com.google.appengine.tools.development.LocalURLFetchServiceStreamHandler Maven / Gradle / Ivy
/*
* Copyright 2021 Google LLC
*
* 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
*
* https://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.google.appengine.tools.development;
import static com.google.appengine.tools.development.StreamHandlerFactory.getDeclaredMethod;
import static com.google.appengine.tools.development.StreamHandlerFactory.invoke;
import com.google.apphosting.api.ApiProxy;
import com.google.apphosting.utils.security.urlfetch.URLFetchServiceStreamHandler;
import com.google.appengine.repackaged.com.google.common.annotations.VisibleForTesting;
import java.io.IOException;
import java.lang.reflect.Method;
import java.net.HttpURLConnection;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Extension to {@link URLFetchServiceStreamHandler} that can fall back to a
* default stream handler when the url fetch service is not available.
*
* The Dev AppServer registers a custom stream handler, which is global (not
* classloader global, jvm global). In addition, the jdk only lets you set a
* custom stream handler once, so once it's set, it's set. This is
* unfortunate, because you may have a program like an integration test or a
* remote api test that spends some time operating in an App Engine context and
* some time operating in a non-App Engine context. Without the ability to fall
* back to a default stream handler, you are effectively prevented from doing
* anything involving stream handlers once you stop operating in an App Engine
* context.
*
*/
public class LocalURLFetchServiceStreamHandler extends URLFetchServiceStreamHandler {
private static boolean useNativeHandlers = false;
@Nullable private final URLStreamHandler fallbackHandler;
private final Method openConnection1Arg;
private final Method openConnection2Arg;
/**
* Constructs a LocalURLFetchServiceStreamHandler
*
* @param fallbackHandler Receives requests to open connections when the url fetch service is not
* available.
*/
public LocalURLFetchServiceStreamHandler(@Nullable URLStreamHandler fallbackHandler) {
this.fallbackHandler = fallbackHandler;
// There's no good way to get at the openConnection() methods on a
// StreamHandler because they are protected. We resort to reflection,
// which is ugly and fragile, but at least URLFetchServiceStreamHandler
// doesn't need to know anything about it.
openConnection1Arg = getDeclaredMethod(fallbackHandler.getClass(), "openConnection", URL.class);
openConnection2Arg = getDeclaredMethod(
fallbackHandler.getClass(), "openConnection", URL.class, Proxy.class);
}
private boolean useFallBackHandler() {
// No delegate means the url fetch service is unavailable. Alternatively
// if appengine-web.xml is configured to use native handlers.
return fallbackHandler != null && (ApiProxy.getDelegate() == null || useNativeHandlers);
}
@Override
protected HttpURLConnection openConnection(URL u) throws IOException {
if (useFallBackHandler()) {
return (HttpURLConnection) invoke(fallbackHandler, openConnection1Arg, u);
}
return super.openConnection(u);
}
@Override
protected URLConnection openConnection(URL u, Proxy p) throws IOException {
if (useFallBackHandler()) {
return (HttpURLConnection) invoke(fallbackHandler, openConnection2Arg, u, p);
}
return super.openConnection(u, p);
}
public URLStreamHandler getFallbackHandler() {
return fallbackHandler;
}
public static void setUseNativeHandlers(boolean useNativeHandlers) {
LocalURLFetchServiceStreamHandler.useNativeHandlers = useNativeHandlers;
}
@VisibleForTesting
static boolean getUseNativeHandlers() {
return useNativeHandlers;
}
}