🎨 Improve Elixir coding practices

config/.credo.exs

@@ -79,7 +79,7 @@
         {Credo.Check.Readability.AliasOrder, []},
         {Credo.Check.Readability.FunctionNames, []},
         {Credo.Check.Readability.LargeNumbers, []},
-        {Credo.Check.Readability.MaxLineLength, [priority: :low, max_length: 100]},
+        {Credo.Check.Readability.MaxLineLength, [max_length: 98]},
         {Credo.Check.Readability.ModuleAttributeNames, []},
         {Credo.Check.Readability.ModuleDoc, []},
         {Credo.Check.Readability.ModuleNames, []},
@@ -102,7 +102,7 @@
         {Credo.Check.Refactor.CyclomaticComplexity, []},
         {Credo.Check.Refactor.FunctionArity, []},
         {Credo.Check.Refactor.LongQuoteBlocks, []},
-        {Credo.Check.Refactor.MapInto, []},
+        {Credo.Check.Refactor.MapInto, false},
         {Credo.Check.Refactor.MatchInCondition, []},
         {Credo.Check.Refactor.NegatedConditionsInUnless, []},
         {Credo.Check.Refactor.NegatedConditionsWithElse, []},
@@ -121,7 +121,7 @@
         {Credo.Check.Warning.ExpensiveEmptyEnumCheck, []},
         {Credo.Check.Warning.IExPry, []},
         {Credo.Check.Warning.IoInspect, []},
-        {Credo.Check.Warning.LazyLogging, []},
+        {Credo.Check.Warning.LazyLogging, false},
         {Credo.Check.Warning.OperationOnSameValues, []},
         {Credo.Check.Warning.OperationWithConstantResult, []},
         {Credo.Check.Warning.RaiseInsideRescue, []},

guides/introduction/getting-started.md

@@ -237,7 +237,7 @@ defmodule LoginServer.Auth.Actions do
     # Send the response to the client
     Client.send(client, render)
 
-    # We continue to receive packets from the client
+    # We continue to receive packages from the client
     {:cont, client}
   end
 
@@ -295,7 +295,7 @@ SUCCESS 127.0.0.1:1234  # Client response
 ```
 
 ```
-# Back to terminal 1, we also received several messages due to the application logs
+#Back to terminal 1, we also received several messages due to the application logs
 XX:XX:XX.XX [info]  Login server started on port 3000
 XX:XX:XX.XX [info]  New connection: 226167fe-493f-47ea-ae81-5f94e0e728ed
 XX:XX:XX.XX [info]  New message from 226167fe-493f-47ea-ae81-5f94e0e728ed (len: 5)

lib/elven_gard.ex

@@ -1,5 +1,5 @@
 defmodule ElvenGard do
   @moduledoc """
-  Documentation for ElvenGard.
+  Documentation for ElvenGard
   """
 end

lib/elven_gard/exceptions.ex

@@ -1,19 +1,35 @@
 defmodule ElvenGard.TypeOptionError do
   @moduledoc """
-  Raised when wrong options are given to `c:ElvenGard.Type.encode/2` or `c:ElvenGard.Type.decode/2`
+  Exception raised when wrong options are given to `c:ElvenGard.Type.encode/2` or `c:ElvenGard.Type.decode/2`
   """
+
   defexception [:message]
 end
 
 defmodule ElvenGard.UnknownViewError do
   @moduledoc """
-  Raised when a view is not found
+  Exception raised when a view is not found
   """
+
   defexception [:parent, :type]
 
   @impl true
   def message(%{parent: parent, type: type}) do
-    "unable to find the `render/2` function with the '#{inspect(type)}' key " <>
+    "Unable to find the `render/2` function with the '#{inspect(type)}' key " <>
       "(from #{inspect(parent)})"
   end
 end
+
+defmodule ElvenGard.FieldTypeError do
+  @moduledoc """
+  Exception raised when the type of a protocol field is not defined
+  """
+
+  defexception [:field_name, :field_type, :packet_name]
+
+  @impl true
+  def message(%{field_name: field_name, field_type: field_type, packet_name: packet_name}) do
+    "invalid type #{inspect(field_type)} for the field #{inspect(field_name)} " <>
+      "(packet: #{inspect(packet_name)})"
+  end
+end

lib/elven_gard/frontend.ex

@@ -33,21 +33,20 @@ defmodule ElvenGard.Frontend do
 
     # Check is there is any protocol
     unless protocol do
-      raise "Please, specify a packet_protocol for #{caller}"
+      raise "please, specify a packet_protocol for #{caller}"
     end
 
