@Robert. Right you are. I checked the docs and db.get is a magic get anything function. Sorry for the noise.
So I'm going for door #2 now. In ServePhoto "photo" must be the correctly returned key. Otherwise accessing "photo.photo" would give an error. So photo.photo must truly be a false value. This means to me that although "photo" is a valid object, the photo.photo property never got set properly. This takes us back to "UploadPhoto". It's unlikely that photo.put() failed. And it's likely that "db.Blob" created a valid db.Blob object. However accessing "photo.photo" doesn't return the db.Blob object, but rather the underlying data that came into it. Therefore I think your original hunch that the incoming data for db.Blob is an empty string is correct. I've struggled with multi-part posts so I'm not 100% sure about the html. One thing that looks suspicious is the hard coding of the hostname:port in the post action. Are you sure you don't want simply "/uploadphoto"? That could send the uploads to the wrong place, for example different ports use different datastores on the Dev Server. On Sep 14, 9:17 am, Robert Kluin <[email protected]> wrote: > db.get() will grab an entity of _any_ kind. Model.get checks that the > key is for the correct kind of entity before fetching it. Either will > work. When I use db.get I usually include a check to make sure the > keys are the correct kind. > > The key he posted in his initial thread is a Photo. > > Robert > > On Tue, Sep 14, 2010 at 11:34, John McLaughlin > > > > <[email protected]> wrote: > > The one thing that looked off to me is that the line in ServePhoto > > > photo = db.get(self.request.get("photo_id")) > > > might want to be > > > photo = Photo.get(self.request.get("photo_id")) > > > I think db.get is a datastore method, not an inherited method from > > db.Model > > > On Sep 13, 8:09 pm, Robert Kluin <[email protected]> wrote: > >> I glanced over your code, nothing really major jumped out at me. If > >> you are not getting an exception in ServePhoto then the model is > >> clearly getting created and successfully fetched. > > >> So, here are my first thoughts: > >> Have you tried logging some debug info in the UploadPhoto and > >> ServePhoto handlers? Specifically are you sure data is actually in > >> the photo property and it is not just an empty string or something? > >> Maybe you could try logging len(photo.photo) right before saving it, > >> then again right after fetching it. > > >> What happens when you remove the if and simply return photo.photo? > > >> Robert > > >> class ServePhoto (webapp.RequestHandler): > >> def get(self): > >> photo = db.get(self.request.get("photo_id")) > >> if photo.photo: > >> self.response.headers['Content-Type'] = "image/jpg" > >> self.response.out.write(photo.photo) > >> else: > >> self.error(404) > > >> ------ > >> Robert Kluin > >> Ezox Systems, LLC > > >> On Sun, Sep 12, 2010 at 22:03, Raymond > > >> <[email protected]> wrote: > >> > Hi All, > > >> > I have been trying to understand how to upload and download images > >> > from to a Blobstore and have hit a wall. > >> > I have essentially made a modified version of the Guestbook example > >> > provided by google and modified it to suit my needs, I have tested the > >> > guestbook app as is and got it working, somehow somewhere I am making > >> > a simple mistake that frustrate every attempt at getting it working in > >> > my own code. > >> > I have stripped down my code to the essential in the hope of > >> > understanding what is wrong, but I am still stuck. > > >> > What am I attempting to do ? > >> > Upload in a blobstore an image and display it in a web page. > > >> > What is my code ? > > >> > 1) My upload form served from a static page > > >> > ... > >> > <form action="http://192.168.0.196:8083/uploadphoto"; > >> > enctype="multipart/form-data" method="post"> > >> > <div><label>Attempt at uploading a picture using a form</label></ > >> > deiv> > >> > <div><input type="file" name="photo" /></div> > >> > <div><input type="submit" value="Upload Photo" /></div> > >> > </form> > >> > ... > > >> > 2) My db model : > > >> > class Photo(db.Model): > >> > photo = db.BlobProperty() > >> > date = db.DateTimeProperty(auto_now_add=True) > > >> > 3) The code uploading the photo and saving it in the blobstore > > >> > class UploadPhoto(webapp.RequestHandler): > >> > def post(self): > >> > photo = Photo() > >> > img = self.request.get('photo') > >> > photo.photo = db.Blob(img) > >> > photo.put() > > >> > 4) The code creating the web page displaying the images : > > >> > class PhotoPage(webapp.RequestHandler): > >> > def get(self): > >> > self.response.out.write('<html><pre>') > >> > self.response.out.write('<h1>Date&Time Photo</h1>') > >> > photos = db.GqlQuery("SELECT * FROM Photo ORDER BY date > >> > DESC LIMIT > >> > 10") > >> > for photo in photos: > >> > self.response.out.write('<p>%s ' % photo.date) > >> > self.response.out.write('<img > >> > src="servephoto?photo_id=%s" /></p>' > >> > % photo.key()) > >> > self.response.out.write('</pre></body></html>') > > >> > 5) The code serving the images : > > >> > class ServePhoto (webapp.RequestHandler): > >> > def get(self): > >> > photo = db.get(self.request.get("photo_id")) > >> > if photo.photo: > >> > self.response.headers['Content-Type'] = "image/jpg" > >> > self.response.out.write(photo.photo) > >> > else: > >> > self.error(404) > > >> > Everything seem to work until this last stage, I can select an image > >> > in my form, upload it, Something is written in Binary in the > >> > Blobstore. > >> > When I visit the page supposed to display the image I see all info but > >> > a broken image icon. > >> > I checked the source code and the HTML seem to be just fine, here it > >> > is with one record in the blobstore, I get the blob key which mena > >> > that there is a record with some binary stuff in it. > > >> > <html><pre><h1>Date&Time Photo</h1><p>2010-09-13 00:31:14.477698 > >> > <img > >> > src="servephoto?photo_id=agt0ZXN0cmF5c3Bvc3ILCxIFUGhvdG8YWww" /></p></ > >> > pre></body></html> > > >> > I also know that the ServePhoto class is called and executed but it if > >> > photo.photo always return false and execute self-eror(404). > >> > I tried replacing this with a different error code and it always > >> > display the error code so I am sure the if statement get a false. > > >> > My questions is, why would the if statement get a false if there is > >> > effectively an image in the blobstore (Proved by the fact that I can > >> > retrieve it's key) ? > > >> > I am sorry for the long post, and hope I am not too confusing. > > >> > Thanks for any hint that would get me on the right way and forgive me > >> > if the answer is obvious, I probably need new eyes. > > >> > Raymond > > >> > -- > >> > You received this message because you are subscribed to the Google > >> > Groups "Google App Engine" group. > >> > To post to this group, send email to [email protected]. > >> > To unsubscribe from this group, send email to > >> > [email protected]. > >> > For more options, visit this group > >> > athttp://groups.google.com/group/google-appengine?hl=en. > > > -- > > You received this message because you are subscribed to the Google Groups > > "Google App Engine" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group > > athttp://groups.google.com/group/google-appengine?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. 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