[WIP] SNS implementation (#40)

* Beginning of SNS implementation

* ExAws.SNS.Client.publish defcallback

* working requests for SNS

* no need to rehash an empty string on every request

* initial work towards a working publish impl

* publish works now

* working tests after master merge

* update contributing md for passing travis ci

* Use percent encoding for canonical query strings, per AWS docs

Author: bruce

CONTRIBUTING.md

@@ -21,7 +21,8 @@ Running the test suite for ex_aws requires a few things:
               "kinesis:ListStreams",
               "lambda:ListFunctions",
               "s3:ListAllMyBuckets",
-              "sqs:ListQueues"
+              "sns:ListTopics",
+              "sqs:ListQueues",
           ],
           "Resource": "*"
       }

lib/ex_aws/config/defaults.ex

@@ -43,6 +43,11 @@ defmodule ExAws.Config.Defaults do
         host: {"$region", "sqs.$region.amazonaws.com"},
         region: "us-east-1",
         port: 80
+      ],
+      sns: [
+        host: "sns.us-east-1.amazonaws.com",
+        scheme: "https://",
+        region: "us-east-1"
       ]
     ]
   end

lib/ex_aws/sns.ex

@@ -0,0 +1,5 @@
+defmodule ExAws.SNS do
+  use ExAws.SNS.Client
+
+  def config_root, do: Application.get_all_env(:ex_aws)
+end

lib/ex_aws/sns/client.ex

@@ -0,0 +1,149 @@
+defmodule ExAws.SNS.Client do
+  use Behaviour
+
+  @moduledoc """
+  Defines an SNS Client
+
+  By default you can use ExAws.SNS
+
+  ## Usage
+
+  ```
+  defmodule MyApp.SNS do
+    use ExAws.SNS.Client, otp_app: :my_otp_app
+  end
+  ```
+
+  In your config:
+
+  ```
+  config :my_otp_app, :ex_aws,
+    sns: [], # SNS config goes here
+  ```
+
+  You can now use MyApp.SNS as the root module for the SNS API without
+  needing to pass in a particular configuration. This enables different OTP
+  apps to configure their AWS configurations separately.
+
+  The alignment with a particular OTP app while convenient is however entirely
+  optional.
+
+  The following also works:
+
+  ```
+  defmodule MyApp.SNS do
+    use ExAws.SNS.Client
+
+    def config_root do
+      Application.get_all_env(:my_aws_config_root)
+    end
+  end
+  ```
+
+  ExAws now expects the config for that client to live under `:my_aws_config_root`:
+
+  ```elixir
+  config :my_aws_config_root
+    sns: [] # SNS config goes here
+  ```
+
+  Default config values can be found in ExAws.Config.
+
+  ## General notes
+
+  TODO
+
+  ## Examples
+
+  TODO
+
+  http://docs.aws.amazon.com/sns/latest/APIReference/API_Operations.html
+  """
+
+  ## Topics
+  ######################
+
+  @type topic_name :: binary
+  @type topic_arn  :: binary
+  @type topic_attribute_name ::
+    :policy |
+    :display_name |
+    :delivery_policy
+
+  @doc "List topics"
+  defcallback list_topics() :: ExAws.Request.response_t
+  defcallback list_topics(opts :: [next_token: binary]) :: ExAws.Request.response_t
+
+  @doc "Create topic"
+  defcallback create_topic(topic_name :: topic_name) :: ExAws.Request.response_t
+
+  @doc "Get topic attributes"
+  defcallback get_topic_attributes(topic_arn :: topic_arn) :: ExAws.Request.response_t
+
+  @doc "Set topic attributes"
+  defcallback set_topic_attributes(attribute_name :: topic_attribute_name,
+                                   attribute_value :: binary,
+                                   topic_arn :: topic_arn) :: ExAws.Request.response_t
+
+  @doc "Delete topic"
+  defcallback delete_topic(topic_arn :: topic_arn) :: ExAws.Request.response_t
+
+  ## Publishing
+  ######################
+
+  @type message_attribute :: %{
+    :name => binary,
+    :data_type => :string | :number | :binary,
+    :value => {:string, binary} | {:binary, binary}
+  }
+  @type publish_opts :: [
+    {:message_attributes, [message_attribute]} |
+    {:message_structure, :json} |
+    {:subject, binary} |
+    {:target_arn, binary} |
+    {:topic_arn, binary}]
+
+  @doc """
+  Publish message to a target/topic ARN
+
+  You must set either :target_arn or :topic_arn but not both via the options argument.
+
+  Do NOT assume that because your message is a JSON blob that you should set
+  message_structure: to :json. This has a very specific meaning, please see
+  http://docs.aws.amazon.com/sns/latest/api/API_Publish.html for details.
+  """
+  defcallback publish(message :: binary, opts :: publish_opts) :: ExAws.Request.response_t
+
+  ## Requests
+  ######################
+
+  @doc """
+  Enables custom request handling.
+
+  By default this just forwards the request to the `ExAws.SNS.Request.request/3`.
+  However, this can be overriden in your client to provide pre-request adjustments to headers, params, etc.
+  """
+  defcallback request(client_struct :: %{}, data :: %{}, action :: atom)
+
+  @doc "Retrieves the root AWS config for this client"
+  defcallback config_root() :: Keyword.t
+
+  defmacro __using__(opts) do
+    boilerplate = __MODULE__
+    |> ExAws.Client.generate_boilerplate(opts)
+
+    quote do
+      defstruct config: nil, service: :sns
+
+      unquote(boilerplate)
+
+      @doc false
+      def request(client, action, data) do
+        ExAws.SNS.Request.request(client, action, data)
+      end
+
+      defoverridable config_root: 0, request: 3
+    end
+  end
+
+end

