com.helger.photon.api.servlet.APIXServletHandler Maven / Gradle / Ivy
/**
* Copyright (C) 2014-2020 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.helger.photon.api.servlet;
import java.io.IOException;
import javax.annotation.Nonnull;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.helger.commons.ValueEnforcer;
import com.helger.commons.functional.ISupplier;
import com.helger.commons.http.CHttp;
import com.helger.commons.http.EHttpMethod;
import com.helger.commons.lang.GenericReflection;
import com.helger.commons.mutable.MutableInt;
import com.helger.http.EHttpVersion;
import com.helger.photon.api.APIPath;
import com.helger.photon.api.GlobalAPIInvoker;
import com.helger.photon.api.IAPIInvoker;
import com.helger.photon.api.IAPIRegistry;
import com.helger.photon.api.InvokableAPIDescriptor;
import com.helger.photon.app.PhotonUnifiedResponse;
import com.helger.servlet.response.UnifiedResponse;
import com.helger.web.scope.IRequestWebScope;
import com.helger.web.scope.IRequestWebScopeWithoutResponse;
import com.helger.xservlet.handler.simple.IXServletSimpleHandler;
/**
* Abstract API servlet. Use {@link IAPIRegistry} to register API functions
* dynamically and {@link IAPIInvoker} to invoke them afterwards.
*
* @author Philip Helger
*/
public class APIXServletHandler implements IXServletSimpleHandler
{
private static final Logger LOGGER = LoggerFactory.getLogger (APIXServletHandler.class);
private final ISupplier m_aRegistryFactory;
private final ISupplier m_aInvokerFactory;
public APIXServletHandler ()
{
this ( () -> GlobalAPIInvoker.getInstance ().getRegistry (), () -> GlobalAPIInvoker.getInstance ().getInvoker ());
}
public APIXServletHandler (@Nonnull final ISupplier aRegistryFactory,
@Nonnull final ISupplier aInvokerFactory)
{
m_aRegistryFactory = ValueEnforcer.notNull (aRegistryFactory, "RegistryFactory");
m_aInvokerFactory = ValueEnforcer.notNull (aInvokerFactory, "InvokerFactory");
}
@Nonnull
public PhotonUnifiedResponse createUnifiedResponse (@Nonnull final EHttpVersion eHttpVersion,
@Nonnull final EHttpMethod eHttpMethod,
@Nonnull final HttpServletRequest aHttpRequest,
@Nonnull final IRequestWebScope aRequestScope)
{
return new PhotonUnifiedResponse (eHttpVersion, eHttpMethod, aHttpRequest, aRequestScope);
}
@Override
public void handleRequest (@Nonnull final IRequestWebScopeWithoutResponse aRequestScope,
@Nonnull final UnifiedResponse aUnifiedResponse) throws Exception
{
final EHttpMethod eHttpMethod = aRequestScope.getHttpMethod ();
if (eHttpMethod == null)
{
// Should have been caught in AbstractXServlet.service ...
LOGGER.error ("Missing HTTP method in request: " + aRequestScope.getRequest ());
// No such action
aUnifiedResponse.setStatus (CHttp.HTTP_NOT_IMPLEMENTED);
return;
}
final APIPath aAPIPath = APIPath.createForServlet (aRequestScope);
final IAPIRegistry aRegistry = m_aRegistryFactory.get ();
final IAPIInvoker aInvoker = m_aInvokerFactory.get ();
final InvokableAPIDescriptor aInvokableDescriptor = aRegistry.getAPIByPath (aAPIPath);
if (aInvokableDescriptor == null)
{
LOGGER.warn ("Unknown API " + eHttpMethod + " '" + aAPIPath.getPath () + "' requested!");
// No such action
aUnifiedResponse.setStatus (CHttp.HTTP_NOT_FOUND);
}
else
{
// Is the declaration applicable for the current scope?
// Check for required headers and parameters
final MutableInt aStatusCode = new MutableInt (CHttp.HTTP_BAD_REQUEST);
if (!aInvokableDescriptor.canExecute (aRequestScope, aStatusCode))
{
final int nStatusCode = aStatusCode.intValue ();
LOGGER.warn ("API " +
eHttpMethod +
" '" +
aAPIPath.getPath () +
"' cannot be executed for the current request. Returning HTTP " +
nStatusCode);
aUnifiedResponse.setStatus (nStatusCode);
}
else
{
// Don't cache the result. The executor may overwrite it
aUnifiedResponse.disableCaching ();
try
{
// Main API invocation
aInvoker.invoke (aInvokableDescriptor, aRequestScope, GenericReflection.uncheckedCast (aUnifiedResponse));
if (aUnifiedResponse.isStatusCodeDefined () || aUnifiedResponse.isRedirectDefined ())
{
// Status codes are not meant to be cached
aUnifiedResponse.removeCaching ();
}
else
if (!aUnifiedResponse.isStatusCodeDefined () &&
!aUnifiedResponse.isRedirectDefined () &&
!aUnifiedResponse.hasContent ())
{
// Set "No Content" response
aUnifiedResponse.setStatus (CHttp.HTTP_NO_CONTENT);
}
}
catch (final IOException | ServletException ex)
{
// Re-throw
throw ex;
}
catch (final Throwable t)
{
throw new ServletException ("Error invoking API " + eHttpMethod + " '" + aAPIPath.getPath () + "'", t);
}
}
}
}
}