     # Check is there is any handler
     unless handler do
-      raise "Please, specify a packet_handler for #{caller}"
+      raise "please, specify a packet_handler for #{caller}"
     end
 
     quote do
-      alias ElvenGard.Structures.Client
-
       @behaviour unquote(parent)
       @behaviour :ranch_protocol
 
-      # TODO: Use `Application.get_env` inside function for a live update
+      alias ElvenGard.Structures.Client
+
       @timeout Application.get_env(:elven_gard, :response_timeout, 2000)
 
       @doc false
@@ -169,7 +168,7 @@ defmodule ElvenGard.Frontend do
 
       defp do_handle_packet(x, _client) do
         raise """
-        Unable to handle packet #{inspect(x)}.
+        unable to handle packet #{inspect(x)}.
         Please check that your protocol returns a tuple in the form of {header, \
         %{param1: :val1, param2: :val2, ...} or a list of tuples
         """

lib/elven_gard/packet.ex

@@ -21,9 +21,10 @@ defmodule ElvenGard.Packet do
     )
 
     quote do
-      require Logger
       import unquote(parent)
 
+      require Logger
+
       @before_compile unquote(parent)
       @desc nil
     end
@@ -43,7 +44,7 @@ defmodule ElvenGard.Packet do
         {:cont, client}
       end
 
-      def fetch_definitions() do
+      def get_packet_definitions() do
         @elven_packet_definitions
       end
     end

lib/elven_gard/protocol.ex

@@ -1,7 +1,7 @@
 defmodule ElvenGard.Protocol do
   @moduledoc """
   Transform a raw packet (packet received by a client) into a packet that can be
-  pattern match by a PacketHandler.
+  pattern match by a PacketHandler
 
   /!\\ No side effect: Cannot change or modify the current `ElvenGard.Structures.Client`
 
@@ -66,10 +66,11 @@ defmodule ElvenGard.Protocol do
 
     quote do
       @behaviour unquote(parent)
-      @before_compile unquote(parent)
 
       alias ElvenGard.Structures.Client
 
+      @before_compile unquote(parent)
+
       @doc """
       Successively applies functions `pre_encode`, `encode` and `post_encode`
       """

lib/elven_gard/protocol/binary.ex

@@ -3,6 +3,7 @@ defmodule ElvenGard.Protocol.Binary do
   TODO: Documentation for ElvenGard.Protocol.Binary
   """
 
+  alias ElvenGard.FieldTypeError
   alias ElvenGard.Structures.{Client, PacketDefinition}
 
   @aliases [
@@ -17,7 +18,7 @@ defmodule ElvenGard.Protocol.Binary do
   @doc false
   defmacro __using__(model: model) do
     expanded_model = Macro.expand(model, __CALLER__)
-    defs = expanded_model.fetch_definitions()
+    defs = expanded_model.get_packet_definitions()
 
     :ok = check_types!(defs)
 
@@ -39,7 +40,7 @@ defmodule ElvenGard.Protocol.Binary do
       end
 
       ## Define sub decoders
-      Enum.each(unquote(model).fetch_definitions(), fn packet ->
+      Enum.each(unquote(model).get_packet_definitions(), fn packet ->
         name = packet.name
         fields = Macro.escape(packet.fields)
 
@@ -89,8 +90,7 @@ defmodule ElvenGard.Protocol.Binary do
   @spec check_type!(atom, atom, term) :: term
   defp check_type!(type, name, def_name) do
     unless Keyword.has_key?(type.__info__(:functions), :decode) do
-      raise "Invalid type '#{inspect(type)}' for '#{inspect(name)}' " <>
-              "for packet '#{inspect(def_name)}'"
+      raise FieldTypeError, field_type: type, field_name: name, packet_name: def_name
     end
   end
 end

lib/elven_gard/protocol/binary/padding_type.ex

@@ -25,7 +25,7 @@ defmodule ElvenGard.Protocol.Binary.PaddingType do
     bytes = Keyword.get(opts, :bytes)
 
     if bits == nil and bytes == nil and fill == nil do
-      raise TypeOptionError, message: "You must specify a size (bytes/bits/fill) for a padding"
+      raise TypeOptionError, "you must specify a size (bytes/bits/fill) for a padding"
     end
 
     case {fill, bits, bytes} do

lib/elven_gard/protocol/binary/string_type.ex

@@ -20,7 +20,7 @@ defmodule ElvenGard.Protocol.Binary.StringType do
     bytes = Keyword.get(opts, :bytes)
 
     if bits == nil and bytes == nil do
-      raise TypeOptionError, message: "You must specify a size in bytes/bits for a string"
+      raise TypeOptionError, "you must specify a size in bytes/bits for a string"
     end
 
     size = if bits != nil, do: Kernel.trunc(bits / 8), else: bytes

lib/elven_gard/protocol/textual.ex

@@ -3,6 +3,7 @@ defmodule ElvenGard.Protocol.Textual do
   TODO: Documentation for ElvenGard.Protocol.Textual
   """
 
