Is there any unique identifier associated with a Dropbox file that doesn't change with revisions/changes/renaming, that can be accessed via the RESTful API? I want to store it in the database and keep track of some operations on the file.
Unfortunately, no, the Dropbox API does not currently expose any sort of file ID or hash like this.
Edit: The Dropbox API v2 does now offer file IDs that persist across moves/renames. You can find more information under "Path formats" in the documentation.
The file ID is available as the id field on the FileMetadata object, e.g., as returned by /files/get_metadata.
The new Dropbox API v2 supports IDs for files and folders.
However, it doesn't automatically differentiate file/folder moves, renames, etc. from deletions and creations in the event stream. You can use a service like Kloudless which provides a unified cloud storage API that includes file/folder IDs for Dropbox. Kloudless also normalizes the event stream and provides access to several other cloud storage services through a single API. (I work at Kloudless)
来源：https://stackoverflow.com/questions/15209512/dropbox-file-unique-identifier-restful-api