Fix LOCAL INFILE options in mysql driver handshake

lib/myxql.ex

@@ -23,6 +23,7 @@ defmodule MyXQL do
           | {:prepare, :force_named | :named | :unnamed}
           | {:disconnect_on_error_codes, [atom()]}
           | {:enable_cleartext_plugin, boolean()}
+          | {:local_infile, boolean()}
           | DBConnection.start_option()
 
   @type option() :: DBConnection.option()
@@ -103,6 +104,8 @@ defmodule MyXQL do
 
     * `:enable_cleartext_plugin` - Set to `true` to send password as cleartext (default: `false`)
 
+    * `:local_infile` - Set to `true` to enable LOCAL INFILE capability (default: `false`)
+
    The given options are passed down to DBConnection, some of the most commonly used ones are
    documented below:
 

lib/myxql/client.ex

@@ -27,7 +27,8 @@
       :max_packet_size,
       :charset,
       :collation,
-      :enable_cleartext_plugin
+      :enable_cleartext_plugin,
+      :local_infile
     ]
 
     @sock_opts [mode: :binary, packet: :raw, active: false]
@@ -67,7 +68,8 @@
         socket_options: (opts[:socket_options] || []) ++ @sock_opts,
         charset: Keyword.get(opts, :charset),
         collation: Keyword.get(opts, :collation),
-        enable_cleartext_plugin: Keyword.get(opts, :enable_cleartext_plugin, false)
+        enable_cleartext_plugin: Keyword.get(opts, :enable_cleartext_plugin, false),
+        local_infile: Keyword.get(opts, :local_infile, false)
       }
     end
 
@@ -135,7 +137,32 @@
 
   def com_query(client, statement, result_state \\ :single) do
     with :ok <- send_com(client, {:com_query, statement}) do
-      recv_packets(client, &decode_com_query_response/3, :initial, result_state)
+      case recv_packets(client, &decode_com_query_response/3, :initial, result_state) do
+        {:ok, {:local_infile, filename}} ->
+          case handle_local_infile(client, filename) do
+            :ok ->
+              recv_packets(client, &decode_com_query_response/3, :initial, result_state)
+
+            error ->
+              error
+          end
+
+        other ->
+          other
+      end
+    end
+  end
+
+  def handle_local_infile(client, filename) do
+    case File.read(filename) do
+      {:ok, content} ->
+        with :ok <- send_packet(client, content, 2),
+             :ok <- send_packet(client, <<>>, 3) do
+          :ok
+        end
+
+      {:error, reason} ->
+        send_packet(client, <<>>, 2)
     end
   end
 
@@ -265,6 +292,15 @@
           {:many, results} -> {:ok, [result | results]}
         end
 
+      {:local_infile, filename} ->
+        case handle_local_infile(client, filename) do
+          :ok ->
+            recv_packets(rest, decoder, decoder_state, result_state, timeout, client)
+
+          {:error, reason} ->
+            {:error, reason}
+        end
+
       {:error, _} = error ->
         error
     end

lib/myxql/protocol.ex

@@ -180,6 +180,7 @@ defmodule MyXQL.Protocol do
       ])
       |> maybe_put_capability_flag(:client_connect_with_db, !is_nil(config.database))
       |> maybe_put_capability_flag(:client_ssl, is_list(config.ssl_opts))
+      |> maybe_put_capability_flag(:client_local_files, config.local_infile)
 
     if config.ssl_opts && !has_capability_flag?(server_capability_flags, :client_ssl) do
       {:error, :server_does_not_support_ssl}
@@ -331,6 +332,12 @@ defmodule MyXQL.Protocol do
     {:halt, decode_ok_packet_body(rest)}
   end
 
+  def decode_com_query_response(<<0xFB, rest::binary>>, "", :initial) do
+    {filename, _remaining} = take_string_nul(rest)
+
+    {:local_infile, filename}
+  end
+
   def decode_com_query_response(<<0xFF, rest::binary>>, "", :initial) do
     {:halt, decode_err_packet_body(rest)}
   end
@@ -513,6 +520,11 @@ defmodule MyXQL.Protocol do
     {:cont, :initial, {:many, [resultset | results]}}
   end
 
+  defp decode_resultset(<<0xFB, rest::binary>>, _next_data, :initial, _row_decoder) do
+    {filename, ""} = take_string_nul(rest)
+    {:local_infile, filename}
+  end
+
   defp decode_resultset(payload, _next_data, :initial, _row_decoder) do
     {:cont, {:column_defs, decode_int_lenenc(payload), []}}
   end

lib/myxql/protocol/types.ex

@@ -27,14 +27,16 @@ defmodule MyXQL.Protocol.Types do
   def encode_int_lenenc(int) when int < 0xFFFFFFFFFFFFFFFF, do: <<0xFE, int::uint8()>>
 
   def decode_int_lenenc(binary) do
-    {integer, ""} = take_int_lenenc(binary)
+    {integer, _rest} = take_int_lenenc(binary)
     integer
   end
 
   def take_int_lenenc(<<int::uint1(), rest::binary>>) when int < 251, do: {int, rest}
+  def take_int_lenenc(<<0xFB, rest::binary>>), do: {nil, rest}
   def take_int_lenenc(<<0xFC, int::uint2(), rest::binary>>), do: {int, rest}
   def take_int_lenenc(<<0xFD, int::uint3(), rest::binary>>), do: {int, rest}
   def take_int_lenenc(<<0xFE, int::uint8(), rest::binary>>), do: {int, rest}
+  def take_int_lenenc(<<0xFF, rest::binary>>), do: {:error, rest}
 
   # https://dev.mysql.com/doc/internals/en/string.html#packet-Protocol::FixedLengthString
   defmacro string(size) do
@@ -68,8 +70,13 @@ defmodule MyXQL.Protocol.Types do
 
   def take_string_nul(""), do: {nil, ""}
 
-  def take_string_nul(binary) do
-    [string, rest] = :binary.split(binary, <<0>>)
-    {string, rest}
+  def take_string_nul(binary) when is_binary(binary) do
+    case :binary.split(binary, <<0>>) do
+      [string] ->
+        {string, ""}
+
+      [string, rest] ->
+        {string, rest}
+    end
   end
 end