CHUVASH.eu

Do you prefer REST over CSOM as I do? I’ll skip the whys. Andrew Connell put it already in wrtiting so nicely. Well, if you do prefer REST, then you must have discovered some shortcomings of REST, or its incompleteness compared to CSOM. I think of:

1. Inability to filter items based on multivalued taxonomy fields
2. Inability to filter items based on user fields where user is added through a group, rather than directly, e.g. AssignedTo=[Me] combined with a SharePoint group.
3. …

In such situations I was forced to use CSOM. Until yesterday. Yesterday I learned that we can actually use CAML queries in REST requests.

This enables using REST in all situations. The REST API is still developed and many features are added. Maybe a particular operation that needs a CAML query today, can be supported in the core REST API and can be easily refactored then.

But until then, we can use CAML queries in REST requests. Here are the important things about it:

• A REST request with a CAML query is always a POST request
• A REST request with a CAML query has always to have X-RequestDigest http header (actually because it is a POST request)
• A REST request with a CAML query should always have the attached CAML query in the request body (and not in a query string). We don’t want to mess with long urls, do we?
• A REST request with a CAML query must have the http header “Content-Type: application/json;odata=verbose” unless you use xml in the request body.

HTTP headers you have to provide in REST requests with CAML queries

You can use jQuery or SP.RequestExecutor to make an ajax call. The REST endpoint is:

_api/web/Lists/GetByTitle('<your list title>')/GetItems

The request body (if you use json, and I bet, you do) is in this format:

{ "query" :
   {"__metadata": 
      { "type": "SP.CamlQuery" }
      , "ViewXml": "<YOUR CAML QUERY>" 
   }
}

Here is the boilerplate for a REST request with a CAML Query:

function getDataWithCaml(listName, caml) {
    var endpoint = "/_api/web/lists/GetByTitle('" 
        + listName + "')/GetItems";
    var requestData = { "query" :
           {"__metadata": 
              { "type": "SP.CamlQuery" }
              , "ViewXml": caml
           }
        };
    return jQuery.ajax({
        url: endpoint,
        method: "POST",
        data: requestData,
        headers: {
            "X-RequestDigest": $("#__REQUESTDIGEST").val(),
            "Accept": "application/json; odata=verbose",
            "Content-Type": "application/json; odata=verbose"
        }
    });
}

This function is just an example. It has no error handling, and it takes for granted that your list is in the root site for on your (sub-)domain (“/”). So take it as an example only.

Here is how the function can be invoked

var caml = "<View><Query><Where><Or><Eq><FieldRef Name='AssignedTo' /><Value Type='Integer'><UserID/></Value></Eq><Membership Type='CurrentUserGroups'><FieldRef Name='AssignedTo' /> </Membership></Or></Where></Query></View>";
getDataWithCaml("Tasks", caml);