def new_book():
form = NewBookForm()
if form.validate_on_submit():
if form.book_title.data is None:
flash("Fill in a book title to create a book!")
return redirect(url_for('show_books'))
book = Book(book_title=form.book_title.data)
author = form.author.data
book.authors.append(author)
book.user = g.user
if book.book_title in db.session.query(Book.book_title).all():
flash('This book title already exists.')
return redirect(url_for('new_book'))
db.session.add(book)
db.session.commit()
flash('Book successfully added.')
return redirect(url_for('show_books'))
return render_template('newbook.html', form=form)