lib/ex_aws/sns/impl.ex

@@ -0,0 +1,79 @@
+defmodule ExAws.SNS.Impl do
+  import ExAws.Utils, only: [camelize_key: 1, camelize_keys: 1]
+
+  @moduledoc false
+  # Implementation of the AWS SNS API.
+  #
+  # See ExAws.SNS.Client for usage.
+
+  ## Topics
+  ######################
+
+  def list_topics(client, opts \\ []) do
+    opts = opts
+    |> Enum.into(%{})
+    |> camelize_keys
+
+    request(client, :list_topics, opts)
+  end
+
+  def create_topic(client, topic_name) do
+    request(client, :create_topic, %{"Name" => topic_name})
+  end
+
+  def get_topic_attributes(client, topic_arn) do
+    request(client, :get_topic_attributes, %{"TopicArn" => topic_arn})
+  end
+
+  def set_topic_attributes(client, attribute_name, attribute_value, topic_arn) do
+    request(client, :set_topic_attributes, %{
+      "AttributeName" => attribute_name |> camelize_key,
+      "AttributeValue" => attribute_value,
+      "TopicArn" => topic_arn
+    })
+  end
+
+  def delete_topic(client, topic_arn) do
+    request(client, :delete_topic, %{"TopicArn" => topic_arn})
+  end
+
+  def publish(client, message, opts) do
+    opts = opts |> Enum.into(%{})
+
+    message_attrs = opts
+    |> Map.get(:message_attributes, [])
+    |> build_message_attributes
+
+    params = opts
+    |> Map.drop([:message_attributes])
+    |> camelize_keys
+    |> Map.put("Message", message)
+    |> Map.merge(message_attrs)
+
+    request(client, :publish, params)
+  end
+
+  defp build_message_attributes(attrs) do
+    attrs
+    |> Stream.with_index
+    |> Enum.reduce(%{}, &build_message_attribute/2)
+  end
+
+  def build_message_attribute({%{name: name, data_type: data_type, value: {value_type, value}}, i}, params) do
+    param_root = "MessageAttribute.#{i}"
+    value_type = value_type |> String.capitalize
+
+    params
+    |> Map.put(param_root <> ".Name", name)
+    |> Map.put(param_root <> ".Value.#{value_type}Value", value)
+    |> Map.put(param_root <> ".Value.DataType", data_type)
+  end
+
+  ## Request
+  ######################
+
+  defp request(%{__struct__: client_module} = client, action, params) do
+    client_module.request(client, action, params)
+  end
+
+end

lib/ex_aws/sns/request.ex

@@ -0,0 +1,25 @@
+defmodule ExAws.SNS.Request do
+  @moduledoc false
+  # SNS specific request logic.
+
+  @empty_body_hash ExAws.Auth.Utils.hash_sha256("")
+
+  def request(client, action, params) do
+    query = params
+    |> Map.put("Action", Mix.Utils.camelize(Atom.to_string(action)))
+    |> URI.encode_query
+    |> String.replace("+", "%20")
+    |> String.replace("%7E", "~")
+
+    headers = [
+      {"x-amz-content-sha256", @empty_body_hash}
+    ]
+
+    ExAws.Request.request(:post, client.config |> url(query), "", headers, client)
+  end
+
+  defp url(%{scheme: scheme, host: host}, query) do
+    [scheme, host, "/?", query]
+    |> IO.iodata_to_binary
+  end
+end

lib/ex_aws/utils.ex

@@ -32,13 +32,13 @@ defmodule ExAws.Utils do
     end
   end
 
-  defp camelize_key(key) when is_atom(key) do
+  def camelize_key(key) when is_atom(key) do
     key
     |> Atom.to_string
     |> camelize
   end
 
