An App Engine application cannot:
- write to the filesystem. Applications must use the App Engine
datastore for storing persistent data.
What you need to do is presenting a form with a file upload field to the user.
When the form is submitted, the file is uploaded and the Blobstore creates a blob from the file's contents and returns a blob key useful to retrieve and serve the blob later.
The maximum object size permitted is 2 gigabytes.
Here is a working snippet that you can try as is:
#!/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('<html><body>')
self.response.out.write('<form action="%s" method="POST" enctype="multipart/form-data">' % upload_url)
self.response.out.write("""Upload File: <input type="file" name="file"><br> <input type="submit"
name="submit" value="Submit"> </form></body></html>""")
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:
in your specific case you could use a BlobProperty (limited to 1MB) to store your request:
class Photo(db.Model):
imageblob = db.BlobProperty()
then adapt your webapp.RequestHandler to save your request:
class Upload(webapp.RequestHandler):
def post(self):
image = self.request.get("Filedata")
photo = Photo()
photo.imageblob = db.Blob(image)
photo.put()
EDIT2:
You don't need to change your app.yaml, just add a new handler and map it in your WSGI.
To retrieve the stored photo you should add another handler to serve your photos:
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")
then map your new DownloadImage class:
application = webapp.WSGIApplication([
...
('/i', DownloadImage),
...
], debug=True)
You would be able to get images with a url like:
yourapp/i?photo_id = photo_key
As requested, if for any odd reason you really want to serve your images using this kind of url www.mysite.com/i/photo_key.jpg , you may want to try with this:
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")
with a slightly different mapping:
application = webapp.WSGIApplication([
...
('/i/(\d+)\.jpg', DownloadImage),
...
], debug=True)
