はじめに
curl は、CLIベースの HTTPクライアントとして有名ですね。HTTPの仕組みとして、リダイレクトされた場合には、300番台のステータスコードが返ってきますが、勝手にリダイレクト先のアドレスにはアクセスしてくれません。
root@22718a86e84c:/share# curl -v http://google.com * Rebuilt URL to: http://google.com/ * Trying 172.217.31.174... * Connected to google.com (172.217.31.174) port 80 (#0) > GET / HTTP/1.1 > Host: google.com > User-Agent: curl/7.47.0 > Accept: */* > < HTTP/1.1 302 Found < Cache-Control: private < Content-Type: text/html; charset=UTF-8 < Referrer-Policy: no-referrer < Location: http://www.google.co.jp/?gfe_rd=cr&dcr=0&ei=bKttWoeaFqvB8wfwrKDwDQ < Content-Length: 271 < Date: Sun, 28 Jan 2018 10:52:28 GMT < <HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8"> <TITLE>302 Moved</TITLE></HEAD><BODY> <H1>302 Moved</H1> The document has moved <A HREF="http://www.google.co.jp/?gfe_rd=cr&dcr=0&ei=bKttWoeaFqvB8wfwrKDwDQ">here</A>. </BODY></HTML> * Connection #0 to host google.com left intact
これを、自動でリダイレクトさせるオプションがあったのでメモです。
-L：リダイレクトさせるオプション
-Lオプションを使うとリダイレクトしてくれます。
root@22718a86e84c:/share# curl -v -L http://google.com
* Rebuilt URL to: http://google.com/
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0* Trying 172.217.31.174...
* Connected to google.com (172.217.31.174) port 80 (#0)
> GET / HTTP/1.1
> Host: google.com
> User-Agent: curl/7.47.0
> Accept: */*
>
< HTTP/1.1 302 Found
< Cache-Control: private
< Content-Type: text/html; charset=UTF-8
< Referrer-Policy: no-referrer
< Location: http://www.google.co.jp/?gfe_rd=cr&dcr=0&ei=Tq1tWsXCMqzB8wfZiJyQDg
< Content-Length: 271
< Date: Sun, 28 Jan 2018 11:00:30 GMT
<
* Ignoring the response-body
{ [271 bytes data]
100 271 100 271 0 0 9374 0 --:--:-- --:--:-- --:--:-- 9678
* Connection #0 to host google.com left intact
* Issue another request to this URL: 'http://www.google.co.jp/?gfe_rd=cr&dcr=0&ei=Tq1tWsXCMqzB8wfZiJyQDg'
* Trying 172.217.27.163...
* Connected to www.google.co.jp (172.217.27.163) port 80 (#1)
> GET /?gfe_rd=cr&dcr=0&ei=Tq1tWsXCMqzB8wfZiJyQDg HTTP/1.1
> Host: www.google.co.jp
> User-Agent: curl/7.47.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Sun, 28 Jan 2018 11:00:30 GMT
< Expires: -1
< Cache-Control: private, max-age=0
< Content-Type: text/html; charset=Shift_JIS
< P3P: CP="This is not a P3P policy! See g.co/p3phelp for more info."
< Server: gws
< X-XSS-Protection: 1; mode=block
< X-Frame-Options: SAMEORIGIN
< Set-Cookie: 1P_JAR=2018-01-28-11; expires=Tue, 27-Feb-2018 11:00:30 GMT; path=/; domain=.google.co.jp
< Set-Cookie: NID=122=ZqDI7fbiq0GEYlX3-Y02ySoN5sW6eRkle3e77hyGW3Xz4Ub_44OTHrqqsk_p8I3aKuiBUTCI8ioaQD_QEpAT779wMPV4dlVH_CS61fVEKQgkGrZWbp58ZKIYzvwrrkgS; expires=Mon, 30-Jul-2018 11:00:30 GMT; path=/; domain=.google.co.jp; HttpOnly
< Accept-Ranges: none
< Vary: Accept-Encoding
< Transfer-Encoding: chunked
<
{ [764 bytes data]
100 11542 0 11542 0 0 80711 0 --:--:-- --:--:-- --:--:-- 80711
* Connection #1 to host www.google.co.jp left intact
おわりに
自動化するときに便利ですね。こんな感じで使えそうです。
root@22718a86e84c:/share# curl -s -L -I http://google.com | grep "200 OK" HTTP/1.1 200 OK
