books/main.py

from flask import Flask
from flask import render_template
from flask import request
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow
from flask_bootstrap import Bootstrap

app = Flask(__name__)
### what is this value? I gather I should chagne it?
DB_URL = 'postgresql+psycopg2://ddp:NWNlfa01@127.0.0.1:5432/library'
app.config['SQLALCHEMY_DATABASE_URI'] = DB_URL
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config.from_mapping( SECRET_KEY=b'\xd6\x04\xbdj\xfe\xed$c\x1e@\xad\x0f\x13,@G')
db = SQLAlchemy(app)
ma = Marshmallow(app)
Bootstrap(app)

from author import Author, AuthorForm, AuthorSchema
from publisher import Publisher, PublisherForm, PublisherSchema

####################################### CLASSES / DB model #######################################
book_author_link = db.Table('book_author_link', db.Model.metadata,
    db.Column('book_id', db.Integer, db.ForeignKey('book.id')),
    db.Column('author_id', db.Integer, db.ForeignKey('author.id'))
)

book_publisher_link = db.Table('book_publisher_link', db.Model.metadata,
    db.Column('book_id', db.Integer, db.ForeignKey('book.id')),
    db.Column('publisher_id', db.Integer, db.ForeignKey('publisher.id'))
)

book_genre_link = db.Table('book_genre_link', db.Model.metadata,
    db.Column('book_id', db.Integer, db.ForeignKey('book.id')),
    db.Column('genre_id', db.Integer, db.ForeignKey('genre_lst.id'))
)

class Book_Sub_Book_Link(db.Model):
    __tablename__ = "book_sub_book_link"
    book_id = db.Column(db.Integer, db.ForeignKey('book.id'), unique=True, nullable=False, primary_key=True)
    sub_book_id = db.Column(db.Integer, db.ForeignKey('book.id'), unique=True, nullable=False, primary_key=True)
    sub_book_num = db.Column(db.Integer)

    def __repr__(self):
        return "<book_id: {}, sub_book_id: {}, sub_book_num: {}>".format(self.book_id, self.sub_book_id, self.sub_book_num)

class Book(db.Model):
    id = db.Column(db.Integer, unique=True, nullable=False, primary_key=True)
    title = db.Column(db.String(100), unique=True, nullable=False)
    year_published = db.Column(db.Integer)
    rating = db.Column(db.String(20))
    condition = db.Column(db.String(20))
    owned = db.Column(db.String(20))
    covertype = db.Column(db.String(20))
    notes = db.Column(db.Text)
    blurb = db.Column(db.Text)
    created = db.Column(db.Date)
    modified = db.Column(db.Date)

    author = db.relationship('Author', secondary=book_author_link)
    publisher = db.relationship('Publisher', secondary=book_publisher_link)
    genre = db.relationship('Genre_Lst', secondary=book_genre_link )
    parent_ref = db.relationship('Book_Sub_Book_Link', secondary=Book_Sub_Book_Link.__table__, primaryjoin="Book.id==Book_Sub_Book_Link.sub_book_id", secondaryjoin="Book.id==Book_Sub_Book_Link.book_id" )
    child_ref = db.relationship('Book_Sub_Book_Link', secondary=Book_Sub_Book_Link.__table__, primaryjoin="Book.id==Book_Sub_Book_Link.book_id", secondaryjoin="Book.id==Book_Sub_Book_Link.sub_book_id" )

    def __repr__(self):
        return "<id: {}, author: {}, title: {}, year_published: {}, rating: {}, condition: {}, owned: {}, covertype: {}, notes: {}, blurb: {}, created: {}, modified: {}, publisher: {}>".format(self.id, self.author, self.title, self.year_published, self.rating, self.condition, self.owned, self.covertype, self.notes, self.blurb, self.created, self.modified, self.publisher )

#$class Publisher(db.Model):
#    id = db.Column(db.Integer, unique=True, nullable=False, primary_key=True)
#    name = db.Column(db.String(50), unique=False, nullable=False)
#
#    def __repr__(self):
#        return "<id: {}, name: {}>".format(self.id, self.name)

class Genre_Lst(db.Model):
    __tablename__ = "genre_lst"
    id = db.Column(db.Integer, unique=True, nullable=False, primary_key=True)
    genre = db.Column(db.String(20), unique=False, nullable=False)

    def __repr__(self):
        return "<id: {}, genre: {}>".format(self.id, self.genre)

