python - HTTP/1.1 中的 400 Bad Request 但 HTTP/1.0 中没有

Question

我正在尝试向这个 url 发送一个 HEAD 请求:

http://ubuntu-releases.mirror.net.in/releases/16.04.2/ubuntu-16.04.2-desktop-amd64.iso

并获取文件的大小。我当前的 head 请求如下所示:

head_request = "HEAD " + file_path + " HTTP/1.0%s" % ('\r\n\r\n')
socket.socket(socket.AF_INET, socket.SOCK_STREAM).send(head_request)

其中 file_path 是 "/releases/16.04.2/ubuntu-16.04.2-desktop-amd64.iso"。这非常有效，但是当我用 1.1 替换 1.0 时，我得到了一个 400 HTTP Bad Request。

head_request = "HEAD " + file_path + " HTTP/1.1%s" % ('\r\n\r\n')

为什么会这样？

Answer 1

在 HTTP/1.1 中，您必须提供 Host: header 。

使用 netcat (nc) 实用程序的演示:

$ nc ubuntu-releases.mirror.net.in 80 <<END
HEAD /releases/16.04.2/ubuntu-16.04.2-desktop-amd64.iso HTTP/1.0

END
HTTP/1.1 200 OK
Date: Sat, 04 Mar 2017 07:25:22 GMT
Server: Apache/2.4.18 (Ubuntu)
Last-Modified: Wed, 15 Feb 2017 21:44:24 GMT
ETag: "5ca30000-5489895805e00"
Accept-Ranges: bytes
Content-Length: 1554186240
Connection: close
Content-Type: application/x-iso9660-image

$ nc ubuntu-releases.mirror.net.in 80 <<END
HEAD /releases/16.04.2/ubuntu-16.04.2-desktop-amd64.iso HTTP/1.1

END

HTTP/1.1 400 Bad Request
Date: Sat, 04 Mar 2017 07:25:33 GMT
Server: Apache/2.4.18 (Ubuntu)
Connection: close
Content-Type: text/html; charset=iso-8859-1

$ nc ubuntu-releases.mirror.net.in 80 <<END
HEAD /releases/16.04.2/ubuntu-16.04.2-desktop-amd64.iso HTTP/1.1
Host: ubuntu-releases.mirror.net.in

END

HTTP/1.1 200 OK
Date: Sat, 04 Mar 2017 07:27:27 GMT
Server: Apache/2.4.18 (Ubuntu)
Last-Modified: Wed, 15 Feb 2017 21:44:24 GMT
ETag: "5ca30000-5489895805e00"
Accept-Ranges: bytes
Content-Length: 1554186240
Content-Type: application/x-iso9660-image