Merge pull request #26 from graphql-elixir/ordered_by

Release v0.5.0

Author: seanabrahams

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.5.0 (2016-07-01)
+
+* Add `ordered_by` and `ordered_by_direction` options for Ecto connections so we can sort a connection by field.
+
 ## 0.4.0 (2016-06-22)
 
 * Update optional dependency for Ecto to support both Ecto v1.x and v2.x.

README.md

@@ -11,7 +11,7 @@ This library relies on the [GraphQL Elixir](https://github.com/graphql-elixir/gr
 Add `graphql_relay` to your list of dependencies in `mix.exs`:
 
     def deps do
-      [{:graphql_relay, "~> 0.4"}]
+      [{:graphql_relay, "~> 0.5"}]
     end
 
 ## Configuration

examples/todo/mix.exs

@@ -36,7 +36,7 @@ defmodule Todo.Mixfile do
      {:phoenix_html, "~> 2.6"},
      {:phoenix_live_reload, "~> 1.0", only: :dev},
      {:cowboy, "~> 1.0"},
-     {:graphql_relay, "~> 0.4"},
+     {:graphql_relay, "~> 0.5"},
      {:plug_graphql, "~> 0.3"}]
   end
 

examples/todo/mix.lock

@@ -1,12 +1,12 @@
 %{"connection": {:hex, :connection, "1.0.3", "3145f7416be3df248a4935f24e3221dc467c1e3a158d62015b35bd54da365786", [:mix], []},
   "cowboy": {:hex, :cowboy, "1.0.4", "a324a8df9f2316c833a470d918aaf73ae894278b8aa6226ce7a9bf699388f878", [:rebar, :make], [{:cowlib, "~> 1.0.0", [hex: :cowlib, optional: false]}, {:ranch, "~> 1.0", [hex: :ranch, optional: false]}]},
   "cowlib": {:hex, :cowlib, "1.0.2", "9d769a1d062c9c3ac753096f868ca121e2730b9a377de23dec0f7e08b1df84ee", [:make], []},
-  "db_connection": {:hex, :db_connection, "1.0.0-rc.2", "c5b2329651ef046d85e47ec2c947cb0e3d10a69eb49fdb71e365e72d6758e4c5", [:mix], [{:sbroker, "~> 1.0.0-beta.2", [hex: :sbroker, optional: true]}, {:poolboy, "~> 1.5", [hex: :poolboy, optional: true]}, {:connection, "~> 1.0.2", [hex: :connection, optional: false]}]},
+  "db_connection": {:hex, :db_connection, "1.0.0-rc.3", "d9ceb670fe300271140af46d357b669983cd16bc0d01206d7d3222dde56cf038", [:mix], [{:sbroker, "~> 1.0.0-beta.3", [hex: :sbroker, optional: true]}, {:poolboy, "~> 1.5", [hex: :poolboy, optional: true]}, {:connection, "~> 1.0.2", [hex: :connection, optional: false]}]},
   "decimal": {:hex, :decimal, "1.1.2", "79a769d4657b2d537b51ef3c02d29ab7141d2b486b516c109642d453ee08e00c", [:mix], []},
-  "ecto": {:hex, :ecto, "2.0.1", "cf97a4d353e14af3d3cc3b4452cfbd18b3aeee1fb4075475efeccec3853444a9", [:mix], [{:poison, "~> 1.5 or ~> 2.0", [hex: :poison, optional: true]}, {:sbroker, "~> 1.0-beta", [hex: :sbroker, optional: true]}, {:mariaex, "~> 0.7.7", [hex: :mariaex, optional: true]}, {:postgrex, "~> 0.11.2", [hex: :postgrex, optional: true]}, {:db_connection, "~> 1.0-rc.2", [hex: :db_connection, optional: true]}, {:decimal, "~> 1.0", [hex: :decimal, optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, optional: false]}]},
+  "ecto": {:hex, :ecto, "2.0.2", "b02331c1f20bbe944dbd33c8ecd8f1ccffecc02e344c4471a891baf3a25f5406", [:mix], [{:poison, "~> 1.5 or ~> 2.0", [hex: :poison, optional: true]}, {:sbroker, "~> 1.0-beta", [hex: :sbroker, optional: true]}, {:mariaex, "~> 0.7.7", [hex: :mariaex, optional: true]}, {:postgrex, "~> 0.11.2", [hex: :postgrex, optional: true]}, {:db_connection, "~> 1.0-rc.2", [hex: :db_connection, optional: true]}, {:decimal, "~> 1.0", [hex: :decimal, optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, optional: false]}]},
   "fs": {:hex, :fs, "0.9.2", "ed17036c26c3f70ac49781ed9220a50c36775c6ca2cf8182d123b6566e49ec59", [:rebar], []},
   "graphql": {:hex, :graphql, "0.3.1", "d3bb5467877456cc2b33debc75407e9216567b10e35e83d5195e2d51e835e8c7", [:mix], []},
-  "graphql_relay": {:hex, :graphql_relay, "0.0.17", "d5ce633b85c9103ab0507dd3c4e9103d8d14ea9bd316d35fb9cbc9ba31234c5c", [:mix], [{:poison, "~> 1.5 or ~> 2.0", [hex: :poison, optional: false]}, {:graphql, "~> 0.3", [hex: :graphql, optional: false]}, {:ecto, "~> 1.1.4", [hex: :ecto, optional: true]}]},
+  "graphql_relay": {:hex, :graphql_relay, "0.5.0", "8ea16397d4dc4cc0d7bf8d47df0d4d8ad2710e59ddda78fcb581b90352b48159", [:mix], [{:poison, "~> 1.5 or ~> 2.0", [hex: :poison, optional: false]}, {:graphql, "~> 0.3", [hex: :graphql, optional: false]}]},
   "phoenix": {:hex, :phoenix, "1.1.6", "7bf19002669c8f692f5a9c8d30dab7b49f3dc56228d5bde92a12fb426b4783c2", [:mix], [{:poison, "~> 1.5 or ~> 2.0", [hex: :poison, optional: false]}, {:plug, "~> 1.0", [hex: :plug, optional: false]}, {:cowboy, "~> 1.0", [hex: :cowboy, optional: true]}]},
   "phoenix_ecto": {:hex, :phoenix_ecto, "3.0.0", "b947aaf03d076f5b1448f87828f22fb7710478ee38455c67cc3fe8e9a4dfd015", [:mix], [{:ecto, "~> 2.0.0-rc", [hex: :ecto, optional: false]}, {:phoenix_html, "~> 2.6", [hex: :phoenix_html, optional: true]}]},
   "phoenix_html": {:hex, :phoenix_html, "2.6.0", "b9f7e091eb3d908586d9634596478fb9e577ee033d76f4ff327a745569bdd2d8", [:mix], [{:plug, "~> 0.13 or ~> 1.0", [hex: :plug, optional: false]}]},

