(Lianja) 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 Lianja Extension Download Chilkat Lianja Extension

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

loRest = createobject("CkRest")

// 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.
llSuccess = loRest.Connect("graph.microsoft.com",443,.T.,.T.)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

// (Make sure your token was obtained with the FilesRead or Files.ReadWrite scope.)
loOauth2 = createobject("CkOAuth2")
loOauth2.AccessToken = "MICROSOFT_GRAPH_ACCESS_TOKEN"
loRest.SetAuthOAuth2(loOauth2)

// Send the GET request to download the file.
lcUriPath = "/v1.0/me/drive/root:/Misc/wildlife/penguins.jpg:/content"
llSuccess = loRest.SendReqNoBody("GET",lcUriPath)
if (loRest.LastMethodSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    release loOauth2
    return
endif

// 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.
lnStatusCode = loRest.ReadResponseHeader()
? "Response Status Code = " + str(lnStatusCode)
if (lnStatusCode = 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.
    loDiscard = createobject("CkBinData")
    loRest.ReadRespBd(loDiscard)
    loRest.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.
    loRest.ClearAuth()

    // Follow the redirect URL...
    loRedirectUrl = loRest.RedirectUrl()
    ? "Redirect Host: " + loRedirectUrl.Host
    ? "Redirect URI Path: " + loRedirectUrl.PathWithQueryParams

    llSuccess = loRest.Connect(loRedirectUrl.Host,loRedirectUrl.Port,loRedirectUrl.Ssl,.T.)
    if (llSuccess <> .T.) then
        ? loRest.LastErrorText
        release loRest
        release loOauth2
        release loDiscard
        return
    endif

    // Send the request..
    llSuccess = loRest.SendReqNoBody("GET",loRedirectUrl.Path)
    release loRedirectUrl
    if (loRest.LastMethodSuccess <> .T.) then
        ? loRest.LastErrorText
        release loRest
        release loOauth2
        release loDiscard
        return
    endif

    lnStatusCode = loRest.ReadResponseHeader()
    ? loRest.LastErrorText
    ? "Redirect Response Status Code = " + str(lnStatusCode)

endif

if (lnStatusCode >= 300) then

    // Read the error response body.
    loSbJson = createobject("CkStringBuilder")
    llSuccess = loRest.ReadRespSb(loSbJson)
    if (llSuccess <> .T.) then
        ? loRest.LastErrorText
        release loRest
        release loOauth2
        release loDiscard
        release loSbJson
        return
    endif

    loJsonErr = createobject("CkJsonObject")
    loJsonErr.EmitCompact = .F.
    loJsonErr.LoadSb(loSbJson)
    ? loJsonErr.Emit()

    release loRest
    release loOauth2
    release loDiscard
    release loSbJson
    release loJsonErr
    return
endif

// Stream the response body directly to a local file.
lcLocalPath = "qa_output/penguins.jpg"

loStream = createobject("CkStream")
loStream.SinkFile = lcLocalPath

llSuccess = loRest.ReadRespBodyStream(loStream,.T.)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    release loOauth2
    release loDiscard
    release loSbJson
    release loJsonErr
    release loStream
    return
endif

? "Successfully streamed a OneDrive file to the local filesystem."


release loRest
release loOauth2
release loDiscard
release loSbJson
release loJsonErr
release loStream