cURL works from Terminal, but not from PHP

Question

I\'m running into a rather strange issue.

I\'m trying to log into a remote moodle install using curl from PHP.

I have a curl command, which works perfectly in th

Answer 1

This could have been debugged better by seeing everything that was actually done by cURL. This is done by adding the verbose flag to the command: -v.

$ curl localhost/login [...] -v

We can get the same output from PHP's curl by adding the CURLOPT_VERBOSE option. Note that by adding this line you are instructing cURL to output the same information to STDOUT - it will not be returned and content will not be sent to the browser, so this must be debugged in the terminal.

curl_setopt($curl, CURLOPT_VERBOSE, 1);

By doing it this way, you can get a consistent and comparable output of both HTTP requests, it should look sommthing like this:

POST / HTTP/1.1
Host: localhost:3000
Pragma: no-cache
Origin: http://moodle.tsrs.org
Accept-Language: en-US,en;q=0.8
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Cache-Control: no-cache
Cookie: MoodleSession=ngcidh028m37gm8gbdfe07mvs7; MOODLEID_=%25F1%25CD%2519D%25B2k%25FE%251D%25EFH%25E5t%25B1%2503%258E; MoodleSessionTest=NhzaTNij6j; _ga=GA1.2.925953522.1416155774; _gat=1; __utmt=1; __utma=147409963.925953522.1416155774.1416642544.1416692798.3; __utmb=147409963.1.10.1416692798; __utmc=147409963; __utmz=147409963.1416155774.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)
Connection: keep-alive
Content-Length: 250
Expect: 100-continue
Content-Type: application/x-www-form-urlencoded; boundary=------------------------b4d79f17a3887f2d

< HTTP/1.1 100 Continue
< HTTP/1.1 200 OK
< X-Powered-By: Express
< Content-Type: application/json; charset=utf-8
< Content-Length: 2
< ETag: W/"2-mZFLkyvTelC5g8XnyQrpOw"
< Date: Thu, 22 Dec 2016 19:13:40 GMT
< Connection: keep-alive

Left: Command line cURL as provided in the question (with extra -v flag)

Right: PHP cURL as posted in the question (with CURLOUT_VERBOSE enabled)

As you can see, the headers aren't the same, and this makes that clear. The PHP invocation is missing Accept-Encoding and Referer headers.

---

If that didn't turn up anything, let's try changing some more cURL settings in PHP back to the original cURL defaults.

Internally, PHP opts to override some defaults in cURL without telling you. While these settings should be fine, let's change them back by explicitly reseting them back to cURL defaults:

curl_setopt($curl, CURLOPT_DNS_CACHE_TIMEOUT, 60);
curl_setopt($curl, CURLOPT_DNS_USE_GLOBAL_CACHE, 0);
curl_setopt($curl, CURLOPT_MAXREDIRS, -1);
curl_setopt($curl, CURLOPT_NOSIGNAL, 0);