jsuntest.cs

using System;
using System.Data;
using System.Data.SqlTypes;
using System.Data.SqlClient;
using Microsoft.SqlServer.Server;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml;
using System.Xml.XPath;

/**
 * The JSONTransformer class provides methods to encode XML datasets
 * into JSON. These methods are intended to be used by a 
 * Microsoft SQL Server 2005 or higher.
 * @author Adam Presley
 */
public partial class JSONTransformer
{
   /**
    * This method takes an XML dataset and serializes it to a 
    * JSON string acceptable for AJAX/client use.
    * 
    * 
    * DECLARE @resultSetXML VARCHAR(max);
    * DECLARE @rootNodeName VARCHAR(75);
    * DECLARE @elementNodeName VARCHAR(75);
    * DECLARE @result VARCHAR(max);
    * 
    * SET @rootNodeName = 'addresses';
    * SET @elementNodeName = 'address';
    * 
    * SET @resultSetXML = (
    *     SELECT
    *         id
    *         , firstName
    *         , lastName
    *         , email
    *         , phone
    *         , postalCode
    * FROM address
    *     ORDER BY
    *         firstName, lastName 
    * FOR XML AUTO, ROOT('addresses'));
    *     
    * SELECT dbo.SQLJsonEncode(@resultSetXML, @rootNodeName, @elementNodeName) AS jsonResult;
    * 
    * 
    * @author Adam Presley
    * @param resultSetXML - The SQL result set serialized to XML
    * @param rootNodeName - The name of the XML root node
    * @param elementNodeName - The name of a record's XML node
    * @returns A string containing the resultset as JSON.
    */
   [SqlFunction()]
   public static string Encode(string resultSetXML, string rootNodeName, string elementNodeName) {
      XmlDocument xmlDoc = new XmlDocument();
      DataSet dataset = new DataSet();
      StringBuilder result = new StringBuilder();
      int recordCount = 0;
      int currentIndex = 0;

      /*
       * Create an XPath iterator.
       */
      XmlTextReader reader = new XmlTextReader(new StringReader(resultSetXML));
      XPathDocument xdoc = new XPathDocument(reader);
      XPathNavigator nav = xdoc.CreateNavigator();
      XPathNodeIterator iter = nav.Select(rootNodeName + "/" + elementNodeName);

      recordCount = iter.Count;
      currentIndex = 0;

      result.Append("{ \"recordcount\": \"" + recordCount.ToString() + "\", \"data\": [ ");

      while (iter.MoveNext()) {
         XPathNavigator item = iter.Current;
         result.Append("{ ");

         /*
          * If we have attributes iterate over them and add them to
          * the JSON object.
          */
         if (item.HasAttributes) {
            item.MoveToFirstAttribute();
            string line = "";

            do {
               string name = item.Name;
               string value = item.Value;

               line += "\"" + name + "\": \"" + __jsonEscape(value) + "\", ";
            } while (item.MoveToNextAttribute());

            /*
             * Remove trailing comma
             */
            line = line.Substring(0, line.Length - 2);
            result.Append(line);
         }

         result.Append(" }");
         if (currentIndex < recordCount - 1) result.Append(", ");
         currentIndex++;
      }

      result.Append(" ]}");

      reader.Close();
      return result.ToString();
   }

   /**
    * This method escapes a string in a format suitable
    * for JSON and JavaScript.
    * @author Adam Presley
    * @param data - The piece of data to JavaScript encode
    * @returns A string properly encoded for JavaScript
    */
   private static string __jsonEscape(string data) {
      string result = data;

      result = result.Replace("\"", "\\\"");

      return result;
   }
}