Add simpler prerendering API. Fixes #607

src/Microsoft.AspNetCore.SpaServices/Prerendering/ISpaPrerenderer.cs

@@ -0,0 +1,28 @@
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.SpaServices.Prerendering
+{
+    /// <summary>
+    /// Represents a service that can perform server-side prerendering for
+    /// JavaScript-based Single Page Applications. This is an alternative
+    /// to using the 'asp-prerender-module' tag helper.
+    /// </summary>
+    public interface ISpaPrerenderer
+    {
+        /// <summary>
+        /// Invokes JavaScript code to perform server-side prerendering for a
+        /// Single-Page Application. This is an alternative to using the
+        /// 'asp-prerender-module' tag helper.
+        /// </summary>
+        /// <param name="moduleName">The JavaScript module that exports a prerendering function.</param>
+        /// <param name="exportName">The name of the export from the JavaScript module, if it is not the default export.</param>
+        /// <param name="customDataParameter">An optional JSON-serializable object to pass to the JavaScript prerendering function.</param>
+        /// <param name="timeoutMilliseconds">If specified, the prerendering task will time out after this duration if not already completed.</param>
+        /// <returns></returns>
+        Task<RenderToStringResult> RenderToString(
+            string moduleName,
+            string exportName = null,
+            object customDataParameter = null,
+            int timeoutMilliseconds = default(int));
+    }
+}