PUBLISH-SUBSCRIBE SYSTEM

• US 20110282921A1
• Filed: 05/14/2010
• Published: 11/17/2011
• Est. Priority Date: 05/14/2010
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: QNX Software Systems Company (Blackberry Limited)
• Inventors: Dodge, Dan
• Granted Patent: US 9,026,567 B2
• Time in Patent Office: Days
• US Class Current: 707/822
• CPC Class Codes: G06F 16/16 File or folder operations, e.g. details of user interfaces specifically adapted to file systems
• CPC Class Codes: G06F 16/168 Details of user interfaces specifically adapted to file systems, e.g. browsing and visualisation, 2d or 3d GUIs query results presentation G06F16/156
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques
• CPC Class Codes: G06F 16/9535 Search customisation based on user profiles and personalisation
• CPC Class Codes: G06F 16/9538 Presentation of query results
• CPC Class Codes: G06F 16/958 Organisation or management of web site content, e.g. publishing, maintaining pages or automatic linking
• CPC Class Codes: G06F 9/542 Event management; Broadcasting; Multicasting; Notifications
• CPC Class Codes: H04L 51/214 using selective forwarding
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/55 Push-based network services

Abstract

A publish-subscribe system publishes events associated with one or more objects represented by files within a file system. The files may be accessed using a file system application programming interface by both publishers and subscribers. Each file may contain an identifier and a plurality of attributes and each attribute may have a name and a value. The files and the associated objects may be persisted to compensate for restarts and failures of a computing platform hosting the system for publish-subscribe.

Claims

1. A system comprising:

a distributed service-oriented computer architecture programmed to service publish-subscribe events including;

a processor invoking a first file open operation, in a file system application programming interface within the distributed service-oriented computer architecture, to prepare to publish an object;

the processor invoking one or more file write operations, in the file system application programming interface, to publish events associated with the object;

the processor invoking a second file open operation, in the file system application programming interface, to subscribe to the object; and

the processor invoking one or more file read operations, in the file system application programming interface, to receive the events associated with the object.

2. The system of claim 1, where the first file open operation further comprises the processor creating a publish-subscribe file associated with the object when the publish-subscribe file does not exist.

3. The system of claim 1, where the first file open operation further comprises the processor opening, in a write-mode, a publish-subscribe file associated with the object.

4. The system of claim 1, where the second file open operation further comprises the processor opening, in a read-mode, a publish-subscribe file associated with the object.

5. The system of claim 1, where the processor is programmed to execute any of the one or more file read operations as a non-blocking event and returns from the file read operation when no events associated with the object have been published since a previous invocation of the file read operation.

6. The system of claim 1, where the processor is programmed to execute any of the one or more file read operations as a blocking event and defers returning from the file read operation, when no events associated with the object have been published since a previous invocation of the file read operation, until at least one event associated with the object is published.

7. The system of claim 1, where the file system application programming interface comprises a POSIX compliant application programming interface.

8. A method in a computer system for publish-subscribe comprising:

receiving from a publisher application a first invocation of a file open function in a file system application programming interface in the computer system including a name for a publish-subscribe file;

receiving from the publisher application one or more invocations of a file write function in the file system application programming interface in the computer system and, responsive to data elements included in each file write invocation, adding, modifying or deleting one or more attributes contained in the publish-subscribe file;

receiving from a subscriber application a second invocation of the file open function in the file system application programming interface in the computer system including the name for the publish-subscribe file; and

receiving from the subscriber application one or more invocations of a file read function in the file system application programming interface in the computer system and, responsive to arguments included in each file read invocation, returning either all of the attributes contained in the publish-subscribe file, or one or more attributes contained in the publish-subscribe file that have changed since a previous invocation of the file read operation.

9. The method of claim 8, further comprising:

sending a notification to the subscriber application responsive to receiving, from the publisher application, any of the one or more invocations of the file write function; and

where each of the one or more invocations of the file read function by the subscriber application is further responsive to the sending of the notification.

10. The method of claim 8, further comprising:

receiving from a second publisher application a third invocation of the file open function in the file system application programming interface in the computer system including the name for a second publish-subscribe file; and

receiving from the second publisher application one or more further invocations of the file write function in the file system application programming interface in the computer system and, responsive to arguments included in each further file write invocation, adding, modifying or deleting one or more attributes contained in the second publish-subscribe file.

11. The method of claim 10, further comprising:

receiving from the subscriber application a fourth invocation of the file open function in the file system application programming interface in the computer system including a name for the second publish-subscribe file; and

receiving from the subscriber application one or more further invocations of a file read function in the file system application programming interface in the computer system and, responsive to arguments included in each further file read invocation, returning either all of the attributes contained in the second publish-subscribe file, or alternatively one or more attributes contained in the second publish-subscribe file that have changed since a previous invocation of the file read operation for the second publish-subscribe file.

