com.threewks.thundr.gmail.GmailModule.java Source code

Introduction

Here is the source code for com.threewks.thundr.gmail.GmailModule.java

Source

/*
 * This file is a component of thundr, a software library from 3wks.
 * Read more: http://3wks.github.io/thundr/
 * Copyright (C) 2015 3wks, <thundr@3wks.com.au>
 *
 * 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.threewks.thundr.gmail;

import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.store.DataStoreFactory;
import com.google.api.services.gmail.GmailScopes;
import com.threewks.thundr.configuration.ConfigurationException;
import com.threewks.thundr.injection.BaseModule;
import com.threewks.thundr.injection.InjectionContext;
import com.threewks.thundr.injection.UpdatableInjectionContext;
import com.threewks.thundr.logger.Logger;
import com.threewks.thundr.module.DependencyRegistry;
import com.threewks.thundr.route.Router;
import org.apache.commons.lang3.StringUtils;

import java.io.IOException;
import java.util.Collection;
import java.util.Collections;

public class GmailModule extends BaseModule {

    @Override
    public void requires(DependencyRegistry dependencyRegistry) {
        super.requires(dependencyRegistry);
    }

    @Override
    public void configure(UpdatableInjectionContext injectionContext) {
        super.configure(injectionContext);

        // applications using this module must provide a 'host' config property (used to construct the callback URL)
        getRequiredProperty(injectionContext, "host");

        // applications using this module must provide an OAuth client id and secret
        String clientId = getRequiredProperty(injectionContext, "gmailOAuthClientId");
        String clientSecret = getRequiredProperty(injectionContext, "gmailOAuthClientSecret");

        // applications using this module must inject a DataStoreFactory and HttpTransport instance
        DataStoreFactory dataStoreFactory = getRequredDependency(injectionContext, DataStoreFactory.class);
        HttpTransport httpTransport = getRequredDependency(injectionContext, HttpTransport.class);

        JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
        Collection<String> scopes = Collections.singleton(GmailScopes.GMAIL_COMPOSE);

        try {
            GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(httpTransport, jsonFactory,
                    clientId, clientSecret, scopes).setDataStoreFactory(dataStoreFactory).build();
            injectionContext.inject(flow).named("gmailAuthorizationCodeFlow").as(GoogleAuthorizationCodeFlow.class);
        } catch (IOException e) {
            throw new ConfigurationException(e, "Couldn't initialize GoogleAuthorizationCodeFlow");
        }
    }

    @Override
    public void start(UpdatableInjectionContext injectionContext) {
        super.start(injectionContext);
        addRoutes(injectionContext);
    }

    /**
     * Add the routes required by this module.
     *
     * @param injectionContext the injection context to get the router from.
     */
    private void addRoutes(InjectionContext injectionContext) {
        Router router = injectionContext.get(Router.class);

        // optional config property to override the root path of the gmail setup routes (to prevent clashes)
        String gmailAdminRootPath = getOptionalProperty(injectionContext, "gmailAdminRootPath", "/admin/gmail");

        router.get(String.format("%s/setup", gmailAdminRootPath), GmailAdminController.class, "setup",
                "gmail.admin.setup");
        router.get(String.format("%s/setup/oauth2callback", gmailAdminRootPath), GmailAdminController.class,
                "oauthCallback", "gmail.admin.oauthCallback");
    }

    /**
     * Get a required string property from the injection context.
     *
     * @param injectionContext the injection context to get the property from.
     * @param propertyName the name of the property.
     * @return
     */
    private String getRequiredProperty(InjectionContext injectionContext, String propertyName) {
        String property = injectionContext.get(String.class, propertyName);
        if (StringUtils.isBlank(property)) {
            throw new ConfigurationException(
                    "Property `%s` not found. Did you forget to add it to application.properties?", propertyName);
        }
        return property;
    }

    /**
     * Get an optional string property from the injection context.
     *
     * @param injectionContext the injection context to get the property from.
     * @param propertyName the name of the property.
     * @param defaultValue the default value to use if the property is not present.
     * @return the property value, or the default value if not found.
     */
    private String getOptionalProperty(InjectionContext injectionContext, String propertyName,
            String defaultValue) {
        String property = injectionContext.get(String.class, propertyName);
        if (StringUtils.isBlank(property)) {
            Logger.info("No value found for property: %s, using default value: %s", propertyName, defaultValue);
            property = defaultValue;
        }
        return property;
    }

    /**
     * Get a required dependency from the injection context.
     *
     * @param injectionContext the injection context to get the depdency from.
     * @param type the type of the dependency.
     * @param <T> the type of the return type.
     * @return the dependency.
     */
    private <T> T getRequredDependency(InjectionContext injectionContext, Class<T> type) {
        T dependency = injectionContext.get(type);
        if (dependency == null) {
            throw new ConfigurationException(
                    "Required dependency of type `%s` not found. Did you forget to inject it?", type.getName());
        }
        return dependency;
    }

}