-  defp camelize_key(key) when is_binary(key) do
+  def camelize_key(key) when is_binary(key) do
     key |> camelize
   end
 

mix.lock

@@ -1,16 +1,16 @@
-%{"certifi": {:hex, :certifi, "0.4.0"},
-  "earmark": {:hex, :earmark, "0.2.1"},
-  "ex_doc": {:hex, :ex_doc, "0.11.4"},
-  "hackney": {:hex, :hackney, "1.6.0"},
-  "httpoison": {:hex, :httpoison, "0.8.3"},
-  "httpotion": {:hex, :httpotion, "2.0.0"},
+%{"certifi": {:hex, :certifi, "0.4.0", "a7966efb868b179023618d29a407548f70c52466bf1849b9e8ebd0e34b7ea11f", [:rebar3], []},
+  "earmark": {:hex, :earmark, "0.2.1", "ba6d26ceb16106d069b289df66751734802777a3cbb6787026dd800ffeb850f3", [:mix], []},
+  "ex_doc": {:hex, :ex_doc, "0.11.4", "a064bdb720594c3745b94709b17ffb834fd858b4e0c1f48f37c0d92700759e02", [:mix], [{:earmark, "~> 0.1.17 or ~> 0.2", [hex: :earmark, optional: true]}]},
+  "hackney": {:hex, :hackney, "1.6.0", "8d1e9440c9edf23bf5e5e2fe0c71de03eb265103b72901337394c840eec679ac", [:rebar3], [{:ssl_verify_fun, "1.1.0", [hex: :ssl_verify_fun, optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, optional: false]}, {:metrics, "1.0.1", [hex: :metrics, optional: false]}, {:idna, "1.2.0", [hex: :idna, optional: false]}, {:certifi, "0.4.0", [hex: :certifi, optional: false]}]},
+  "httpoison": {:hex, :httpoison, "0.8.3", "b675a3fdc839a0b8d7a285c6b3747d6d596ae70b6ccb762233a990d7289ccae4", [:mix], [{:hackney, "~> 1.6.0", [hex: :hackney, optional: false]}]},
+  "httpotion": {:hex, :httpotion, "2.0.0", "f9d19c482854adae8a8a6e4c828948a0165242d2233089085de183f92e81cb01", [:mix], []},
   "ibrowse": {:git, "https://github.com/cmullaparthi/ibrowse.git", "ea3305d21f37eced4fac290f64b068e56df7de80", [tag: "v4.1.2"]},
-  "idna": {:hex, :idna, "1.2.0"},
-  "jsx": {:hex, :jsx, "2.5.3"},
-  "metrics": {:hex, :metrics, "1.0.1"},
-  "mimerl": {:hex, :mimerl, "1.0.2"},
-  "mixunit": {:hex, :mixunit, "0.9.2"},
-  "poison": {:hex, :poison, "1.2.1"},
-  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.0"},
+  "idna": {:hex, :idna, "1.2.0", "ac62ee99da068f43c50dc69acf700e03a62a348360126260e87f2b54eced86b2", [:rebar3], []},
+  "jsx": {:hex, :jsx, "2.5.3", "4fd156ddd08aeea2a9e537fff31d93a7c57b017076996c5b3c35a0728b97de02", [:mix, :rebar], [{:mixunit, "~> 0.9.1", [hex: :mixunit, optional: false]}]},
+  "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], []},
+  "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], []},
+  "mixunit": {:hex, :mixunit, "0.9.2", "4ace17bd1998c8853db5df4e081ec9bcf2b7b5ab04683a18b7ee2aad4c6320d0", [:mix], []},
+  "poison": {:hex, :poison, "1.2.1", "a9e550f224bdff3a10d7f0651a72998b13098ab08e74f9c5737fc3c009c149f4", [:mix], []},
+  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.0", "edee20847c42e379bf91261db474ffbe373f8acb56e9079acb6038d4e0bf414f", [:rebar, :make], []},
   "ssl_verify_hostname": {:hex, :ssl_verify_hostname, "1.0.5"},
-  "sweet_xml": {:hex, :sweet_xml, "0.5.0"}}
+  "sweet_xml": {:hex, :sweet_xml, "0.5.0", "d8f1b98527fbe829e9e4b3ad7a71f91ecc84e2e4ccd6c0c8a89b8e12cdcd7837", [:mix], []}}

test/default_helper.exs

@@ -18,6 +18,12 @@ defmodule Test.S3 do
   def config_root, do: Application.get_all_env(:ex_aws)
 end
 
+defmodule Test.SNS do
+  use ExAws.SNS.Client
+
+  def config_root, do: Application.get_all_env(:ex_aws)
+end
+
 ## Other
 
 defmodule Test.JSONCodec do

test/lib/ex_aws/sns/integration_test.exs

@@ -0,0 +1,7 @@
+defmodule ExAws.SNS.IntegrationTest do
+  use ExUnit.Case, async: true
+
+  test "basic sanity check" do
+    assert {:error, {:http_error, 400, _}} = ExAws.SNS.list_topics(next_token: "foo")
+  end
+end