From 8eb0599a7f4ee8e38cd34e2bff0a5905e2c8581c Mon Sep 17 00:00:00 2001
From: Marc Neudert <marc.neudert@gmail.com>
Date: Fri, 2 Dec 2016 11:58:48 +0100
Subject: [PATCH] adds support for CSV response encoding

---
 README.md                               | 12 ++++++++--
 lib/instream/connection/query_runner.ex |  2 +-
 lib/instream/query/headers.ex           | 29 +++++++++++++++++++++++--
 test/instream/response_test.exs         | 13 +++++++++--
 4 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index a0ca6a9d..24d47a7c 100644
--- a/README.md
+++ b/README.md
@@ -275,8 +275,16 @@ Every query can be executed asynchronously by passing `[async: true]` to
 `MyApp.MyConnection.execute()`. The result will then always be an immediate
 `:ok` without waiting for the query to be actually executed.
 
-To access the raw (undecoded) response of a query you can pass
-`[result_as: :raw]` to `MyApp.MyConnection.execute()`.
+By default the response of a query will be a map decoded from your server's
+JSON response.
+
+Alternatively you can pass `[result_as: format]` to
+`MyApp.MyConnection.execute/2` to change the result format to one of the
+following:
+
+- `:csv`  - CSV encoded response
+- `:json` - JSON encoded response (implicit default)
+- `:raw`  - Raw server format (JSON string)
 
 #### Administrative Queries
 
diff --git a/lib/instream/connection/query_runner.ex b/lib/instream/connection/query_runner.ex
index 66342c1a..a61ff107 100644
--- a/lib/instream/connection/query_runner.ex
+++ b/lib/instream/connection/query_runner.ex
@@ -53,7 +53,7 @@ defmodule Instream.Connection.QueryRunner do
   @spec read(Query.t, Keyword.t, map) :: any
   def read(%Query{} = query, opts, %{ module: conn }) do
     config  = conn.config()
-    headers = Headers.assemble(config)
+    headers = Headers.assemble(config, opts)
     url     =
       config
       |> URL.query()
diff --git a/lib/instream/query/headers.ex b/lib/instream/query/headers.ex
index 3067f2df..8ea5b4e6 100644
--- a/lib/instream/query/headers.ex
+++ b/lib/instream/query/headers.ex
@@ -6,9 +6,10 @@ defmodule Instream.Query.Headers do
   @doc """
   Assembles the headers for a query.
   """
-  @spec assemble(Keyword.t) :: list
-  def assemble(config) do
+  @spec assemble(Keyword.t, Keyword.t) :: list
+  def assemble(config, options \\ []) do
     assemble_auth(config[:auth])
+    ++ assemble_encoding(options[:result_as])
   end
 
   @doc """
@@ -39,6 +40,30 @@ defmodule Instream.Query.Headers do
     end
   end
 
+  @doc """
+  Assembles headers for response encoding.
+
+  ## Usage
+
+      iex> assemble_encoding(nil)
+      []
+
+      # not handled here...
+      iex> assemble_encoding(:raw)
+      []
+
+      iex> assemble_encoding(:csv)
+      [{'Accept', 'application/csv'}]
+
+      iex> assemble_encoding(:json)
+      [{'Accept', 'application/json'}]
+  """
+  @spec assemble_encoding(nil | atom) :: list
+  def assemble_encoding(nil),   do: []
+  def assemble_encoding(:csv),  do: [{ 'Accept', 'application/csv' }]
+  def assemble_encoding(:json), do: [{ 'Accept', 'application/json' }]
+  def assemble_encoding(:raw),  do: []
+
 
   defp basic_auth_header(nil,  _),   do: []
   defp basic_auth_header(_,    nil), do: []
diff --git a/test/instream/response_test.exs b/test/instream/response_test.exs
index a64d263a..fca2551d 100644
--- a/test/instream/response_test.exs
+++ b/test/instream/response_test.exs
@@ -6,16 +6,25 @@ defmodule Instream.ResponseTest do
   alias Instream.TestHelpers.Connection
 
 
-  test "parsed response" do
+  test "response format: default (parsed)" do
     response = Database.show() |> Connection.execute()
 
     assert is_map(response)
   end
 
-  test "raw response" do
+  @tag influxdb_version: "1.1.0"
+  test "response format: csv" do
+    response = Database.show() |> Connection.execute([ result_as: :csv ])
+
+    assert is_binary(response)
+    assert "name," <> _ = response
+  end
+
+  test "response format: raw" do
     response = Database.show() |> Connection.execute([ result_as: :raw ])
 
     assert is_binary(response)
+    assert "{" <> _ = response
   end