telegram-django-bot 1.1.0

Telegram Django Bot

This library provides a Python high-level interface for creating Telegram Bots. It standardizes the coding in the best practice of the web development. The library is based on Django and Python-Telegram-Bot. It also provides viewset interface for managing data with.

If you start a new project, you could use Telegram django bot template with preconfigured settings.

Install

You can install via pip:

$ pip install telegram_django_bot

Then you can configure it in your app:

1. Add “telegram_django_bot” to your INSTALLED_APPS setting like this:

INSTALLED_APPS = [
    ...
    'telegram_django_bot',
    'django_json_widget', # needed for django admin site
]

If you are planning to use Django in asynchronous mode, then you need to set DJANGO_ALLOW_ASYNC_UNSAFE = True (otherwise DB writings will be failed).

2. Run python manage.py migrate to create the telegram_django_bot models (checked that the AUTH_USER_MODEL selected in settings).

3. Set up constants in Django settings file:

• TELEGRAM_ROOT_UTRLCONF - (same as ROOT_URLCONF for WEB) for using django notation in callback (routing) (strongly recommended)

  Not necessary, but useful settings:

• TELEGRAM_TOKEN - for adding “triggers”,

• TELEGRAM_TEST_USER_IDS - for adding tests for your bot,

• Make sure, that LANGUAGE_CODE, LANGUAGE_CODE, USE_I18N are also used in the library for language localization.

4. This step connects Telegram Django Bot with Python-Telegram-Bot. Add RouterCallbackMessageCommandHandler in handlers for using TELEGRAM_ROOT_UTRLCONF :

updater = Updater(bot=TG_DJ_Bot(settings.TELEGRAM_TOKEN))
updater.dispatcher.add_handler(RouterCallbackMessageCommandHandler())

or in 20.x version :

bot = TG_DJ_Bot(settings.TELEGRAM_TOKEN)
application = ApplicationBuilder().bot(bot).build()
application.add_handler(RouterCallbackMessageCommandHandler())

Quick start

Normally, Python-Telegram-Bot gives the next opportunities for bot creation:

• Python Interface for communication with Telegram API;

• Web service to get updates from telegram;

and Django:

• Django ORM (communication with Database);

• Administration panel for management.

Telegram Django Bot provides next special opportunities:

• using Viewsets (typical action with model (create, update, list, delete));

• using Django localization.

• using function routing like urls routing in Django.

• creating general menu items with no-coding (through Django Admin Panel);

• collecting stats from user actions in the bot;

• other useful staff.

The key feature of the lib is TelegramViewSet - a class for managing Django ORM model. It is designed in a similar way as Django rest framework Viewset , but has a significant difference: while DRF Viewset provides a response in serializable format (usually in json format) to frontend app, TelegramViewSet provides a response to the user in telegram interface in message format with buttons. So, you will manage data and receive responses in human format by executing TelegramViewSet method. The methods use some kind of templates for generating human responses (it is possible to overwrite these templates). By default, TelegramViewSet has 5 methods:

• create - create a new instance of the specified ORM model;

• change - update instance fields of specified ORM model;

• show_elem - show fields of the element and buttons with actions of this instance;

• show_list - show list of model elements (with pagination);

• delete - delete the instance

So, if, for example, you have a model of some request in your project:

from django.db import models

class Request(models.Model):
    text = models.TextField()
    importance_level = models.PositiveSmallIntegerField()  # for example it will be integer field
    project = models.ForeignKey('Project', on_delete=models.CASCADE)
    tags = models.ManyToManyField('Tags')

The next piece of code gives the opportunity for full managing (create, update, show, delete) of this model from Telegram:

from telegram_django_bot import forms as td_forms
from telegram_django_bot.td_viewset import TelegramViewSet


class RequestForm(td_forms.TelegramModelForm):
    class Meta:
        model = Request
        fields = ['text', 'importance_level', 'project', 'tags']


class RequestViewSet(TelegramViewSet):
    model_form = RequestForm
    queryset = Request.objects.all()
    viewset_name = 'Request'

If you need, you can add extra actions to RequestViewSet for managing (see details information below) or change existing functions. There are several parameters and secondary functions in TelegramViewSet for customizing logic if it is necessary.