12. The method of claim 8, where any of the attributes in the one or more file write invocations further includes a quality parameter;

and a corresponding attribute in the publish-subscribe file is modified only when the quality parameter included with the attribute in the file write invocation is equal to or greater than a quality parameter associated with the corresponding attribute in the publish-subscribe file.

13. The method of claim 8, where the file system application programming interface in the computer system comprises a POSIX compliant application programming interface.

14. A method for publish-subscribe comprising:

receiving from one or more publisher applications one or more invocations of a file open function in a file system application programming interface in the computer system each invocation including a name for one of one or more publish-subscribe files in a directory;

receiving from the one or more publisher applications one or more invocations of a file write function in the file system application programming interface in the computer system, each invocation directed to one of the one or more publish-subscribe files, and, responsive to data elements included in each file write function, adding, modifying or deleting one or more attributes contained in the one of the one or more publish-subscribe files;

receiving from a subscriber application an invocation of the file open function in the file system application programming interface in the computer system including the name for the directory or a name of a proxy file associated with the directory; and

receiving from the subscriber application an invocation of a file read function in the file system application programming interface the computer system and, responsive to arguments included in the file read function, returning either all of the attributes contained in each of the one of the one or more publish-subscribe files, or one or more attributes contained in each of the one of the one or more publish-subscribe files that have changed since a previous invocation of the file read function.

15. The method of claim 14, further comprising:

sending a notification to the subscriber application responsive to receiving each invocation of the file write function from any of the one or more publisher applications; and

where the invocation of the file read function by the subscriber application is further responsive to the sending of the notification.

16. The method of claim 14, further comprising:

sending a notification to the subscriber application responsive to creation or deletion of any of the one or more publish-subscribe files in the directory; and

where the file read function further returning the name of the created or deleted publish-subscribe file and a file creation or deletion indicator.

17. A method for publish-subscribe comprising:

creating or opening a publish-subscribe file responsive to an invocation of a file open operation in a file system application programming interface in a computer system to prepare to publish an object;

adding, modifying or deleting in the publish-subscribe file one or more attributes associated with the object responsive to data elements included in an invocation of a file write operation in the file system application programming interface in the computer system to publish events associated with the object;

opening the publish-subscribe file responsive to an invocation of a file open operation in the file system application programming interface in the computer system to subscribe to the object; and

reading the publish-subscribe file responsive to an invocation of a file read operation in the file system application programming interface in the computer system to receive published events associated with the object.

18. The method of claim 17, where the invocation of the file read operation is non-blocking and returns immediately when there have been no changes in the publish-subscribe file since a previous invocation of the file read operation.

19. The method of claim 17, where the invocation of the file read operation is blocking and defers returning, when there have been no changes in the publish-subscribe file since a previous invocation of the file read operation, until at least one attribute in the publish-subscribe file is added, modified or deleted.

20. The method of claim 17, where the file system application programming interface in the computer system comprises a POSIX compliant application programming interface.

21. A communication system comprising:

a files system application programming interface within a publish-subscribe computer system including a processor programmed to execute;

file open and file write functions that can be invoked by one or more publisher applications to publish one or more objects, and

file open and file read functions that can be invoked by one or more subscriber applications to subscribe to the one or more objects;

a file system manager providing file creation, modification and deletion operations, within a file system, responsive to the invocation of functions in the file system application programming interface by the one or more publisher applications; and

file system contents including a mount point and one or more files and directories under the mount point;

where the files under the mount point represent published objects.

22. The system of claim 21, where:

the file system manager further sending a notification to the one or more subscriber applications responsive to a file or directory under the mount point being accessed; and

where invocation of the file read function by the one or more subscriber applications is further responsive to the sending of the notification.

23. The system of claim 21, the files under the mount point each containing attributes associated with a corresponding published object.

24. The system of claim 21, where the file system is persistent, and where files and directories under the mount point survive restarts or service outages of the file system.

25. The system of claim 24, where all of the files contained in any directory under the mount point are stored in an atomic operation in the file system.

26. The system of claim 21, where the file system application programming interface comprises a POSIX compliant application programming interface.

27. A system for publish-subscribe comprising:

one or more publisher applications publishing events associated with one or more objects;

one or more subscriber applications subscribing to events associated with the one or more objects; and

a file system receiving, through a files system application programming interface of a computer system, events published by the publisher applications and providing, through the file system application programming interface, published events to the subscriber applications.

28. The system of claim 27, where the file system application programming interface comprises a POSIX compliant application programming interface.

29. The system of claim 27, where the one or more objects are represented by corresponding files under a mount point in file system content and the events associated with the one or more objects are represented by attributes in the corresponding files.

30. The system of claim 27, where the file system is persistent, and where files and directories under the mount point survive restarts or service outages of the file system.