使用Gatsby.js，如何添加特定于路由的og：image元标记？

Question

我已经使用以下代码在React Helmet中为我的根路由设置了社交共享图像：

<meta property="og:url" content="https://foo.com" />
<meta property="og:image" content="https://myhostedimg.png" />

我有一个单独的路线，或盖茨比的“页面”，我想设置另一个og:image值。由于没有任何东西将og:image链接到og:url，我如何在我的页面上指定自定义og:url和og:image链接？

Answer 1

选项1：您可以在主layout文件中进行路径嗅探，然后将两个道具（一个用于图像，一个用于路径）传递到任何组件控制元数据。

在这个例子中，我的元数据组件名为metadata，但无论你的组件结构是什么，它都应该有意义：

// Setup react stuff
import React from 'react'
import PropTypes from 'prop-types'

// Get your custom gatsby components - assuming a pretty basic layout here
import Metadata from '../components/Metadata'
import Header from '../components/Header'
import Footer from '../components/Footer'

// Get images you want, also assuming you have these in a static folder and you don't need to use `gatsby-image` to get them
import ogImgOne from './og-img-one.png'
import ogImgTwo from './og-img-two.png'

// Setup template wrapper
export default class TemplateWrapper extends React.Component {

  // We want to render different base templates depending on the path the user hits
  render() {

    // Page 1
    if (this.props.location.pathname === "/") {
      return (
        <div className="page1">
          <Header />
          <Metadata ogImgSrc={ ogImgOne } 
                    ogUrl={ this.props.location.pathname } />
          <div>
            { this.props.children() }
          </div>
          <Footer />
        </div>
      )
    } 

    // Page 2
    if (this.props.location.pathname === "/page-2/") {
      return (
        <div className="page2">
          <Metadata ogImgSrc={ ogImgTwo } 
                    ogUrl={ this.props.location.pathname } />
          <Header />
          <div>
            { this.props.children() }
          </div>
          <Footer />
        </div>
      )
    }
  }
}

选项2只使用React Helmet，它与盖茨比开箱即用（至少从v2.x开始）。在此设置中，您可以设置使用头盔的元数据组件，然后轻松覆盖Gatsby页面中的这些预设。头盔只会覆盖您指定的元数据项，如果不需要调整则保留其他元数据项。只需导入/调用页面/组件中的Helmet即可轻松覆盖：

metadata.js：

import React from 'react'
import Helmet from 'react-helmet'

import icon from '../../images/logo.png'
import socialBanner from '../../images/PFB_2018_social.jpg'

const Metadata = () => (
  <div>
    <Helmet>
      <title>Whatever</title>

      <meta property='og:image' content={ socialBanner } />
      <meta property='og:locale' content='en_US' />
      <meta property='og:type' content='website' />
      <meta property='og:title' content='Whatever' />
      <meta property='og:description' content="Description" />
      <meta property='og:url' content='https://example.org' />
      <meta property='og:updated_time' content='2019-01-31' />
    </Helmet>
  </div>
)

export default Metadata

页面example.js：

import React from 'react'
import Helmet from 'react-helmet'

export default class Example extends React.Component {
  render() {
    return (
      <div>

            {/* Custom metadata - assuming something coming from Node.js in pageContext prop */}
            <Helmet>
              <title>Override here</title>

              { /* Example from pageContext prop, gatsby-node.js */}
              <meta property='og:title' content={ `${this.props.pageContext.title} | Your brand` } />

              { /* Image from gatsby-node.js example, using gatsby-image for override */}
              <meta property='og:image' content={ this.props.pageContext.images[0].localFile.childImageSharp.fluid.src } />

              { /* Get path from location string */}
              <meta property='og:url' content={ this.props.location.href } />

            </Helmet>
      </div>
    )
  }
}