Let’ s Build |> 使用 Elixir，Phoenix 和 React 打造克隆版的 Slack (part 3 — Frontend Authentication)
上一篇博文中我们已经实现用户认证相关的API接口，接下来我们添加前端的登录注册界面并实现用户认证。
关于样式用法的备注：在React项目中，我喜欢作用域在组件内的样式，也就是将CSS定义在组件所属的js文件中，并使用行内样式。我将全局CSS（比如Twitter Bootstrap）只用作基本的页面元素样式。
在JS文件中有许多使用CSS的方法，比如 CSS Modules,Radium,Styled-Components或者直接使用JavaScript对象。在这个项目中我们采用Aphrodite
这次提交，可以看到我们是怎么为项目配置全局样式的。下载最新版的bootstrap和font-awesome，创建index.css文件写入一些基本样式。并将其全部import到我们项目的入口文件中。
我们需要在App组件中添加两个新的路由，一个是登录/login,另一个是注册/signup
sling/web/src/containers/App/index.js
// @flow
import React,{ Component } from 'react';
import { browserRouter,Match,Miss } from 'react-router';
import Home from '../Home';
import NotFound from '../../components/NotFound';
import Login from '../Login';
import Signup from '../Signup';
class App extends Component {
render() {
return (
<browserRouter>
<div style={{ display: 'flex',flex: '1' }}>
<Match exactly pattern="/" component={Home} />
<Match pattern="/login" component={Login} />
<Match pattern="/signup" component={Signup} />
<Miss component={NotFound} />
</div>
</browserRouter>
);
}
}
export default App;
Login和Signup组件比较相似，都包含一些基本的布局，并且都是从子表单中传递数据到组件的action中提交。
sling/web/src/containers/Signup/index.js
// @flow
import React,{ Component,PropTypes } from 'react';
import { connect } from 'react-redux';
import { signup } from '../../actions/session';
import SignupForm from '../../components/SignupForm';
import Navbar from '../../components/Navbar';
type Props = {
signup: () => void,}
class Signup extends Component {
static contextTypes = {
router: PropTypes.object,}
props: Props
handleSignup = data => this.props.signup(data,this.context.router);
render() {
return (
<div style={{ flex: '1' }}>
<Navbar />
<SignupForm onSubmit={this.handleSignup} />
</div>
);
}
}
export default connect(null,{ signup })(Signup);
sling/web/src/containers/Login/index.js
// @flow
import React,PropTypes } from 'react';
import { connect } from 'react-redux';
import { login } from '../../actions/session';
import LoginForm from '../../components/LoginForm';
import Navbar from '../../components/Navbar';
type Props = {
login: () => void,}
class Login extends Component {
static contextTypes = {
router: PropTypes.object,}
props: Props
handleLogin = data => this.props.login(data,this.context.router);
render() {
return (
<div style={{ flex: '1' }}>
<Navbar />
<LoginForm onSubmit={this.handleLogin} />
</div>
);
}
}
export default connect(null,{ login })(Login);
如你所见，我们引入NavBar组件，目的是让我们的页面更好看一些。
sling/web/src/components/Navbar/index.js
// @flow
import React from 'react';
import { Link } from 'react-router';
import { css,StyleSheet } from 'aphrodite';
const styles = StyleSheet.create({
navbar: {
display: 'flex',alignItems: 'center',padding: '0 1rem',height: '70px',background: '#fff',BoxShadow: '0 1px 1px rgba(0,.1)',},link: {
color: '#555459',fontSize: '22px',fontWeight: 'bold',':hover': {
textdecoration: 'none',':focus': {
textdecoration: 'none',});
const Navbar = () =>
<nav className={css(styles.navbar)}>
<Link to="/" className={css(styles.link)}>Sling</Link>
</nav>;
export default Navbar;
react-router使用说明：react项目中，以前我们使用react-router-redux,它在action中采用dispatch(push(/login))方式实现路由跳转。但是在v4版本的react-router中已经没有这个功能，为了实现上述跳转功能我们必须传递参数this.context.router到action中实现跳转。
Signup组件与Login组件非常相近，SignupForm和LoginForm也非常相似。
sling/web/src/components/SignupForm/index.js