#class PublisherSchema(ma.SQLAlchemyAutoSchema):
#    class Meta: model = Publisher

class Genre_LstSchema(ma.SQLAlchemyAutoSchema):
    class Meta: model = Genre_Lst

class Book_Sub_Book_LinkSchema(ma.SQLAlchemyAutoSchema):
    class Meta: model = Book_Sub_Book_Link

class BookSchema(ma.SQLAlchemyAutoSchema):
    author = ma.Nested(AuthorSchema, many=True)
    publisher = ma.Nested(PublisherSchema, many=True)
    genre = ma.Nested(Genre_LstSchema, many=True)
    parent_ref = ma.Nested(Book_Sub_Book_LinkSchema, many=True)
    child_ref = ma.Nested(Book_Sub_Book_LinkSchema, many=True)
    class Meta: model = Book

### DDP: do I need many=True on Author as books have many authors? (or in BookSchema declaration above?)
book_schema = BookSchema()
books_schema = BookSchema(many=True)

####################################### ROUTES #######################################
@app.route("/books", methods=["GET"])
def books():
    books = Book.query.outerjoin(Book_Sub_Book_Link, Book.id==Book_Sub_Book_Link.book_id).order_by(Book.id, Book_Sub_Book_Link.sub_book_num).all()

    subs = db.engine.execute ( "select * from book_sub_book_link" )
    for row in subs:
       index = next((i for i, item in enumerate(books) if item.id == row.sub_book_id), -1)
       books[index].parent_id = row.book_id
       books[index].sub_book_num = row.sub_book_num

    books_s = books_schema.dump(books)
    return render_template("books.html", books=books, tst=books_s)
#    return render_template("books.html", books=books_s)

@app.route("/book/<id>", methods=["GET"])
def book(id):
    book = Book.query.get(id)
    book_s = book_schema.dump(book)

	######
	###
	### okay, this manual hacking of sub_book is currently going to be needed, because in the jinja2 I want to list the book, and more than just the id numhber of the sub_book, I want the details... (sub_book_schema needs a book relationship BUT, dependencies mean I can't define a book schema inside sub_book schema, and I am definitely not sure how to join it anyway... for another time.
	###
	#####
    # force sub books for jinja2 to be able to use
    subs = db.engine.execute ( "select bsb.book_id, bsb.sub_book_id, bsb.sub_book_num, book.title, book.rating, book.year_published, book.notes, bal.author_id as author_id, author.surname||', '||author.firstnames as author from book_sub_book_link bsb, book, book_author_link bal, author where bsb.book_id = {} and book.id = bsb.sub_book_id and book.id = bal.book_id and bal.author_id = author.id".format( id ) )
    sub_book=[]
    for row in subs:
        # get genres for sub book and add by hand first
        tmp_g = []
        genres = db.engine.execute ( "select genre_lst.id, genre_lst.genre from genre_lst, book_genre_link bgl where genre_lst.id = bgl.genre_id and bgl.book_id = {}".format( row.sub_book_id ) )
        for genre in genres:
            tmp_g.append( { 'id': genre.id, 'genre': genre.genre } )

        sub_book.append( { 'sub_book_id': row.sub_book_id, 'sub_book_num': row.sub_book_num, 'title' : row.title, 'rating': row.rating, 'year_published' : row.year_published, 'notes' : row.notes, 'author_id' : row.author_id, 'author' : row.author, 'genres' : tmp_g } )

    book_s['sub_book'] = sub_book

    print( "parent book details:" )
    print( book.parent_ref )
    print( "child book details:" )
    print( book.child_ref )

    return render_template("book.html", books=book_s, subs=sub_book )

@app.route("/", methods=["GET"])
def main_page():
    return render_template("main.html")

if __name__ == "__main__":
    app.run(host="0.0.0.0", debug=True)