= 15 do
+    << 0x8 :: 4, size :: 4 >> <> string
+  end
+  defp do_encode(string, size) when size <= 255 do
+    << 0xD0, size :: 8 >> <> string
+  end
+  defp do_encode(string, size) when size <= 65_535 do
+    << 0xD1, size :: 16 >> <> string
+  end
+  defp do_encode(string, size) when size <= 4_294_967_295 do
+    << 0xD2, size :: 32 >> <> string
+  end
+end
+
+defimpl Boltex.PackStream.Encoder, for: List do
+  def encode(list) do
+    binary = Enum.map_join list, &Boltex.PackStream.Encoder.encode/1
+
+    do_encode binary, byte_size(binary)
+  end
+
+  defp do_encode(binary, list_size) when list_size <= 15 do
+    << 0x9 :: 4, list_size :: 4 >> <> binary
+  end
+  defp do_encode(binary, list_size) when list_size <= 255 do
+    << 0xD4, list_size :: 8 >> <> binary
+  end
+  defp do_encode(binary, list_size) when list_size <= 65_535 do
+    << 0xD5, list_size :: 16 >> <> binary
+  end
+  defp do_encode(binary, list_size) when list_size <= 4_294_967_295 do
+    << 0xD6, list_size :: 32 >> <> binary
+  end
+  defp do_encode(binary, _size) do
+    << 0xD7 >> <> binary <> <<0xDF>>
+  end
+end
+
+defimpl Boltex.PackStream.Encoder, for: Map do
+  def encode(map) do
+    do_encode map, map_size(map)
+  end
+
+  defp do_encode(map, size) when size <= 15 do
+    << 0xA :: 4, size :: 4 >> <> encode_kv(map)
+  end
+  defp do_encode(map, size) when size <= 255 do
+    << 0xD8, size :: 8 >> <> encode_kv(map)
+  end
+  defp do_encode(map, size) when size <= 65_535 do
+    << 0xD9, size :: 16 >> <> encode_kv(map)
+  end
+  defp do_encode(map, size) when size <= 4_294_967_295 do
+    << 0xDA, size :: 32 >> <> encode_kv(map)
+  end
+
+  defp encode_kv(map) do
+    Boltex.Utils.reduce_to_binary map, &do_reduce_kv/1
+  end
+
+  defp do_reduce_kv({key, value}) do
+    Boltex.PackStream.Encoder.encode(key) <>
+    Boltex.PackStream.Encoder.encode(value)
+  end
+end
diff --git a/lib/boltex/utils.ex b/lib/boltex/utils.ex
new file mode 100644
index 0000000..333217e
--- /dev/null
+++ b/lib/boltex/utils.ex
@@ -0,0 +1,14 @@
+defmodule Boltex.Utils do
+  def reduce_to_binary(enumerable, transform) do
+    Enum.reduce enumerable, <<>>, fn(data, acc) -> acc <> transform.(data) end
+  end
+
+  def hex_encode(bytes) do
+    for << i <- bytes >>, do: Integer.to_string(i, 16)
+  end
+
+  def hex_decode(hex_list) do
+    for(hex <- hex_list, do: Integer.parse(hex, 16) |> elem(0))
+    |> reduce_to_binary(&<<&1>>)
+  end
+end