javascript - 将 Apollo Client 与 NextJS 一起使用时服务器端渲染数据?
问题描述
我的组件目前在浏览器上补水,这是我想避免的。当您访问该链接时,我希望它与它需要显示的所有数据一起预先水合,即在服务器上呈现。目前,该组件如下所示:
import { graphql } from "react-apollo";
import gql from 'graphql-tag';
import withData from "../../apollo/with-data";
import getPostsQuery from '../../apollo/schemas/getPostsQuery.graphql';
const renderers = {
paragraph: (props) => <Typography variant="body2" gutterBottom {...props} />,
};
const GET_POSTS = gql`${getPostsQuery}`;
const PostList = ({data: {error, loading, posts}}) => {
let payload;
if(error) {
payload = (<div>There was an error!</div>);
} else if(loading) {
payload = (<div>Loading...</div>);
} else {
payload = (
<>
{posts.map((post) => (
<div>
<div>{post.title}</div>
<div>{post.body}</div>
</div>
))}
</>
);
}
return payload;
};
export default withData(graphql(GET_POSTS)(PostList));
如您所见,它Loading...
首先在后台获取帖子时显示文本。我不想要那个。我希望它已经与获取的数据预先水合。
作为参考,我的 Apollo 初始化如下所示:
// apollo/with-data.js
import React from "react";
import PropTypes from "prop-types";
import { ApolloProvider, getDataFromTree } from "react-apollo";
import initApollo from "./init-apollo";
export default ComposedComponent => {
return class WithData extends React.Component {
static displayName = `WithData(${ComposedComponent.displayName})`;
static propTypes = {
serverState: PropTypes.object.isRequired
};
static async getInitialProps(ctx) {
const headers = ctx.req ? ctx.req.headers : {};
let serverState = {};
// Evaluate the composed component's getInitialProps()
let composedInitialProps = {};
if (ComposedComponent.getInitialProps) {
composedInitialProps = await ComposedComponent.getInitialProps(ctx);
}
// Run all graphql queries in the component tree
// and extract the resulting data
if (!process.browser) {
const apollo = initApollo(headers);
// Provide the `url` prop data in case a graphql query uses it
const url = { query: ctx.query, pathname: ctx.pathname };
// Run all graphql queries
const app = (
<ApolloProvider client={apollo}>
<ComposedComponent url={url} {...composedInitialProps} />
</ApolloProvider>
);
await getDataFromTree(app);
// Extract query data from the Apollo's store
const state = apollo.getInitialState();
serverState = {
apollo: {
// Make sure to only include Apollo's data state
data: state.data
}
};
}
return {
serverState,
headers,
...composedInitialProps
};
}
constructor(props) {
super(props);
this.apollo = initApollo(this.props.headers, this.props.serverState);
}
render() {
return (
<ApolloProvider client={this.apollo}>
<ComposedComponent {...this.props} />
</ApolloProvider>
);
}
};
};
// apollo/init-apollo.js
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloClient } from 'apollo-client';
import { ApolloLink } from 'apollo-link';
import { onError } from 'apollo-link-error';
import { HttpLink } from 'apollo-link-http';
import fetch from 'isomorphic-fetch';
let apolloClient = null;
// Polyfill fetch() on the server (used by apollo-client)
if (!process.browser) {
global.fetch = fetch;
}
const create = (headers, initialState) => new ApolloClient({
initialState,
link: ApolloLink.from([
onError(({ graphQLErrors, networkError }) => {
if (graphQLErrors) {
graphQLErrors.forEach(({ message, locations, path }) => console.log(
`[GraphQL error]: Message: ${message}, Location: ${locations}, Path: ${path}`,
));
}
if (networkError) console.log(`[Network error]: ${networkError}`);
}),
new HttpLink({
// uri: 'https://dev.schandillia.com/graphql',
uri: process.env.CMS,
credentials: 'same-origin',
}),
]),
ssrMode: !process.browser, // Disables forceFetch on the server (so queries are only run once)
cache: new InMemoryCache(),
});
export default function initApollo(headers, initialState = {}) {
// Make sure to create a new client for every server-side request so that data
// isn't shared between connections (which would be bad)
if (!process.browser) {
return create(headers, initialState);
}
// Reuse client on the client-side
if (!apolloClient) {
apolloClient = create(headers, initialState);
}
return apolloClient;
}
更新:我尝试将https://github.com/zeit/next.js/tree/canary/examples/with-apollo上的官方 withApollo 示例合并到我的项目中,但它在以下位置引发了一个不变的错误getDataFromTree()
:
元素类型无效:应为字符串(用于内置组件)或类/函数(用于复合组件)但得到:未定义。
/init/apollo.js
对于、/components/blog/PostList.jsx
和/pages/Blog/jsx
文件,我使用了与示例 repo 中完全相同的代码。在我的具体情况下,唯一的区别是我有一个明确_app.jsx
的内容如下:
