Add evaluate tx

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 - Support for Tx Submission
+- Support for Tx Evaluation
 
 ## [v0.1.0](https://github.com/wowica/xogmios/releases/tag/v0.1.0) (2024-02-13)
 

lib/xogmios/tx_submission.ex

@@ -7,7 +7,7 @@ defmodule Xogmios.TxSubmission do
   alias Xogmios.TxSubmission.Response
   alias Xogmios.TxSubmission.Server
 
-  @tx_submit_timeout 2_000
+  @request_timeout 2_000
 
   @doc """
   Starts a new Tx Submission process linked to the current process.
@@ -29,18 +29,37 @@ defmodule Xogmios.TxSubmission do
   """
   @spec submit_tx(pid() | atom(), String.t()) :: {:ok, any()} | {:error, any()}
   def submit_tx(client \\ __MODULE__, cbor) do
-    with {:ok, message} <- build_message(cbor),
-         {:ok, %Response{} = response} <- call_tx_submission(client, message) do
+    with {:ok, message} <- build_submit_message(cbor),
+         {:ok, %Response{} = response} <- call(client, message) do
       {:ok, response.result}
     end
   end
 
-  defp build_message(cbor),
+  @doc """
+  Evaluates the execution units of scripts present in a given transaction.
+
+  This function is synchronous and takes two arguments:
+
+  1. (Optional) A process reference. If none given, it defaults to the linked process `__MODULE__`.
+  2. The CBOR of a transaction. Unlike `submit_tx/1`, this function does not expect the transaction to be signed. Please refer to the [official Ogmios docs](https://ogmios.dev/mini-protocols/local-tx-submission/#evaluating-transactions) for more details on the type of transaction that is accepted.
+  """
+  @spec evaluate_tx(pid() | atom(), String.t()) :: {:ok, any()} | {:error, any()}
+  def evaluate_tx(client \\ __MODULE__, cbor) do
+    with {:ok, message} <- build_evaluate_message(cbor),
+         {:ok, %Response{} = response} <- call(client, message) do
+      {:ok, response.result}
+    end
+  end
+
+  defp build_submit_message(cbor),
     do: {:ok, Messages.submit_tx(cbor)}
 
-  defp call_tx_submission(client, message) do
+  defp build_evaluate_message(cbor),
+    do: {:ok, Messages.evaluate_tx(cbor)}
+
+  defp call(client, message) do
     try do
-      case GenServer.call(client, {:submit_tx, message}, @tx_submit_timeout) do
+      case GenServer.call(client, {:send, message}, @request_timeout) do
         {:ok, response} -> {:ok, response}
         {:error, reason} -> {:error, reason}
       end
@@ -69,7 +88,7 @@ defmodule Xogmios.TxSubmission do
       end
 
       @impl true
-      def handle_call({:submit_tx, message}, from, state) do
+      def handle_call({:send, message}, from, state) do
         {:store_caller, _from} = send(state.ws_pid, {:store_caller, from})
         :ok = :websocket_client.send(state.ws_pid, {:text, message})
         {:noreply, state}

lib/xogmios/tx_submission/messages.ex

@@ -25,6 +25,23 @@ defmodule Xogmios.TxSubmission.Messages do
     json
   end
 
+  def evaluate_tx(cbor) do
+    json = ~s"""
+    {
+      "jsonrpc": "2.0",
+      "method": "evaluateTransaction",
+      "params": {
+          "transaction": {
+            "cbor": "#{cbor}"
+          }
+      }
+    }
+    """
+
+    validate_json!(json)
+    json
+  end
+
   defp validate_json!(json) do
     case Jason.decode(json) do
       {:ok, _decoded} -> :ok

test/support/tx_submission/test_handler.ex

@@ -15,15 +15,26 @@ defmodule TxSubmission.TestHandler do
     {:ok, state}
   end
 
+  @valid_cbor_value %{
+    "method" => "submitTransaction",
+    "params" => %{"transaction" => %{"cbor" => "valid-cbor-value"}}
+  }
+
+  @invalid_cbor_value %{
+    "method" => "submitTransaction",
+    "params" => %{"transaction" => %{"cbor" => "invalid-cbor-value"}}
+  }
+
+  @valid_tx_evaluation_cbor %{
+    "method" => "evaluateTransaction",
+    "params" => %{"transaction" => %{"cbor" => "valid-cbor-value"}}
+  }
+
   @impl true
   # Sends response back to client
   def websocket_handle({:text, payload}, state) do
     case Jason.decode(payload) do
-      {:ok,
-       %{
-         "method" => "submitTransaction",
-         "params" => %{"transaction" => %{"cbor" => "valid-cbor-value"}}
-       }} ->
+      {:ok, @valid_cbor_value} ->
         payload =
           Jason.encode!(%{
             "method" => "submitTransaction",
@@ -36,11 +47,7 @@ defmodule TxSubmission.TestHandler do
 
         {:reply, {:text, payload}, state}
 
-      {:ok,
-       %{
-         "method" => "submitTransaction",
-         "params" => %{"transaction" => %{"cbor" => "invalid-cbor-value"}}
-       }} ->
+      {:ok, @invalid_cbor_value} ->
         # Actual error returned from a malformed CBOR
         payload =
           Jason.encode!(%{
@@ -70,6 +77,20 @@ defmodule TxSubmission.TestHandler do
 
         {:reply, {:text, payload}, state}
 
+      {:ok, @valid_tx_evaluation_cbor} ->
+        payload =
+          Jason.encode!(%{
+            "method" => "evaluateTransaction",
+            "result" => [
+              %{
+                "budget" => %{"cpu" => 18_563_120, "memory" => 54_404},
+                "validator" => %{"index" => 0, "purpose" => "spend"}
+              }
+            ]
+          })
+
+        {:reply, {:text, payload}, state}
+
       result ->
         Logger.error("Did not match #{inspect(result)}")
         {:reply, {:text, payload}, state}

test/tx_submission_test.exs

@@ -24,6 +24,10 @@ defmodule Xogmios.TxSubmissionTest do
     def submit_tx(pid \\ __MODULE__, cbor) do
       TxSubmission.submit_tx(pid, cbor)
     end
+
+    def evaluate_tx(pid \\ __MODULE__, cbor) do
+      TxSubmission.evaluate_tx(pid, cbor)
+    end
   end
 
   test "transaction submission" do
@@ -39,4 +43,13 @@ defmodule Xogmios.TxSubmissionTest do
 
     assert reason =~ "Invalid transaction"
   end
+
+  test "transaction evaluation" do
+    pid = start_supervised!({DummyClient, url: @ws_url})
+    assert is_pid(pid)
+    Process.sleep(1_000)
+
+    assert {:ok, [%{"budget" => _budget, "validator" => _validator}]} =
+             DummyClient.evaluate_tx(_cbor = "valid-cbor-value")
+  end
 end