(C# UWP/WinRT) SharePoint -- Download Newer Files

Demonstrates how to download all files from a SharePoint folder that are newer than the local files.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

//  This requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  -------------------------------------------------------------------------
//  The following comments apply to SharePoint Windows classic authentication.
//  -------------------------------------------------------------------------
//  For example, imagine our SharePoint endpoint is https://xyzoffice.mycompany.com/
//  The SHAREPOINT_NTLM_DOMAIN would be "mycompany.com"
//  The SHAREPOINT_HTTPS_DOMAIN would be "xyzoffice.mycompany.com"
//  Also, the SHAREPOINT_USERNAME would be just the name, not a full email address.
//  for example, "chilkat" instead of "chilkat@mycompany.com"

Chilkat.Http http = new Chilkat.Http();

//  If SharePoint Windows classic authentication is used, then set the
//  Login, Password, LoginDomain, and NtlmAuth properties.
http.Login = "SHAREPOINT_USERNAME";
http.Password = "SHAREPOINT_PASSWORD";
http.LoginDomain = "SHAREPOINT_NTLM_DOMAIN";
http.NtlmAuth = true;

//  -------------------------------------------------------------------------
//  The more common case is to use SharePoint Online authentication (via the SPOIDCRL cookie).
//  If so, do not set Login, Password, LoginDomain, and NtlmAuth, and instead
//  establish the cookie as shown at SharePoint Online Authentication
//  -------------------------------------------------------------------------

//  First we'll download a list of all the files in the /Documents folder.
//  This provides the names and last-modified date/times of the files located
//  on the SharePoint server.
http.Accept = "application/json;odata=verbose";

Chilkat.StringBuilder sbJson = new Chilkat.StringBuilder();
bool success = await http.QuickGetSbAsync("https://SHAREPOINT_HTTPS_DOMAIN/_api/web/GetFolderByServerRelativeUrl('/Documents')/Files",sbJson);
if (success != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

//  Before proceeding, make sure the local directory where we'll be downloading files exists.
Chilkat.FileAccess fac = new Chilkat.FileAccess();
fac.DirEnsureExists("qa_output/sharepoint/Documents");

//  OK.. load the JSON and iterate over each file
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.LoadSb(sbJson);

int numFiles = json.SizeOfArray("d.results");
Debug.WriteLine("Number of Files in the SharePoint /Documents folder = " + Convert.ToString(numFiles));

Chilkat.CkDateTime lastModRemote = new Chilkat.CkDateTime();
Chilkat.CkDateTime lastModLocal = null;

Chilkat.StringBuilder localPath = new Chilkat.StringBuilder();
Chilkat.StringBuilder fileUrl = new Chilkat.StringBuilder();

int i = 0;
while (i < numFiles) {
    json.I = i;

    string filename = json.StringOf("d.results[i].Name");
    string sLastModified = json.StringOf("d.results[i].TimeLastModified");

    Debug.WriteLine(Convert.ToString(i + 1) + ": " + filename + " (" + sLastModified + ")");

    lastModRemote.SetFromTimestamp(sLastModified);

    bool bDownload = false;
    //  Check to see if the local file exists.  If not, then download.
    localPath.SetString("qa_output/sharepoint/Documents/");
    localPath.Append(filename);
    if (fac.FileExists(localPath.GetAsString()) != true) {
        Debug.WriteLine("This file does not exist locally.");
        bDownload = true;
    }
    else {
        //  Get the local file's date time and compare with the remote file date/time.
        lastModLocal = fac.GetLastModified(localPath.GetAsString());
        if (fac.LastMethodSuccess == true) {
            //  Get the difference in seconds between the local and remote last-modified times.
            //  if the return value is negative, then the caller's time is
            //  older than the argument.  (in this case, a negative return value means
            //  the local file is older than the remote file.

            //  Note: The DiffSeconds method was found to be missing in the Chilkat .NET build
            //  (and possibly in other builds). It will be present in the v9.5.0.67 release and later.
            int numSeconds = lastModLocal.DiffSeconds(lastModRemote);
            if (numSeconds < 0) {
                Debug.WriteLine("The local file is older than the remote file.");
                bDownload = true;
            }

        }
        else {
            Debug.WriteLine("Unable to get the local file's last-modified date/time.");
            Debug.WriteLine(fac.LastErrorText);
        }

    }

    if (bDownload == true) {
        fileUrl.SetString("https://SHAREPOINT_HTTPS_DOMAIN/_api/web/GetFolderByServerRelativeUrl('/Documents')/Files('");
        fileUrl.Append(filename);
        fileUrl.Append("')/$value");

        Debug.WriteLine("Downloading " + filename);

        success = await http.DownloadAsync(fileUrl.GetAsString(),localPath.GetAsString());
        if (success != true) {
            Debug.WriteLine(http.LastErrorText);
            return;
        }

        //  Set the local file's last-modified date/time to that of the server's.
        fac.SetLastModified(localPath.GetAsString(),lastModRemote);

    }

    i = i + 1;
}

Debug.WriteLine("All finished.");