In this example, TelegramModelForm was used. TelegramModelForm is a descendant of Django ModelForm. So, you could use labels, clean functions and other parameters and functions for managing logic and displaying.

TelegramViewSet is designed to answer next user actions: clicking buttons and sometimes sending messages. The library imposes Django URL notation for mapping user actions to TelegramViewSet methods (or usual handlers). Usually, for correct mapping you just need to set TELEGRAM_ROOT_UTRLCONF and use RouterCallbackMessageCommandHandler in dispatcher as it is mentioned above in the Install paragraph.

For correct mapping RequestViewSet you should write in the TELEGRAM_ROOT_UTRLCONF file something like this:

from django.urls import re_path
from .views import RequestViewSet

urlpatterns = [
    re_path(r"^rv/", RequestViewSet, name='RequestViewSet'),
]

From this point, you can use buttons with callback data “rv/<function_code>” for function calling. For example:

• “rv/cr” - RequestViewSet.create method;

• “rv/sl” - RequestViewSet.show_list;

See these examples for great understanding:

1. Telegram django bot template

2. Drive Bot

Deep in details

In this chapter, we will analyze how everything works. The main task of the library is to unify the code and provide frequently used functions for developing a bot, that is why a lot of logic is based on resources and paradigms of Django <https://www.djangoproject.com/>`_ and Python-Telegram-Bot . Let’s analyze key features of the library on the example of Telegram django bot template .

Important

The template is based on 13.x Python-Telegram-Bot version (synchronous version). So, the next examples is suitable for that version. For use with 20.x versions you need to do some modification.

Since Telegram bots are designed as a tool for responding to user requests, writing a bot begins from the user request handler. For this, the standard tools of the Python-Telegram-Bot library are used ﹣ telegram.ext.Update:

from telegram.ext import Updater

def main():
    ...

    updater = Updater(bot=TG_DJ_Bot(TELEGRAM_TOKEN))
    add_handlers(updater)
    updater.start_polling()
    updater.idle()

if __name__ == '__main__':
    main()

As indicated in the example, to run the bot (Update) you need to specify a few things (the Python-Telegram-Bot library standard):

1. an instance of the telegram.Bot model with the specified API token. In this case, a descendant telegram_django_bot.tg_dj_bot.TG_DJ_Bot of the telegram.Bot class is used. It has additional functionality for convenience (we will return to it later); 2. Handlers that will be called in response to user requests.

In the example, the list of handlers is specified in the add_handlers function:

from telegram_django_bot.routing import RouterCallbackMessageCommandHandler

...

def add_handlers(updater: Updater):
    dp=updater.dispatcher
    dp.add_handler(RouterCallbackMessageCommandHandler())

The example adds 1 super handler RouterCallbackMessageCommandHandler, which allows you to write handlers in the style of handling link requests in the same way as it is done in Django. RouterCallbackMessageCommandHandler allows you to handle messages, user commands and button clicks by users. In other words, it replaces the handlers MessageHandler, CommandHandler, CallbackQueryHandler . Since the Telegram Django Bot library is an extension, it does not prohibit the use of standard handlers of the Python-Telegram-Bot library for handle user requests. (sometimes it is simply necessary, for example, if you need to process responses to surveys (you need to use PollAnswerHandler)).

Django notation of routing handlers is that paths to handlers are described in a separate file or files. As in the Django standard, the main file (root) for routing is specified in the project settings, where paths to handlers or paths to groups of handlers are stored. The TELEGRAM_ROOT_UTRLCONF (same as ROOT_URLCONF for WEB) attribute is used to specify the path to the file. In the example template, we have the following settings:

bot_conf.settings.py:

TELEGRAM_ROOT_UTRLCONF = 'bot_conf.utrls'

bot_conf.utrls.py:

from django.urls import re_path, include

urlpatterns = [
    re_path('', include(('base.utrls', 'base'), namespace='base')),
]

That is, only 1 group of handlers is connected in the file (which corresponds to the base application at the conceptual level). You can add several groups as well, this can be convenient if you create several folders (applications) for storing code. As you can see Django functions are imported without any redefinition.

