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Framework Services - File Delete via HTTP POST

This service supports deleting a single file from both Mifar storage host and Mifar database using an HTTP GET and POST operation. The service program takes care of all database communications so a client of this service does not have to know how to talk to a Mifar database. A diagram of a delete operation is listed below.

Steps involved in a file delete operation.
Client Program Delete Service Database Engine
1. Verification and Delete message
-------------------------------> 2. Consult local mifar.conf file

3.Check Permissions

------------------------------->

<-------------------------------

4. Check file on local disk

5. Delete file entry from DB
------------------------------->
6. Delete file from local disk <-------------------------------
Redirect (success) or message (error)
<-------------------------------

1. Verification and Delete message

The Client Program sends the following GET and POST data to the Delete Service.
  • The user's login name and password (POST)
  • The file unique ID and name (GET)
  • The store permission group (GET)
  • The store ID (GET)

2. Consult local mifar.conf file

The local configuration file gives information like which database host to talk with, where to store file on the disk, who is allowed to store files on the local computer, what kind of service the computer provides, etc. The Delete Service first checks if it can locate this conifguration file. then according to the config file, the Delete Service checks
  • if the user has assess to the delete service
  • if the user can access the store where the file is located

3. Check Permmissions.

The Delete Service sends the user's login name and password to the Database Engine. The database checks if they are valid or not and sends back reponse messaage to the service program.

4. Check file on local disk

The Delete Service checks if the file that the Client Program requested
  • is on the local disk
  • is a valid file
  • is writable by the user

5. Delete file entry from DB

The Download Service sends delete-file-entry message to the Database Engine. The database sends back a response message to the service.

6. Delete file from local disk

If the Database Engine responds with deleting file ok message, the Delete Servcie then deletes file from the local disk. If the service gets an error response message from the database, the Delete Service will not delete file from the local disk, and it sends message to the Database Engine to request rolling back the transaction.

6. Send file (success) or message (error)

The The Delete Service checks
  • if the GET/POST data sent by the Client Program are set or not
  • if the user has access to the delete service and can access the store where the file is located
  • if the user has permission to access the database or not according to the Database Engine's response message
  • if the file is located in the local disk, is valid and is writable
  • if the file entry has been successfully deleted from the database according to the Datbase Engine's response message
If any of the above fails, the service returns an error page to the Client Program. Otherwise, the service send redirect message to the Client Program.

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If you have any problems with the page contact Chris Piker at the
Division of Physiologic Imaging.