Multiple user access for single file

Question

Dears  I am building a web-application that will send xml files to a web-service to perform several operation . Multiple users will need to access a single xml file and they will need to ( READ  WRITE ) on the same file  so if a user is writing and another user is reading from the same file we will have a big error in this manner . So please assest me in this issue . thank you

sravanthi vasanta · Answer

It is possible using with application

Harsh Kapoor · Answer

Ask from User for the operation Read/Write. and if User check the checkbox for the Write operation then dont give the file into Write mode to another user means User 2 take care with the validations. and if the User 1 requested for the Read then allow with Write operation to another one User 2 if raised a request for Write operation. So when User 1 raised a request for Write operation then prompt that  This file has been Checked-Out by User 2. Thanks and Regards Harsh

Lajapathy Arun · Answer

What about using Lock for this situation?

Sam Hobbs · Answer

This is an example of the advantages of database systems; the developers of database systems have already written code for things like that; correct? You might be able to find sample code someplace to help you. You could write your own little database system that manages each row of the XML file; what I mean by row is whatever you need to define as a peice of the data that each user updates. You could lock each peice so it can be updated by one user only at a time. The next problem is when to write the updated data out to disk; if you write the entire XML file out to disk each time a peice has been updated then tht might be a problem. So what you can do is to write transactions out to disk whenever the data is updated and write the entire XML file out periodically. The transactions could be used for a variety of things but the important thing is that you need to be able to re-create the XML file if the system crashes or there is any other problem. Note that good database systems such as SQL Server does things like that built-in.

Muralidharan Deenathayalan · Answer

I think  it is not possible. 1) You can do this.... if any one starts writing to the file you can throw a validation message to the user saying you can not do this operation.Try later... something like that. 2) Otherwise you need to have multiple version of the same file like how VSS or SVN are handling... 3) Create each file for each user. Hope this helps you.