// @flow
import React,{ Component } from 'react';
import { Field,reduxForm } from 'redux-form';
import { Link } from 'react-router';
import { css,StyleSheet } from 'aphrodite';
import Input from '../Input';
const styles = StyleSheet.create({
card: {
maxWidth: '500px',padding: '3rem 4rem',margin: '2rem auto',});
type Props = {
onSubmit: () => void,submitting: boolean,handleSubmit: () => void,}
class SignupForm extends Component {
props: Props
handleSubmit = data => this.props.onSubmit(data);
render() {
const { handleSubmit,submitting } = this.props;
return (
<form
className={`card ${css(styles.card)}`}
onSubmit={handleSubmit(this.handleSubmit)}
>
<h3 style={{ marginBottom: '2rem',textAlign: 'center' }}>Create an account</h3>
<Field
name="username"
type="text"
component={Input}
placeholder="Username"
className="form-control"
/>
<Field
name="email"
type="email"
component={Input}
placeholder="Email"
className="form-control"
/>
<Field
name="password"
type="password"
component={Input}
placeholder="Password"
className="form-control"
/>
<button
type="submit"
disabled={submitting}
className="btn btn-block btn-primary"
>
{submitting ? 'Submitting...' : 'Sign up'}
</button>
<hr style={{ margin: '2rem 0' }} />
<Link to="/login" className="btn btn-block btn-secondary">
Login to your account
</Link>
</form>
);
}
}
const validate = (values) => {
const errors = {};
if (!values.username) {
errors.username = 'required';
}
if (!values.email) {
errors.email = 'required';
}
if (!values.password) {
errors.password = 'required';
} else if (values.password.length < 6) {
errors.password = 'Minimum of 6 characters';
}
return errors;
};
export default reduxForm({
form: 'signup',validate,})(SignupForm);
sling/web/src/components/LoginForm/index.js
// @flow
import React,}
class LoginForm extends Component {
props: Props
handleSubmit = data => this.props.onSubmit(data);
render() {
const { handleSubmit,textAlign: 'center' }}>Login to Sling</h3>
<Field name="email" type="text" component={Input} placeholder="Email" />
<Field name="password" type="password" component={Input} placeholder="Password" />
<button
type="submit"
disabled={submitting}
className="btn btn-block btn-primary"
>
{submitting ? 'Logging in...' : 'Login'}
</button>
<hr style={{ margin: '2rem 0' }} />
<Link to="/signup" className="btn btn-block btn-secondary">
Create a new account
</Link>
</form>
);
}
}
const validate = (values) => {
const errors = {};
if (!values.email) {
errors.email = 'required';
}
if (!values.password) {
errors.password = 'required';
}
return errors;
};
export default reduxForm({
form: 'login',})(LoginForm);
上述表单组件均采用redux-form,这也是我们能够获取输入数据的原因。this.props.handleSubmit是redux-form提供的特定属性,使我们能够基于name从Field组件中获取输入的数据。submittingprop也是redux-form提供的特定prop，其值为布尔型，onSubmit被触发时submitting会被设为true。
自定义Field 组件，包含input以及显示error功能。
sling/web/src/components/Input/index.js
// @flow
import React from 'react';
type Props = {
input: Object,label?: string,type?: string,placeholder?: string,style?: Object,Meta: Object,}
const Input = ({ input,label,type,placeholder,style,Meta }: Props) =>
<div style={{ marginBottom: '1rem' }}>
{label && <label htmlFor={input.name}>{label}</label>}
<input
{...input}
type={type}
placeholder={placeholder}
className="form-control"
style={style && style}
/>
{Meta.touched && Meta.error &&
<div style={{ fontSize: '85%',color: 'rgb(255,59,48)' }}>{Meta.error}</div>