+  alias ElvenGard.FieldTypeError
   alias ElvenGard.Structures.{Client, PacketDefinition}
 
   @aliases [
@@ -14,7 +15,7 @@ defmodule ElvenGard.Protocol.Textual do
   @doc false
   defmacro __using__(model: model, separator: separator) do
     expanded_model = Macro.expand(model, __CALLER__)
-    defs = expanded_model.fetch_definitions()
+    defs = expanded_model.get_packet_definitions()
 
     check_types!(defs)
 
@@ -43,7 +44,7 @@ defmodule ElvenGard.Protocol.Textual do
       defp pre_textual_decode(x) when is_list(x), do: Enum.map(x, &textual_decode/1)
 
       ## Define sub decoders
-      Enum.each(unquote(model).fetch_definitions(), fn packet ->
+      Enum.each(unquote(model).get_packet_definitions(), fn packet ->
         name = packet.name
         fields = Macro.escape(packet.fields)
         sep = unquote(separator) |> Macro.escape()
@@ -112,8 +113,7 @@ defmodule ElvenGard.Protocol.Textual do
   @spec check_type!(atom, atom, term) :: term
   defp check_type!(type, name, def_name) do
     unless Keyword.has_key?(type.__info__(:functions), :decode) do
-      raise "Invalid type '#{inspect(type)}' for '#{inspect(name)}' " <>
-              "for packet '#{inspect(def_name)}'"
+      raise FieldTypeError, field_type: type, field_name: name, packet_name: def_name
     end
   end
 end

lib/elven_gard/structures/client.ex

@@ -1,12 +1,14 @@
 defmodule ElvenGard.Structures.Client do
   @moduledoc """
-  Manage a socket.
+  Manage a socket
+
   You can store some metadata on this structure.
   """
 
   @keys [:id, :socket, :transport, :metadata]
   @enforce_keys @keys
-  defstruct @keys ++ [protocol: nil]
+
+  defstruct @keys ++ [:protocol]
 
   @type t :: %__MODULE__{}
   @type metadata_key :: [term, ...] | term

lib/elven_gard/structures/field_definition.ex

@@ -5,6 +5,7 @@ defmodule ElvenGard.Structures.FieldDefinition do
 
   @keys [:name, :type, :description, :opts]
   @enforce_keys @keys
+
   defstruct @keys
 
   @type t :: %__MODULE__{}

lib/elven_gard/structures/packet_definition.ex

@@ -3,11 +3,12 @@ defmodule ElvenGard.Structures.PacketDefinition do
   Structure for a packet's definition
   """
 
+  alias ElvenGard.Structures.FieldDefinition
+
   @keys [:name, :description, :fields, :tags]
   @enforce_keys @keys
-  defstruct @keys
 
-  alias ElvenGard.Structures.FieldDefinition
+  defstruct @keys
 
   @type t :: %__MODULE__{}
   @type empty_string :: String.t() | nil

lib/elven_gard/type.ex

@@ -14,7 +14,7 @@ defmodule ElvenGard.Type do
   @callback encode(decoded_term, opts :: list) :: term
 
   @doc """
-  Transforms a packet received by a client into a term that can be used by `ElvenGard.Protocol`
+  Transforms a packet received by a client into a term that can be used by a protocol
 
   NOTE: The result of this function will then be used by `c:ElvenGard.Protocol.decode/1`
   """

lib/elven_gard/view.ex

@@ -5,19 +5,20 @@ defmodule ElvenGard.View do
 
   alias ElvenGard.UnknownViewError
 
+  @anno if :erlang.system_info(:otp_release) >= '19', do: [generated: true], else: [line: -1]
+
   @doc """
   Build a packet to send to the client
   """
   @callback render(type :: atom, opts :: map) :: term
 
-  @anno if :erlang.system_info(:otp_release) >= '19', do: [generated: true], else: [line: -1]
-
   @doc false
   defmacro __using__(_) do
     parent = __MODULE__
 
     quote do
       @behaviour unquote(parent)
+
       @before_compile unquote(parent)
     end
   end

mix.exs

@@ -113,7 +113,7 @@ defmodule ElvenGard.MixProject do
   end
 
   defp extras() do
-    ["README.md": [title: "Overview"]] ++ Path.wildcard("guides/**/*.md")
+    ["README.md": [title: "Project Description"]] ++ Path.wildcard("guides/**/*.md")
   end
 
   defp groups_for_extras() do