從谷歌雲存儲獲取的圖像在App Engine中

Question

我想在我的App Engine後端，每次得到的圖像我設法得到它，我得到以下錯誤

com.google.api.client.googleapis.json.GoogleJsonResponseException: 503 Service Unavailable 
{ 
    "code": 503, 
    "errors": [ 
    { 
     "domain": "global", 
     "message": "java.io.IOException: The Application Default Credentials are not available. They are available if running in Google Compute Engine. Otherwise, the environment variable GOOGLE_APPLICATION_CREDENTIALS must be defined pointing to a file defining the credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.", 
     "reason": "backendError" 
    } 
    ], 
    "message": "java.io.IOException: The Application Default Credentials are not available. They are available if running in Google Compute Engine. Otherwise, the environment variable GOOGLE_APPLICATION_CREDENTIALS must be defined pointing to a file defining the credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information." 
} 

現在是我的理解是，當從App Engine後端請求Application Default Credentials已足夠。

應用程序默認憑證提供了一種簡單的方式來獲取 授權憑證以用於調用Google API。

它們最適用於呼叫需要具有相同的 身份和授權級別的獨立於用戶的 應用程序。這是推薦的方法，用於授權撥打 Google Cloud API，特別是在您構建部署到Google App Engine或Google Compute Engine虛擬 機器的應用程序 時。

從here

採取這是我正在嘗試使用Java API

HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport(); 
GoogleCredential credential = GoogleCredential.getApplicationDefault(); 

if(credential.createScopedRequired()){ 
    credential = credential.createScoped(StorageScopes.all()); 
} 

Storage.Builder storageBuilder = new Storage.Builder(httpTransport,new JacksonFactory(),credential); 
Storage storage = storageBuilder.build(); 

Storage.Objects.Get getObject = storage.objects().get("myBucket", name); 

ByteArrayOutputStream out = new ByteArrayOutputStream(); 
      getObject.getMediaHttpDownloader().setDirectDownloadEnabled(false); 
getObject.executeMediaAndDownloadTo(out); 

byte[] oldImageData = out.toByteArray(); 
out.close(); 

ImagesService imagesService = ImagesServiceFactory.getImagesService(); 

Image oldImage = ImagesServiceFactory.makeImage(oldImageData); 
Transform resize = ImagesServiceFactory.makeResize(width, height); 

return imagesService.applyTransform(resize, oldImage); 

我只是使用證書錯誤得到的圖像或可我不使用應用程序的默認憑據？

Answer 1

如果您想從App Engine訪問您的Google Cloud Storage數據。你應該使用Google Cloud Storage Client Library

Github Project