Added message validation with structured casting

README.md

@@ -89,10 +89,15 @@ Next, you can declare `mutation/5` where the first argument is mutation name, se
 defmodule ExampleApp.Store.Counter do
   use Storex.Store
 
-  def init(session_id, params) do
+  def init(session_id, _params) do
     {:ok, 0}
   end
 
+  # Params have binary keys and result of `init/2` function can return `key` which will be the key for mutations.
+  # def init(session_id, %{"someKey" => someKeyValue}) do
+  #   {:ok, 0, someKeyValue}
+  # end
+
   # `increase` is mutation name, `data` is payload from front-end, `session_id` is current session id of connecton, `initial_params` with which store was initialized, `state` is store current state.
   def mutation("increase", _data, _session_id, _initial_params, state) do
     state = state + 1

lib/storex/handler/cowboy.ex

@@ -37,12 +37,11 @@ defmodule Storex.Handler.Cowboy do
   end
 
   def websocket_handle({:text, frame}, state) do
-    Jason.decode(frame, keys: :atoms)
-    |> case do
-      {:ok, message} ->
-        Socket.message_handle(message, state)
-        |> map_response()
-
+    with {:ok, decoded_message} <- Jason.decode(frame),
+         {:ok, cast_message} <- Storex.Message.cast(decoded_message) do
+      Socket.message_handle(cast_message, state)
+      |> map_response()
+    else
       {:error, _} ->
         {:reply, {:close, 1007, "Payload is malformed."}, state}
     end

lib/storex/handler/plug.ex

@@ -24,12 +24,11 @@ defmodule Storex.Handler.Plug do
   end
 
   def handle_in({message, [opcode: :text]}, state) do
-    Jason.decode(message, keys: :atoms)
-    |> case do
-      {:ok, message} ->
-        Socket.message_handle(message, state)
-        |> map_response()
-
+    with {:ok, decoded_message} <- Jason.decode(message),
+         {:ok, cast_message} <- Storex.Message.cast(decoded_message) do
+      Socket.message_handle(cast_message, state)
+      |> map_response()
+    else
       {:error, _} ->
         {:stop, "Payload is malformed.", 1007, state}
     end

lib/storex/http.ex

@@ -51,7 +51,7 @@ defmodule Storex.HTTP do
 
   defp get_params(params) do
     params
-    |> Jason.decode(keys: :atoms)
+    |> Jason.decode()
   end
 
   defp get_state(module, params) do

lib/storex/message.ex

@@ -0,0 +1,50 @@
+defmodule Storex.Message do
+  @derive {Jason.Encoder, only: [:type, :store, :data, :request, :session]}
+  defstruct [:type, :store, :data, :request, :session]
+
+  def cast(%{
+        "type" => "join",
+        "store" => store,
+        "data" => data,
+        "request" => request,
+        "session" => session
+      }) do
+    {:ok, %__MODULE__{type: "join", store: store, data: data, request: request, session: session}}
+  end
+
+  def cast(%{"type" => "join", "store" => store, "data" => data, "request" => request}) do
+    {:ok, %__MODULE__{type: "join", store: store, data: data, request: request}}
+  end
+
+  def cast(%{
+        "type" => "mutation",
+        "store" => store,
+        "data" => %{"name" => name, "data" => data},
+        "request" => request,
+        "session" => session
+      }) do
+    {:ok,
+     %__MODULE__{
+       type: "mutation",
+       store: store,
+       data: %{name: name, data: data},
+       request: request,
+       session: session
+     }}
+  end
+
+  def cast(%{
+        "type" => "error",
+        "store" => store,
+        "data" => data,
+        "request" => request,
+        "session" => session
+      }) do
+    {:ok,
+     %__MODULE__{type: "error", store: store, data: data, request: request, session: session}}
+  end
+
+  def cast(_) do
+    {:error, "Unknown message type"}
+  end
+end

lib/storex/store.ex

@@ -2,7 +2,7 @@ defmodule Storex.Store do
   @doc """
   Called when store session starts.
   """
-  @callback init(session_id :: binary(), params :: any()) ::
+  @callback init(session_id :: binary(), params :: %{binary() => any()}) ::
               {:ok, state :: any()}
               | {:ok, state :: any(), key :: binary()}
               | {:error, reason :: binary()}
@@ -11,7 +11,7 @@ defmodule Storex.Store do
               name :: binary(),
               data :: any(),
               session_id :: binary(),
-              params :: any(),
+              params :: %{binary() => any()},
               state :: any()
             ) ::
               {:reply, message :: any(), state :: any()}
@@ -20,7 +20,7 @@ defmodule Storex.Store do
   @doc """
   Called when store session ends.
   """
-  @callback terminate(session_id :: binary(), params :: any(), state :: any()) :: any()
+  @callback terminate(session_id :: binary(), params :: %{binary() => any()}, state :: any()) :: any()
   @optional_callbacks terminate: 3
 
