VB.NET

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. VB.NET

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 New Chilkat.StringBuilder
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 New Chilkat.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 New Chilkat.BinData
success = http.DownloadBd(url,fileData)
If (success = False) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


Dim sbErrorResponse As New Chilkat.StringBuilder
Dim responseCode As Integer = http.LastStatus
If (responseCode = 401) Then
    Debug.WriteLine("If invalid credentials, then it is likely the access token expired.")
    Debug.WriteLine("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)
    Debug.WriteLine("Error response code = " & responseCode)
    Debug.WriteLine("Error:")
    Debug.WriteLine(sbErrorResponse.GetAsString())
    Exit Sub
End If


Debug.WriteLine("Success.")

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