Deploy a XML file in your Sharepoint Solution to the Web Application Folder

This is a small trick I’ve been using these days in a Sharepoint Solution in order to add a xml file with some data which some webpart will read later on a Sharepoint site and make use of it. There are many ways to accomplish this each one with it’s benefits and drawbacks.

The first approach I thought of was to deploy the xml file in the _layouts folder and then query the data using a WebClient request from my webpart, the problem I found is that if anonymous access wasn’t enabled for the site, the request failed with a 401 Unauthorized exception because the ASP.Net credentials where the ones used by default to access the resource. One solution was to enable the impersonation at the web.config file of the application and then, the current user’s credentials would be used instead, but as I didn’t know where my solution would be deployed and didn’t have any control over the web.config file configuration, I rejected this approach.

Finally, I decided to deploy locally the xml file in the bin folder of the application and then accessing it with a simple StreamReader. The first problem was how to deploy the file ? Finally, I found the small trick I was talking about, you can deploy any file from a Sharepoint Solution in the bin folder of the web application just by doing the same as you do with a normal assembly .dll file, with the <Assembly> tag in the manifest.xml file:

<Assemblies><Assembly DeploymentTarget=“WebApplication“ Location=“MyData.xml“ /></Assemblies>

When the Solution is deployed, the xml file will be copied to all the bin folders of the selected web application. This raises the obvious drawback of this approach: There’s one xml file for each web application and there’s no easy way to globally manage them.
Since we will be accessing the xml file from our webpart, and assuming we haven’t set our trust level to Full (because we know it’s a bad thing to do!), we must grant our assembly the FileIOPermission  in order to be able to read the file. We can do this in the manifest.xml with the following section:

<CodeAccessSecurity><PolicyItem><PermissionSet class=“NamedPermissionSet“ version=“1“ Description=“Permission set for OurAssembly“><IPermission class=“System.Security.Permissions.FileIOPermission“ version=“1“ Unrestricted=“true“ /> </PermissionSet><Assemblies><Assembly Name=“OurAssembly“ /></ Assemblies></PolicyItem></CodeAccessSecurity>

Please note that I’ve set the unrestricted=true attribute just to keep it simple but you should set the Read attribute to the appropiate folder.Now, we can read the file from our webpart:

string loc = HttpContext.Current.Server.MapPath("/") + "bin\";
using (StreamReader reader = new StreamReader(loc + @"MyData.xml"))
{
    XDoc = XDocument.Load(reader, LoadOptions.None);
}

And that’s all, with this approach we can deploy all kinds of xml data and even .dll configuration files or any other localresource you might need. I hope it’s helpful and don’t forget to leave a comment if so !