sentiment.py

from rasa.nlu.components import Component
from rasa.nlu import utils
from rasa.nlu.model import Metadata

import nltk
from nltk.classify import NaiveBayesClassifier
import os

import typing
from typing import Any, Optional, Text, Dict

SENTIMENT_MODEL_FILE_NAME = "sentiment_classifier.pkl"

class SentimentAnalyzer(Component):
    """A custom sentiment analysis component"""
    name = "sentiment"
    provides = ["entities"]
    requires = ["tokens"]
    defaults = {}
    language_list = ["en"]
    print('initialised the class')

    def __init__(self, component_config=None):
        super(SentimentAnalyzer, self).__init__(component_config)

    def train(self, training_data, cfg, **kwargs):
        """Load the sentiment polarity labels from the text
           file, retrieve training tokens and after formatting
           data train the classifier."""


        with open('labels.txt', 'r') as f:
            labels = f.read().splitlines()

        training_data = training_data.training_examples #list of Message objects
        tokens = [list(map(lambda x: x.text, t.get('tokens'))) for t in training_data]
        processed_tokens = [self.preprocessing(t) for t in tokens]
        labeled_data = [(t, x) for t,x in zip(processed_tokens, labels)]
        self.clf = NaiveBayesClassifier.train(labeled_data)



    def convert_to_rasa(self, value, confidence):
        """Convert model output into the Rasa NLU compatible output format."""

        entity = {"value": value,
                  "confidence": confidence,
                  "entity": "sentiment",
                  "extractor": "sentiment_extractor"}

        return entity
        

    def preprocessing(self, tokens):
        """Create bag-of-words representation of the training examples."""
        
        return ({word: True for word in tokens})


    def process(self, message, **kwargs):
        """Retrieve the tokens of the new message, pass it to the classifier
            and append prediction results to the message class."""
        
        if not self.clf:
            # component is either not trained or didn't
            # receive enough training data
            entity = None
        else:
            tokens = [t.text for t in message.get("tokens")]
            tb = self.preprocessing(tokens)
            pred = self.clf.prob_classify(tb)

            sentiment = pred.max()
            confidence = pred.prob(sentiment)

            entity = self.convert_to_rasa(sentiment, confidence)

            message.set("entities", [entity], add_to_output=True)


    def persist(self, file_name, model_dir):
        """Persist this model into the passed directory."""
        classifier_file = os.path.join(model_dir, SENTIMENT_MODEL_FILE_NAME)
        utils.json_pickle(classifier_file, self)
        return {"classifier_file": SENTIMENT_MODEL_FILE_NAME}

    @classmethod
    def load(cls,
             meta: Dict[Text, Any],
             model_dir=None,
             model_metadata=None,
             cached_component=None,
             **kwargs):
        file_name = meta.get("classifier_file")
        classifier_file = os.path.join(model_dir, file_name)
        return utils.json_unpickle(classifier_file)
 

hi JustinaPetr
"training_data" what kind of format does it follow, can you little elaborated on that?

thanks

Hi, I have read How to Enhance Rasa NLU Models with Custom Components, this tutorial is useful for me, thanks to your work!

I use the default to train, but the entities of Hello stupid bot is pos.

May you share the nlu.md please?

Thank you very much, looking forward to your reply, good day.

Input: Hello stupid bot
Output: neg with confidence of 0.333...

Python: 3.6.4
rasa: 1.18
rasa-sdk: 1.1.1

I find after train() and before persist(), the clf has been correctly trained.

So the problem is the utils.json_pickle in persist().

I change it to

with open(classifier_file, 'wb') as f:
    pickle.dump(self, f, pickle.HIGHEST_PROTOCOL)

and the load()

with open(classifier_file, 'rb') as f:
        return pickle.load(f)

it works!