This one deals with the removal of a document from a SharePoint site. Though this can also be achieved using CSOM but there’s one situation where the CSOM won’t be of any help, i.e., deleting a file from the root folder of a Web(SiteCollection/SubSite). Since, the root files do not belong to any List, these files cannot be handled using standard CSOM logic. For this, I am going to rely on the RPC call to the author.dll. In my previous two posts, https://realmpksharepoint.wordpress.com/2014/04/29/upload-large-files-to-the-sharepoint-documentlibrary-using-rpc-from-a-desktop-application-c/ & https://realmpksharepoint.wordpress.com/2014/05/09/renamemove-an-existing-sharepoint-file-using-rpc-c/ , I have demonstrated how a document (residing in the root or anywhere else) can be uploaded, moved, or renamed using RPC.

private void RemoveDocument(string documentName)
{
    string requestUrl = this.ctx.Url + "/_vti_bin/_vti_aut/author.dll";
    string method = GetEncodedString("remove documents:15.0.0.4420");
    string serviceName = GetEncodedString(ctx.Web.ServerRelativeUrl);

    string url_List = GetEncodedString(String.Concat("[", documentName, "]"));
    rpcCallString = "method={0}&service_name={1}&url_list={2}\n";

    rpcCallString = String.Format(rpcCallString, method, serviceName, url_List).Replace("_", "%5f");

    HttpWebRequest wReq = WebRequest.Create(requestUrl) as HttpWebRequest;
    wReq.Method = "POST";
    wReq.Headers["Content"] = "application/x-vermeer-urlencoded";
    wReq.Headers["X-Vermeer-Content-Type"] = "application/x-vermeer-urlencoded";
    wReq.UserAgent = "FrontPage";
    wReq.UseDefaultCredentials = false;

    Uri targetSite = new Uri(this.ctx.Web.Url);
    SharePointOnlineCredentials spCredentials = (SharePointOnlineCredentials)this.ctx.Credentials;

    string authCookieValue = spCredentials.GetAuthenticationCookie(targetSite);
    wReq.CookieContainer = new CookieContainer();
    wReq.CookieContainer.Add(
        new Cookie("FedAuth",
            authCookieValue.TrimStart("SPOIDCRL=".ToCharArray()),
            String.Empty,
            targetSite.Authority));

    using (IO.Stream requestStream = wReq.GetRequestStream())
    {
        byte[] rpcHeader = Encoding.UTF8.GetBytes(rpcCallString);
        requestStream.Write(rpcHeader, 0, rpcHeader.Length);
        requestStream.Close();

        GetResponse(wReq);
    }
}

private string GetResponse(HttpWebRequest webRequest)
{
    string responseString = String.Empty;
    using (WebResponse webResponse = webRequest.GetResponse())
    {
        using (StreamReader reader = new StreamReader(webResponse.GetResponseStream()))
        {
            responseString = reader.ReadToEnd();
            byte[] fileBuffer = Encoding.UTF8.GetBytes(responseString);
        }
    }
    
    if ((responseString.IndexOf("message=successfully") < 0) && (responseString.IndexOf("msg=Save Conflict") < 0))
    {
        throw new Exception(responseString);
    }
    return responseString;
}

Now, let’s evaluate this.

• Here we are using method “remove documents” and, “15.0.0.4420” is server extension version.
• Service name is server relative URL of your site.
• documentName is the name of the document to be deleted. For ex. if the doc ToBeDeleted.aspx resides in the root folder of the site then, documentName will be ToBeDeleted.aspx.
• For authentication, we’re using the CookieContainer of HTTPWebRequest.

Here is the example of how will you call this upload method.

RemoveDocument("ToBeDeleted.aspx");

One utility method has been used here for encoding of string. Here it is for your reference.

public string GetEncodedString(string sourceString)
{
    if (!String.IsNullOrEmpty(sourceString))
    { 
        return HttpUtility.UrlEncode(sourceString).Replace(".", "%2e").Replace("_", "%5f");
    }
    else
    {
        return sourceString;
    }
}