在上传到Google App引擎之前调整图片大小

Question

I would like to be able resize an image blob before I save it to a database with google app engine

from google.appengine.api import images
from google.appengine.ext import blobstore
from google.appengine.ext.webapp import blobstore_handlers
from google.appengine.ext import db

class ImageModel(db.Model):
    image1 = blobstore.BlobReferencePropert(required = True)


class UploadImageHandler(BaseHandler, blobstore_handlers.BlobstoreUploadHandler):
    def post(self):
            upload_files = self.get_uploads('image1')
            blob_info = upload_files[0]
            blob_key = blob_info.key()
            img = images.Image(blob_key = blob_key)
            img.resize(width = 500, height = 500)

            i = ImageModel(image1 = img)
            i.put()

Of course this doesn't work since img is no longer a blob. How to I convert the image back into a blob and then upload to database. I don't want to serve the image dynamically and resize. I need to have a resized image in the database.

Answer 1

now blobstore support write file directly https://developers.google.com/appengine/docs/python/blobstore/overview#Writing_Files_to_the_Blobstore

so you can have something like this.

# resize your img

# create file
file_name = files.blobstore.create(mime_type='application/octet-stream')
with files.open(file_name, 'a') as f:
    f.write(img)    

# Finalize the file. Do this before attempting to read it.
files.finalize(file_name)

# Get the file's blob key
blob_key = files.blobstore.get_blob_key(file_name)