lib/graphql/relay/connection/ecto.ex

@@ -57,22 +57,60 @@ if Code.ensure_loaded?(Ecto) do
       resolve(repo, query, args)
     end
 
+    @doc """
+    Pass in an Ecto.Repo, an Ecto.Query, and Relay args to have the query
+    executed and results returned in the format Relay requires.
+
+    If you wish to have the results ordered by some field other than `id`,
+    use `ordered_by` and `ordered_by_direction`.
+
+    Example for returning data in reverse chronological order (newest first)
+    like you would do for a page listing blog posts:
+
+      args = %{
+        first: 10,
+        ordered_by: :inserted_at,
+        ordered_by_direction: :desc
+      }
+
+    Your GraphQL resolve function for the connection will look something like:
+
+      resolve: fn(blog, args, _ctx) ->
+        # Order by desc inserted_at
+        args = Map.merge(args, %{ordered_by: :inserted_at, ordered_by_direction: :desc})
+        query = Ecto.assoc(blog, :posts)
+        GraphQL.Relay.Connection.Ecto.resolve(Repo, query, args)
+      end
+    """
     def resolve(repo, query, args \\ %{}) do
       before = cursor_to_offset(args[:before])
       # `after` is a keyword http://elixir-lang.org/docs/master/elixir/Kernel.SpecialForms.html#try/1
       a_after = cursor_to_offset(args[:after])
       first = args[:first]
       last = args[:last]
+      ordered_by_property = args[:ordered_by] || :id
+      ordered_by_direction = get_ordered_by_direction(args[:ordered_by_direction] || :asc)
+      opposite_ordered_by_direction = if ordered_by_direction == :asc, do: :desc, else: :asc
       limit = Enum.min([first, last, connection_count(repo, query)])
 
