如何仅使用Javascript中的标头而不是整个内容来获取(使用Fetch API)? [英] How to fetch (using Fetch API) only headers in Javascript, not the whole content?

问题描述

在这里，我有这个样本小提琴，在这里我尝试仅获取 >大图像中的content-type标头，在Javascript中同时使用XMLHttpRequest()和fetch().如果在打开Chrome的开发人员工具/网络"标签(或其他浏览器中的类似工具)的情况下运行小提琴，则会看到，虽然XMLHttpRequest()方法仅获得标头所在的600 B，但fetch()方法却获得了整个7.8 MB的图片，尽管我的代码只需要content-type标头即可.

Here I have this sample fiddle, where I try to get only the content-type header from a large image, using both XMLHttpRequest() and fetch() in Javascript. If you run the fiddle with Chrome's Developer Tools / Network tab (or similar tools in other browsers) open, you'll see that while the XMLHttpRequest() method gets only the 600 B where the headers are located, the fetch() method gets the whole 7.8 MB image, despite my code only needing the content-type headers.

如何使用Fetch APi的fetch()获得标头所需的几个字节(而不是整个内容)?

How can I get just those few bytes needed for the headers (instead of the whole content) using the Fetch APi's fetch()?

注意:我对此感兴趣，因为显然，如果我尝试获取常规Google页面的所有链接的标题，则XMLHttpRequest()方法会使我注销，有时还会更改我的语言，而fetch()方法没有.我认为这是因为前者发送凭据/Cookie等，而后者默认情况下更具限制性" ...

Note: I am interested in this, because apparently, if I try to get the headers of all the links of a regular Google page, the XMLHttpRequest() method logs me out and sometimes changes my language as well, while the fetch() method does not. I assume this is because the former sends the credentials / cookies / etc., while the latter is more 'restrictive' by default...

推荐答案

您需要指定HEAD的方法类型:

You need to specify the method type of HEAD:

fetch(url, {method: 'HEAD'})

查看更新的小提琴

这篇关于如何仅使用Javascript中的标头而不是整个内容来获取(使用Fetch API)?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！