There is following code in the specified included file base.utrls.py :

from django.urls import re_path
from django.conf import settings
from telegram_django_bot.user_viewset import UserViewSet
from .views import start, BotMenuElemViewSet, some_debug_func


urlpatterns = [
    re_path('start', start, name='start'),
    re_path('main_menu', start, name='start'),

    re_path('sb/', BotMenuElemViewSet, name='BotMenuElemViewSet'),
    re_path('us/', UserViewSet, name='UserViewSet'),
]


if settings.DEBUG:
    urlpatterns += [
        re_path('some_debug_func', some_debug_func, name='some_debug_func'),
    ]

So, the end handlers (which are defined in the base.views.py file) are specified here. Thus, if user in the bot writes the command /start, then Updater receives a message about the user’s action and selects the appropriate for the request handler RouterCallbackMessageCommandHandler from a set of handlers. Then the handler RouterCallbackMessageCommandHandler searches the appropriate for string /start path in utrls and finds a suitable path '' + 'start', and then executes corresponding start function.

This distribution of handlers allows you to group part of the handlers into modules and quickly connect or change them, while not being afraid of confusion which handlers need to be called, as it can be if all paths from different modules to handlers are described in one place as required by Python-Telegram-Bot.

In this example file base.utrls.py also ViewSets are used in addition to simple handler functions like def start and def some_debug_func. ViewSet is an aggregator of several functions. The concept of it is that you quite often need to apply the same operations for a dataset, such as create, update, show, delete an example of dataset. There is the class telegram_django_bot.td_viewset.TelegramViewSet in the library for such purposes. The class manages the Django ORM database model. TelegramViewSet has 5 functions for managing the model:

Метод	UTRL	Description
create	cr	Create model
change	up	Change model attributes
delete	de	Deleting a model
show_elem	se	Display a model
show_list	sl	Display a list of models

Thus, if we want to call the BotMenuElemViewSet.create method to create an element, we need to use path ‘sb/cr’, whereby the first part of the path ‘sb/’ the router RouterCallbackMessageCommandHandler will execute the BotMenuElemViewSet class, namely the TelegramViewSet.dispatch method, which in turn will call the create method by analyzing the second part of the path cr.

To sum up the scheme of handlers routing, there are following key points:

1. telegram.ext.Update is used as a receiver of messages from Telegram;

2. Standard handlers of the Python-Telegram-Bot library can be used as handlers. For convenient use Django’s path scheme and TelegramViewSet you need to use RouterCallbackMessageCommandHandler.

3. TelegramViewSet aggregates a set of standard functions for managing data, what is made possible to group code associated with one type of data type in one class (place).

TelegramViewSet features

As described above, TelegramViewSet contains standard functions for data manipulation. Due to such standard data processing methods, it turns out in the example to describe the logic of BotMenuElemViewSet in 40 lines of code, also using some customization for beautiful data displaying.

To use all the features of the TelegramViewSet in your class, it should be inherited from it, as, for example, this is done in the BotMenuElemViewSet:

from telegram_django_bot.td_viewset import TelegramViewSet

class BotMenuElemViewSet(TelegramViewSet):

In order to customize the ViewSet, you must specify 3 required attributes:

1. viewset_name - class name, used to display to telegram users

2. model_form - data form, used to specify which fields of the ORM database model to use in the viewset;

3. queryset - basic query for getting model elements.

The BotMenuElemViewSet is used the following values:

from telegram_django_bot import forms as td_forms
from telegram_django_bot.models import BotMenuElem

class BotMenuElemForm(td_forms.TelegramModelForm):
    form_name = _("Menu elem")

    class Meta:
        model = BotMenuElem
        fields = ['command', "is_visable", "callbacks_db", "message", "buttons_db"]

class BotMenuElemViewSet(TelegramViewSet):
    viewset_name = 'BotMenuElem'
    model_form = BotMenuElemForm
    queryset = BotMenuElem.objects.all()

where BotMenuElemForm is a descendant of the Django ModelFrom class, so it has a similar structure and parameterization methods. `` form_name `` stands for the name of the form and is used in some messages sent to Telegram users.

TelegramViewSet has quite a lot in common with Viewset analogs tailored for WEB development (for example, django-rest-framework viewsets ). However, as part of the development of Telegram bots, TelegramViewSet has some special features:

1. An unusual way to create elements;

2. The display of information in bots is limited and most often comes down to displaying text and buttons, so the viewset in addition to business logic includes the creation of standard responses to user actions in the form of messages with buttons.