       query = if a_after do
-        from things in query, where: things.id > ^a_after
+        case ordered_by_direction do
+          :asc ->
+            query |> where([a], field(a, ^ordered_by_property) > ^a_after)
+          :desc ->
+            query |> where([a], field(a, ^ordered_by_property) < ^a_after)
+        end
       else
         query
       end
 
       query = if before do
-        from things in query, where: things.id < ^before
+        case ordered_by_direction do
+          :asc ->
+            query |> where([a], field(a, ^ordered_by_property) < ^before)
+          :desc ->
+            query |> where([a], field(a, ^ordered_by_property) > ^before)
+        end
       else
         query
       end
@@ -97,13 +135,15 @@ if Code.ensure_loaded?(Ecto) do
       end
 
       query = if first do
-        from things in query, order_by: [asc: things.id], limit: ^limit
+        sort_values = Keyword.new([{ordered_by_direction, ordered_by_property}])
+        query |> order_by(^sort_values) |> limit(^limit)
       else
         query
       end
 
       query = if last do
-        from things in query, order_by: [desc: things.id], limit: ^limit
+        sort_values = Keyword.new([{opposite_ordered_by_direction, ordered_by_property}])
+        query |> order_by(^sort_values) |> limit(^limit)
       else
         query
       end
@@ -112,7 +152,7 @@ if Code.ensure_loaded?(Ecto) do
 
       edges = Enum.map(records, fn(record) ->
         %{
-          cursor: cursor_for_object_in_connection(record),
+          cursor: cursor_for_object_in_connection(record, ordered_by_property),
           node: record
         }
       end)
@@ -140,15 +180,23 @@ if Code.ensure_loaded?(Ecto) do
     def cursor_to_offset(cursor) do
       case Base.decode64(cursor) do
         {:ok, decoded_cursor} ->
-          {int, _} = Integer.parse(String.slice(decoded_cursor, String.length(@prefix)..String.length(decoded_cursor)))
-          int
+          string = String.slice(decoded_cursor, String.length(@prefix)..String.length(decoded_cursor))
+          case Ecto.DateTime.cast(string) do
+            {:ok, date} -> date
+            :error -> string
+          end
         :error ->
           nil
       end
     end
 
-    def cursor_for_object_in_connection(object) do
-      Base.encode64("#{@prefix}#{object.id}")
+    def cursor_for_object_in_connection(object, property \\ :id) do
+      prop = case Map.get(object, property) do
+        %Ecto.DateTime{} = date_time -> Ecto.DateTime.to_iso8601(date_time)
+        prop -> to_string(prop)
+      end
+
+      Base.encode64("#{@prefix}#{prop}")
     end
 
     def connection_count(repo, query) do
@@ -157,6 +205,10 @@ if Code.ensure_loaded?(Ecto) do
       repo.one(count_query)
     end
 
+    defp get_ordered_by_direction(value) when value in [:asc, :desc] do
+      value
+    end
+
     defp make_query_countable(query) do
       query
       |> remove_order

mix.exs

@@ -1,7 +1,7 @@
 defmodule GraphQL.Relay.Mixfile do
   use Mix.Project
 
-  @version "0.4.0"
+  @version "0.5.0"
   @description "Relay helpers for GraphQL Elixir"
   @repo_url "https://github.com/graphql-elixir/graphql_relay"
 

priv/repo/migrations/20160307040347_create_letter.exs

@@ -5,6 +5,13 @@ defmodule EctoTest.Repo.Migrations.CreateLetter do
     create table(:letters) do
       add :letter, :string
       add :second_column, :string
+      add :order, :integer
+      timestamps
+    end
+
+    create table(:numbers) do
+      add :number, :integer
+      add :letter_id, references(:letters, on_delete: :nothing)
       timestamps
     end
   end