telegram: An Elixir repository from elchemista

Telegram library for the Elixir language.

Installation

The package can be installed by adding telegram to your list of dependencies in mix.exs:

def deps do
  [
    {:telegram, git: "https://github.com/visciang/telegram.git", tag: "xxx"}
  ]
end

Telegram API

Telegram Bot API request.

The module expose a light layer over the Telegram Bot API HTTP-based interface, it does not expose any "(data)binding" over the HTTP interface and tries to abstract away only the boilerplate for building / sending / serializing the API requests.

Compared to a full-binded interface it could result less elixir frendly but it will work with any version of the Bot API, hopefully without updates or incompatibily with new BOT API versions (as much as they remain backward compatible).

References:

Given the token of your BOT you can issue any request using:

method: Telegram API method name (ex. "getMe", "sendMessage")
options: Telegram API method specific parameters (you can use elixir native types)

Examples:

Given the bot token (something like):

token = "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11"

getMe

Telegram.Api.request(token, "getMe")

{:ok, %{"first_name" => "Abc", "id" => 1234567, "is_bot" => true, "username" => "ABC"}}

sendMessage

Telegram.Api.request(token, "sendMessage", chat_id: 876532, text: "Hello! .. silently", disable_notification: true)

{:ok,
  %{"chat" => %{"first_name" => "Firstname",
      "id" => 208255328,
      "last_name" => "Lastname",
      "type" => "private",
      "username" => "xxxx"},
    "date" => 1505118722,
    "from" => %{"first_name" => "Yyy",
      "id" => 234027650,
      "is_bot" => true,
      "username" => "yyy"},
    "message_id" => 1402,
    "text" => "Hello! .. silently"}}

getUpdates

Telegram.Api.request(token, "getUpdates", offset: -1, timeout: 30)

{:ok,
  [%{"message" => %{"chat" => %{"first_name" => "Firstname",
        "id" => 208255328,
        "last_name" => "Lastname",
        "type" => "private",
        "username" => "xxxx"},
      "date" => 1505118098,
      "from" => %{"first_name" => "Firstname",
        "id" => 208255328,
        "is_bot" => false,
        "language_code" => "en-IT",
        "last_name" => "Lastname",
        "username" => "xxxx"},
      "message_id" => 1401,
      "text" => "Hello!"},
    "update_id" => 129745295}]}

Sending files

If a API parameter has a InputFile type and you want to send a local file, for example a photo stored locally at "/tmp/photo.jpg", just wrap the parameter value in a tuple {:file, "/tmp/photo.jpg"}. If the file content is in memory wrap it in {:file_content, data, "photo.jpg"} tuple.

sendPhoto

Telegram.Api.request(token, "sendPhoto", chat_id: 876532, photo: {:file, "/tmp/photo.jpg"})
Telegram.Api.request(token, "sendPhoto", chat_id: 876532, photo: {:file_content, photo, "photo.jpg"})

Downloading files

To download a file from the telegram server you need a file_path pointer to the file. With that you can download the file via Telegram.Api.file.

{:ok, res} = Telegram.Api.request(token, "sendPhoto", chat_id: 12345, photo: {:file, "example/photo.jpg"})
# pick the 'file_obj' with the desired resolution
[file_obj | _] = res["photo"]
# get the 'file_id'
file_id = file_obj["file_id"]

getFile

{:ok, %{"file_path" => file_path}} = Telegram.Api.request(token, "getFile", file_id: file_id)
{:ok, file} = Telegram.Api.file(token, file_path)

Reply Markup

If a API parameter has a "A JSON-serialized object" type (InlineKeyboardMarkup, ReplyKeyboardMarkup, etc), just wrap the parameter value in a tuple {:json, value}.

Reference: Keyboards, Inline Keyboards

sendMessage with keyboard

keyboard = [
  ["A0", "A1"],
  ["B0", "B1", "B2"]
]
keyboard_markup = %{one_time_keyboard: true, keyboard: keyboard}
Telegram.Api.request(token, "sendMessage", chat_id: 876532, text: "Here a keyboard!", reply_markup: {:json, keyboard_markup})

Telegram BOT

A simple BOT behaviour and DSL.

Example

defmodule Simple.Bot do
  use Telegram.Bot,
    token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11",
    username: "simple_bot",
    auth: ["user1", "user2"]

  command ["ciao", "hello"], args do
    # handle the commands: "/ciao" and "/hello"

    # reply with a text message
    request("sendMessage",
      chat_id: update["chat"]["id"],
      text: "ciao! #{inspect args}")
  end

  command unknown do
    request("sendMessage", chat_id: update["chat"]["id"],
      text: "Unknow command `#{unknown}`")
  end

  message do
    request("sendMessage", chat_id: update["chat"]["id"],
      text: "Hey! You sent me a message: #{inspect update}")
  end

  edited_message do
    # handler code
  end

  channel_post do
    # handler code
  end

  edited_channel_post do
    # handler code
  end

  inline_query _query do
    # handler code
  end

  chosen_inline_result _query do
    # handler code
  end

  callback_query do
    # handler code
  end

  shipping_query do
    # handler code
  end

  pre_checkout_query do
    # handler code
  end

  any do
    # handler code
  end
end

See Telegram.Bot.Dsl documentation for all available macros.

Options

use Telegram.Bot,
  token: "your bot auth token",   # required
  username: "your bot username",  # required
  auth: ["user1", "user2"],       # optional, list of authorized users
                                  # or authorizing function (String.t -> boolean)
  purge: boolean()                # purge old messages at startup, default: false
  restart: policy                 # optional, default :permanent

Execution model

The bot defined using the Telegram.Bot behaviour is based on Task and will run in a single erlang process, processing updates sequentially.

You can add the bot to you application supervisor tree, for example:

children = [Simple.Bot, ...]
opts = [strategy: :one_for_one, name: MyApplication.Supervisor]
Supervisor.start_link(children, opts)

or directly start and link the bot with:

{:ok, pid} = Simple.Bot.start_link()

elchemista/telegram

Telegram