   defmacro __using__(_opts) do

test/fixtures/stores/text.ex

@@ -1,8 +1,10 @@
 defmodule StorexTest.Store.Text do
   use Storex.Store
 
-  def init(_session, _params) do
-    {:ok, "abc"}
+  def init(_session, params) do
+    initial_value = Map.get(params, "initial_value", "abc")
+
+    {:ok, initial_value}
   end
 
   def mutation("change", [value], _session_id, _params, _state) do

test/storex/handler/cowboy_test.exs

@@ -26,7 +26,8 @@ defmodule StorexTest.Handler.Cowboy do
       {
         "type": "join",
         "store": "StorexTest.Store.Counter",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -44,7 +45,8 @@ defmodule StorexTest.Handler.Cowboy do
       {
         "type": "join",
         "store": "StorexTest.Store.ErrorInit",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -61,7 +63,8 @@ defmodule StorexTest.Handler.Cowboy do
       {
         "type": "join",
         "store": "StorexTest.Store.NotExisting",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -79,7 +82,8 @@ defmodule StorexTest.Handler.Cowboy do
       {
         "type": "join",
         "store": null,
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -97,7 +101,8 @@ defmodule StorexTest.Handler.Cowboy do
       {
         "type": "join",
         "store": "StorexTest.Store.Counter",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -113,7 +118,8 @@ defmodule StorexTest.Handler.Cowboy do
         "data": {
           "name": "increase",
           "data": []
-        }
+        },
+        "request": "#{random_string()}"
       }
       """)
 
@@ -135,7 +141,8 @@ defmodule StorexTest.Handler.Cowboy do
       {
         "type": "join",
         "store": "StorexTest.Store.Counter",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -151,7 +158,8 @@ defmodule StorexTest.Handler.Cowboy do
         "data": {
           "name": "not_existing",
           "data": []
-        }
+        },
+        "request": "#{random_string()}"
       }
       """)
 

test/storex/handler/plug_test.exs

@@ -30,7 +30,8 @@ defmodule StorexTest.Handler.Plug do
       {
         "type": "join",
         "store": "StorexTest.Store.Counter",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -48,7 +49,8 @@ defmodule StorexTest.Handler.Plug do
       {
         "type": "join",
         "store": "StorexTest.Store.ErrorInit",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -65,7 +67,8 @@ defmodule StorexTest.Handler.Plug do
       {
         "type": "join",
         "store": "StorexTest.Store.NotExisting",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -83,7 +86,8 @@ defmodule StorexTest.Handler.Plug do
       {
         "type": "join",
         "store": null,
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -101,7 +105,8 @@ defmodule StorexTest.Handler.Plug do
       {
         "type": "join",
         "store": "StorexTest.Store.Counter",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -117,7 +122,8 @@ defmodule StorexTest.Handler.Plug do
         "data": {
           "name": "increase",
           "data": []
-        }
+        },
+        "request": "#{random_string()}"
       }
       """)
 
@@ -139,7 +145,8 @@ defmodule StorexTest.Handler.Plug do
       {
         "type": "join",
         "store": "StorexTest.Store.Counter",
-        "data": {}
+        "data": {},
+        "request": "#{random_string()}"
       }
       """)
 
@@ -155,7 +162,8 @@ defmodule StorexTest.Handler.Plug do
         "data": {
           "name": "not_existing",
           "data": []
-        }
+        },
+        "request": "#{random_string()}"
       }
       """)
 

test/storex/node_test.exs

@@ -15,6 +15,12 @@ defmodule StorexTest.Node do
     assert result == %{"error" => nil, "state" => %{"counter" => 0}}
   end
 
+  test "test params" do
+    result = run_store("StorexTest.Store.Text", %{"initial_value" => "custom_text"})
+
+    assert result == %{"error" => nil, "state" => "custom_text"}
+  end
+
   test "test error" do
     result = run_store("StorexTest.Store.ErrorInit")
 

test/support/handler_helpers.ex

@@ -1,4 +1,8 @@
 defmodule StorexTest.HandlerHelpers do
+  def random_string(length \\ 10) do
+    for _ <- 1..length, into: "", do: <<Enum.random(?a..?z)>>
+  end
+
   def connection_closed_for_reading?(client) do
     :gen_tcp.recv(client, 0) == {:error, :closed}
   end