如何从 fetch 中获取响应的标头

How to get headers of the response from fetch(如何从 fetch 中获取响应的标头)

问题描述

我在 chrome 版本 52.0.2743.82(64 位)上使用 fetch.我想获取响应中的所有标题.以下代码段仅返回 content-type 但如果您查看 chrome 开发工具，它会显示许多其他响应标头.如何从 fetch 中获取其他标头.

I am using fetch on chrome Version 52.0.2743.82 (64-bit). I want to get all the headers in the response. Following snippet only return content-type but if you peek into chrome dev tools it shows many other response headers. How to get other headers from fetch.

  fetch('https://httpbin.org/get')
    .then(response => {
       const headers = response.headers.entries();
       let header = headers.next();
       while (!header.done){
         console.log(headers.value);
         header = header.next();
       }
    })

我尝试对 github 实现进行 polyfill(手动覆盖).还是没有运气.

I tried polyfilling(manually overriding) the github implementation. Still no luck.

推荐答案

通过ajax请求跨域内容时，无法访问所有header.如果来源相同，您可以访问所有标题.

You can't access all the headers when requesting cross-domain content via ajax. You can access all headers if origin is same.

如 W3 规范此处中所述，只有 Content-Type、Last-modified、Content-Language、Cache-Control、Expires、Pragma 标题是可访问的.

As explained in W3 Specifications here, only Content-Type, Last-modified, Content-Language, Cache-Control, Expires, Pragma headers are accessible.

进一步的 https://httpbin.org/get 仅从可访问的标头列表中发送 Content-Type 标头，所以，你只得到了.

Further https://httpbin.org/get send only Content-Type header from list of accessible headers so, you got that only.

您可以通过发送 Access-Control-Expose-Headers 带有您希望客户端在响应中访问的标头.

You can expose non-standard CORS response headers by sending Access-Control-Expose-Headers with the headers you want the client to access on the response.

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