Harpoon

Harpoon is an http client framework built on top of Tesla that produces clients that are pluggable, behave predictibly, and can easily be mocked.

Installation

If available in Hex, the package can be installed by adding harpoon to your list of dependencies in mix.exs:

def deps do
  [
    {:harpoon, github: "ironbay/harpoon"}
    # Optional
    {:fishermane, github: "ironbay/harpoon"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/harpoon.

Documentation

Harpoon modules are simply Tesla modules. The only requirement is to pass in client() to any HTTP calls. To enable function mocking use the hook macro provided by Fisherman

defmodule Harpoon.Example do
  use Harpoon
  import Fisherman

  plug(Harpoon.Response)
  plug(Tesla.Middleware.BaseUrl, "https://jsonplaceholder.typicode.com/")
  plug(Tesla.Middleware.JSON)

  hook todos() do
    get(client(), "/todos")
  end
end

Any application referencing this module can inject their own middleware or mock certain functions in the module via Fisherman

config :harpoon, %{
  Harpoon.Example => %{
    # Adds middleware to the top
    pre: [Tesla.Middleware.Logger]
    # Adds middleware to the bottom
    post: [],
  },
  # Applies to all Harpoon clients
  :global => %{
  }
}

config :fisherman, %{
  Harpoon.Example => Harpoon.Example.Mock
}

If a mock module is specified, any function with matching arity will be called instead. If hook_catch/2 is defined it will serve as a catch all for all functions and be passed a function name and list of arguments

defmodule Harpoon.Example.Mock do
  require Logger

  def todos() do
    {:ok,
     [
       %{
         "completed" => false,
         "id" => 1,
         "title" => "delectus aut autem",
         "userId" => 1
       },
       %{
         "completed" => true,
         "id" => 2,
         "title" => "quis ut nam facilis et officia qui",
         "userId" => 1
       }
     ]}
  end

  def hook_catch(fun, args) do
    Logger.info(inspect({fun, args}))
  end
end

TODO

Harpoon Clients

• harpoon_twilio