Adding source code files for Chapter 10

Chapter10/webapps/app5.py

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+#app5.py: interacting with db for create, delete and list objects
+from flask import Flask, request, render_template, redirect
+from flask_sqlalchemy import SQLAlchemy
+from werkzeug.exceptions import HTTPException
+import json
+
+app = Flask(__name__)
+app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///student.db'
+app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+db = SQLAlchemy(app)
+
+class Student(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    name = db.Column(db.String(80), nullable=False)
+    grade = db.Column(db.String(20), nullable=True)
+
+    def __repr__(self):
+        return '<Student %r>' % self.name
+
+@app.get('/list')
+def list_students():
+    student_list = Student.query.all()
+    return render_template('app5.html', students=student_list)
+
+
+@app.get('/add')
+def add_student():
+    fname = request.args['fname']
+    lname = request.args.get('lname', '')
+    grade = request.args.get('grade','')
+    student = Student(name=f"{fname} {lname}", grade=grade)
+    db.session.add(student)
+    db.session.commit()
+    return redirect("/list")
+
+@app.get('/delete/<int:id>')
+def del_student(id):
+    todelete = Student.query.filter_by(id=id).first()
+    db.session.delete(todelete)
+    db.session.commit()
+    return redirect("/list")
+
+@app.errorhandler(HTTPException)
+def page_not_found(error):
+    print(error)
+    response = error.get_response()
+    # replace the body with JSON
+    response.data = json.dumps({
+        "code": error.code,
+        "name": error.name,
+        "description": error.description,
+    })
+    return response
+
+if __name__ == '__main__':
+    app.run()