Add nearest_endpoints GraphQL query

lib/archethic_web/graphl_context.ex

@@ -0,0 +1,16 @@
+defmodule ArchethicWeb.GraphQLContext do
+  @moduledoc false
+
+  @behaviour Plug
+
+  def init(opts), do: opts
+
+  def call(conn, _) do
+    context = build_context(conn)
+    Absinthe.Plug.put_options(conn, context: context)
+  end
+
+  def build_context(conn) do
+    %{ip: conn.remote_ip}
+  end
+end

lib/archethic_web/graphql_schema.ex

@@ -111,12 +111,24 @@ defmodule ArchethicWeb.GraphQLSchema do
       end)
     end
 
+    @desc """
+    List all the nodes registered in the network
+    """
     field :nodes, list_of(:node) do
       resolve(fn _, _ ->
         {:ok, Resolver.nodes()}
       end)
     end
 
+    @desc """
+    List the nearest endpoints nodes from the client's IP
+    """
+    field :nearest_endpoints, list_of(:endpoint) do
+      resolve(fn _, %{context: %{ip: ip}} ->
+        {:ok, Resolver.nearest_endpoints(ip)}
+      end)
+    end
+
     @desc """
     Query the network to list the transaction on the type
     """

lib/archethic_web/graphql_schema/p2p_type.ex

@@ -3,6 +3,9 @@ defmodule ArchethicWeb.GraphQLSchema.P2PType do
 
   use Absinthe.Schema.Notation
 
+  @desc """
+  [Node] represents a node in the network
+  """
   object :node do
     field(:first_public_key, :public_key)
     field(:last_public_key, :public_key)
@@ -18,4 +21,12 @@ defmodule ArchethicWeb.GraphQLSchema.P2PType do
     field(:authorization_date, :timestamp)
     field(:origin_public_key, :public_key)
   end
+
+  @desc """
+  [Endpoint] represents a network node's endpoint
+  """
+  object :endpoint do
+    field(:ip, :string)
+    field(:port, :integer)
+  end
 end

lib/archethic_web/graphql_schema/resolver.ex

@@ -204,6 +204,19 @@ defmodule ArchethicWeb.GraphQLSchema.Resolver do
     )
   end
 
+  def nearest_endpoints(ip) do
+    geo_patch = P2P.get_geo_patch(ip)
+    nearest_nodes = P2P.nearest_nodes(P2P.list_nodes(), geo_patch)
+
+    Enum.map(
+      nearest_nodes,
+      &%{
+        ip: :inet.ntoa(&1.ip),
+        port: &1.http_port
+      }
+    )
+  end
+
   def network_transactions(type, page) do
     TransactionChain.list_transactions_by_type(type, [])
     |> paginate_transactions(page)

lib/archethic_web/router.ex

@@ -15,6 +15,7 @@ defmodule ArchethicWeb.Router do
 
   pipeline :api do
     plug(:accepts, ["json"])
+    plug(ArchethicWeb.GraphQLContext)
   end
 
   # Add the on chain implementation of the archethic.io at the root of the webserver