Xojo Plugin

Download Binary File to In-Memory Bytes

See more Google Drive Examples

This example demonstrates how to download the binary content of a file from Google Drive directly into local memory. Xojo Plugin

Dim success As Boolean
success = False

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 New Chilkat.AuthGoogle
gAuth.AccessToken = "GOOGLE-DRIVE-ACCESS-TOKEN"

Dim rest As New Chilkat.Rest

// 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.
Dim bAutoReconnect As Boolean
bAutoReconnect = True
success = rest.Connect("www.googleapis.com",443,True,bAutoReconnect)

// Provide the authentication credentials (i.e. the access token)
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 New Chilkat.Cache
gdCache.Level = 0
gdCache.AddRoot "C:/ckCache/googleDrive"

Dim fileId As String
fileId = gdCache.FetchText("testFolder/abc/123/penguins.jpg")
If (gdCache.LastMethodSuccess <> True) Then
    System.DebugLog("Filepath not found in cache.")
    Return
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 New Chilkat.StringBuilder
success = sbPath.Append("/drive/v3/files/")
success = sbPath.Append(fileId)
success = rest.AddQueryParam("alt","media")

// To download to memory, we'll send the request in one call, then receive
// the response header, and then the response body.
// If the response header indicates failure or an unexpected response, then the
// body is not the data we desire.

// First send the HTTP request.
success = rest.SendReqNoBody("GET",sbPath.GetAsString())
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// Get the response header.
Dim statusCode As Int32
statusCode = rest.ReadResponseHeader()
If (statusCode <> 200) Then
    System.DebugLog("response status code = " + Str(rest.ResponseStatusCode))
    System.DebugLog("response status text = " + rest.ResponseStatusText)
    System.DebugLog("response header: " + rest.ResponseHeader)

    // Read the response body (which should be error text or HTML)
    Dim errResponseBody As String
    errResponseBody = rest.ReadRespBodyString()
    If (rest.LastMethodSuccess = True) Then
        System.DebugLog("response body: " + errResponseBody)
    End If

    Return
End If

// Read the response body, which should contain the file data.
Dim jpgBytes As MemoryBlock
jpgBytes = rest.ReadRespBodyBinary()
If (rest.LastMethodSuccess <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// Save jpgBytes to a file so we can examine the file to verify that it worked.
Dim fac As New Chilkat.FileAccess
success = fac.WriteEntireFile("qa_output/penguins_out.jpg",jpgBytes)

System.DebugLog("File downloaded.")