Forms

Since Telegram does not have the ability to create forms (in the classic Web sense) and communication between the bot and the user takes place in a chat, then the most intuitive solution for filling out a form (creating an element) is filling the form attribute by attribute, when the first element of the form is filled first, then the second, and so on. With this approach, it is necessary to use temporary storage for remembering specified values in order to create an element from the form at the end. TelegramModelForm and TelegramForm are implemented just in such way for taking over this process. The difference between these classes and the standard Django classes is precisely in the modification of the method of filling in the form fields, otherwise they do not differ from standard forms.

TelegramModelForm and TelegramForm as Django descendants of ModelForm and Form have the following parameters, which you may need to customize:

1. The clean function and other form validation process functions ;

2. labels - field names;

3. forms.HiddenInput - designation of hidden fields (hiding fields allows them not to be shown to the user, while using and configuring in forms or in TelegramViewSet).

TelegramViewSet is designed to interact with descendants of the TelegramModelForm class and allows you to use generate forms with different fields, such as CharField, IntegerField or ForeignKey, ManyToManyField. Also, it is a good idea to use the prechoice_fields_values dictionary in TelegramViewSet descendants for improving the convenience of filling out forms for users. It is possible to store a list of frequently used values of form fields in the prechoice_fields_values. This allows users to select the desired values by clicking buttons rather than writing text manually. The template has an example of using this field:

class BotMenuElemViewSet(TelegramViewSet):
    ...

    prechoice_fields_values = {
        'is_visable': (
            (True, '👁 Visable'),
            (False, '🚫 Disabled'),
        )
    }

In this case, 2 values are specified for choosing true or false for the boolean field is_visable. You can also use prechoice_fields_values for CharField, IntegerField or any other fields. Sometimes the list of values needs to be generated dynamically, in which case you can override prechoice_fields_values as a @property function.

Key logic of TelegramViewSet

The main function of the class, which is selected the function for managing data by the request of the user, is TelegramViewSet.dispatch. Let’s analyze its logic in more detail:

def dispatch(self, bot, update, user):

    self.bot = bot
    self.update = update
    self.user = user

    if update.callback_query:
        utrl = update.callback_query.data
    else:
        utrl = user.current_utrl

    self.utrl = utrl

    if settings.DEBUG:
        logging.info(f'utrl: {utrl}')

    utrl_args = self.get_utrl_params(re.sub(f'^{self.prefix}', '', self.utrl))
    if self.has_permissions(bot, update, user, utrl_args):
        chat_action, chat_action_args = self.viewset_routing[utrl_args[0]](*utrl_args[1:])
    else:
        chat_action = self.CHAT_ACTION_MESSAGE
        message = _('Sorry, you do not have permissions to this action.')
        buttons = []
        chat_action_args = (message, buttons)

    res = self.send_answer(chat_action, chat_action_args, utrl)

    utrl_path = utrl.split(self.ARGS_SEPARATOR_SYMBOL)[0]   # log without params as to much varients
    add_log_action(self.user.id, utrl_path)
    return res

Like a regular handler, the function takes 3 arguments as input: bot, update, user. After saving these arguments in class, the determination of the current routing path is occurred. It is determined either by pressing a button in the bot (the callback_data value of the button), or can be stored in the user attribute user.current_utrl. The second option is possible if the user manually enters some information (for example, filled in a text field of form). After that, the arguments are extracted from the path to call a specific function. Storing and interacting with arguments in a path is similar to how sys.argv works. So, for example, the string "sl&1&20" will be converted to the list ['sl', '1', '20']. The separator character between attributes is & by default and can be changed via the TelegramViewSet.ARGS_SEPARATOR_SYMBOL variable.

When using TelegramViewSet you most likely won’t have to interact with the argument string directly, since dispatch converts a string into arguments. And for creating a callback_data button string, that the user can call another method from Telegram interface, you should use TelegramViewSet.gm_callback_data function. In case you need more low-level interaction with function arguments, then you can use the construct_utrl and get_utrl_params functions.

After receiving the utrl_args arguments and checking access rights, the managing method (action) is directly selected and called. The first argument, which is the short name for the function, is popped from the utrl_args. All other arguments are passed as parameters into a function. Inside the function, the necessary business logic and the data formatting for displaying to the user as a response take place. Any such managing function in the TelegramViewSet class must return the action type chat_action and the parameters to that action chat_action_args. By default, the class has only 1 action ﹣ CHAT_ACTION_MESSAGE, which means that the user will receive a text message (possibly with buttons) as an answer for his/her action. The arguments for this action are the text of the message and a list of buttons (can be None).

