Add a controller to get a file's hash

[mjordan]

#32 gets the hash from the hash that Drupal has stored. That hash may have been accurate at the time the file was ingested but we want the current hash of the file.

To do this we need to add a controller that generates a hash for a file. This controller should have two parameters, the digest algorithm and the file's UUID.

[mjordan]

Added. Syntax is curl -v -uadmin:islandora "http://localhost:8000/islandora_riprap/checksum/{file_uuid}/{algorithm}", e.g., curl -v -uadmin:islandora "http://localhost:8000/islandora_riprap/checksum/7bf32c29-8b2f-4ec1-b3f7-df88a8bdca56/sha256"

Response from this request is [{"checksum":"f20ef9a5b3fbd2d61effa147e528189bb1d544a40784d5c4d4089c5f18acc772","file_uuid":"7bf32c29-8b2f-4ec1-b3f7-df88a8bdca56","algorithm":"sha256", "url":"http:\/\/localhost:8000\/sites\/default\/files\/2020-08\/7-Extracted%20Text.txt"}].

Algorithm is one of 'md5', 'sha1', or 'sha256', the ones supported by the filehash module. Access requires the view checksums permission.

[mjordan]

Gonna remove the View created added in #32 since this new controller replaces it.

[mjordan]

Resolved with f713b25.