Add a way to fetch all contract events

Author: ddallaire

README.md

@@ -116,6 +116,9 @@ filter = MyToken.EventFilters.transfer(from_address, nil)
 
 # Get matching events
 {:ok, events} = Ethers.get_logs(filter)
+
+# Get all events from a contract
+{:ok, events} = Ethers.get_logs_for_contract(MyToken.EventFilters, "0x123...")
 ```
 
 ## Documentation

lib/ethers.ex

@@ -584,6 +584,64 @@ defmodule Ethers do
     end
   end
 
+  @doc """
+  Fetches event logs for all events in a contract's EventFilters module.
+
+  This function is useful when you want to get all events from a contract without
+  specifying a single event filter. It will automatically decode each log using
+  the appropriate event selector from the EventFilters module.
+
+  ## Parameters
+  - event_filters_module: The EventFilters module (e.g. `MyContract.EventFilters`)
+  - address: The contract address to filter events from (nil means all contracts)
+
+  ## Overrides and Options
+
+  - `:rpc_client`: The RPC Client to use. It should implement ethereum jsonRPC API. default: Ethereumex.HttpClient
+  - `:rpc_opts`: Extra options to pass to rpc_client. (Like timeout, Server URL, etc.)
+  - `:fromBlock` | `:from_block`: Minimum block number of logs to filter.
+  - `:toBlock` | `:to_block`: Maximum block number of logs to filter.
+
+  ## Examples
+
+  ```elixir
+  # Get all events from a contract
+  {:ok, events} = Ethers.get_logs_for_contract(MyContract.EventFilters, "0x1234...")
+
+  # Get all events with block range
+  {:ok, events} = Ethers.get_logs_for_contract(MyContract.EventFilters, "0x1234...", 
+    fromBlock: 1000, 
+    toBlock: 2000
+  )
+  ```
+  """
+  @spec get_logs_for_contract(module(), Types.t_address() | nil, Keyword.t()) ::
+          {:ok, [Event.t()]} | {:error, atom()}
+  def get_logs_for_contract(event_filters_module, address, overrides \\ []) do
+    overrides = Keyword.put(overrides, :address, address)
+    {opts, overrides} = Keyword.split(overrides, @option_keys)
+
+    {rpc_client, rpc_opts} = get_rpc_client(opts)
+
+    with {:ok, log_params} <-
+           pre_process(event_filters_module, overrides, :get_logs_for_contract, opts) do
+      rpc_client.eth_get_logs(log_params, rpc_opts)
+      |> post_process(event_filters_module, :get_logs_for_contract)
+    end
+  end
+
+  @doc """
+  Same as `Ethers.get_logs_for_contract/3` but raises on error.
+  """
+  @spec get_logs_for_contract!(module(), Types.t_address() | nil, Keyword.t()) ::
+          [Event.t()] | no_return
+  def get_logs_for_contract!(event_filters_module, address, overrides \\ []) do
+    case get_logs_for_contract(event_filters_module, address, overrides) do
+      {:ok, events} -> events
+      {:error, reason} -> raise ExecutionError, reason
+    end
+  end
+
   @doc """
   Combines multiple requests and make a batch json RPC request.
 
@@ -744,6 +802,18 @@ defmodule Ethers do
     end
   end
 
+  defp pre_process(_event_filters_module, overrides, :get_logs_for_contract, _opts) do
+    log_params =
+      overrides
+      |> Enum.into(%{})
+      |> ensure_hex_value(:fromBlock)
+      |> ensure_hex_value(:from_block)
+      |> ensure_hex_value(:toBlock)
+      |> ensure_hex_value(:to_block)
+
+    {:ok, log_params}
+  end
+
   defp pre_process(event_filter, overrides, :get_logs, _opts) do
     log_params =
       event_filter
@@ -806,6 +876,23 @@ defmodule Ethers do
     {:ok, resp}
   end
 
+  defp post_process({:ok, resp}, event_filters_module, :get_logs_for_contract)
+       when is_list(resp) do
+    logs =
+      Enum.flat_map(resp, fn log ->
+        case Event.find_and_decode(log, event_filters_module) do
+          {:ok, decoded_log} -> [decoded_log]
+          {:error, :not_found} -> []
+        end
+      end)
+
+    {:ok, logs}
+  end
+
+  defp post_process({:ok, resp}, _event_filters_module, :get_logs_for_contract) do
+    {:ok, resp}
+  end
+
   defp post_process({:ok, %{"contractAddress" => contract_address}}, _tx_hash, :deployed_address)
        when not is_nil(contract_address),
        do: {:ok, contract_address}

test/ethers/counter_contract_test.exs

@@ -323,6 +323,117 @@ defmodule Ethers.CounterContractTest do
     end
   end
 
+  describe "get_logs_for_contract works with all events" do
+    setup :deploy_counter_contract
+
+    test "can get all events from the contract", %{address: address} do
+      {:ok, tx_hash_1} =
+        CounterContract.set(101) |> Ethers.send_transaction(from: @from, to: address)
+
+      wait_for_transaction!(tx_hash_1)
+
+      {:ok, tx_hash_2} =
