com.google.api.server.spi.request.Auth.java Source code

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Here is the source code for com.google.api.server.spi.request.Auth.java

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/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 *
 * 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.google.api.server.spi.request;

import com.google.api.server.spi.EnvUtil;
import com.google.api.server.spi.auth.EndpointsAuthenticator;
import com.google.api.server.spi.auth.common.User;
import com.google.api.server.spi.config.Authenticator;
import com.google.api.server.spi.config.Singleton;
import com.google.api.server.spi.config.model.ApiMethodConfig;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.http.HttpServletRequest;

/**
 * Utilities for end user authentication.
 */
public class Auth {
    private static final Logger logger = Logger.getLogger(Auth.class.getName());

    private static volatile Map<Class<? extends Authenticator>, Authenticator> authenticatorInstances = new HashMap<Class<? extends Authenticator>, Authenticator>();

    private static final Authenticator DEFAULT_AUTHENTICATOR = new EndpointsAuthenticator();

    private static final Function<Class<? extends Authenticator>, Authenticator> INSTANTIATE_AUTHENTICATOR = new Function<Class<? extends Authenticator>, Authenticator>() {
        @Override
        public Authenticator apply(Class<? extends Authenticator> clazz) {
            try {
                if (clazz.getAnnotation(Singleton.class) != null) {
                    if (!authenticatorInstances.containsKey(clazz)) {
                        authenticatorInstances.put(clazz, clazz.newInstance());
                    }
                    return authenticatorInstances.get(clazz);
                } else {
                    return clazz.newInstance();
                }
            } catch (IllegalAccessException | InstantiationException e) {
                logger.log(Level.WARNING, "Could not instantiate  authenticator: " + clazz.getName());
                return null;
            }
        }
    };

    private final HttpServletRequest request;
    private final Attribute attr;
    private final ApiMethodConfig config;

    @VisibleForTesting
    Auth(HttpServletRequest request) {
        this.request = request;
        attr = Attribute.from(request);
        config = (ApiMethodConfig) attr.get(Attribute.API_METHOD_CONFIG);
    }

    static Auth from(HttpServletRequest request) {
        return new Auth(request);
    }

    @VisibleForTesting
    Iterable<Authenticator> getAuthenticatorInstances() {
        List<Class<? extends Authenticator>> classes = config.getAuthenticators();
        return classes == null ? ImmutableList.of(DEFAULT_AUTHENTICATOR)
                : Iterables.filter(Iterables.transform(classes, INSTANTIATE_AUTHENTICATOR), Predicates.notNull());
    }

    /**
     * Authenticate the request and retrieve a {@code User}. Should only run once per request.
     */
    User authenticate() {
        Iterable<Authenticator> authenticators = getAuthenticatorInstances();
        User user = null;
        if (authenticators != null) {
            for (Authenticator authenticator : authenticators) {
                user = authenticator.authenticate(request);
                if (user != null) {
                    break;
                }
            }
        }
        return user;
    }

    /**
     * Authenticate the request and retrieve an {@code com.google.appengine.api.users.User}. Should
     * only run once per request.
     */
    com.google.appengine.api.users.User authenticateAppEngineUser() {
        if (!EnvUtil.isRunningOnAppEngine()) {
            return null;
        }
        attr.set(Attribute.REQUIRE_APPENGINE_USER, true);
        User user = authenticate();
        attr.set(Attribute.REQUIRE_APPENGINE_USER, false);
        if (user == null) {
            return null;
        }
        com.google.appengine.api.users.User appEngineUser = (com.google.appengine.api.users.User) attr
                .get(Attribute.AUTHENTICATED_APPENGINE_USER);
        if (appEngineUser != null) {
            return appEngineUser;
        } else {
            return user.getEmail() == null ? null
                    : new com.google.appengine.api.users.User(user.getEmail(), "", user.getId());
        }
    }
}