1 files changed, 79 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.AspNet/UriHelper.cs b/src/DotNetOpenAuth.AspNet/UriHelper.cs
new file mode 100644
index 0000000..602f00c
--- /dev/null
+++ b/src/DotNetOpenAuth.AspNet/UriHelper.cs
@@ -0,0 +1,79 @@
+//-----------------------------------------------------------------------
+// <copyright file="UriHelper.cs" company="Microsoft">
+//     Copyright (c) Microsoft. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.AspNet {
+	using System;
+	using System.Text.RegularExpressions;
+	using System.Web;
+	using DotNetOpenAuth.Messaging;
+
+	/// <summary>
+	/// The uri helper.
+	/// </summary>
+	internal static class UriHelper {
+		/// <summary>
+		/// The attach query string parameter.
+		/// </summary>
+		/// <param name="url">
+		/// The url.
+		/// </param>
+		/// <param name="parameterName">
+		/// The parameter name.
+		/// </param>
+		/// <param name="parameterValue">
+		/// The parameter value.
+		/// </param>
+		/// <returns>An absolute URI.</returns>
+		public static Uri AttachQueryStringParameter(this Uri url, string parameterName, string parameterValue) {
+			UriBuilder builder = new UriBuilder(url);
+			string query = builder.Query;
+			if (query.Length > 1) {
+				// remove the '?' character in front of the query string
+				query = query.Substring(1);
+			}
+
+			string parameterPrefix = parameterName + "=";
+
+			string encodedParameterValue = Uri.EscapeDataString(parameterValue);
+
+			string newQuery = Regex.Replace(query, parameterPrefix + "[^\\&]*", parameterPrefix + encodedParameterValue);
+			if (newQuery == query) {
+				if (newQuery.Length > 0) {
+					newQuery += "&";
+				}
+
+				newQuery = newQuery + parameterPrefix + encodedParameterValue;
+			}
+
+			builder.Query = newQuery;
+
+			return builder.Uri;
+		}
+
+		/// <summary>
+		/// Converts an app-relative url, e.g. ~/Content/Return.cshtml, to a full-blown url, e.g. http://mysite.com/Content/Return.cshtml
+		/// </summary>
+		/// <param name="returnUrl">
+		/// The return URL. 
+		/// </param>
+		/// <param name="context">
+		/// The context.
+		/// </param>
+		/// <returns>An absolute URI.</returns>
+		public static Uri ConvertToAbsoluteUri(string returnUrl, HttpContextBase context) {
+			if (Uri.IsWellFormedUriString(returnUrl, UriKind.Absolute)) {
+				return new Uri(returnUrl, UriKind.Absolute);
+			}
+
+			if (!VirtualPathUtility.IsAbsolute(returnUrl)) {
+				returnUrl = VirtualPathUtility.ToAbsolute(returnUrl);
+			}
+
+			Uri publicUrl = context.Request.GetPublicFacingUrl();
+			return new Uri(publicUrl, returnUrl);
+		}
+	}
+}