Create and Update Subscription API

Subscriptions can be created using the following Create methods available through the Subscriptions property of the DocumentStore.

string Create(SubscriptionCreationOptions options,
              string database = null);

string Create<T>(SubscriptionCreationOptions<T> options,
                 string database = null);

string Create<T>(Expression<Func<T, bool>> predicate = null,
                 SubscriptionCreationOptions options = null,
                 string database = null);

Task<string> CreateAsync(SubscriptionCreationOptions options,
                         string database = null,
                         CancellationToken token = default);

Task<string> CreateAsync<T>(SubscriptionCreationOptions<T> options,
                            string database = null,
                            CancellationToken token = default);

Task<string> CreateAsync<T>(Expression<Func<T, bool>> predicate = null,
                            SubscriptionCreationOptions options = null,
                            string database = null,
                            CancellationToken token = default);

A generic version of the subscription creation options object.

public class SubscriptionCreationOptions<T>
{
    public string Name { get; set; }
    public Expression<Func<T, bool>> Filter { get; set; }
    public Expression<Func<T, object>> Projection { get; set; }
    public Action<ISubscriptionIncludeBuilder<T>> Includes { get; set; }
    public string ChangeVector { get; set; }
    public string MentorNode { get; set; }
}

A non-generic version of the subscription creation options object.

Existing subscriptions can be modified using the following Update methods available through the Subscriptions property of the DocumentStore.

string Update(SubscriptionUpdateOptions options, string database = null);

Task<string> UpdateAsync(SubscriptionUpdateOptions options, string database = null,
                    CancellationToken token = default);

SubscriptionUpdateOptions inherits from SubscriptionCreationOptions and adds two additional fields:

public class SubscriptionUpdateOptions : SubscriptionCreationOptions
{
    public long? Id { get; set; }
    public bool CreateNew { get; set; }
}

All subscriptions are eventually translated to an RQL-like statement. These statements have the following parts:

• Functions definition part, like in ordinary RQL. Those functions can contain any JavaScript code, and also supports load and include operations.

• From statement, defining the documents source, ex: from Orders. The from statement can only address collections, therefore, indexes are not supported.

• Where statement describing the criteria according to which it will be decided to either send the documents to the worker or not. Those statements support either RQL like equality operations (=, ==) ,
  plain JavaScript expressions or declared function calls, allowing to perform complex filtering logic.
  The subscriptions RQL does not support any of the known RQL searching keywords.

• Select statement, that defines the projection to be performed. The select statements can contain function calls, allowing complex transformations.

• Include statement allowing to define include path in document.

from Orders as o
where o.Lines[].Product = "products/1-A"

declare function filterLines(doc, productId)
{
    if (!!doc.Lines){
        return doc.Lines.filter(x=>x.Product == productId).length >0;
    }
    return false;
}

from Orders as o
where filterLines(o, "products/1-A")