Ajaxian » img2json: get your image metadata via App Engine
The tradition of placing small, useful services on App Engine continues. This time, Adam Burmister has created img2json, a Google AppEngine service that extracts metadata from image URLs.The metadata can be as simple as width, height, mime type, file size, but it also extract EXIF metadata (camera make, manufacturer, GPS positioning, orientation, etc).
Ajaxian » img2json: get your image metadata via App Engine
Hmmm…using a web service vs. using a JavaScript-based, in-client approach. The webservice seems to be really fast and its based on Google’s distributed (?) app engine. I wonder if feeding this an asset that’s sitting on a content delivery network (Akamai, etc.) would combine with the Google’s App Engine speed to balance off loading that extra script? You’d still ostensibly need the same callback function.
Since you’re using a plain, old URL could you stuff the request URL in an img tag’s src attribute, then use the callback to do a quick swap once it loads? If so, that’s pretty darn effective. (I’d test it, but I’m lazy and kind of sure you’d see a broken image for a bit before it swaps in the good image; however, you could always set this up on a set of positioned or not-displayed images and achieve the same effect. I’m worried this would smack into the same origin policy and don’t want to do this on the server since it could be a blocking performance bottleneck.)
Nice to see App Engine paving the way for utility apps!
Tags: exif, images, javascript
