An App Engine application cannot:

write to the filesystem. Applications must use the App Engine

datastore for storing persistent data.

您需要做的是向用户呈现带有文件上载字段的表单.

提交表单后,文件将上载,Blobstore将从文件内容中创建一个blob,并返回一个blob键,可用于稍后检索和提供blob.

允许的最大对象大小为2千兆字节.

这是一个可以尝试的工作代码段：

#!/usr/bin/env python

#

import os

import urllib

from google.appengine.ext import blobstore

from google.appengine.ext import webapp

from google.appengine.ext.webapp import blobstore_handlers

from google.appengine.ext.webapp import template

from google.appengine.ext.webapp.util import run_wsgi_app

class MainHandler(webapp.RequestHandler):

def get(self):

upload_url = blobstore.create_upload_url('/upload')

self.response.out.write('

')

self.response.out.write('

' % upload_url)

self.response.out.write("""Upload File:

name="submit" value="Submit">

""")

class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):

def post(self):

upload_files = self.get_uploads('file')

blob_info = upload_files[0]

self.redirect('/serve/%s' % blob_info.key())

class ServeHandler(blobstore_handlers.BlobstoreDownloadHandler):

def get(self, resource):

resource = str(urllib.unquote(resource))

blob_info = blobstore.BlobInfo.get(resource)

self.send_blob(blob_info)

def main():

application = webapp.WSGIApplication(

[('/', MainHandler),

('/upload', UploadHandler),

('/serve/([^/]+)?', ServeHandler),

], debug=True)

run_wsgi_app(application)

if __name__ == '__main__':

main()

EDIT1：

在您的特定情况下,您可以使用BlobProperty(限制为1MB)来存储您的请求：

class Photo(db.Model):

imageblob = db.BlobProperty()

然后调整你的webapp.RequestHandler来保存你的请求：

class Upload(webapp.RequestHandler):

def post(self):

image = self.request.get("Filedata")

photo = Photo()

photo.imageblob = db.Blob(image)

photo.put()

EDIT2：

您无需更改app.yaml,只需添加新的处理程序并将其映射到WSGI中即可.

要检索存储的照片,您应该添加另一个处理程序来为照片提供服务：

class DownloadImage(webapp.RequestHandler):

def get(self):

photo= db.get(self.request.get("photo_id"))

if photo:

self.response.headers['Content-Type'] = "image/jpeg"

self.response.out.write(photo.imageblob)

else:

self.response.out.write("Image not available")

然后映射你的新DownloadImage类：

application = webapp.WSGIApplication([

...

('/i', DownloadImage),

...

], debug=True)

您可以使用以下网址获取图片：

yourapp/i?photo_id = photo_key

根据要求,如果出于任何奇怪的原因,您真的想使用这种网址www.mysite.com/i/photo_key.jpg来提供图像,您可能想尝试这样做：

class Download(webapp.RequestHandler):

def get(self, photo_id):

photo= db.get(db.Key(photo_id))

if photo:

self.response.headers['Content-Type'] = "image/jpeg"

self.response.out.write(photo.imageblob)

else:

self.response.out.write("Image not available")

略有不同的映射：

application = webapp.WSGIApplication([

...

('/i/(\d+)\.jpg', DownloadImage),

...

], debug=True)