After the function is processed, a response is sent to the user by send_answer function and the user’s action is logged.

The methods to call in viewset_routing are the create, update, delete, show_elem, show_list methods. You can also add your own methods. Suppose we want to add a def super_method(self, *args) method, then you need to add the following lines in the class:

class SomeViewSetClass(TelegramViewSet):
    ...

    actions = ['create', 'change', 'delete', 'show_elem', 'show_list', 'super_method']

    command_routing_super_method = 'sm'


    def super_method(self, *args):
        ...

Where actions defines the list of available methods and command_routing_<method> defines the path (url; short name) of the method.

As noted above, the dispatch method performs a permissions check by calling the has_permissions method. The check is performed by the classes specified in permission_classes and the default class is AllowAny:

class TelegramViewSet:
    permission_classes = [AllowAny]

Additional TelegramViewSet Tools

This section describes the following class functionality that makes it easier to write code:

1. External filters;

2. Data display setting options;

3. Helper functions for displaying data;

4. Helper functions of business logic;

External filters

Quite often, there is a situation when you need to work not with all the elements of a database table, but with some group (for example, a group of elements with a specific foreign key). For such purposes, you should use the foreign_filters list, which stores the values for filtering when the method is called. How exactly to use these filters is up to you, but usually it is a good idea to use it in the get_queryset function. Thus, it is possible to pass to functions additional arguments that do not break the key logic of standard functions. Using the template example, you can modify BotMenuElemViewSet so that if an additional parameter is specified, then the BotMenuElem list displays only those elements that contain the specified parameter in their command attribute. To do this, you need to make the following changes to the code:

class BotMenuElemViewSet(TelegramViewSet):
    ...

    foreign_filter_amount = 1

    def get_queryset(self):
        queryset = super().get_queryset()
        if self.foreign_filters[0]:
            queryset = queryset.filter(command__contains=self.foreign_filters[0])
        return queryset

Where foreign_filter_amount specifies the number of foreign filters. To call a method with a filter value, you must specify them right after the function name in the path (utrls): "sb/sl&start&2", "sb/sl&start&2&1", "sb/sl&hello. It is worth noting that if we do not want to specify a filter, then we need to skip the argument in the path (utrls) in the next way: "sb/sl&&2".

There is no need to construct and process filters in paths (utrls) directly, since the functions gm_callback_data and get_utrl_params know how to work with them. gm_callback_data also has a parameter add_filters (default True) which defines whether to include filters in the generated path (utrl) or not. If the value is False , then it is necessary in the function arguments manually specify filters: self.gm_callback_data('show_list', 'start', add_filters=False) (will generate "sb/sl&start). This allows you to change the value of filters when generating paths.

A more detailed use of external filters can be seen in the example of Drive Bot .

Data display options

The TelegramViewSet has the following options for displaying model elements:

• updating_fields: list - list of fields that can be changed (displayed when showing the element (show_elem);

• show_cancel_updating_button: bool = True - shows a cancel button when changing fields, which leads back to the displaying element (show_elem);

• deleting_with_confirm: bool = True - ask the user for confirmation when deleting an element;

• cancel_adding_button: InlineKeyboardButtonDJ = None - cancel button when creating an element (create method);

• use_name_and_id_in_elem_showing: bool = True - enables the use of the name and ID of the element when displaying this element (methods show_list and show_elem);

• meta_texts_dict: dict - a dictionary that stores standard texts for display (texts are used in all methods).

However, these fields are not always enough and you need to redefine the logic of helper functions for a beautiful display of information.

