homepage.py

from main import app
from flask import Flask, session, g, redirect, url_for, render_template, abort, flash, make_response, request
import os
import sqlite3
from functools import wraps

# more extension types can be added to the array
EXTENSIONS = ['jpg', 'png']
BOOK_COVERS = '/home/codio/workspace/main/static/book_covers'
app.config['BOOK_COVERS'] = BOOK_COVERS

# ALWAYS check user session
@app.before_request
def user_logged_in():
    user_id = session.get('access_mode')
    if user_id is None:
        # Session not found
        g.user = None
    else:
        g.user= user_id

# Wrappers allow additional functionality
# Code inspired by https://flask.palletsprojects.com/en/2.0.x/patterns/viewdecorators/
def login_req(view):
    @wraps(view)
    def wrapped_view(**kwargs):
        # if no login
        # massive help from https://www.programcreek.com/python/example/100778/flask.g.user 
        if g.user is None:
            # login again
            return redirect(url_for('login'))
        return view(**kwargs)
    # decorated func
    return wrapped_view

# Wrapper
# Code inspired by https://flask.palletsprojects.com/en/2.0.x/patterns/viewdecorators/
def admin_req(view):
    @wraps(view)
    def wrapped_view(**kwargs):
        # check if user is admin 
        if g.user == 'admin':
            # display view
            return view(**kwargs)
        if g.user is None:
            return redirect(url_for('login')) # login again
        # already logged in?
        return redirect(url_for('homepage'))
    return wrapped_view

@app.route('/homepage', methods=['GET','POST'])
@login_req
def homepage():
    if request.method == 'POST':
        # doesnt show stock list unless session user is admin
        if request.form['Submit'] == 'STOCK LEVELS':
            return redirect(url_for('stock_levels'))
        elif request.form['Submit'] == 'LOGOUT':
            # Logout therefore remove everything from session
            session.clear()
            return redirect(url_for('login'))
        elif request.form['Submit'] == 'CART':
            # View shopping cart function
            return redirect(url_for('shopping_cart')) #this function is located in checkout.py file
    else:
        # Connect to database and get ALL book data for ALL books
        con = sqlite3.connect('bookshop_database.db')
        cur = con.cursor()
        cur.execute("SELECT * FROM books")
        # Put into variable
        rows = cur.fetchall()
        # Render the homepage
        return render_template('homepage.html',page=url_for('homepage'),books=rows)

# Add books to stock
@app.route('/homepage/add_book',methods = ['POST'])
def add_book():
    _isbn = request.form['isbn']
    con = sqlite3.connect('bookshop_database.db')
    cur = con.cursor()
    # Check if any existing row that has the same primary key (isbn13)
    cur.execute("SELECT * FROM books WHERE isbn13=?;", [_isbn])
    row = cur.fetchone()
    # session['book'] is nested dictionary
    book_dict = {row[3]:{'title':row[0],'cover':row[5],'isbn':row[3],'price':row[7],'quantity':1,'total_individual_price' : row[7],'qty_left' : row[8],}}
    if 'book' in session:
        # If book isbn has already been added to the cart:
        if row[3] in session['book']: # (row[3] is isbn number (PRIMARY KEY))
            # Quantity of same book + 1
            session['book'][row[3]]['quantity'] += 1
            # Add retail price to the existing total for that book
            session['book'][row[3]]['total_individual_price'] += row[7]
            # Update total cost of cart
            session['total_price'] += row[7]
            # Quantity + 1
            session['total_quantity'] += 1
        # Book with diff isbn13 number added to cart:
        else:
            # Add book to session dict
            session['book'] = dict(list(session['book'].items())+list(book_dict.items()))
            # Price of book added to order
            session['total_price'] += row[7]
            # Quantity + 1
            session['total_quantity'] += 1
    else:
        # If no book has been added yet (notice quantity is set to 1)
        session['book'] = book_dict 
        session['total_price'] = row[7]
        session['total_quantity'] = 1
    return redirect(url_for('homepage'))
    
# Page for viewing stock (admin required)
# Template checks session for admin priviledges before this is run
@app.route('/homepage/stocklist', methods=['GET','POST'])
@admin_req
def stock_levels():
    if request.method == 'POST':
        # 2 buttons (POST)
        if request.form['Submit'] == 'ADD STOCK':
            return redirect(url_for('add_stock'))
        elif request.form['Submit'] == 'GO BACK':
            return redirect(url_for('homepage'))
    else:
        # list all books from db if method not post (default)
        con = sqlite3.connect('bookshop_database.db')
        cur = con.cursor()
        cur.execute("SELECT * FROM books")
        rows = cur.fetchall()
        con.close()
        return render_template('stock_checker.html', page = url_for('stock_levels'), books = rows)

# Add new books or update if isbn (PK) is the same as existing
@app.route('/homepage/stocklist/add_stock', methods=['GET','POST'])
@admin_req
def add_stock():
    if request.method == 'POST':
        if request.form['Submit'] == 'SUBMIT':
            file = request.files["inpt_file"] 
            # When file uploaded is true
            if file: # if the user had given us a file
                # basic function to check if filetype is valid:
                if allowed_file(file.filename):
                    filename = file.filename
                    # Save img file to book covers folder
                    file.save(os.path.join(app.config['BOOK_COVERS'],filename))
                    con = sqlite3.connect('bookshop_database.db')
                    con.row_factory = lambda cursor, row: row[0]
                    cur = con.cursor()
                    # Check if book with same primary key exists
                    cur.execute("SELECT isbn13 FROM books WHERE isbn13=?",(request.form['isbn'],))
                    row = cur.fetchall()
                    # If it does, before we insert we must delete the current row
                    if len(row) != 0: 
                        cur.execute("DELETE FROM books WHERE isbn13=?",(request.form['isbn'],))
                    # we add values that we provided in a form into our database 
                    cur.execute("INSERT INTO books VALUES(?,?,?,?,?,?,?,?,?)",(request.form['book_title'],request.form['author'],request.form['pub_date'],request.form['isbn'],request.form['desc'],filename,request.form['trade_price'],request.form['retail_price'],request.form['qnty'])) 
                    con.commit()
                    con.close()
                    # return to stock page with new stock details added 
                    return redirect(url_for('stock_levels'))
                flash('Bad file extension.')
                # essentially try again
                return redirect(url_for('add_stock'))
            # essentially try again
            flash('No image uploaded.')
            return redirect(url_for('add_stock'))
    else:
        return render_template('add_edit_stock.html',page=url_for('add_stock'))
        
# use of rsplit taken from https://flask.palletsprojects.com/en/2.0.x/patterns/fileuploads/
def allowed_file(filename):
    # a '.' is required in order for it to be a valid filename
    if '.' not in filename:
        return False
    # if there is a '.' then ANY of the allowed extensions
    if filename.rsplit('.', 1)[1].lower() in EXTENSIONS:
        return True
    return False