Patching JSON documents that contain arrays undergoing concurrent modification
In various aspects, a method, system and computer program product provides for concurrent changes to data of a document or a file by a plurality of users at a plurality of user devices. The documents or file may be rendered in JavaScript™ Object Notation (JSON) format. The documents may be patched or changed by employing new functional operations for applying metadata for elements of the arrays associated with the document or file, and to merge changes from made among the various users. The disclosure provides for maintaining and producing new versions of the document or the file, the changes controlled so that data of the arrays are merged atomically and the updates do not fail permitting simultaneous changes to the document or file by multiple users.
1. A computer-implemented method for concurrent changes to data of a document or a file by a plurality of users at a plurality of user devices, comprising:
tagging at a computer at least one document or at least one file to create metadata for elements of at least one array containing data associated with the at least one document or the at least one file, the tagging transforming the at least one array into an array of objects containing a plurality of key/value pairs for each tagged element, and the tagging specifying a rank and an ID for each tagged element to identify positions within the array;
changing at a computer values of data of the at least one array or changing order of objects in the at least one array;
diffing at a computer two tagged documents or files to produce at least one Changes List, the at least one Changes List specifying changes made to the at least one document or the at least one file; and
creating at a computer a new version of the at least one document of file by a merge operation that processes the Changes Lists to create a new version of the at least one document or the at least one file so that changes to the data are merged atomically so that synchronous charges by the plurality of users is applied asynchronously in order, thereby permitting the plurality of users to make changes to the document or the file concurrently in time, wherein the Changes List contains an ADD instruction that instructs the merge operation to add a value at a position identified by a given path and a specified rank position.
2. The computer-implemented method of claim 1 , wherein the format of the data or file is JavaScript Object Notation (JSON) format.
3. The computer-implemented method of claim 1 , wherein in the diffing step, the produced at least one Changes List includes specifying one or more of the following operations:
a REMOVE operation that instructs merge operation to delete data associated with the at least one document or the at least one file;
an ADD operation that instructs the merge operation to add a value at a position in the at least one array;
a REPLACE operation that instructs the merge operation to delete data at a specified location of the at least one array and to add a replacement data at the specified location; and
a MOVE operation to move data of the at least one array at a specified location to a new location of the at least one array.
4. The computer-implemented method of claim 3 , wherein the MOVE operation inserts a new rank position.
5. The computer-implemented method of claim 3 , wherein the REPLACE operation maintains a same rank position for the replacement data.
6. The computer-implemented method of claim 3 , wherein in the merge operation, in case of a conflict in data, the last change is used.
7. The computer-implemented method of claim 1 , wherein the at least one Changes List specifies an address for an array element comprising a path and a rank.
8. The computer-implemented method of claim 1 , wherein the plurality of user devices are in communication with a central processing unit across a network.
9. The computer-implemented method of claim 1 , wherein the at least one Changes List comprising only those changes made at a particular user device to a version of the at least one document or the at least one file are sent to a central processing unit for the merge operation and creating of the new version.
10. The computer-implemented method of claim 1 , wherein the at least one document or at least one file is a different version of the at least one document or the at least one file at least two of the plurality of user devices thereby permitting different changes to the document or the file by different users concurrently in time.
11. A computer program product for facilitating concurrent changes to data of a document or a file by a plurality of users at a plurality of user devices, the computer program product comprising computer instructions embodied on a computer readable medium not being a transitory propagating signal encoding the computer-readable instructions, the computer program product when read and executed by at least one computer performing the following steps:
tagging at the at least one computer at least one document or at least one file to create metadata for elements of at least one array containing data associated with the at least one document or the at least one file, the tagging transforming the at least one array into an array of objects containing a plurality of key/value pairs for each tagged element, and the tagging specifying a rank and an ID for each tagged element to identify positions within the array;
changing at the at least one computer, values of data of the at least one array or changing order of objects in the at least one array;
diffing at the at least one computer two tagged documents or files to produce at least one Changes List, the at least one Changes List specifying changes made to the at least one document or the at least one file; and
creating at the at least one computer a new version of the at least one document of file by a merge operation that processes the Changes Lists to create a new version of the at least one document or the at least one file so that changes to the data are merged atomically so that synchronous charges by the plurality of users is applied asynchronously in order, thereby permitting the plurality of users to make changes to the document or the file concurrently in time, wherein the Changes List contains an ADD instruction that instructs the merge operation to add a value at a position identified by a given path and rank position.
12. The computer program product of claim 11 , wherein a format of the data or file is JavaScript Object Notation (JSON) format.
13. The computer program product of claim 11 , wherein in the diffing step, the produced at least one Changes List includes specifying one or more of the following operations:
a REMOVE operation that instructs merge operation to delete data associated with the at least one document or the at least one file;
an ADD operation that instructs the merge operation to add a value at a position in the at least one array;
a REPLACE operation that instructs the merge operation to delete data at a specified location of the at least one array and to add a replacement data at the specified location; and
a MOVE operation to move data of the at least one array at a specified location to a new location of the at least one array.
14. The computer program product claim 13 , wherein the MOVE operation inserts a new rank position.
15. The computer program product of claim 13 , wherein the REPLACE operation maintains a same rank position for the replacement data.
16. The computer program product of claim 13 , wherein in the merge operation, in case of a conflict in data, the last change is used.
17. The computer program product of claim 11 , wherein the at least one Changes List specifies an address for an array element comprising a path and a rank.
18. The computer program product of claim 11 , wherein the plurality of user devices are in communication with a central processing unit across a network.
19. The computer program product of claim 11 , wherein the at least one Changes List comprising only those changes made at a particular user device to a version of the at least one document or the at least one file are sent to a central processing unit for the merge operation and creating of the new version.
20. The computer-implemented method of claim 11 , wherein the at least one document or at least one file is a different version of the at least one document or the at least one file at least two of the plurality of user devices thereby permitting different changes to the document or the file by different users concurrently in time.
21. The computer-implemented method of claim 1 , wherein the plurality of key/value pairs include a randomly generated identifier, a rank to identify a position in the at least one array, and an original value for an element of the at least one array.
22. The computer-implemented method of claim 11 , wherein the plurality of key/value pairs include a randomly generated identifier, a rank to identify a position in the at least one array, and an original value for an element of the at least one array.
23. The computer-implemented method of claim 1 , wherein the value is added to the end of a list whenever the specified rank position exceeds the number of elements of the list.
24. The computer-implemented method of claim 11 , wherein the value is added to the end of a list whenever the specified rank position exceeds the number of elements of the list.