Add application file

app.py

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+from flask import Flask
+from flask_cors import CORS, cross_origin
+from flask import request
+
+app = Flask(__name__)
+
+# Apply Flask CORS
+CORS(app)
+app.config['CORS_HEADERS'] = 'Content-Type'
+
+@app.route('/')
+@cross_origin(origin='*')
+def home():
+    return 'Welcome to the Flask Calculator API!'
+
+@app.route('/add', methods=['POST', 'GET'])
+@cross_origin(origin='*')
+def add_process():
+    a = int(request.args.get('a'))
+    b = int(request.args.get('b'))
+    kq = a + b
+    return 'Kết quả là: ' + str(kq)
+
+@app.route('/minus', methods=['POST', 'GET'])
+@cross_origin(origin='*')
+def minus_process():
+    a = int(request.args.get('a'))
+    b = int(request.args.get('b'))
+    kq = a - b
+    return 'Kết quả là: ' + str(kq)
+
+# Start Backend
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port='6868')

requirements.txt

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+flask
+flask_cors