Intent routing

[mhaugestad]

I am trying to build in intent routing to my Whatsapp bot using semantic-router (https://github.com/aurelio-labs/semantic-router).
Currently, my understanding is that you can do this by having a handler that is triggered on all incoming messages and then build your custom logic there, ie:

@wa.on_message(text)
def on_message(client: WhatsApp, msg: Message):
    intent = intent_callable(msg.txt) # some function that returns a string with the intent
     match intent:
         case 'PURCHASE':
             ...
         case 'SUPPORT':
             ...
         case 'HELP':
             ...

However, this could quickly become a bit unmaintainable for more complex logic, and I really love the pyWa filtering on the handlers as it makes the code so concise and easy to read and understand. One thing that would be really neat is if it was possible to build some kind of middleware that adds arbitrary information to the msg object and can later be used to filter on. A python interface could look something like this:

import FastaAPI
from .config import settings
from pywa import WhatsApp, filters


server = FastAPI()

app = WhatsApp(
    phone_id=settings.PHONE_ID,
    token=settings.TOKEN,
    server=server,
    callback_url=settings.CALLBACK_URL,
    verify_token=settings.WEBHOOK_VERIFICATION_TOKEN,
    )

def intent_middleware(msg):
    if msg.text == 'I want to buy something':
        msg.intent == 'PURCHASE'
    elif msg.text == 'Please give me some help':
        msg.intent == 'SUPPORT'

def sentiment_middleware(msg):
    if msg.text == 'Love your products':
        msg.sentiment == 'Positive'
    elif msg.text == 'Very bad service!':
        msg.intent == 'Negative'


app.add_middleware(intent_middleware)
app.add_middleware(sentiment_middleware)

@app.on_message(filter.new(lambda _, msg: msg.intent == 'PURCHASE')):
def handle_to_purchase_intent(_: WhatsApp, msg: types.Message):
    msg.reply("Here is our catalogue of products...")

@app.on_message(filter.new(lambda _, msg: msg.sentiment == 'Negative')):
def handle_negative_experience(_: WhatsApp, msg: types.Message):
    msg.reply("I am sorry your experience has not lived up to your expectations")

[david-lev]

Interesting idea (and thanks for introducing semantic-router ;))
I don't even think a new name like middleware is needed, another option is to register a handler that will first handle all messages, add content to them and then call continue_handling

The thing is this: Since the library is designed so that several handlers will handle the same update, it was important to me to make sure that the content of the update cannot be changed (so that we don't have to give a new copy each handler)
If so, maybe it would be possible to add a new field to which information can be written and it will be available at the update level to all handlers

Something like this:

@app.on_message(filters=filters.text, priority=100) # a higher priority will be executed first
def on_every_text_message(_: WhatsApp, m: types.Message):
    m.data["key"] = "value"  # .data is a dict that can be used to store data between handlers
    m.continue_handling() # continue to the next handler

@app.on_message(filter.new(lambda _, msg: msg.data["key"] == "PURCHASE"))
def handle_to_purchase_intent(_: WhatsApp, msg: types.Message):
    msg.reply("Here is our catalogue of products...")

@app.on_message(filter.new(lambda _, msg: msg.data["key"] == "Negative"))
def handle_negative_experience(_: WhatsApp, msg: types.Message):
    msg.reply("I am sorry your experience has not lived up to your expectations")

Do you think this could be useful?

[mhaugestad]

Yes! That would work and looks real neat and tidy! Thanks!

Happy to help in any way I can to implement if needed!

[david-lev]

I think this would be one of the easiest things to implement. just to add the field to BaseUpdate class
The question is how to name the new field. data, shared_data?

[mhaugestad]

No strong preferences on naming, but data is short and sweet, happy to use that!

[david-lev]

Ok, but i think i'll stick with shared_data to avoid conflicts with WhatsApp, the data field is more likely to be used by them in the future.
I already implemented the feature, you can use it by installing pywa from the update-shared-data branch:

pip install https://github.com/david-lev/pywa/archive/update-shared-data.zip

I'll try yo publish new version in the next days

[mhaugestad]

Amazing! Thanks a lot!!