現在、URL の下に 2 つの Web ページを含む非常に単純なアプリケーションを作成しています: localhost:8080/restaurants/ と localhost:8080/restaurants/new。Python コードで SQLAlchemy を使用して操作する sqlite データベースがあります。
私の最初のページ localhost:8080/restaurants/ には、データベースで利用可能なレストランのリストが含まれています。私の 2 番目のページ localhost:8080/restaurants/new は、localhost:8080/restaurants に表示されるように、新しいレストランを注文するためのフォームがある場所です。ただし、localhost:8080/restaurants/new のフォームに新しいレストラン名を入力すると、新しいレストランを表示するために localhost:8080/restaurants/ にリダイレクトされず、代わりに同じ URL リンクに残ります。 localhost:8080/restaurants/new に "No data received" というメッセージが表示されます。以下は私のコードです：
import cgi
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
#import libraries and modules
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from database_setup import Base, Restaurant, MenuItem
#create and connect to database
engine = create_engine('sqlite:///restaurantmenu.db')
Base.metadata.bind=engine
DBSession = sessionmaker(bind=engine)
session = DBSession()
class webServerHandler(BaseHTTPRequestHandler):
""" class defined in the main method"""
def do_GET(self):
try:
#look for url then ends with '/hello'
if self.path.endswith("/restaurants"):
self.send_response(200)
#indicate reply in form of html to the client
self.send_header('Content-type', 'text/html')
#indicates end of https headers in the response
self.end_headers()
#obtain all restaurant names from databse
restaurants = session.query(Restaurant).all()
output = ""
output += "<html><body><a href='/restaurants/new'>Add A New Restaurant</a>"
output += "</br></br>"
for restaurant in restaurants:
output += restaurant.name
output += """<div>
<a href='#'>Edit</a>
<a href='#'>Delete</a>
</div>"""
output += "</br></br>"
output += "</body></html>"
self.wfile.write(output)
print output
return
if self.path.endswith("/restaurants/new"):
self.send_response(200)
self.send_header('Content-type', 'text/html')
self.end_headers()
output = ""
output += "<html><body>"
output += "<h1>Add New Restaurant</h1>"
output += "<form method='POST' enctype='multipart/form-data action='/restaurants/new'>"
output += "<input name='newRestaurant' type='text' placeholder='New Restaurant Name'>"
output += "<input name='Create' type='submit' label='Create'>"
output += "</form></body></html>"
self.wfile.write(output)
return
except IOError:
self.send_error(404, "File %s not found" % self.path)
def do_POST(self):
try:
if self.path.endswith("/restaurants/new"):
ctype, pdict = cgi.parse_header(self.headers.getheader('content-type'))
#check of content-type is form
if ctype == 'mulitpart/form-data':
#collect all fields from form, fields is a dictionary
fields = cgi.parse_multipart(self.rfile, pdict)
#extract the name of the restaurant from the form
messagecontent = fields.get('newRestaurant')
#create the new object
newRestaurantName = Restaurant(name = messagecontent[0])
session.add(newRestaurantName)
session.commit()
self.send_response(301)
self.send_header('Content-type', 'text/html')
self.send_header('Location','/restaurants')
self.end_headers()
except:
pass
def main():
"""An instance of HTTPServer is created in the main method
HTTPServer is built off of a TCP server indicating the
transmission protocol
"""
try:
port = 8080
#server address is tuple & contains host and port number
#host is an empty string in this case
server = HTTPServer(('', port), webServerHandler)
print "Web server running on port %s" % port
#keep server continually listening until interrupt occurs
server.serve_forever()
except KeyboardInterrupt:
print "^C entered, stopping web server...."
#shut down server
server.socket.close()
#run main method
if __name__ == '__main__':
main()
参考までに、データベースを作成する database_setup ファイルを次に示します。
import sys
#importing classes from sqlalchemy module
from sqlalchemy import Column, ForeignKey, Integer, String
#delcaritive_base , used in the configuration
# and class code, used when writing mapper
from sqlalchemy.ext.declarative import declarative_base
#relationship in order to create foreign key relationship
#used when writing the mapper
from sqlalchemy.orm import relationship
#create_engine to used in the configuration code at the
#end of the file
from sqlalchemy import create_engine
#this object will help set up when writing the class code
Base = declarative_base()
class Restaurant(Base):
"""
class Restaurant corresponds to restaurant table
in the database to be created.
table representation for restaurant which
is in the database
"""
__tablename__ = 'restaurant'
#column definitions for the restaurant table
id = Column(Integer, primary_key=True)
name = Column(String(250), nullable=False)
class MenuItem(Base):
"""
class MenuItem corresponds to restaurant table
table representation for menu_item which
is in the database
"""
__tablename__ = 'menu_item'
#column definitions for the restaurant table
name = Column(String(80), nullable=False)
id = Column(Integer, primary_key=True)
course = Column(String(250))
description = Column(String(250))
price = Column(String(8))
restaurant_id = Column(Integer, ForeignKey('restaurant.id'))
restaurant = relationship(Restaurant)
#create an instance of create_engine class
#and point to the database to be used
engine = create_engine(
'sqlite:///restaurantmenu.db')
#that will soon be added into the database. makes
#the engine
Base.metadata.create_all(engine)
新しいレストランを追加できない理由がわかりません