问题
When I run cURL on an object to see its HTTP response headers (I just added agent flag to emulate a browser request):
curl -I -A "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.85 Safari/537.36" http://b17db03a092ebf708b42-9afd7fe2d9c9c6937aeab44904ac3403.r3.cf5.rackcdn.com/artist/samplesong/13111c20aee51aeb480ecbd988cd8cc9.mp3
I have:
HTTP/1.1 200 OK Content-Length: 481005 Accept-Ranges: bytes Last-Modified: Tue, 08 Sep 2015 18:37:54 GMT ETag: e9f52648c48c707cb9c17e1871787ad8 X-Timestamp: 1441737473.83703 Access-Control-Allow-Origin: * Content-Type: audio/mpeg X-Trans-Id: tx6531dbbd8dc541eeaf824-0055f0765eiad3 Cache-Control: public, max-age=259169 Expires: Sat, 12 Sep 2015 18:11:11 GMT Date: Wed, 09 Sep 2015 18:11:42 GMT Connection: keep-alive
As you can see, there is a Access-Control-Allow-Origin line.
But when I request the exact same URL with Safari, Chrome or Firefox (without cache):
Accept-Ranges:bytes Cache-Control:public, max-age=55773 Connection:keep-alive Content-Length:1 Content-Range:bytes 203184-203184/480621 Content-Type:audio/mpeg Date:Wed, 09 Sep 2015 18:14:12 GMT ETag:b1d4c80b2d5d42a4bf6c1ae5efb289e6 Expires:Thu, 10 Sep 2015 09:43:45 GMT Last-Modified:Mon, 07 Sep 2015 09:19:19 GMT X-Timestamp:1441617558.54283 X-Trans-Id:txe8e3941ab1774f4d97794-0055ed5c71iad3
Access-Control-Allow-Origin just disappeared !
Any idea why the http response header works with cURL but not with Browser ? Thanks.
回答1:
There is no difference between cURL and your browser behaviour.
When you add the -I flag in your curl call, you send a 'HEAD' request. In your browser, it was a 'GET' request.
If you curl this url with the -i flag (-i includes the HTTP-header in the output.), you will lose the "Access-Control-Allow-Origin" line :
curl -i -A "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.85 Safari/537.36" http://b17db03a092ebf708b42-9afd7fe2d9c9c6937aeab44904ac3403.r3.cf5.rackcdn.com/artist/samplesong/13111c20aee51aeb480ecbd988cd8cc9.mp3 > C:/curl_return.log
And if you open the file you got :
HTTP/1.1 200 OK
Content-Length: 480621
Accept-Ranges: bytes
Last-Modified: Mon, 07 Sep 2015 09:19:19 GMT
ETag: b1d4c80b2d5d42a4bf6c1ae5efb289e6
X-Timestamp: 1441617558.54283
Content-Type: audio/mpeg
X-Trans-Id: tx76217fcbee85481d844ab-0055ed6d83iad3
Cache-Control: public, max-age=56913
Expires: Thu, 10 Sep 2015 10:57:04 GMT
Date: Wed, 09 Sep 2015 19:08:31 GMT
Connection: keep-alive
ID3.................................................................
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来源：https://stackoverflow.com/questions/32486949/http-header-in-response-exists-with-a-curl-request-but-not-with-browser-request