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 Bot 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

Available Bot behaviours:

Telegram.Bot: compatible with the Sync/Async dispatch model
Telegram.ChatBot: compatible with the ChatBot dispatch model

The library defines some general purpose Bot behaviours each implementing a specific telegram updates dispatch model.

Dispatch model

Essentially we can define stateless / statefull bot.

A stateless Bot has no memory of previous conversations, it just receives updates, process them and so on.
A statefull Bot instead can remember what happened in the past. The state here refer to a specific chat, a conversation (chat_id) between a user and a bot "instance".

Some executable examples are available under: example/example_*.exs.

Telegram Bot Supervisor

Telegram.Bot.Sync.Supervisor: stateless synchronous.
Telegram.Bot.Async.Supervisor: stateless asynchronous.
Telegram.Bot.ChatBot.Supervisor: statefull (per chat).

Sample app

A chat_bot app: https://github.com/visciang/telegram_example

kingdomcoding / telegram

Telegram