bookapp.py

import re
import traceback

from bookdb import BookDB

DB = BookDB()


def book(book_id):
    page = '''
    <h1>{title}</h1>
    <table>
    <tr><th>Author</th><td>{author}</td></tr>
    <tr><th>Publisher</th><td>{publisher}</td></tr>
    <tr><th>ISBN</th><td>{isbn}</td></tr>
    </table>
    <a href="/">Back to the list </a>
    '''
    book = DB.title_info(book_id)
    if book is None:
        raise NameError
    return page.format(**book)


def books():
    all_books = DB.titles()
    body = ['<h1>My Bookshelf</h1>', '<ul>']
    item_template = '<li><a href="/book/{id}">{title}</a></li>'
    for book in all_books:
        body.append(item_template.format(**book))
    body.append('</ul>')
    return '\n'.join(body)


def resolve_path(path):
    funcs = {
        '': books,
        'book': book
    }

    path = path.strip('/').split('/')

    func_name = path[0]
    args = path[1:]
    try:
        func = funcs[func_name]
    except KeyError:
        raise NameError
    return func, args


def application(environ, start_response):
    headers = [('Content-type', 'text/html')]
    try:
        path = environ.get('PATH_INFO', None)
        if path is None:
            raise NameError
        func, args = resolve_path(path)
        body = func(*args)
        status = '200 OK'
    except NameError:
        status = '404 Not Found'
        body = '<h1>Not Found</h1>'
    except Exception:
        status = '500 Internal Server Error'
        body = '<h1>Internal Server Error</h1>'
        print(traceback.format_exc())
    finally:
        headers.append(('Content-length', str(len(body))))
        start_response(status, headers)
        return [body.encode('utf8')]


if __name__ == '__main__':
    from wsgiref.simple_server import make_server
    srv = make_server('localhost', 8080, application)
    srv.serve_forever()