ASP.NET permissions

Will · August 7th, 2010, 04:25 PM

I have written some code using the XMLTextWriter to write some stuff into an XML file. However It keeps throwing an exception saying that Access to the file is denied.

I have gone and changed the security settings for this file so that "Everyone" has full control over the file however I still incur this error when attempting to write to this file.

What else would cause this? I am building and running the application using the built in server within visual web developer.

Any ideas?

Cheers

Imar · August 8th, 2010, 03:48 AM

Can you provide more information such as the relevant code and the exact error message? Maybe there are other things (temp folder for example) involved, or maybe the error message is sneding you in the wrong direction.

Cheers,

Imar

Will · August 8th, 2010, 05:07 AM

Sure,

The exception message that I get is:

Access to the path 'C:\Program Files\Common Files\Microsoft Shared\DevServer\10.0\ErrorLog.xml' is denied.

It seems to be occurring when this fires:

XmlTextWriter textWriter = new XmlTextWriter("ErrorLog.xml", Encoding.UTF8);

However when googling for solutions I was advised that I would need to set the permissions on the actual file itself.

The code I am attemtping to use is to record each time an exception occurs:

Code:

public static void CreateXMLErrorLog(Exception error)
{
    //Create xml log entry
    XmlTextWriter textWriter = new XmlTextWriter("ErrorLog.xml", Encoding.UTF8);

    //Construct xml
    textWriter.WriteStartDocument();
    textWriter.WriteStartElement("error");
    textWriter.WriteStartElement("date", DateTime.Now.ToShortDateString());
    textWriter.WriteEndElement();
    textWriter.WriteStartElement("time", DateTime.Now.ToShortTimeString());
    textWriter.WriteEndElement();
    textWriter.WriteStartElement("errorDetails", error.ToString());
    textWriter.WriteEndElement();
    textWriter.WriteEndElement();
    textWriter.WriteEndDocument();
    textWriter.Close();
  }

First time i've used that so I was hoping to test the results from it.

Imar · August 8th, 2010, 05:28 AM

Are you running this on Windows 7? I think access is blocked to the Program Files folder if you're not running this as an Administrator. Setting permissions then doesn't make a difference.

Try specifying a path like this:

Code:

 
XmlTextWriter textWriter = new XmlTextWriter(@"C:\Test\ErrorLog.xml"), Encoding.UTF8);

And assign the permissions to the C:\Test folder. Does it work then?

Imar

Will · August 8th, 2010, 05:56 AM

Yes it works when I make those changes and use the test file as suggested.

I closed VS down and ran it as an administrator and tried it again using the original code and I got no exception this time but it doesn't seem to have written anything into the XML file.

Thanks for your help!

Imar · August 8th, 2010, 06:10 AM

Hui Will,

It's generally a bad idea to write to Program Files from your application. You're better off storing data in the user's folder or in a folder outside Windows folders.

Cheers,

Imar

Will · August 8th, 2010, 06:17 AM

Ok, I wanted to have the file as an xml file that logs any errors that occur.

When I put this onto a server will this work? I had just intended to include an XML file in the application and have the errors written to that file path but this is a bad idea?

Imar · August 8th, 2010, 06:33 AM

Quote:

When I put this onto a server will this work?

That will depend on the server and its configuration.

Quote:

I had just intended to include an XML file in the application and have the errors written to that file path but this is a bad idea?

Probably. Again, it depends. For a web application, you could write to App_Data instead. For other types of applications, I prefer to create a separate folder like d:\LogFiles and create a sub folder for each application that needs to log. Easier to configure and manage.....

Imar

Will · August 8th, 2010, 08:01 AM

Thanks for the help, will look into the App_Data.

Cheers

Will · August 8th, 2010, 12:57 PM

Alright I don't seem to have the permissions issue I was having when attempting to write to the App_Data folder? Is this because ASP.NET is automatically configured to have access to this folder?

I don't know too much about the App_Data folder, is this a protected folder by default? Would it be a good place to store .pdf or other types of files that I don't want made available to the public and then just read them from the folder?

I am now using this code to create an error log but I am overwriting previous entries each time...

Code:

public static void CreateXMLErrorLog(Exception error)
  {
    //Create xml log entry
    XmlTextWriter textWriter = new XmlTextWriter(HttpContext.Current.Server.MapPath("~/App_Data/ErrorLog.xml"), Encoding.UTF8);

    //Construct xml
    textWriter.WriteStartDocument();
    textWriter.WriteStartElement("error");
    textWriter.WriteElementString("date", DateTime.Now.ToShortDateString());
    textWriter.WriteElementString("time", DateTime.Now.ToShortTimeString());
    textWriter.WriteElementString("errorDetails", error.ToString());
    textWriter.WriteEndElement();
    textWriter.WriteEndDocument();
    textWriter.Close();
  }

This is just because of the XmlTextWriter I suppose what would be a better option so that I can just add in new entries instead of overwriting each time?