/* eslint-disable max-len */
import '../static/styles/fonts.scss';
import '../static/styles/style.scss';
import '../static/styles/some.css';
import CssBaseline from '@material-ui/core/CssBaseline';
import { ThemeProvider } from '@material-ui/styles';
import jwt from 'jsonwebtoken';
import withRedux from 'next-redux-wrapper';
import App, {
Container,
} from 'next/app';
import Head from 'next/head';
import React from 'react';
import { Provider } from 'react-redux';
import makeStore from '../reducers';
import mainTheme from '../themes/main-theme';
import getSessIDFromCookies from '../utils/get-sessid-from-cookies';
import getLanguageFromCookies from '../utils/get-language-from-cookies';
import getUserTokenFromCookies from '../utils/get-user-token-from-cookies';
import removeFbHash from '../utils/remove-fb-hash';
class MyApp extends App {
static async getInitialProps({ Component, ctx }) {
let userToken;
let sessID;
let language;
if (ctx.isServer) {
ctx.store.dispatch({ type: 'UPDATEIP', payload: ctx.req.headers['x-real-ip'] });
userToken = getUserTokenFromCookies(ctx.req);
sessID = getSessIDFromCookies(ctx.req);
language = getLanguageFromCookies(ctx.req);
const dictionary = require(`../dictionaries/${language}`);
ctx.store.dispatch({ type: 'SETLANGUAGE', payload: dictionary });
if(ctx.res) {
if(ctx.res.locals) {
if(!ctx.res.locals.authenticated) {
userToken = null;
sessID = null;
}
}
}
if (userToken && sessID) { // TBD: validate integrity of sessID
const userInfo = jwt.verify(userToken, process.env.JWT_SECRET);
ctx.store.dispatch({ type: 'ADDUSERINFO', payload: userInfo });
}
ctx.store.dispatch({ type: 'ADDSESSION', payload: sessID }); // component will be able to read from store's state when rendered
}
const pageProps = Component.getInitialProps ? await Component.getInitialProps(ctx) : {};
return { pageProps };
}
componentDidMount() {
// Remove the server-side injected CSS.
const jssStyles = document.querySelector('#jss-server-side');
if (jssStyles) {
jssStyles.parentNode.removeChild(jssStyles);
}
// Register serviceWorker
if ('serviceWorker' in navigator) { navigator.serviceWorker.register('/serviceWorker.js'); }
// Handle FB's ugly redirect URL hash
removeFbHash(window, document);
}
render() {
const { Component, pageProps, store } = this.props;
return (
<Container>
<Head>
<meta name="viewport" content="user-scalable=0, initial-scale=1, minimum-scale=1, width=device-width, height=device-height, shrink-to-fit=no" />
<meta httpEquiv="X-UA-Compatible" content="IE=edge,chrome=1" />
<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png" />
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png" />
<link rel="icon" type="image/png" sizes="194x194" href="/favicon-194x194.png" />
<link rel="icon" type="image/png" sizes="192x192" href="/android-chrome-192x192.png" />
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png" />
<link rel="manifest" href="/site.webmanifest" />
<link rel="mask-icon" href="/safari-pinned-tab.svg" color="#663300" />
<meta name="msapplication-TileColor" content="#da532c" />
<meta name="msapplication-TileImage" content="/mstile-144x144.png" />
</Head>
<ThemeProvider theme={mainTheme}>
{/* CssBaseline kickstart an elegant, consistent, and simple baseline to build upon. */}
<CssBaseline />
<Provider store={store}>
<Component {...pageProps} />
</Provider>
</ThemeProvider>
</Container>
);
}
}
export default withRedux(makeStore)(MyApp);
摆脱这个文件不是一个选项,因为这是我处理一些预加载 cookie 逻辑的地方。
供参考的 repo 位于https://github.com/amitschandillia/proost/tree/master/web
解决方案
使用 Next.js 和 Apollo 时,您需要实现 2 个关键目标:SSR 和缓存网络数据。两者兼顾是一个艰难的平衡。但这是可能的。
这样做的方法是:
- 在您的 getInitialProps 函数中,使用 apolloclient 获取在页面加载时应该可见的数据。如果操作正确,数据将与 HTML ie (SSR) 一起检索,并且在初始页面加载时不会显示烦人的加载程序。
现在,如果您有一些页面数据需要编辑、添加或删除,并且您希望在更改后更新页面而不刷新页面,那么以上是不够的。因为例如,如果您编辑数据,典型/推荐的 Apollo 方法是不做任何事情。阿波罗为您神奇地处理这一切。除了初始数据必须来自 apollo 缓存并且它必须有一个 Id 字段。现在,由于您直接从服务器加载了初始数据,很可能您没有从先前缓存的数据中读取数据。
因此,需要下面的第 2 步来启用数据更改时数据的自动刷新。
- 您知道要编辑的任何数据都必须来自缓存。所以不要试图使用来自 getInitialProps 的数据来填充这些数据。相反,您可以使用 useQuery 或其等效项来使用与 getInitialProps 查询相同的 Graphql 查询来查询相同的数据。现在发生的情况是,阿波罗这次没有从网络中获取数据,而是从服务器上一次查询中获取数据。然后突然之间,你看到的不是加载......到处都是,而是立即加载数据。然后在您编辑数据的同时,它也会立即更新,因为数据首先是从缓存中填充的,现在更新会更改缓存的数据并自动刷新您的页面。
这样,您就可以毫不费力地继续使用所有您喜欢的最新工具,例如 useQuery 和 getDataFromTree。
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