For those who wish to serve the local GCS files that have been created by the GAE GCS library, one solution is to expose a Java Servlet like this:
package my.applicaion.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;
public final class GoogleCloudStorageServlet
extends HttpServlet
{
@Override
protected void doGet(final HttpServletRequest request, final HttpServletResponse response)
throws ServletException, IOException
{
final BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
final String fileName = "/gs" + request.getPathInfo();
final BlobKey blobKey = blobstoreService.createGsBlobKey(fileName);
blobstoreService.serve(blobKey, response);
}
}
and in your web.xml:
<servlet>
<servlet-name>GoogleCloudStorage</servlet-name>
<servlet-class>my.applicaion.servlet.GoogleCloudStorageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>GoogleCloudStorage</servlet-name>
<url-pattern>/gcs/*</url-pattern>
</servlet-mapping>
If you host this servlet in your GAE application, the URL for accessing a GCS file with bucket bucket-name
and with name fileName
is http://localhost:8181:/gcs/bucket-name/fileName
, the local GAE development server port number being 8181
.
This works at least from GAE v1.9.50.
And if you intend to have the local GCS server working in a unit test with Jetty, here is a work-around, hopefully with the right comments:
final int localGcsPortNumber = 8081;
final Server localGcsServer = new Server(localGcsPortNumber);
final ServletContextHandler context = new ServletContextHandler(ServletContextHandler.NO_SESSIONS);
final String allPathSpec = "/*";
context.addServlet(new ServletHolder(new HttpServlet()
{
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
final BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
final String fileName = "/gs" + request.getRequestURI();
final BlobKey blobKey = blobstoreService.createGsBlobKey(fileName);
if (blobKey != null)
{
// This is a work-around over the "ServeBlobFilter" which does not take the "Content-Type" from the "blobInfo", but attempts to retrieve it from the "blobKey"
final BlobInfo blobInfo = BlobStorageFactory.getBlobInfoStorage().loadGsFileInfo(blobKey);
if (blobInfo != null)
{
final String contentType = blobInfo.getContentType();
if (contentType != null)
{
response.addHeader(HttpHeaders.CONTENT_TYPE, contentType);
}
}
}
blobstoreService.serve(blobKey, response);
}
}), allPathSpec);
// The filter is responsible for taken the "blobKey" from the HTTP header and for fulfilling the response with the corresponding GCS content
context.addFilter(ServeBlobFilter.class, allPathSpec, EnumSet.of(DispatcherType.REQUEST));
// This attribute must be set, otherwise a "NullPointerException" is thrown
context.getServletContext().setAttribute("com.google.appengine.devappserver.ApiProxyLocal", LocalServiceTestHelper.getApiProxyLocal());
localGcsServer.setHandler(context);
localGcsServer.start();