Emotion Detection Application

A Python Flask web application that detects emotions in text using the IBM Watson NLP Emotion Prediction API. Built for the IBM/Coursera Developing AI Applications with Python and Flask final project.

• Watson NLP emotion analysis (anger, disgust, fear, joy, sadness)
• Dominant emotion detection
• Flask web UI with textarea and Analyze button
• REST endpoint: /emotionDetector?textToAnalyze=...
• Error handling for invalid input and API failures
• Unit tests for five emotion categories
• PEP8-compliant, pylint-ready code

emotion_detection_app/
├── EmotionDetection/
│ ├── __init__.py
│ └── emotion_detection.py # Watson API integration
├── templates/
│ └── index.html # Web UI
├── static/
│ ├── mywebscript.js # RunSentimentAnalysis()
│ └── styles.css
├── server.py # Flask application
├── test_emotion_detection.py # unittest suite
├── requirements.txt
└── README.md

1. User enters text in index.html and clicks Analyze Emotion.

2. JavaScript RunSentimentAnalysis() calls /emotionDetector?textToAnalyze=<text> via fetch().

3. Flask route in server.py calls emotion_detector(text).

4. emotion_detection.py sends a requests.post() to Watson NLP:

   https://sn-watson-emotion.labs.skills.network/v1/watson.runtime.nlp.v1/NlpService/EmotionPredict
   

5. JSON response is parsed; dominant emotion is the highest score.

6. Flask returns a formatted plain-text response to the browser.

• Python 3.8 or newer
• Internet access (Watson Skills Network endpoint)

cd emotion_detection_app
pip install -r requirements.txt

python server.py

Open: http://localhost:5000

curl "http://localhost:5000/emotionDetector?textToAnalyze=I%20am%20glad%20this%20happened"

Sample response:

For the given statement, the system response is
'anger': 0.001,
'disgust': 0.002,
'fear': 0.003,
'joy': 0.95,
'sadness': 0.01.
The dominant emotion is joy.

Tests call the live Watson API. Ensure you have network connectivity.

python -m unittest test_emotion_detection.py -v

Run pylint for PEP8 compliance:

pylint EmotionDetection/emotion_detection.py
pylint server.py
pylint test_emotion_detection.py

Target score: 10/10

• Python 3
• Flask
• requests
• IBM Watson NLP (Skills Network)
• unittest
• pylint

Educational project for Coursera/IBM certification.