(VB.NET) Get Object MetaData from Google Cloud Storage

Demonstrates how to download a Google Cloud Storage object's metadata.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' 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]?projection=full"

Dim http As New Chilkat.Http

http.AuthToken = sbToken.GetAsString()

' Construct a URL to download the metadata for the object named "starfish.jpg" located in 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}?projection=full"

' If there is an error response, then we didn't actually download the metadata,
' but instead we downloaded an error response..
Dim sbMetaData As New Chilkat.StringBuilder
Dim success As Boolean = http.DownloadSb(url,"utf-8",sbMetaData)
If (success = False) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If



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
    Debug.WriteLine("Error response code = " & responseCode)
    Debug.WriteLine("Error:")
    Debug.WriteLine(sbMetaData.GetAsString())
    Exit Sub
End If



Debug.WriteLine(sbMetaData.GetAsString())
Debug.WriteLine("Success.")

' Sample output:

' {
'  "kind": "storage#object",
'  "id": "chilkat-ocean/starfish.jpg/1502670320090292",
'  "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg",
'  "name": "starfish.jpg",
'  "bucket": "chilkat-ocean",
'  "generation": "1502670320090292",
'  "metageneration": "1",
'  "contentType": "image/jpeg",
'  "timeCreated": "2017-08-14T00:25:20.040Z",
'  "updated": "2017-08-14T00:25:20.040Z",
'  "storageClass": "MULTI_REGIONAL",
'  "timeStorageClassUpdated": "2017-08-14T00:25:20.040Z",
'  "size": "6229",
'  "md5Hash": "LpxZ2/JmI2fcl9/dqF2gSA==",
'  "mediaLink": "https://www.googleapis.com/download/storage/v1/b/chilkat-ocean/o/starfish.jpg?generation=1502670320090292&alt=media",
'  "acl": [
'   {
'    "kind": "storage#objectAccessControl",
'    "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-owners-933037264567",
'    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-owners-933037264567",
'    "bucket": "chilkat-ocean",
'    "object": "starfish.jpg",
'    "generation": "1502670320090292",
'    "entity": "project-owners-933037264567",
'    "role": "OWNER",
'    "projectTeam": {
'     "projectNumber": "933037264567",
'     "team": "owners"
'    },
'    "etag": "CLT5kpW71dUCEAE="
'   },
'   {
'    "kind": "storage#objectAccessControl",
'    "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-editors-933037264567",
'    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-editors-933037264567",
'    "bucket": "chilkat-ocean",
'    "object": "starfish.jpg",
'    "generation": "1502670320090292",
'    "entity": "project-editors-933037264567",
'    "role": "OWNER",
'    "projectTeam": {
'     "projectNumber": "933037264567",
'     "team": "editors"
'    },
'    "etag": "CLT5kpW71dUCEAE="
'   },
'   {
'    "kind": "storage#objectAccessControl",
'    "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-viewers-933037264567",
'    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-viewers-933037264567",
'    "bucket": "chilkat-ocean",
'    "object": "starfish.jpg",
'    "generation": "1502670320090292",
'    "entity": "project-viewers-933037264567",
'    "role": "READER",
'    "projectTeam": {
'     "projectNumber": "933037264567",
'     "team": "viewers"
'    },
'    "etag": "CLT5kpW71dUCEAE="
'   },
'   {
'    "kind": "storage#objectAccessControl",
'    "id": "chilkat-ocean/starfish.jpg/1502670320090292/user-starfish@chilkat-176611.iam.gserviceaccount.com",
'    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/user-starfish@chilkat-176611.iam.gserviceaccount.com",
'    "bucket": "chilkat-ocean",
'    "object": "starfish.jpg",
'    "generation": "1502670320090292",
'    "entity": "user-starfish@chilkat-176611.iam.gserviceaccount.com",
'    "role": "OWNER",
'    "email": "starfish@chilkat-176611.iam.gserviceaccount.com",
'    "etag": "CLT5kpW71dUCEAE="
'   }
'  ],
'  "owner": {
'   "entity": "user-starfish@chilkat-176611.iam.gserviceaccount.com"
'  },
'  "crc32c": "9RjgwQ==",
'  "etag": "CLT5kpW71dUCEAE="
' }
'