(PureBasic) 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 PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkBinData.pb"
IncludeFile "CkOAuth2.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkUrl.pb"
IncludeFile "CkStream.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRest.pb"

Procedure ChilkatExample()

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

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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.
    success.i = CkRest::ckConnect(rest,"graph.microsoft.com",443,1,1)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; (Make sure your token was obtained with the FilesRead or Files.ReadWrite scope.)
    oauth2.i = CkOAuth2::ckCreate()
    If oauth2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkOAuth2::setCkAccessToken(oauth2, "MICROSOFT_GRAPH_ACCESS_TOKEN")
    CkRest::ckSetAuthOAuth2(rest,oauth2)

    ; Send the GET request to download the file.
    uriPath.s = "/v1.0/me/drive/root:/Misc/wildlife/penguins.jpg:/content"
    success = CkRest::ckSendReqNoBody(rest,"GET",uriPath)
    If CkRest::ckLastMethodSuccess(rest) <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    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.
    statusCode.i = CkRest::ckReadResponseHeader(rest)
    Debug "Response Status Code = " + Str(statusCode)
    If statusCode = 302
        ; 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.
        discard.i = CkBinData::ckCreate()
        If discard.i = 0
            Debug "Failed to create object."
            ProcedureReturn
        EndIf

        CkRest::ckReadRespBd(rest,discard)
        CkRest::ckDisconnect(rest,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.
        CkRest::ckClearAuth(rest)

        ; Follow the redirect URL...
        redirectUrl.i = CkRest::ckRedirectUrl(rest)
        Debug "Redirect Host: " + CkUrl::ckHost(redirectUrl)
        Debug "Redirect URI Path: " + CkUrl::ckPathWithQueryParams(redirectUrl)

        success = CkRest::ckConnect(rest,CkUrl::ckHost(redirectUrl),CkUrl::ckPort(redirectUrl),CkUrl::ckSsl(redirectUrl),1)
        If success <> 1
            Debug CkRest::ckLastErrorText(rest)
            CkRest::ckDispose(rest)
            CkOAuth2::ckDispose(oauth2)
            CkBinData::ckDispose(discard)
            ProcedureReturn
        EndIf

        ; Send the request..
        success = CkRest::ckSendReqNoBody(rest,"GET",CkUrl::ckPath(redirectUrl))
        CkUrl::ckDispose(redirectUrl)

        If CkRest::ckLastMethodSuccess(rest) <> 1
            Debug CkRest::ckLastErrorText(rest)
            CkRest::ckDispose(rest)
            CkOAuth2::ckDispose(oauth2)
            CkBinData::ckDispose(discard)
            ProcedureReturn
        EndIf

        statusCode = CkRest::ckReadResponseHeader(rest)
        Debug CkRest::ckLastErrorText(rest)
        Debug "Redirect Response Status Code = " + Str(statusCode)

    EndIf

    If statusCode >= 300

        ; Read the error response body.
        sbJson.i = CkStringBuilder::ckCreate()
        If sbJson.i = 0
            Debug "Failed to create object."
            ProcedureReturn
        EndIf

        success = CkRest::ckReadRespSb(rest,sbJson)
        If success <> 1
            Debug CkRest::ckLastErrorText(rest)
            CkRest::ckDispose(rest)
            CkOAuth2::ckDispose(oauth2)
            CkBinData::ckDispose(discard)
            CkStringBuilder::ckDispose(sbJson)
            ProcedureReturn
        EndIf

        jsonErr.i = CkJsonObject::ckCreate()
        If jsonErr.i = 0
            Debug "Failed to create object."
            ProcedureReturn
        EndIf

        CkJsonObject::setCkEmitCompact(jsonErr, 0)
        CkJsonObject::ckLoadSb(jsonErr,sbJson)
        Debug CkJsonObject::ckEmit(jsonErr)

        CkRest::ckDispose(rest)
        CkOAuth2::ckDispose(oauth2)
        CkBinData::ckDispose(discard)
        CkStringBuilder::ckDispose(sbJson)
        CkJsonObject::ckDispose(jsonErr)
        ProcedureReturn
    EndIf

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

    stream.i = CkStream::ckCreate()
    If stream.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStream::setCkSinkFile(stream, localPath)

    success = CkRest::ckReadRespBodyStream(rest,stream,1)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkOAuth2::ckDispose(oauth2)
        CkBinData::ckDispose(discard)
        CkStringBuilder::ckDispose(sbJson)
        CkJsonObject::ckDispose(jsonErr)
        CkStream::ckDispose(stream)
        ProcedureReturn
    EndIf

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


    CkRest::ckDispose(rest)
    CkOAuth2::ckDispose(oauth2)
    CkBinData::ckDispose(discard)
    CkStringBuilder::ckDispose(sbJson)
    CkJsonObject::ckDispose(jsonErr)
    CkStream::ckDispose(stream)


    ProcedureReturn
EndProcedure