How long to blob urls served by the app engine remain valid?

问题

I was wondering if anyone knew how long image urls served back from the google app engine blob store remain valid for?

I have been tracking on url that i served an image from the blob store on 1/3/13 and its still there.

I am ask specifically so i can cache the image url instead of attempting to serve it repeatedly. If i did this i would still check if the image is there, but how often would i need to check that

thanks!

回答1:

They remain valid until either you

a. call delete_serving_url, or
b. delete the underling blob.

来源：https://stackoverflow.com/questions/14331245/how-long-to-blob-urls-served-by-the-app-engine-remain-valid