}
</div>;
export default Input;
Signup组件和Login组件需要从session.js中import action
sling/web/src/actions/session.js
import { reset } from 'redux-form';
import api from '../api';
function setCurrentUser(dispatch,response) {
localStorage.setItem('token',JSON.stringify(response.Meta.token));
dispatch({ type: 'AUTHENTICATION_SUCCESS',response });
}
export function login(data,router) {
return dispatch => api.post('/sessions',data)
.then((response) => {
setCurrentUser(dispatch,response);
dispatch(reset('login'));
router.transitionTo('/');
});
}
export function signup(data,router) {
return dispatch => api.post('/users',response);
dispatch(reset('signup'));
router.transitionTo('/');
});
}
export function logout(router) {
return dispatch => api.delete('/sessions')
.then(() => {
localStorage.removeItem('token');
dispatch({ type: 'logoUT' });
router.transitionTo('/login');
});
}
为使redux action方便发送http请求，通常将其封装在API工具文件中,我们也遵照规范实现。
sling/web/src/api/index.js
const API = process.env.REACT_APP_API_URL;
function headers() {
const token = JSON.parse(localStorage.getItem('token'));
return {
Accept: 'application/json','Content-Type': 'application/json',Authorization: `Bearer: ${token}`,};
}
function parseResponse(response) {
return response.json().then((json) => {
if (!response.ok) {
return Promise.reject(json);
}
return json;
});
}
function queryString(params) {
const query = Object.keys(params)
.map(k => `${encodeURIComponent(k)}=${encodeURIComponent(params[k])}`)
.join('&');
return `${query.length ? '?' : ''}${query}`;
}
export default {
fetch(url,params = {}) {
return fetch(`${API}${url}${queryString(params)}`,{
method: 'GET',headers: headers(),})
.then(parseResponse);
},post(url,data) {
const body = JSON.stringify(data);
return fetch(`${API}${url}`,{
method: 'POST',body,patch(url,{
method: 'PATCH',delete(url) {
return fetch(`${API}${url}`,{
method: 'DELETE',};
使用这些helper函数，在redux action中只需调用api.post(/url,data)然后处理返回结果即可。另，每次请求header中均已包含来自localStorage的jwt token。
create-react-app 支持.env环境变量。我们在根路径下创建.env文件,存入REACT_APP_*=xxx,运行时即可通过process.env.REACT_APP_*读取值，看下我们的实现。
REACT_APP_API_URL=http://localhost:4000/api
当用户注册或登录成功，action会发起AUTHENTICATION_SUCCESS。我们需要创建reducer来监听action分发出的数据并将其存储到redux state中。
sling/web/src/reducers/session.js
const initialState = {
isAuthenticated: false,currentUser: {},};
export default function (state = initialState,action) {
switch (action.type) {
case 'AUTHENTICATION_SUCCESS':
return {
...state,isAuthenticated: true,currentUser: action.response.data,};
case 'logoUT':
return {
...state,isAuthenticated: false,};
default:
return state;
}
}
然后把session reducer放入总的reducer中，
sling/web/src/reducers/index.js
import { combineReducers } from 'redux';
import { reducer as form } from 'redux-form';
import session from './session';
const appReducer = combineReducers({
form,session,});
export default function (state,action) {
if (action.type === 'logoUT') {
return appReducer(undefined,action);
}
return appReducer(state,action);
}
目前session reducer 处理AUTHENTICATION_SUCCESS 和logoUT两种action,并改变了isAuthenticated和currentUser的值。接下来我们将redux state connect到Home组件中，当用户登录时就可以看到当前用户。
sling/web/src/containers/Home/index.js
// @flow
import React,PropTypes } from 'react';
import { connect } from 'react-redux';
import { Link } from 'react-router';
import { logout } from '../../actions/session';
