Service Worker 注册错误:不支持的 MIME 类型 ('text/html') [英] Service Worker registration error: Unsupported MIME type ('text/html')

问题描述

我正在使用 create-react-app 和 express 服务器.

I'm using create-react-app with an express server.

create-react-app 有一个预配置的 ServiceWorker 来缓存本地资产 (https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/template/README.md#making-a-progressive-web-app).

create-react-app has a pre-configured ServiceWorker that caches local assets (https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/template/README.md#making-a-progressive-web-app).

当我尝试在我的服务器上发布时遇到的问题是 service-worker.js 文件可用，但是当我尝试注册它时，我的浏览器控制台出现错误.

The problem I encountered when I tried to publish on my server is that the service-worker.js file was available, but I was getting errors in my browser console when it tried to register it.

在 Firefox 上，我收到此错误:

On Firefox, I got this error:

Service Worker 注册时出错:

Error during service worker registration:

TypeError:ServiceWorker 脚本位于 https://my-domain.com/service-worker.js 范围 https://my-domain.com/ 在安装过程中遇到错误.>

TypeError: ServiceWorker script at https://my-domain.com/service-worker.js for scope https://my-domain.com/ encountered an error during installation.

在 Chrome 上，我收到了更具描述性的错误:

On Chrome, I get the more descriptive error:

Service Worker 注册期间出错:DOMException:无法注册 ServiceWorker:脚本具有不受支持的 MIME 类型 ('text/html').

Error during service worker registration: DOMException: Failed to register a ServiceWorker: The script has an unsupported MIME type ('text/html').

果然，如果我查看我的开发者工具的网络选项卡并搜索 service-worker.js 文件，我可以看到它在 HTTP 标头中具有错误的 MIME 类型.

Sure enough, if I look in the Network tab of my developer tools and search for the service-worker.js file, I can see that it has the wrong MIME type in the HTTP headers.

不过，我不明白为什么它的 MIME 类型有误?

I could not understand, though, why it has the wrong MIME type?

推荐答案

在我的 Express 服务器应用程序中，我有一个通配符(星号/*)路由重定向到 index.html:

In my Express server application, I have one wildcard (asterisk / *) route that redirects to index.html:

// Load React App
// Serve HTML file for production
if (env.name === "production") {
  app.get("*", function response(req, res) {
    res.sendFile(path.join(__dirname, "public", "index.html"));
  });
}

这是一种非常常见的设计模式.然而，这意味着对未知文本文件的任何请求最初都会被重定向到 index.html，因此返回的 MIME 类型为 "text/html"，即使它是实际上是 JavaScript 或 SVG 或其他类型的纯文本文件.

This is a very common design pattern. However, it means that any requests for unknown text files initially get redirected to index.html, and therefore return with the MIME type of "text/html", even if it's actually a JavaScript or SVG or some other kind of plaintext file.

我找到的解决方案是为 service-worker.js before 通配符路由添加一个特定的路由:

The solution I found was to add a specific route for service-worker.js before the wildcard route:

app.get("/service-worker.js", (req, res) => {
  res.sendFile(path.resolve(__dirname, "public", "service-worker.js"));
});
app.get("*", function response(req, res) {
  res.sendFile(path.join(__dirname, "public", "index.html"));
});

现在，当浏览器查找 service-worker.js 时，Express 将返回它并带有正确的 MIME 类型.

Now, when the browser looks for service-worker.js, Express will return it with the correct MIME type.

(请注意，如果您尝试在通配符后添加 service-worker.js 路由，它将不起作用，因为通配符路由将覆盖.)

(Note that if you try adding the service-worker.js route after the wildcard, it won't work because the wildcard route will override.)

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