Python Flask website

Question

I'm new to programming and in back-end. Right now I'm trying to learn flask, so I wrote a very simple website that currently encrypts and decrypts the message using RSA and DES.

I feel like my app.py file is just bad and should do it much better. I mean, there're a lot of repeating code like this:

@app.route('/rsa_encrypt', methods=['GET', 'POST']) def RSA_enc(): global get_form if request.method == "GET": get_form = True return render_template('rsa_encrypt.html', gf=get_form) else: get_form = False rsa = RSA(request.form.get('pt'), p=request.form.get('p'), q=request.form.get('q'), e=request.form.get('e')) return render_template('rsa_encrypt.html', gf=get_form, rsa=rsa, gspn=gspn) 

I tried to write some decorators for those routes, but they didn't work well.

Can you take a look and tell me what should I do better? It works but I think not as well as it should.

app.py

from flask import Flask, render_template, request, url_for, jsonify from ciphers import RSA, DES from prime import generate_semiprime_number as gspn app = Flask(__name__) get_form = None @app.route('/') def index(): return render_template('index.html') @app.route('/rsa_encrypt', methods=['GET', 'POST']) def RSA_enc(): global get_form if request.method == "GET": get_form = True return render_template('rsa_encrypt.html', gf=get_form) else: get_form = False rsa = RSA(request.form.get('pt'), p=request.form.get('p'), q=request.form.get('q'), e=request.form.get('e')) return render_template('rsa_encrypt.html', gf=get_form, rsa=rsa, gspn=gspn) @app.route('/rsa_decrypt', methods=['GET', 'POST']) def RSA_dec(): global get_form if request.method == "GET": get_form = True return render_template('rsa_decrypt.html', gf=get_form) else: get_form = False ct = [int(x) for x in request.form.get('ct')[1:-1].split(',')] rsa = RSA(ciphertext=ct, p=request.form.get('p'), q=request.form.get('q'), e=request.form.get('e')) return render_template('rsa_decrypt.html', gf=get_form, rsa=rsa) @app.route('/des_encrypt', methods=['GET', 'POST']) def DES_enc(): global get_form if request.method == "GET": get_form = True return render_template('des_encrypt.html', gf=get_form) else: get_form = False des = DES(request.form.get('pt'), user_key=request.form.get('key')) return render_template('des_encrypt.html', gf=get_form, des=des) @app.route('/des_decrypt', methods=['GET', 'POST']) def DES_dec(): global get_form if request.method == "GET": get_form = True return render_template('des_decrypt.html', gf=get_form) else: get_form = False des = DES(ciphertext=request.form.get('ct'), user_key=request.form.get('key')) return render_template('des_decrypt.html', gf=get_form, des=des) @app.route('/gpsn', methods=['POST']) def _gpsn(): return jsonify({'result' : str(gspn(request.form['bits']))}) if __name__ == '__main__': app.run() 

Other files repository. It's also hosted so you can quickly take a look.

Answer 1

Your main issue is (as you've already noticed) one of code repetition. Some simple helper methods here will do the trick; caveat - untested:

from flask import Flask, render_template, request, url_for, jsonify from ciphers import RSA, DES from prime import generate_semiprime_number as gspn app = Flask(__name__) get_form = None @app.route('/') def index(): return render_template('index.html') def do_rsa(encrypting): global get_form direction = 'en' if encrypting else 'de' tmpl = f'rsa_{direction}crypt.html' if request.method == 'GET': return render_template(tmpl, gf=True) kwargs = {'p': request.form.get('p'), 'q': request.form.get('q'), 'e': request.form.get('e')} if encrypting: rsa = RSA(request.form.get('pt'), **kwargs) else: ct = [int(x) for x in request.form.get('ct')[1:-1].split(',')] rsa = RSA(ciphertext=ct, **kwargs) kwargs = {} if encrypting: kwargs['gpsn'] = gpsn return render_template(tmpl, gf=False, rsa=rsa, **kwargs) @app.route('/rsa_encrypt', methods=('GET', 'POST')) def RSA_enc(): return do_rsa(True) @app.route('/rsa_decrypt', methods=('GET', 'POST')) def RSA_dec(): return do_rsa(False) def do_des(encrypting): global get_form direction = 'en' if encrypting else 'de' tmpl = f'des_{direction}crypt.html' if request.method == 'GET': return render_template(tmpl, gf=True) kwargs = {'user_key': request.form.get('key')} if encrypting: des = DES(request.form.get('pt'), **kwargs) else: des = DES(ciphertext=request.form.get('ct'), **kwargs) return render_template(tmpl, gf=False, des=des) @app.route('/des_encrypt', methods=('GET', 'POST')) def DES_enc(): return do_des(True) @app.route('/des_decrypt', methods=('GET', 'POST')) def DES_dec(): return do_des(False) @app.route('/gpsn', methods=('POST',)) def _gpsn(): return jsonify({'result' : str(gspn(request.form['bits']))}) if __name__ == '__main__': app.run()