Đăng nhập ứng dụng, Website bằng tài khoản Google.

Giới thiệu

Trong trường hợp khi truy cập 1 website hay ứng dụng ta thường thấy có chức năng đăng nhập mà không cần sử dụng tài khoản của ứng dụng, web đó. Ví dụ trên trang codelearn

Tạo ứng dụng Google+ để đăng nhập với google

Truy cập Google Cloud Platform để tạo project. Chọn Edit để thiết lập ProjectID Điền đầy đủ thông tin và ấn Create Sau khi tạo project xong kích hoạt Google+ API bằng cách: Nhập Google+ API vào ô search Enable Google+ API Sau khi enable dịch vụ thực hiện các bước sau để lấy thông tin: CONFIGURE CONSENT SCREEN: Tạo mới OAuth client ID

*ClientID và Client Secret sẽ dùng để cấu hình bên Java Application hoặc Java Web App.

Tạo ứng dụng Java Web

Trước hết mình đang sử dụng server tomcat v8.5 và project cấu hình về Maven. Trong file pom.xml them dependency sau:

    <!-- https://mvnrepository.com/artifact/com.google.api-client/google-api-client -->
	<dependency>
		<groupId>com.google.api-client</groupId>
		<artifactId>google-api-client</artifactId>
		<version>1.32.1</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/com.google.http-client/google-http-client -->
	<dependency>
		<groupId>com.google.http-client</groupId>
		<artifactId>google-http-client</artifactId>
		<version>1.39.2</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/com.google.http-client/google-http-client-gson -->
	<dependency>
		<groupId>com.google.http-client</groupId>
		<artifactId>google-http-client-gson</artifactId>
		<version>1.39.2</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/com.google.http-client/google-http-client-apache-v2 -->
	<dependency>
		<groupId>com.google.http-client</groupId>
		<artifactId>google-http-client-apache-v2</artifactId>
		<version>1.39.2</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/com.google.http-client/google-http-client -->
	<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore -->
	<dependency>
		<groupId>org.apache.httpcomponents</groupId>
		<artifactId>httpcore</artifactId>
		<version>4.4.14</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
	<dependency>
		<groupId>org.apache.httpcomponents</groupId>
		<artifactId>httpclient</artifactId>
		<version>4.5.13</version>
	</dependency>
	<dependency>
		<groupId>jstl</groupId>
		<artifactId>jstl</artifactId>
		<version>1.2</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
	<dependency>
		<groupId>javax.servlet</groupId>
		<artifactId>javax.servlet-api</artifactId>
		<version>4.0.1</version>
		<scope>provided</scope>
	</dependency>
	<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/fluent-hc -->
	<dependency>
		<groupId>org.apache.httpcomponents</groupId>
		<artifactId>fluent-hc</artifactId>
		<version>4.5.13</version>
	</dependency>	

Tạo 1 file GoogleUtils.java

import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken;
import com.google.api.client.googleapis.auth.oauth2.GoogleIdTokenVerifier;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;

import java.io.IOException;

import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.fluent.Form;
import org.apache.http.client.fluent.Request;
import com.google.gson.Gson;
import com.google.gson.JsonObject;

import auth.GooglePoJo;

public class GoogleUtils {
	private final static String GOOGLE_CLIENT_ID = "YOUR_GOOGLE_CLIENT_ID";
	private final static String GOOGLE_CLIENT_SECRET = "YOUR_GOOGLE_CLIENT_SECRET"
	private final static String GOOGLE_REDIRECT_URI = "http://localhost:8080/<project-name>/login-google";
	private final static String GOOGLE_GRANT_TYPE = "authorization_code";
	private final static String GOOGLE_LINK_GET_TOKEN = "https://accounts.google.com/o/oauth2/token";
	private final static String GOOGLE_LINK_GET_USER_INFO = 		"https://www.googleapis.com/oauth2/v1/userinfo?access_token=";

