B4X
Get Object MetaData from Google Cloud Storage

Demonstrates how to download a Google Cloud Storage object's metadata.
Chilkat B4X Downloads

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]?projection=full"

Dim http As ChilkatHttp
http.Initialize("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 ChilkatStringBuilder
sbMetaData.Initialize
success = http.DownloadSb(url, "utf-8", sbMetaData)
If success = False Then
    Log(http.LastErrorText)
    Return
End If


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
    Log("Error response code = " & responseCode)
    Log("Error:")
    Log(sbMetaData.GetAsString)
    Return
End If


Log(sbMetaData.GetAsString)
Log("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="
'  }
'