Project Web App - get Project ID from project related site via REST

Question

This is in SP2016 / Project Server 2016 on-prem. (Also, full disclosure, my first experience with Project Server / PWAs.)

Let's say I have a PWA set up at the URL http://servername/pwa/MyProjects. I set up the "Connected SharePoint Sites" to automatically create a project site when a project is published to the PWA. Then I publish a project called "Project1".

Now I have a SharePoint site at the URL http://servername/pwa/MyProjects/Project1.

Is there a way to get the Project ID of the published project from the related SharePoint site, via SharePoint REST API?

Meaning, I want to use

http://servername/pwa/MyProjects/Project1/_api/web/Some-endpoint-I-don't-know

in order to get the ID of the related project so that I can then use

http://servername/pwa/MyProjects/_api/ProjectServer/projects('use-the-ID-here')

to get access to the project through the Project Server REST API.

I know it is there somewhere because on the QuickLaunch of the SharePoint site, there is a link to "Project Details" that has a URL of

http://servername/pwa/MyProjects/ProjectDrilldown.aspx?ProjUid=GUID-is-here&ret=1

Is there a way I can get the GUID without resorting to scraping the page?

Answer 1

This applies for SharePoint Online/Project Online, however assuming it's the same for on-prem.

The Project GUID is stored as a site property called MSPWAPROJUID for the Project Site.

This is accessible using the /_api/Web/AllProperties end point.

ie. http://servername/pwa/MyProjects/Project1/_api/Web/AllProperties

Using JS

 var ProjectUID;
 ExecuteOrDelayUntilScriptLoaded(getProjectUIDProperty, "sp.js");

 function getProjectUIDProperty() { 
            var ctx = new SP.ClientContext.get_current(); 
            this.web = ctx.get_web(); 
            this.props =  this.web.get_allProperties(); 
            ctx.load(this.web); 
            ctx.load(this.props);                    
            ctx.executeQueryAsync(Function.createDelegate(this, gotProperty), Function.createDelegate(this, failedGettingProperty)); 
        }
         
function gotProperty() {                
             ProjectUID = this.props.get_item('MSPWAPROJUID');
        }
         
function failedGettingProperty() { 
            alert('Error: ' + args.get_message());
        }

Using SPD

Set Variable:ps to [%Workflow Context:Current Site URL%]_api/Web/AllProperties/

Dictionary:

Accept: application/json; odata=nometadata
Content-Type: application/json; odata=nometadata