Helper functions for displaying data

The TelegramViewSet class describes the following helper functions for generating a response message:

• def gm_no_elem - if no element with this ID was found;

• def gm_success_created - successful creation of the model;

• def gm_next_field - when moving to the next form attribute;

• def gm_next_field_choice_buttons - generates buttons to select options for a specific form attribute (used inside gm_next_field);

• def gm_value_error - error output when adding a form attribute;

• def gm_self_variant - generates a message about the need to write the value manually by the user;

• def gm_show_elem_or_list_fields - displays model fields in the message (used in show_elem with full_show=True, and in show_list ﹣with full_show=False);

• def gm_value_str - generates a string displaying a specific attribute (used in gm_show_elem_or_list_fields);

• def gm_show_elem_create_buttons - displays available buttons (actions) when showing a model element (calling show_elem) ;

• def gm_show_list_button_names - generates the names of item buttons when displaying the list (calling show_list);

Depending on the need for customization, it is necessary to redefine these functions.

Helper functions of business logic

The TelegramViewSet class uses the following helper functions:

• def get_queryset - allows you to modify Model queries to the database (most often used to filter elements, as in the example above);

• def create_or_update_helper - main logic for create and update methods;

• def show_list_get_queryset - allows you to customize the selection of items to display in show_list;

handler_decor

When writing your own handlers, it is recommended to use a wrapper like telegram_django_bot.utils.handler_decor, which performs the following functions:

• Getting or creating a user in the database;

• In case of an error inside the handler function, returns an error message to the user;

• Logs the handler call;

• Tracks where the user came from;

• Choice of language for sending messages to the user (in the case of localization enabled);

This handler is also used inside RouterCallbackMessageCommandHandler, and as a result in calling TelegramViewSet classes.

Localization

The library expands the Django localization tools for use in Telegram. To support the use of different languages, the main elements of the Python-Telegram-Bot library are redefined in telegram_django_bot.telegram_lib_redefinition:

1. telegram.Bot -> telegram_django_bot.BotDJ ;

2. telegram.ReplyMarkup -> telegram_django_bot.ReplyMarkupDJ ;

3. telegram.KeyboardButton -> telegram_django_bot.KeyboardButtonDJ ;

4. telegram.InlineKeyboardButton -> telegram_django_bot.InlineKeyboardButtonDJ ;

5. telegram.InlineKeyboardMarkup -> telegram_django_bot.InlineKeyboardMarkupDJ.

When using these classes in code, multilingual support comes down to the following steps:

1. Specifying the necessary settings in the settings.py file: LANGUAGES - list of languages, LANGUAGE_CODE - default language;

2. Create folder with translations: $ django-admin makemessages -l <language_code>

3. Necessary texts for translation are wrapped in gettext and gettext_lazy from django.utils.translation (how it works in Django read here )

4. Run command $ django-admin makemessages -a to update texts for translation (created in locale folder)

5. Generation of translation files $ django-admin compilemessages.

Only a part of the functions uses localization in the template. It is made for easy understanding. The usage of localization can be seen in the example functions some_debug_func.

Extra lib features

The library provides some additional tools for the convenience of developing and managing the bot.

Embedded ORM lib models

For the correct work of TelegramViewSet and other components the Django ORM model representing the user in Telegram must be inherited from telegram_django_bot.models.TelegramUser, as these components use its fields. TelegramUser inherited from django.contrib.auth.models.AbstractUser (which allows you to authorize users on the site if necessary) and has the following additional fields:

• id - redefined to use user ID from telegrams;

• seed_code - arbitrary value from 1 to 100 to randomly group users for tests and analysis;

• telegram_username - username of the user in telegram;

• telegram_language_code - telegram language code (some languages have dialects and as a result the code designation is more than 2 symbols);

• timezone - the user’s time zone (for determining the time);

• current_utrl - path (utrl) of the last user action (used in TelegramViewSet);

• current_utrl_code_dttm - time of the last action, when saving the path;

• current_utrl_context_db - path context (utrl);

• current_utrl_form_db - intermediate data for the form. Acts as a temporary data store when filling out a form;

Fields current_utrl_<suffix> are needed for TelegramViewSet, TelegramModelForm and are needed in exceptional cases when writing code. The model also has the following methods (property) to simplify interaction with model fields:

• current_utrl_form (property) - returns the current temporarily stored path form data (utrl);

• current_utrl_context (property) - returns the current path context (utrl);

• save_form_in_db - saves the form in the current_utrl_form_db field;

• save_context_in_db - saves the context in the field current_utrl_context_db;

• clear_status - clears the data associated with the used path (fields current_utrl_<suffix>) ;

• language_code (property) - returns the language code in which messages should be generated for the user;

If you want, you can create your self Django ORM model representing the user, you just need to copy id, telegram_username, telegram_language_code, current_utrl, current_utrl_code_dttm, current_utrl_context_db, current_utrl_form_db and corresponding functions.

