In my last post I described many of the REST endpoints available in SharePoint to manage role assignments. In this post, I will provide a concrete example of using these endpoints in a provisioning-like scenario. I say provision-like because real provisioning scenarios tend to be very specific and one-offs (i.e. I need 7 sites, each with 5 lists and 3 groups, based on a naming convention by organization, and these permissions, and blah and blah and blah). Such specific requirements can’t be written into a one size fits all solution, so I’m just going to mimic them by creating a whole bunch of role assignments, and then deal with some of the issues of initiating a bunch of ajax calls in a short period of time.
In this post, I’m going to create a better CORS Wrapper for SharePoint REST operations, and demonstrate using it for CRUD operations on a Picture library. First, I want to remove the dependency of jQuery, using fetch instead. As I covered in a previous post, Ugly SPA Revisited using Fetch and REST, fetch is new enough and implementations are spotty enough, even in evergreen browsers, that I will need to polyfill fetch and ES6 promise in order to support a reasonable cross-section of browsers.
By implementing the full range of CRUD operations on document libraries, we’ll have an opportunity to see if there are other issues that need to be addressed in our wrapper. My last post really only did one simple REST operation across CORS boundaries.
In my last post I talked about the REST service calls of what I said at the time was possibly the ugliest SPA of all time. I wanted to do it with no dependencies, which means interacting with XMLHttpRequest directly, and that isn’t anybody’s idea of pretty. No dependencies also means no promises, and once you’ve programmed with promises for a while, working without them on networking code feels like a step backwards. In this post I’m going to rewrite the ugly SPA with the following changes:
- I’m going to use fetch for all REST calls. fetch is the future, or so they tell me. And it gives me a comfortable promises-based API.
- I’m also going to use “odata=nometadata” for all of my REST calls. As I mentioned in my last post, this may not work in a SharePoint 2013 environment unless Service Pack 1 has been installed and changes have been made to the SharePoint web.config to support JSON light. So if you’re on 2013 and it doesn’t support JSON light, you need to use “odata=verbose” as shown in my previous post.
As I work through the code, I’ll point out differences between “odata=nometadata” and “odata=verbose”. There really aren’t that many differences.