Why does curl not work, but wget works?

Question

I am using both curl and wget to get this url: http://opinionator.blogs.nytimes.com/2012/01/19/118675/

For curl, it returns no output at all, but with wget, it returns the entire HTML source:

Here are the 2 commands. I've used the same user agent, and both are coming from the same IP, and are following redirects. The URL is exactly the same. For curl, it returns immediately after 1 second, so I know it's not a timeout issue.

curl -L -s "http://opinionator.blogs.nytimes.com/2012/01/19/118675/" --max-redirs 10000 --location --connect-timeout 20 -m 20 -A "Mozilla/5.0 (Windows NT 5.2; rv:2.0.1) Gecko/20100101 Firefox/4.0.1" 2>&1

wget http://opinionator.blogs.nytimes.com/2012/01/19/118675/ --user-agent="Mozilla/5.0 (Windows NT 5.2; rv:2.0.1) Gecko/20100101 Firefox/4.0.1" 

If NY Times might be cloaking, and not returning the source to curl, what could be different in the headers curl is sending? I assumed since the user agent is the same, the request should look exactly the same from both of these requests. What other "footprints" should I check?

Solution

The way to solve is to analyze your curl request by doing curl -v ... and your wget request by doing wget -d ... which shows that curl is redirected to a login page

> GET /2012/01/19/118675/ HTTP/1.1
> User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
> Host: opinionator.blogs.nytimes.com
> Accept: */*
> 
< HTTP/1.1 303 See Other
< Date: Wed, 08 Jan 2014 03:23:06 GMT
* Server Apache is not blacklisted
< Server: Apache
< Location: http://www.nytimes.com/glogin?URI=http://opinionator.blogs.nytimes.com/2012/01/19/118675/&OQ=_rQ3D0&OP=1b5c69eQ2FCinbCQ5DzLCaaaCvLgqCPhKP
< Content-Length: 0
< Content-Type: text/plain; charset=UTF-8

followed by a loop of redirections (which you must have noticed, because you have already set the --max-redirs flag).

On the other hand, wget follows the same sequence except that it returns the cookie set by nytimes.com with its subsequent request(s)

---request begin---
GET /2012/01/19/118675/?_r=0 HTTP/1.1
User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
Accept: */*
Host: opinionator.blogs.nytimes.com
Connection: Keep-Alive
Cookie: NYT-S=0MhLY3awSMyxXDXrmvxADeHDiNOMaMEZFGdeFz9JchiAIUFL2BEX5FWcV.Ynx4rkFI

The request sent by curl never includes the cookie.

The easiest way I see to modify your curl command and obtain the desired resource is by adding -c cookiefile to your curl command. This stores the cookie in the otherwise unused temporary "cookie jar" file called "cookiefile" thereby enabling curl to send the needed cookie(s) with its subsequent requests.

For example, I added the flag -c x directly after "curl " and I obtained the output just like from wget (except that wget writes it to a file and curl prints it on STDOUT).

Comments

[Eric Zheng]

-v is usually very helpful