Uploading an Image from an external link to google cloud storage using google app engine python

To upload an external image you have to get it and save it. To get the image you van use this code:

from google.appengine.api import urlfetch

file_name = 'image.jpg'
url = 'http://example.com/%s' % file_name
result = urlfetch.fetch(url)
if result.status_code == 200:
    doSomethingWithResult(result.content)

To save the image you can use the app engine GCS client code shown here

import cloudstorage as gcs
import mimetypes

doSomethingWithResult(content):

    gcs_file_name = '/%s/%s' % ('bucket_name', file_name)
    content_type = mimetypes.guess_type(file_name)[0]
    with gcs.open(gcs_file_name, 'w', content_type=content_type,
                  options={b'x-goog-acl': b'public-read'}) as f:
        f.write(content)

    return images.get_serving_url(blobstore.create_gs_key('/gs' + gcs_file_name))

Here is my new solution (2019) using the google-cloud-storage library and upload_from_string() function only (see here):

from google.cloud import storage
import urllib.request

BUCKET_NAME = "[project_name].appspot.com" # change project_name placeholder to your preferences
BUCKET_FILE_PATH = "path/to/your/images" # change this path

def upload_image_from_url_to_google_storage(img_url, img_name):
    """
    Uploads an image from a URL source to google storage.
    - img_url: string URL of the image, e.g. https://picsum.photos/200/200
    - img_name: string name of the image file to be stored
    """
    storage_client = storage.Client()
    bucket = storage_client.get_bucket(BUCKET_NAME)
    blob = bucket.blob(BUCKET_FILE_PATH + "/" + img_name + ".jpg")

    # try to read the image URL
    try:
        with urllib.request.urlopen(img_url) as response:
            # check if URL contains an image
            info = response.info()
            if(info.get_content_type().startswith("image")):
                blob.upload_from_string(response.read(), content_type=info.get_content_type())
                print("Uploaded image from: " + img_url)
            else:
                print("Could not upload image. No image data type in URL")
    except Exception:
        print('Could not upload image. Generic exception: ' + traceback.format_exc())