Method and implementation of session-based file locking for network applications

• US 20030182285A1
• Filed: 03/07/2003
• Published: 09/25/2003
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Toshiba Corporation, Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Toshiba Corporation, Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Su, William, Nguyen, Truc, Kuwata, Katie
• Granted Patent: US 7,246,119 B2
• Time in Patent Office: Days
• US Class Current: 707/8
• CPC Class Codes: G06F 16/958 Organisation or management of web site content, e.g. publishing, maintaining pages or automatic linking
• CPC Class Codes: Y10S 707/922 Communications
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

A file locking method and implementation are disclosed which allows a plurality of user sessions to open and read a file, but at any one time, only one session will be allowed to change the data displayed in the browser window and to update the file. This file locking method sets up a file access priority by using file locks that are date-time stamped and session stamped. The types of lock associated with the present invention include read lock, authority lock, write lock, and folder lock. When a session/user requests access to a file, the application will check a lock table associated with the requested file. For each lock on the file, there is an entry in the lock table for each of the attributes of the lock: lock type, session owner, date-time stamp. Depending on the lock and the existing locks on the file, the requesting session may be granted a lock. After the access request is fulfilled, the file lock may be removed. When a session expires, all the locks owned by this session will be invalidated and removed.

Claims

1. A system for managing document access, comprising:

file storage means adapted for storing and manipulating files and file folders;

communication means adapted to communicate with an external computer; and

control means adapted to control access to the file storage means by the communication means;

wherein the control means creates a lock for controlling access to at least one of a file and a folder stored on the file storage means, the lock having attributes, the attributes including a date-time stamp.

2. The system for managing document access of claim 1 wherein the lock is implemented as a temporary file having a file name with the attributes of the lock encoded in the file name.

3. The system for managing document access of claim 2 wherein the date-time stamp is encoded in milliseconds.

4. The system for managing document access of claim 2 wherein the attributes further comprise a lock name.

5. The system for managing document access of claim 2 wherein the lock attributes further comprise a session identification.

6. The system for managing document access of claim 2 wherein the lock attributes further comprise a type of lock.

7. The system for managing document access of claim 2 wherein the control means creates the lock at the beginning of a session received by the communications means removes the lock when the session is closed.

8. The system for managing document access of claim 7 wherein the session is closed by one of the group consisting of the communications means receives a communication indicating when the session is closed and after a period of inactivity has elapsed.

9. The system for managing document access of claim 7 wherein the system is on an embedded web server system and the session is conducted by a session-based application.

10. A method to manage access, comprising

receiving a request to initiate a lock on a resource, the resource selected from the group consisting of a file and a folder, by a session having a session identification;

creating a temporary file having a file name with a lock attribute encoded therein;

granting the lock request when the resource is available; and

updating the file name by pre-appending the session identification and a date-time stamp indicative of the date and time when the lock was placed.

11. The method of claim 10 wherein the lock attribute is selected from the group consisting of read lock, authority lock, write lock, and folder lock.

12. The method of claim 11 wherein the date-time stamp is encoded in milliseconds.

13. The method of claim 12 wherein the lock attribute further comprises the name of the lock.

14. The method of claim 13 wherein the resource is located on a web server having a session based application.

15. The method of claim 14 wherein the session request is to open a document and the document is sent to the session.

16. The method of claim 14 wherein the session request is to save a document, the steps further comprising:

saving the document on the web server;

removing the write lock; and

updating the session status.

17. The method of claim 14 wherein the session request is to modify a file, the steps further comprising updating the session status.

18. The method of claim 14 wherein the session request is to modify a folder, the steps further comprising:

modifying the folder;

removing the folder lock; and

updating the session status.

19. The method of claim 14 further comprising removing the lock at the termination of the session.

20. The method of claim 19 wherein the session is terminated by one of the group consisting of receiving a communication closing the session and after a period of inactivity.

21. A computer-readable medium of instructions, comprising:

means for receiving a request to initiate a lock on a resource, the resource selected from the group consisting of a file and a folder, by a session having a session identification;

means for creating a temporary file having a file name with a lock attribute encoded therein;

means for granting the lock request when the resource is available; and

means for updating the file name by pre-appending the session identification and a date-time stamp indicative of the date and time when the lock was placed.

22. The computer readable means of claim 21 wherein lock attribute further comprises an attribute that is selected from the group consisting of read lock, authority lock, write lock, and folder lock, and the name of the lock;

and

wherein the date-time stamp is encoded in milliseconds.

23. The computer readable means of claim 21 wherein the computer readable means is on a web server, the web server further comprising a session-based application.

24. A computer readable medium having stored thereon instructions which when executed by a processor, cause the processor to perform the steps of:

receiving a request to initiate a lock on a resource, the resource selected from the group consisting of a file and a folder, by a session having a session identification;

creating a temporary file having a file name with a lock attribute encoded therein;

granting the lock request when the resource is available; and

updating the file name by pre-appending the session identification and a date-time stamp indicative of the date and time when the lock was placed.

25. The computer readable medium of claim 24 wherein lock attribute further comprises an attribute that is selected from the group consisting of read lock, authority lock, write lock, and folder lock, and the name of the lock;

and

wherein the date-time stamp is encoded in milliseconds.

26. The computer readable medium of claim 25 wherein the computer readable medium is on a web server, the web server further comprising a session-based application.