akbertram/activityinfo — comment on commit 6cc62c9e7102b03b2e64f9ae527eb768b84fdbe8
File: sigmah/src/main/java/org/sigmah/shared/command/handler/GetUploadUrlHandler.java line 32
By akbertram:

The "key" is like the filename within an S3 bucket, so it should be set to the blob id.