Python Google App Engine Image object

Question

Using Python Image Library PIL and Google App Engine Blobstore...

This:

img = images.Image(blob_key=image)
logging.info(img.size)
self.response.headers['Content-Type'] = 'image/jpeg'
self.response.out.write(img)

Has Attribute error:

AttributeError: 'Image' object has no attribute 'size'

So the Image instance from google app engine does not have size?

So then how does this work:

img = images.Image(blob_key=image)
img.resize(width, height)
img.im_feeling_lucky()
thumbnail = img.execute_transforms(output_encoding=images.JPEG)
self.response.headers['Content-Type'] = 'image/jpeg'
self.response.out.write(thumbnail)

What am I missing?

EDIT:

The fix was using the get_serving_url and not use my image server as proposed by @voscausa. Due to the fact that my object was parsed by jinja2 templating it was impossible to create a Image object via jinja2. So the final solution worked as below:

class Mandelbrot(db.Model):
  image = blobstore.BlobReferenceProperty()

@property
def image_url(self):
  return images.get_serving_url(self.image)

This way I could parse the image url to my page like:

<img src=
{% if mandelbrot.image %}
  "{{ mandelbrot.image_url }}" 
{% else %} 
  "./assets/img/preloader.gif"
{% endif %}
/>

To explain a bit more. The first method without the resize does not serve a valid image resource. That is the issue and not the size. — Jimmy Kane
– Jimmy Kane, Commented Dec 11, 2012 at 13:39
Your question really isn't about PIL, you should change the title. Google might use PIL to implement its Image class but it's a completely separate thing. — Mark Ransom
– Mark Ransom, Commented Dec 11, 2012 at 16:39

voscausa · Accepted Answer · 2012-12-11 16:32:12Z

3

I'am not familiair with PIL, because I use another solution from Google for serving and sizing images. Google can serve the images for you, using Google High Performance Image serving. This means:

you have to create once, a serving_url for images in the blobstore using : get_serving_url
You can change the size of the served image. The original is not changed
Google will serve the images almost for free for you. You do not need a handler. You only pay the bandwidth

Here is an example. You can change the =s0, to change the size. s0 returns the original size.

https://lh6.ggpht.com/1HjICy6ju1e2GIg83L0qdliUBmPHUgKV8FP3QGK8Qf2pHVBfwkpO_V38ifAPm-9m20q_3ueZzdRCYQNyDE3pmA695iaLunjE=s0

get_serving_url docs: https://developers.google.com/appengine/docs/python/images/functions

Code :

class Dynamic(db.Model):          # key : name
    name = db.StringProperty() 
    blob_ref = blobstore.BlobReferenceProperty()
    serving_url = db.LinkProperty()

dyn= Dynamic.get_by_key_name(key_name)
try :       # get url with size = 0
    dyn.serving_url = images.get_serving_url(dyn.blob_ref, size=None, secure_url=True)
except DeadlineExceededError : 
    try :             # sometimes this request fails, retry. This always works fine
        dyn.serving_url = images.get_serving_url(dyn.blob_ref, size=None, secure_url=True)
    except DeadlineExceededError :
        logging.error('Image API get_serving_url deadline error after retry' %(dyn.key().name()))                        
        return None
    dyn.put()

edited Dec 11, 2012 at 16:32

answered Dec 10, 2012 at 23:46

voscausa

11.8k2 gold badges43 silver badges70 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Jimmy Kane Over a year ago

Agreed that this is the best approach. Thank you for your answer. But a quick question. If you wanted to get the serving url via a template ? eg: object.image = self._save_to_blobstore_and_get_key(image) How could someone when parsing the object to a template retrieve the url without first creating an image object?

voscausa Over a year ago

I use a datastore entity with references to the blobstore (last uploaded version) and the serving_url. When I create the template I use this entity to fill the template and also add the size (s=xxx) to the template. I did not understand your code, so I have edited my answer to add the code.

Jimmy Kane Over a year ago

Yes your example is correct, though you where faster! Also your example is saving up resources while not always calling the get_serving_url() Also please see my corrected example

voscausa Over a year ago

Looks OK. You can add the dynamic size (=sxxx) to your template and if size is not defined you can add a default : =s0 Like : {{ mandelbrot.image_url }}=s{{ mandelbrot.size|default('0') }}

themihai Over a year ago

just a note : you may also use google cloud storage to store the images and get the serving url not only the blobstore.

Blender · Accepted Answer · 2012-12-10 23:06:23Z

1

It looks like the GAE version of PIL doesn't implement .size. Use something like this instead:

logging.info((img.width, img.height))

answered Dec 10, 2012 at 23:06

Blender

300k55 gold badges462 silver badges512 bronze badges

1 Comment

Jimmy Kane Over a year ago

My issue @Blender is not getting the size but serving the image. Disregard the size. It was just for reference as well.

Collectives™ on Stack Overflow

Python Google App Engine Image object

2 Answers 2

5 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related