(Xojo Plugin) OneDrive -- Streaming REST Download to File

Downloads the contents of a DriveItem directly to a file in the local filesystem using the Chilkat REST class.

Note: This example requires Chilkat v9.5.0.69 or greater.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM

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

Dim rest As New Chilkat.Rest

// Use your previously obtained access token here:
// See the following examples for getting an access token:
//    Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
//    Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
//    Refresh Access Token (Azure AD v2.0 Endpoint).
//    Refresh Access Token (Azure AD Endpoint).

// First connect to graph.microsoft.com.  If there's a connectivity problem, we'll find out here.
Dim success As Boolean
success = rest.Connect("graph.microsoft.com",443,True,True)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// (Make sure your token was obtained with the FilesRead or Files.ReadWrite scope.)
Dim oauth2 As New Chilkat.OAuth2
oauth2.AccessToken = "MICROSOFT_GRAPH_ACCESS_TOKEN"
success = rest.SetAuthOAuth2(oauth2)

// Send the GET request to download the file.
Dim uriPath As String
uriPath = "/v1.0/me/drive/root:/Misc/wildlife/penguins.jpg:/content"
success = rest.SendReqNoBody("GET",uriPath)
If (rest.LastMethodSuccess <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// NOTE: This way of doing the HTTP GET (i.e. download) may be more cumbersome, but it 
// allows for finer control of handling errors.  The connection establishment, the sending of the
// request, the reading of the response header, and the reading of the response body (i.e. the file data)
// are handled by separate method calls.  If the response header indicates an error, we can read
// the response body and treat it differently than if reading the file data.

// Read the response header.
Dim statusCode As Int32
statusCode = rest.ReadResponseHeader()
System.DebugLog("Response Status Code = " + Str(statusCode))
If (statusCode = 302) Then
    // This is a redirect.  Read the response body, if any, and then follow the redirect.
    // Usually the response body will be empty for a redirect, but we need to be sure to read
    // the response body just in case it exists.
    Dim discard As New Chilkat.BinData
    success = rest.ReadRespBd(discard)
    success = rest.Disconnect(10)

    // For OneDrive, the redirect URL does not need authorization because the only way
    // to have obtained the direct download URL is from an authenticated request.
    // In fact, if we leave the authentication present, the GET request to the redirect URL will fail.

    // Note: The ClearAuth method is introduced in v9.5.0.69.
    success = rest.ClearAuth()

    // Follow the redirect URL...
    Dim redirectUrl As Chilkat.Url
    redirectUrl = rest.RedirectUrl()
    System.DebugLog("Redirect Host: " + redirectUrl.Host)
    System.DebugLog("Redirect URI Path: " + redirectUrl.PathWithQueryParams)

    success = rest.Connect(redirectUrl.Host,redirectUrl.Port,redirectUrl.Ssl,True)
    If (success <> True) Then
        System.DebugLog(rest.LastErrorText)
        Return
    End If

    // Send the request..
    success = rest.SendReqNoBody("GET",redirectUrl.Path)

    If (rest.LastMethodSuccess <> True) Then
        System.DebugLog(rest.LastErrorText)
        Return
    End If

    statusCode = rest.ReadResponseHeader()
    System.DebugLog(rest.LastErrorText)
    System.DebugLog("Redirect Response Status Code = " + Str(statusCode))

End If

If (statusCode >= 300) Then

    // Read the error response body.
    Dim sbJson As New Chilkat.StringBuilder
    success = rest.ReadRespSb(sbJson)
    If (success <> True) Then
        System.DebugLog(rest.LastErrorText)
        Return
    End If

    Dim jsonErr As New Chilkat.JsonObject
    jsonErr.EmitCompact = False
    success = jsonErr.LoadSb(sbJson)
    System.DebugLog(jsonErr.Emit())

    Return
End If

// Stream the response body directly to a local file.
Dim localPath As String
localPath = "qa_output/penguins.jpg"

Dim stream As New Chilkat.Stream
stream.SinkFile = localPath

success = rest.ReadRespBodyStream(stream,True)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

System.DebugLog("Successfully streamed a OneDrive file to the local filesystem.")