	private GoogleUtils() {

	}

	public static String getToken(final String code) throws ClientProtocolException,IOException  {
		String response = Request.Post(GOOGLE_LINK_GET_TOKEN)
				.bodyForm(Form.form().add("client_id", GOOGLE_CLIENT_ID)
						.add("client_secret", GOOGLE_CLIENT_SECRET)
						.add("redirect_uri", GOOGLE_REDIRECT_URI)
						.add("code", code).add("grant_type", GOOGLE_GRANT_TYPE)
						.build())
				.execute().returnContent().asString();
		JsonObject jobj = new Gson().fromJson(response, JsonObject.class);
		String accessToken = jobj.get("access_token").toString().replaceAll("\"", "");
		return accessToken;
	}
	public static GooglePoJo getUserInfo(final String accessToken) throws ClientProtocolException, 
IOException {
		String link = GOOGLE_LINK_GET_USER_INFO + accessToken;
		String response = Request.Get(link).execute().returnContent().asString();
		GooglePoJo googlePojo = new Gson().fromJson(response, GooglePoJo.class);
		System.out.println(googlePojo);
		return googlePojo;
	}
}

Tạo 1 file GooglePoJo.java

public class GooglePoJo {
 	private String id;
  	private String email;
 	private boolean verified_email;
  	private String name;
  	private String given_name;
  	private String family_name;
  	private String link;
  	private String picture;
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public boolean isVerified_email() {
		return verified_email;
	}
	public void setVerified_email(boolean verified_email) {
		this.verified_email = verified_email;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
	this.name = name;
	}
	public String getGiven_name() {
		return given_name;
	}
	public void setGiven_name(String given_name) {
		this.given_name = given_name;
	}
	public String getFamily_name() {
		return family_name;
	}
	public void setFamily_name(String family_name) {
		this.family_name = family_name;
	}
	public String getLink() {
		return link;
	}
	public void setLink(String link) {
		this.link = link;
	}
	public String getPicture() {
		return picture;
	}
	public void setPicture(String picture) {
		this.picture = picture;
	}
	public GooglePoJo() {
	// TODO Auto-generated constructor stub
	}
	public GooglePoJo(String id, String email, boolean verified_email, String name, String given_name,
		String family_name, String link, String picture) {
		super();
		this.id = id;
		this.email = email;
		this.verified_email = verified_email;
		this.name = name;
		this.given_name = given_name;
		this.family_name = family_name;
		this.link = link;
		this.picture = picture;
	} }

Tạo 1 file Servlet

package controller;
	
import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.http.client.fluent.Request;

import auth.GooglePoJo;
import utils.GoogleUtils;

/**
* Servlet implementation class LoginGoogleServlet
*/
@WebServlet("/login-google")
public class LoginGoogleServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	
	/**
	* @see HttpServlet#HttpServlet()
	*/
	public LoginGoogleServlet() {
		super();
		// TODO Auto-generated constructor stub
	}

	/**
	* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	*/
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, 
IOException {
		// TODO Auto-generated method stub
		String code = request.getParameter("code");
		if (code == null || code.isEmpty()) {
			RequestDispatcher dis = request.getRequestDispatcher("/views/index.jsp");
			dis.forward(request, response);
			} else {
			String accessToken = GoogleUtils.getToken(code);
			GooglePoJo googlePojo = GoogleUtils.getUserInfo(accessToken);
			request.setAttribute("pojo", googlePojo);
			RequestDispatcher dis = request.getRequestDispatcher("/views/google.jsp");
			dis.forward(request, response);
			}
	}

	/**
	* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	*/
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, 
IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

Tạo file index.jsp và google.jsp như sau: -index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<a href="https://accounts.google.com/o/oauth2/auth?
	scope=email&redirect_uri=YOUR_REDIRECT_URI&
	response_type=code&client_id=YOUR_GOOGLE_CLIENT_ID
	&approval_prompt=force">Sign in with Google
</a>
</body>
</html> -google.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h1>${pojo.id }</h1>
	<h1>${pojo.email }</h1>

</body>
</html>

Link tham khảo: Staring With API

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