How to proliferate access permission to Javascript MVC apps

Question

I recently finished one of my first AgilityJS projects, which is a web-based file browser that lets you create and manage folders and files, and navigate around the folder tree. I followed the various AgilityJS recommendations regarding the design and ended up with all my HTML and Javascript in a single Javascript file.

Now, I would like to provide a "read-only" version of this app which does not have the ability to add/edit/remove files and folders. I'd like to have 2 user types on the website, one type which can only read the files and folders, and another user type who can administer.

My question is, how do I proliferate these permission differences to my AgilityJS app? I know how to secure my endpoints and operations on the server side, but I'm wonder about the best way to do this on the client side. Should I create a separate version of the app with a limited set of functionality? Should I simply hide certain buttons/features? Are there theories, frameworks, etc.? which deal with this issue? Any point in the right direction would be helpful.

Answer 1

LOL - probably one could write books about that topic. Some very basic ideas:

1. I would start with the philosophical debate according to MVC. There are people argue with the help of MVC that any piece of code and also any piece of data model should never be implemented twice. Business logic and model to the server. The opposite view is focussing on serving users at any cost - even if that means to double maintain code or the model for the sake of avoiding extra round trips. The way in between defines a master source for business code and model and makes sure to follow on other places that leading master (the master will be changed first). Take your choice. Your answer to that question results into boundaries for how the user interface can/have to look like for the user.

2. You need to think by hard about a permissions concept. Looking at Microsoft I would assume that they invested for all their applications a couple of dozens man years to make up the permission concepts. The ideal permission concept very much depends on your application. So it is close to impossible to work this out without knowing at least a very little of your application. However the permission concept has to come up with policies deciding on roles, groups, access rigths, access levels, context driven permissions (eg. based IP address), permissions black or white listing (permissions each user has at creation). An example from Microsoft: http://office.microsoft.com/en-us/windows-sharepoint-services-help/permission-levels-and-permissions-HA010100149.aspx

3. Data on the client is not secured!!! Whatever you do on the client, be it data hiding, encryption, compression... - if this is done on the client there are ways to read the data (even by disabling the data manipulation) or by reverting those. Somebody can send data to your server, where the client should not even have given an update form could be implemented by hackers. So as soon as you start to implement permissions make sure, that for all data you send to clients users are permitted to read and that you inlcude permissions checking for each time you add/update data to the database.