I am working on sending a GET request to an API from my Google App Engine application. However, Google App Engine automatically appends AppEngine-Google; (+http://code.google.com/appengine; appid: APPID) to the end of my User-Agent, causing my request to return 403 forbidden. Is there any way around having this appended to my User-Agent or is there another way to successfully reach the API?
No, you can't stop AppEngine appending an identifier to the User-Agent of each request. I guess this is a security measure to identify "spammers" easily. What we ended up doing is hosting a "proxy" on a Compute Engine instance which you pass the URL to fetch via a query-parameter and it returns the contents of that URL.