The library also describes additional models to improve the usability of the bot:

• ActionLog - stores user actions. Records help to collect analytics and make triggers that work on certain actions;

• TeleDeepLink - stores data on which links new users have clicked (to analyze input traffic);

• BotMenuElem - Quite often a bot needs messages that have only static data. These pages can be help and start messages. BotMenuElem allows you to configure such pages through the admin panel, without having to write anything in the code. In BotMenuElem there is the ability to customize pages depending on the starting deeplinks. BotMenuElem can not only add buttons to the message, but also send different files. To do this, you must specify media and the file format message_format. BotMenuElem allows you to quickly change bot menu blocks without having to make changes to the code;

• BotMenuElemAttrText - helper model for BotMenuElem, responsible for translating texts into other languages. The elements themselves are created depending on the specified languages in the LANGUAGES settings. You only need to fill in the translation in the translated_text field;

• Trigger - allows you to create triggers depending on certain actions. For example, remind the user that he has left incomplete order, or give a discount if it is inactive for a long time. For triggers to work, you need to add tasks from telegram_django_bot.tasks.create_triggers to CeleryBeat schedule;

• UserTrigger - helper model for Trigger, controlling to whom triggers have already been sent;

Additional functions of TG_DJ_Bot

To improve convenience, TG_DJ_Bot has several high-level functions:

• send_format_message - Allows you to send a message of an arbitrary type (internally, depending on the message_format selects the appropriate method of the Python-Telegram-Bot library). An important feature of this function is that if the user clicks on the button, then the previous message of the bot is changed, rather than a new one being sent. If, nevertheless you need to send a new message to the user, then you need to set the parameter only_send=True ;

• edit_or_send - wrapper of the send_format_message method for sending text messages with buttons;

• send_botmenuelem - Sends a BotMenuElem to the user. The update argument can be empty;

• task_send_message_handler - created for sending messages to many users. Handles situations where the user blocked the bot, deleted or when the limit for sending messages to users is reached;

Utils

The following additional functions are provided in the libraries:

• telegram_django_bot.utils.add_log_action - to create a user ActionLog;

• telegram_django_bot.utils.CalendarPagination - class for generating a calendar with buttons;

• telegram_django_bot.user_viewset.UserViewSet - telegram user class for changing language and time zone;

Routing details

In this section, we will analyze the work of RouterCallbackMessageCommandHandler and telegram_reverse in a little more detail.

As described earlier RouterCallbackMessageCommandHandler is used to be able to write handlers in the style Django. Also RouterCallbackMessageCommandHandler provides the ability to handle calls to BotMenuElem as through commands, and through callback. This is achieved by using the functions all_command_bme_handler and all_callback_bme_handler. By default, BotMenuElem call handling is enabled and handled after no suitable path was found in the description of utrls (paths in Django notation). If there is no BotMenuElem element match is found, the BotMenuElem is considered to be configured incorrectly and an error message is returned to the user. You can create a class with the only_utrl=True attribute, what is disable calls to BotMenuElem.

The example template contains the use of the telegram_reverse function, the essence of which is to generate a path (string) to the handler specified in the function argument. The function is analogous to the reverse Django function and avoids errors when changing paths.

Tests

The library also extends the django.test.TestCase capabilities for use with Telegram through the TD_TestCase class.

The simplest approach for testing the bot is to generate messages that the bot expects from Telegram and send a response to Telegram (to check that the bot’s response messages are in the correct format). Class TD_TestCase has a function create_update for easy and fast creation of Telegram.Update which generates the request telegram user. So the overall design looks like this:

1. A Telegram.Update is created for emitting a user request;

2. The handle_update lambda function, which uses RouterCallbackMessageCommandHandler, is called with created update. It does its staff and as a result sends a real message to the test user. Due to this, the correctness of the response data format is checked by Telegram;

3. The correctness of the sent data and changes in the database is checked using the standard tools django.test.TestCase.

You need to specify at least one test user ID in the TELEGRAM_TEST_USER_IDS settings section for correct tests work. Messages will be sent to that user, so the bot needs to have permission to write to that user.

In the tests folder you could find test examples.