Dynamic url feature

README.md

@@ -102,6 +102,10 @@ config :ethereumex,
 iex> Ethereumex.HttpClient.web3_client_version
 {:ok, "Parity//v1.7.2-beta-9f47909-20170918/x86_64-macos/rustc1.19.0"}
 
+# Using the url option will overwrite the configuration
+iex> Ethereumex.HttpClient.web3_client_version(url: "http://localhost:8545")
+{:ok, "Parity//v1.7.2-beta-9f47909-20170918/x86_64-macos/rustc1.19.0"}
+
 iex> Ethereumex.HttpClient.web3_sha3("wrong_param")
 {:error, %{"code" => -32602, "message" => "Invalid params: invalid format."}}
 

lib/ethereumex/client/behaviour.ex

@@ -76,6 +76,6 @@ defmodule Ethereumex.Client.Behaviour do
   # actual request methods
 
   @callback request(binary(), list(binary()), keyword()) :: {:ok, any() | [any()]} | error
-  @callback single_request(map()) :: {:ok, any() | [any()]} | error
+  @callback single_request(map(), keyword()) :: {:ok, any() | [any()]} | error
   @callback batch_request([{atom(), list(binary())}]) :: {:ok, [any()]} | error
 end

lib/ethereumex/client/macro.ex

@@ -419,14 +419,17 @@ defmodule Ethereumex.Client.Macro do
 
       @spec request(binary(), list(binary() | boolean | map), keyword()) ::
               {:ok, any() | [any()]} | error
+      def request(_name, _params, batch: true, url: _url),
+        do: raise("Cannot use batch and url options at the same time")
+
       def request(name, params, batch: true) do
         name |> add_request_info(params)
       end
 
-      def request(name, params, _) do
+      def request(name, params, opts) do
         name
         |> add_request_info(params)
-        |> server_request
+        |> server_request(opts)
       end
 
       @spec batch_request([{atom(), list(binary())}]) :: {:ok, [any()]} | error
@@ -441,8 +444,8 @@ defmodule Ethereumex.Client.Macro do
         |> server_request
       end
 
-      defp server_request(params) do
-        GenServer.call(__MODULE__, {:request, params})
+      defp server_request(params, opts \\ []) do
+        GenServer.call(__MODULE__, {:request, params, opts})
       end
 
       def start_link do
@@ -453,11 +456,11 @@ defmodule Ethereumex.Client.Macro do
         GenServer.cast(__MODULE__, :reset_id)
       end
 
-      def single_request(params) do
+      def single_request(params, opts) do
         {:error, :not_implemented}
       end
 
-      defoverridable single_request: 1
+      defoverridable single_request: 2
     end
   end
 end

lib/ethereumex/client/server.ex

@@ -3,27 +3,31 @@ defmodule Ethereumex.Client.Server do
 
   @moduledoc false
 
+  def init(args) do
+    {:ok, args}
+  end
+
   def start_link(module) when is_atom(module) do
     GenServer.start_link(__MODULE__, {module, 0}, name: module)
   end
 
-  def handle_call({:request, params}, _from, {module, id}) when is_list(params) do
+  def handle_call({:request, params, opts}, _from, {module, id}) when is_list(params) do
     params =
       params
       |> Enum.with_index()
       |> Enum.map(fn {req_data, index} ->
         Map.put(req_data, "id", index + id)
       end)
 
-    response = apply(module, :single_request, [params])
+    response = apply(module, :single_request, [params, opts])
 
     {:reply, response, {module, id + Enum.count(params)}}
   end
 
-  def handle_call({:request, params}, _from, {module, id}) do
+  def handle_call({:request, params, opts}, _from, {module, id}) do
     params = Map.put(params, "id", id)
 
-    response = apply(module, :single_request, [params])
+    response = apply(module, :single_request, [params, opts])
 
     {:reply, response, {module, id + 1}}
   end

lib/ethereumex/http_client.ex

@@ -3,24 +3,25 @@ defmodule Ethereumex.HttpClient do
   import Ethereumex.Config
   @moduledoc false
 
-  @spec single_request(map()) :: {:ok, any() | [any()]} | error
-  def single_request(payload) do
+  @spec single_request(map(), []) :: {:ok, any() | [any()]} | error
+  def single_request(payload, opts \\ []) do
     payload
     |> encode_payload
-    |> post_request
+    |> post_request(opts)
   end
 
   @spec encode_payload(map()) :: binary()
   defp encode_payload(payload) do
     payload |> Poison.encode!()
   end
 
-  @spec post_request(binary()) :: {:ok | :error, any()}
-  defp post_request(payload) do
+  @spec post_request(binary(), []) :: {:ok | :error, any()}
+  defp post_request(payload, opts) do
     headers = [{"Content-Type", "application/json"}]
     options = Ethereumex.Config.http_options()
+    url = Keyword.get(opts, :url) || rpc_url()
 
-    with {:ok, response} <- HTTPoison.post(rpc_url(), payload, headers, options),
+    with {:ok, response} <- HTTPoison.post(url, payload, headers, options),
          %HTTPoison.Response{body: body, status_code: code} = response do
       decode_body(body, code)
     else

test/ethereumex/client/macro_test.exs

@@ -4,10 +4,10 @@ defmodule Ethereumex.Client.MacroTest do
   defmodule ClientMock do
     use Ethereumex.Client.Macro
 
-    def single_request(payload) do
+    def single_request(payload, opts) do
       %{"method" => method, "jsonrpc" => "2.0", "params" => params} = payload
 
-      {method, params}
+      {method, params, opts}
     end
   end
 
@@ -19,7 +19,11 @@ defmodule Ethereumex.Client.MacroTest do
     end
 
     def assert_method({ex_method, eth_method}, params, payload) do
-      {^eth_method, ^payload} = apply(ClientMock, String.to_atom(ex_method), params)
+      {^eth_method, ^payload, _opts} = apply(ClientMock, String.to_atom(ex_method), params)
+    end
+
+    def assert_opts({ex_method, _eth_method}, params, opts) do
+      {_eth_method, _payload, ^opts} = apply(ClientMock, String.to_atom(ex_method), params)
     end
 
     def make_tuple(ex_method) do
@@ -69,7 +73,18 @@ defmodule Ethereumex.Client.MacroTest do
     topics: ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b"]
   }
 
-  test ".web3_client_version/0", do: Helpers.check("web3_client_version")
+  describe ".web3_client_version/0" do
+    test "with configuration url", do: Helpers.check("web3_client_version")
+
+    test "with dynamic url",
+      do:
+        Helpers.assert_opts(
+          {"web3_client_version", "web3_client_version"},
+          [[url: "http://localhost:4000"]],
+          url: "http://localhost:4000"
+        )
+  end
+
   test ".net_version/0", do: Helpers.check("net_version")
   test ".net_peer_count/0", do: Helpers.check("net_peer_count")
   test ".net_listening/0", do: Helpers.check("net_listening")