In this post, I am going to demonstrate how to rename an existing file using RPC. The code is along the same line as this one, https://realmpksharepoint.wordpress.com/2014/04/29/upload-large-files-to-the-sharepoint-documentlibrary-using-rpc-from-a-desktop-application-c/

public void RenamePage(string oldUrl, string newUrl)
{
    string requestUrl = this.ctx.Url + "/_vti_bin/_vti_aut/author.dll";
    string method = GetEncodedString("move document:15.0.0.4420");
    
    string serviceName = GetEncodedString(this.ctx.Web.ServerRelativeUrl);
    oldUrl = GetEncodedString(oldUrl);
    newUrl = GetEncodedString(newUrl);
    string urlList = GetEncodedString("[]");
    
    rpcCallString = "method={0}&service_name={1}&oldUrl={2}&newUrl={3}&url_list={4}&rename_option=findbacklinks&put_option=edit\n";

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

    HttpWebRequest wReq = WebRequest.Create(requestUrl) as HttpWebRequest;
    wReq.Method = "POST";

    wReq.Headers["Content"] = "application/x-vermeer-rpc";
    wReq.Headers["X-Vermeer-Content-Type"] = "application/x-vermeer-rpc";

    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));

    wReq.BeginGetRequestStream(new AsyncCallback(gotRequestStream), wReq);
}

private void gotRequestStream(IAsyncResult asynchronousResult)
{
    HttpWebRequest webRequest = (HttpWebRequest)asynchronousResult.AsyncState;
    Stream requestStream = webRequest.EndGetRequestStream(asynchronousResult);
    List<byte> uploadData = new List<byte>();
    uploadData.AddRange(Encoding.UTF8.GetBytes(rpcCallString));
    
    byte[] fileData = uploadData.ToArray();
    requestStream.Write(fileData, 0, fileData.Length);
    requestStream.Close();
    webRequest.BeginGetResponse(new AsyncCallback(gotResponse), webRequest);
}

private void gotResponse(IAsyncResult asynchronousResult)
{
    HttpWebRequest webRequest = (HttpWebRequest)asynchronousResult.AsyncState;
    HttpWebResponse webResponse = (HttpWebResponse)webRequest.EndGetResponse(asynchronousResult);
    Stream responseStream = webResponse.GetResponseStream();
    StreamReader reader = new StreamReader(webResponse.GetResponseStream());
    
    string responseString = String.Empty;
    responseString = reader.ReadToEnd();
    byte[] fileBuffer = Encoding.UTF8.GetBytes(responseString);
    responseStream.Close();
    reader.Close();
    webResponse.Close();
    
    if (responseString.IndexOf("\n
message=successfully"

) < 0)
    {
        throw new Exception(responseString);
    }
}

Now, let’s evaluate this.

• Here we are using method “move document” and, “15.0.0.4420” is server extension version.
• Service name is server relative URL of your site.
• oldUrl is the current url of the page and newUrl is the new url to be set.
• For authentication, we’re using the CookieContainer of HTTPWebRequest.

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

RenamePage("default.aspx", "defaultNew.aspx");

Here a utility method, GetEncodedString 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;
    }
}

Check out here to get some additional info about move document, http://msdn.microsoft.com/en-us/library/ms440627%28v=office.14%29.aspx.