import Navbar from '../../components/Navbar';
type Props = {
logout: () => void,currentUser: Object,isAuthenticated: boolean,}
class Home extends Component {
static contextTypes = {
router: PropTypes.object,}
props: Props
handlelogout = () => this.props.logout(this.context.router);
render() {
const { currentUser,isAuthenticated } = this.props;
return (
<div style={{ flex: '1' }}>
<Navbar />
<ul>
<li><Link to="/login">Login</Link></li>
<li><Link to="/signup">Signup</Link></li>
</ul>
{isAuthenticated &&
<div>
<span>{currentUser.username}</span>
<button type="button" onClick={this.handlelogout}>logout</button>
</div>
}
</div>
);
}
}
export default connect(
state => ({
isAuthenticated: state.session.isAuthenticated,currentUser: state.session.currentUser,}),{ logout }
)(Home);
到目前为止，当用户登录后，我会显示当前用户的username。并且添加link,可直接路由到注册和登录页面。以上只是理论实现，当你尝试注册时你会发现报错No ‘Access-Control-Allow-Origin’ header is present on the requested resource.这是一个http 请求跨域的错误，我们需要在server端处理它。
为处理这个跨域错误，我们需要安装第三方库 {:cors_plug,"~> 1.1"},然后在sling/api/sling/endpoint.ex中添加配置。
#above content
plug CORSPlug
plug Sling.Router
end
最后重启Phoenix Server即可，这样就解决了跨域问题。
目前，用户可以登录成功，但是当刷新页面时就会被剔出。接下来我们就解决这个问题。
保存用户会话（Persisting User Sessions）
我们在Server端已经实现/sessions/refresh接口。新建一个authenticateaction当用户刷新页面时调用。显然这个调用需要放在App组件中，因为它是我们的根组件，也就是页面刷新会首先加载这个组件。
sling/web/src/containers/App/index.js
// @flow
import React,Miss } from 'react-router';
import { connect } from 'react-redux';
import { authenticate } from '../../actions/session';
import Home from '../Home';
import NotFound from '../../components/NotFound';
import Login from '../Login';
import Signup from '../Signup';
type Props = {
authenticate: () => void,}
class App extends Component {
componentDidMount() {
const token = localStorage.getItem('token');
if (token) {
this.props.authenticate();
}
}
props: Props
render() {
return (
<browserRouter>
<div style={{ display: 'flex',flex: '1' }}>
<Match exactly pattern="/" component={Home} />
<Match pattern="/login" component={Login} />
<Match pattern="/signup" component={Signup} />
<Miss component={NotFound} />
</div>
</browserRouter>
);
}
}
export default connect(
null,{ authenticate }
)(App);
组件的钩子函数componentDidMount会首先检查localStorage中的token。若token存在就会调用authenticate函数请server端认证用户。
sling/web/src/actions/session.js
export function authenticate() {
return dispatch => api.post('/sessions/refresh')
.then((response) => {
setCurrentUser(dispatch,response);
})
.catch(() => {
localStorage.removeItem('token');
window.location = '/login';
});
}
api.post(‘/sessions/refresh’)没有发送任何数据，其实默认在header中包含token数据。所以Guardian才会找到token并实现用户认证。若认证失败就会从localStorage移除token,并跳转到登录页面。
路由保护（Protecting Routes）
在我们的APP中有这样的要求，登录用户才能看到home页面。未登录的用户只能看到注册和登录页面，
前面我们已经实现了基本的路由跳转。但是React-router v4还提供了一些新的功能。比如可以直接渲染<Redirect/> 组件。我们可以向无状态组件中传入参数然后决定是渲染<Match />组件还是渲染<Redirect />组件。官方文档
下面我们实现<MatchAuthenticated /> 和 <RedirectAuthenticated />两个stateless 组件
sling/web/src/components/MatchAuthenticated/index.js
// @flow
import React from 'react';
import { Match,Redirect } from 'react-router';
type Props = {
component: any,pattern: string,exactly?: boolean,willAuthenticate: boolean,}
const MatchAuthenticated = ({
pattern,exactly,isAuthenticated,willAuthenticate,component: Component,}: Props) =>
<Match
exactly={exactly}
pattern={pattern}
render={(props) => {
