B4X

Download Object from Google Cloud Storage

See more Google Cloud Storage Examples

Demonstrates how to download an object from Google Cloud Storage to a file. B4X

Dim success As Boolean = False

'  This example 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 
'  scope "https://www.googleapis.com/auth/cloud-platform"

'  In this example, Get Google Cloud Storage OAuth2 Access Token, 
'  the service account access token was saved to a text file.  This example fetches the access token from the file..
Dim sbToken As ChilkatStringBuilder
sbToken.Initialize
sbToken.LoadFile("qa_data/tokens/googleCloudStorageAccessToken.txt", "utf-8")

'  Send a GET equivalent to this curl command.

'  curl -X GET \
'      -H "Authorization: Bearer [OAUTH2_TOKEN]" \
'      -o "[SAVE_TO_LOCATION]" \
'      "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/[OBJECT_NAME]?alt=media"

Dim http As ChilkatHttp
http.Initialize("http")

http.AuthToken = sbToken.GetAsString

'  Construct a URL to download an object named "starfish.jpg" from the "chilkat-ocean" bucket.
http.SetUrlVar("bucket_name", "chilkat-ocean")
http.SetUrlVar("object_name", "starfish.jpg")
Dim url As String = "https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?alt=media"

'  If there is an error response, then we didn't actually download the file data,
'  but instead we downloaded an error response..
Dim fileData As ChilkatBinData
fileData.Initialize
success = http.DownloadBd(url, fileData)
If success = False Then
    Log(http.LastErrorText)
    Return
End If


Dim sbErrorResponse As ChilkatStringBuilder
sbErrorResponse.Initialize
Dim responseCode As Int = http.LastStatus
If responseCode = 401 Then
    Log("If invalid credentials, then it is likely the access token expired.")
    Log("Your app should automatically fetch a new access token and re-try.")
End If


If responseCode <> 200 Then
    '  Get the error response
    sbErrorResponse.AppendBd(fileData, "utf-8", 0, 0)
    Log("Error response code = " & responseCode)
    Log("Error:")
    Log(sbErrorResponse.GetAsString)
    Return
End If


Log("Success.")

'  Save the downloaded data to a file.
success = fileData.WriteFile("qa_output/starfish.jpg")