Add download, json-parsing

issues/config/config.exs

@@ -0,0 +1,3 @@
+use Mix.Config
+
+config :issues, github_url: "https://api.github.com"

issues/lib/issues/cli.ex

@@ -7,28 +7,55 @@ defmodule Issues.CLI do
   """
 
   def run(argv) do
-    parse_args(argv)
+    argv
+    |> parse_args
+    |> process
   end
 
+  @doc """
+  `argv` can be -h or --help, which returns :help.
+  Otherwise it is a github user name, project name, and (optionally)
+  the number of entries to format.
+
+  Return a tuple of `{ user, project, count }`, or `:help` if help was given
+  """
   def parse_args(argv) do
-    parse =
-      OptionParser.parse(argv,
-        switches: [help: :boolean],
-        aliases: [h: :help]
-      )
+    OptionParser.parse(argv,
+      switches: [help: :boolean],
+      aliases: [h: :help]
+    )
+    |> elem(1)
+    |> args_to_internal_representation
 
-    case parse do
-      {[help: true], _, _} ->
-        :help
+  end
 
-      {_, [user, project, count], _} ->
-        {user, project, String.to_integer(count)}
+  def args_to_internal_representation([user, project, count]) do
+    { user, project, String.to_integer(count) }
+  end
 
-      {_, [user, project], _} ->
-        {user, project, @default_count}
+  def args_to_internal_representation([user, project]) do
+    { user, project, @default_count }
+  end
 
-      _ ->
-        :help
-    end
+  def args_to_internal_representation(_) do # either bad arg or --help
+    :help
+  end
+
+  def process(:help) do
+    IO.puts """
+    usage: issues <user> <project> [count | #{@default_count}]
+    """
+    System.halt(0)
+  end
+
+  def process({user, project, count}) do
+    Issues.GithubIssues.fetch(user, project)
+    |> decode_response()
+  end
+
+  def decode_response({:ok, body}), do: body
+  def decode_response({:error, error}) do
+    IO.puts "Error fetching from Github: #{error["message"]}"
+    System.halt(2)
   end
 end

issues/lib/issues/github_issues.ex

@@ -0,0 +1,30 @@
+defmodule Issues.GithubIssues do
+  
+  @user_agent [ { "User-agent", "Elixir dave@pragprog.com" } ]
+  # use a module attribute to fetch the value at compile time
+  @github_url Application.get_env(:issues, :github_url)
+  
+  def fetch(user, project) do
+    issues_url(user, project)
+    |> HTTPoison.get(@user_agent)
+    |> handle_response 
+  end
+
+  def issues_url(user, project) do
+    "#{@github_url}/repos/#{user}/#{project}/issues"
+  end
+
+  def handle_response( {:ok, %{status_code: status_code, body: body}} ) do
+    {
+      status_code |> check_for_error(),
+      body |> Poison.Parser.parse!()
+    }
+  end
+
+  def handle_response( {_, %{status_code: _, body: body}} ) do
+    { :error, body }
+  end
+
+  defp check_for_error(200), do: :ok
+  defp check_for_error(_), do: :error
+end

issues/mix.exs

@@ -21,6 +21,8 @@ defmodule Issues.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
+      {:httpoison, "~> 1.8.0"},
+      {:poison, "~> 5.0"},
       # {:dep_from_hexpm, "~> 0.3.0"},
       # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
     ]