(Excel) Download File (Stream to Local Filesystem)

This example demonstrates how to download the content of a file from Google Drive. The file is streamed to the local filesystem.

Download Excel Class Modules Chilkat Excel Class Modules

success = True

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

' This example uses a previously obtained access token having permission for the 
' Google Drive scope.

Dim gAuth As Chilkat.AuthGoogle
Set gAuth = Chilkat.NewAuthGoogle
gAuth.AccessToken = "GOOGLE_DRIVE_ACCESS_TOKEN"

Dim rest As Chilkat.Rest
Set rest = Chilkat.NewRest

' Connect using TLS.
' A single REST object, once connected, can be used for many Google Drive REST API calls.
' The auto-reconnect indicates that if the already-established HTTPS connection is closed,
' then it will be automatically re-established as needed.

bAutoReconnect = True
success = rest.Connect("www.googleapis.com",443,True,bAutoReconnect)

' Provide the authentication credentials (i.e. the access token)
Dim success As Boolean
success = rest.SetAuthGoogle(gAuth)

' ------------------------------------------------------------------------------
' To download a file, we must know the file ID.
' In a previous example (see Build Local Metadata Cache
' we built a local cache to make it easy to lookup file IDs given a file path.
' Let's say we want to download "testFolder/abc/123/penguins.jpg".
' First we lookup the fileId in the cache.  With the fileId, we can download the file.
Dim gdCache As Chilkat.Cache
Set gdCache = Chilkat.NewCache
gdCache.Level = 0
gdCache.AddRoot "C:/ckCache/googleDrive"


fileId = gdCache.FetchText("testFolder/abc/123/penguins.jpg")
If (gdCache.LastMethodSuccess <> True) Then
    Debug.Print "Filepath not found in cache."
    Exit Sub
End If

' We need to send a GET request like this:
' GET https://www.googleapis.com/drive/v3/files/fileId?alt=media
' The fileId is part of the path.
Dim sbPath As Chilkat.StringBuilder
Set sbPath = Chilkat.NewStringBuilder
success = sbPath.Append("/drive/v3/files/")
success = sbPath.Append(fileId)
success = rest.AddQueryParam("alt","media")

' Create a stream object with a SinkFile set to the path where the downloaded file will go.
Dim fileStream As Chilkat.Stream
Set fileStream = Chilkat.NewStream
fileStream.SinkFile = "qa_output/penguins.jpg"
' Indicate that the response body should stream directly to fileStream,
' but only if the response status is 200.  
success = rest.SetResponseBodyStream(200,True,fileStream)

' Download the file, streaming the content to the SinkFile.

jsonResponse = rest.FullRequestNoBody("GET",sbPath.GetAsString())
If (rest.LastMethodSuccess <> True) Then
    Debug.Print rest.LastErrorText
    Exit Sub
End If

' A successful response will have a status code equal to 200.
If (rest.ResponseStatusCode <> 200) Then
    Debug.Print "response status code = "; rest.ResponseStatusCode
    Debug.Print "response status text = "; rest.ResponseStatusText
    Debug.Print "response header: "; rest.ResponseHeader
    Exit Sub
End If

Debug.Print "File downloaded."