REST interface payload for Project Server

Question

I am trying to update some properties of an object using the REST interface.

I am able to read the information with the GET request, but when I'm PATCH-ing (MERGE-ing) I always get a 403 Forbidden error.

I am totally new to the REST interface, and frankly, I didn't find any information or example regarding a project server payload or any example for that matter.

This is how the JSON data looks when I GET it from the server:

{
  -d: {
      -__metadata: {
        .........
       }
       ActualFinish:0001-01-01T00:00:00
       ActualOvertime: null
       ...
       PercentComplete: 0 (this is what I want to change to 100)
       ...
      }
}

This is how my payload looks right now:

{d:PercentComplete=100}

It's not working. How the normal payload should look? Do I need any additional headers, other than the

Accept: application/json;odata=verbose

As I said, I didn't find an example for these kind of updates.

Answer 1

You need three additional headers:

1. "X-RequestDigest":"value"
   A unique security token to validate your requests.
2. "X-HTTP-Method": "MERGE"
   To indicate that you're performing an update
3. "If-Match":*
   To handle concurrent requests. This actually has 2 values viz. item.__metadata.etag representing the actual item tag and * to handle any value.
   

As an example refer to this excellent answer by Vadim: SharePoint 2013 REST api to update list item- Uncaught ReferenceError: etag is not defined