if (isAuthenticated) { return <Component {...props} />; }
if (willAuthenticate) { return null; }
if (!willAuthenticate && !isAuthenticated) { return <Redirect to={{ pathname: '/login' }} />; }
return null;
}}
/>;
export default MatchAuthenticated;
sling/web/src/components/RedirectAuthenticated/index.js
// @flow
import React from 'react';
import { Match,}
const RedirectAuthenticated = ({
pattern,}: Props) =>
<Match
exactly={exactly}
pattern={pattern}
render={(props) => {
if (isAuthenticated) { return <Redirect to={{ pathname: '/' }} />; }
if (willAuthenticate) { return null; }
if (!willAuthenticate && !isAuthenticated) { return <Component {...props} />; }
return null;
}}
/>;
export default RedirectAuthenticated;
在构建以上组件的过程中，我们发现需要传递一些像willAuthenticate这样的参数以保证路径跳转正常运行。以willAuthenticate为例，当认证请求已经发起，但是认证是否成功还未知，这种中间状态就需要willAuthenticate=true来处理，以保证不会出现错误的页面跳转。
现在我们来修改App组件，使用自定义组件替换React-router的<Match />。
sling/web/src/containers/App/index.js
// @flow
import React,Miss } from 'react-router';
import { connect } from 'react-redux';
import { authenticate,unauthenticate } from '../../actions/session';
import Home from '../Home';
import NotFound from '../../components/NotFound';
import Login from '../Login';
import Signup from '../Signup';
import MatchAuthenticated from '../../components/MatchAuthenticated';
import RedirectAuthenticated from '../../components/RedirectAuthenticated';
type Props = {
authenticate: () => void,unauthenticate: () => void,}
class App extends Component {
componentDidMount() {
const token = localStorage.getItem('token');
if (token) {
this.props.authenticate();
} else {
this.props.unauthenticate();
}
}
props: Props
render() {
const { isAuthenticated,willAuthenticate } = this.props;
const authProps = { isAuthenticated,willAuthenticate };
return (
<browserRouter>
<div style={{ display: 'flex',flex: '1' }}>
<MatchAuthenticated exactly pattern="/" component={Home} {...authProps} />
<RedirectAuthenticated pattern="/login" component={Login} {...authProps} />
<RedirectAuthenticated pattern="/signup" component={Signup} {...authProps} />
<Miss component={NotFound} />
</div>
</browserRouter>
);
}
}
export default connect(
state => ({
isAuthenticated: state.session.isAuthenticated,willAuthenticate: state.session.willAuthenticate,{ authenticate,unauthenticate }
)(App);
我们已经替换掉Match组件，并传递必要的认证参数。最后还需要添加一个unauthenticate action，当认证失败时用于改变willAuthenticate的值。
sling/web/src/actions/session.js
export function authenticate() {
return (dispatch) => {
dispatch({ type: 'AUTHENTICATION_REQUEST' });
return api.post('/sessions/refresh')
.then((response) => {
setCurrentUser(dispatch,response);
})
.catch(() => {
localStorage.removeItem('token');
window.location = '/login';
});
};
}
export const unauthenticate = () => ({ type: 'AUTHENTICATION_FAILURE' });
在认证的流程中，首先发起 AUTHENTICATION_REQUEST 开始认证，执行完setCurrentUser函数发起AUTHENTICATION_SUCCESS说明认证成功，认证失败则会发起AUTHENTICATION_FAILURE。根据这个流程我们相应的修正 session reducer。
sling/web/src/reducers/session.js
const initialState = {
isAuthenticated: false,willAuthenticate: true,action) {
switch (action.type) {
case 'AUTHENTICATION_REQUEST':
return {
...state,};
case 'AUTHENTICATION_SUCCESS':
return {
...state,willAuthenticate: false,};
case 'AUTHENTICATION_FAILURE':
return {
...state,};
default:
return state;
}
}
这部分就此结束，下一篇将会进入到我们应用的核心：允许用户建立聊天室。
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