Unable to read from XML file in a SharePoint Timer Job

Question

I have a custom timer job which should read some data from an XML file and save it in a word file. I tested this code in a simple web part and it works perfectly fine. However it is not working with custom timer job. Here is the code -

public override void Execute(Guid targetInstanceId)
    {
        #if (DEBUG)
            System.Diagnostics.Trace.Assert(false);
        #endif


        // get a reference to the current site collection's content database
        SPWebApplication webApplication = this.Parent as SPWebApplication;
        SPContentDatabase contentDb = webApplication.ContentDatabases[targetInstanceId];


        //Define a string builder object
        StringBuilder stringBuilder = new System.Text.StringBuilder();
        //double revenue = 0;
        //creating object of configuration class

        //Reading page size from xml configuration file
        int intPageLimit = weeklyConfig.readPageSize();
        //Reading column name from xml configuration file
        List<string> strList = weeklyConfig.readColumnName();
        //Reading list name from xml configuration file
        string strListName = weeklyConfig.readListName();
        //Reading Library name from xml 
        string strLibraryName = weeklyConfig.readLibraryName();
        stringBuilder.Append(intPageLimit);
        foreach (string str in strList)
        {
            stringBuilder.Append(str);
        }
        stringBuilder.Append(strListName);
        stringBuilder.Append(strLibraryName);
        SPFolder customerDocLib = null;
        customerDocLib = contentDb.Sites[0].RootWeb.Folders["Reports"];
        byte[] byteArray = Encoding.ASCII.GetBytes(stringBuilder.ToString());
        MemoryStream stream = new MemoryStream(byteArray);
        string fileName = "TestReport_" + DateTime.Now.ToString("MMddyyyyhhmmss") + ".doc";//Creating .doc file
        customerDocLib.Files.Add(fileName, stream);//writing memory stream to doc file and saving it into SharePoint document library
    }

Here is the code which creates the XML file. I have added this code in an Event Receiver at feature level. I'm saving this XML file in inetpub's virtual directory where my site collection is deployed. Path - C:/inetpub/wwwroot/wss/VirtualDirectories/38118/Configuration/ConfigFile.xml

public static void CreateConfigFile(String path)
    {
        //Use an xml Writer
        using (XmlWriter writer = XmlWriter.Create(path + "/ConfigFile.xml"))
        {
            //Start the Xml Document
            writer.WriteStartDocument();
            //Create Root element
            writer.WriteStartElement("Root");
            //Write Element in the root element
            writer.WriteElementString("PageSize", "33");
            writer.WriteElementString("Column", "Title");
            writer.WriteElementString("Column", "SalesPerson");
            writer.WriteElementString("Column", "SalesTarget");
            writer.WriteElementString("Column", "Achieved");
            writer.WriteElementString("Column", "UnitPrice");
            writer.WriteElementString("Column", "TotalRevenue");
            writer.WriteElementString("ListName", "SalesList");
            writer.WriteElementString("LibraryName", "Reports");
            //End the root element
            writer.WriteEndElement();
            //End the Xml Document
            writer.WriteEndDocument();
        }



    }

These are the methods I'm using to read from the XML file. These work totally fine with a webpart. But it gives an exception "Object reference not set for an instance of an object" when used in a timer job.

public class configuration : LayoutsPageBase
{
   public List<string> readColumnName()
    {
        XmlReader reader = XmlReader.Create(Server.MapPath("~/AutomatedReport/ConfigFile.xml"));
        List<string> listColumnName = new List<string>();
        string element = "";
        while (reader.Read())
        {
            if (reader.NodeType == XmlNodeType.Element)
            {
                element = reader.Name;
            }

            else if (reader.NodeType == XmlNodeType.Text)
            {
                switch (element)
                {
                    case "Column": listColumnName.Add(reader.Value.ToString());
                        break;
                }
            }
        }
        return listColumnName;
    }

This is only one of the methods I'm using to read. This is reading the column names of a list.

The XML file is generated properly. Where am I going wrong here?

Answer 1

Save your XML file in C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14 directory..... Mostly OWSTimer don't have an access to
Server.MapPath("~/AutomatedReport/ConfigFile.xml")

Answer 2

Have a look at https://spg.codeplex.com for better configuration storage options.