+        CounterContract.reset() |> Ethers.send_transaction(from: @from, to: address)
+
+      wait_for_transaction!(tx_hash_2)
+
+      {:ok, current_block_number} = Ethers.current_block_number()
+
+      assert {:ok, events} =
+               Ethers.get_logs_for_contract(CounterContract.EventFilters, address,
+                 from_block: current_block_number - 2,
+                 to_block: current_block_number
+               )
+
+      assert length(events) == 2
+
+      [set_called_event, reset_called_event] = events
+
+      assert %Event{
+               address: ^address,
+               topics: ["SetCalled(uint256,uint256)", 100],
+               data: [101]
+             } = set_called_event
+
+      assert %Event{
+               address: ^address,
+               topics: ["ResetCalled()"],
+               data: []
+             } = reset_called_event
+    end
+
+    test "can get all events with get_logs_for_contract! function", %{address: address} do
+      {:ok, tx_hash_1} =
+        CounterContract.set(101) |> Ethers.send_transaction(from: @from, to: address)
+
+      wait_for_transaction!(tx_hash_1)
+
+      {:ok, tx_hash_2} =
+        CounterContract.reset() |> Ethers.send_transaction(from: @from, to: address)
+
+      wait_for_transaction!(tx_hash_2)
+
+      {:ok, current_block_number} = Ethers.current_block_number()
+
+      events =
+        Ethers.get_logs_for_contract!(CounterContract.EventFilters, address,
+          from_block: current_block_number - 2,
+          to_block: current_block_number
+        )
+
+      assert [
+               %Ethers.Event{
+                 address: ^address,
+                 topics: ["SetCalled(uint256,uint256)", 100],
+                 data: [101]
+               },
+               %Ethers.Event{
+                 address: ^address,
+                 topics: ["ResetCalled()"],
+                 data: []
+               }
+             ] = events
+    end
+
+    test "can filter logs with from_block and to_block options", %{address: address} do
+      {:ok, tx_hash_1} =
+        CounterContract.set(101) |> Ethers.send_transaction(from: @from, to: address)
+
+      wait_for_transaction!(tx_hash_1)
+
+      {:ok, tx_hash_2} =
+        CounterContract.reset() |> Ethers.send_transaction(from: @from, to: address)
+
+      wait_for_transaction!(tx_hash_2)
+
+      {:ok, current_block_number} = Ethers.current_block_number()
+
+      assert [
+               %Ethers.Event{
+                 address: ^address,
+                 topics: ["SetCalled(uint256,uint256)", 100],
+                 data: [101],
+                 data_raw: "0x0000000000000000000000000000000000000000000000000000000000000065",
+                 log_index: 0,
+                 removed: false,
+                 transaction_hash: ^tx_hash_1,
+                 transaction_index: 0
+               }
+             ] =
+               Ethers.get_logs_for_contract!(CounterContract.EventFilters, address,
+                 from_block: current_block_number - 1,
+                 to_block: current_block_number - 1
+               )
+    end
+
+    test "returns empty list for non-existent contract address" do
+      fake_address = "0x1234567890123456789012345678901234567890"
+
+      assert {:ok, []} =
+               Ethers.get_logs_for_contract(CounterContract.EventFilters, fake_address)
+    end
+  end
+
   describe "override block number" do
     setup :deploy_counter_contract
 

test/ethers_test.exs

@@ -352,6 +352,23 @@ defmodule EthersTest do
     end
   end
 
+  describe "get_logs_for_contract/3" do
+    test "returns error when request fails" do
+      assert {:error, %{reason: :nxdomain}} =
+               Ethers.get_logs_for_contract(HelloWorldContract.EventFilters, nil,
+                 rpc_opts: [url: "http://non.exists"]
+               )
+    end
+
+    test "with bang function, raises error when request fails" do
+      assert_raise Mint.TransportError, "non-existing domain", fn ->
+        Ethers.get_logs_for_contract!(HelloWorldContract.EventFilters, nil,
+          rpc_opts: [url: "http://non.exists"]
+        )
+      end
+    end
+  end
+
   describe "default address" do
     test "is included in the function calls when has default address" do
       assert %Ethers.TxData{

test/support/contracts/counter.sol

@@ -21,5 +21,11 @@ contract Counter {
         storeAmount = newAmount;
     }
 
+    function reset() public {
+        delete storeAmount;
+        emit ResetCalled();
+    }
+
+    event ResetCalled();
     event SetCalled(uint256 indexed oldAmount, uint256 newAmount);
 }