Tag Archives: stackoverflow

cURL and libcurl

curl -G vs curl -X GET

2 Comments

(This is a repost of a stackoverflow answer I once wrote on this topic. Slightly edited. Copied here to make sure I own and store my own content properly.)

curl knows the HTTP method

You normally use curl without explicitly saying which request method to use.

If you just pass in a HTTP URL like curl http://example.com, curl will use GET. If you use -d or -F curl will use POST, -I will cause a HEAD and -T will make it a PUT.

If for whatever reason you’re not happy with these default choices that curl does for you, you can override those request methods by specifying -X [WHATEVER]. This way you can for example send a DELETE by doing curl -X DELETE [URL].

It is thus pointless to do curl -X GET [URL] as GET would be used anyway. In the same vein it is pointless to do curl -X POST -d data [URL]... But you can make a fun and somewhat rare request that sends a request-body in a GET request with something like curl -X GET -d data [URL].

Digging deeper

curl -GET (using a single dash) is just wrong for this purpose. That’s the equivalent of specifying the -G, -E and -T options and that will do something completely different.

There’s also a curl option called --get to not confuse matters with either. It is the long form of -G, which is used to convert data specified with -d into a GET request instead of a POST.

(I subsequently used this answer to populate the curl FAQ to cover this.)

Warnings

Modern versions of curl will inform users about this unnecessary and potentially harmful use of -X when verbose mode is enabled (-v) – to make users aware. Further explained and motivated here.

-G converts a POST + body to a GET + query

You can ask curl to convert a set of -d options and instead of sending them in the request body with POST, put them at the end of the URL’s query string and issue a GET, with the use of `-G. Like this:

curl -d name=daniel -d grumpy=yes -G https://example.com/

… which does the exact same thing as this command:

curl https://example.com/?name=daniel&grumpy=yes
cURL and libcurl

25,000 curl questions on stackoverflow

1 Comment

stackoverflow-logoOver time, I’ve reluctantly come to terms with the fact that a lot of questions and answers about curl is not done on the mailing lists we have setup in the project itself.

A primary such external site with curl related questions is of course stackoverflow – hardly news to programmers of today. The questions tagged with curl is of course only a very tiny fraction of the vast amount of questions and answers that accumulate on that busy site.

The pile of questions tagged with curl on stackoverflow has just surpassed the staggering number of 25,000. Of course, these questions involve persons who ask about particular curl behaviors (and a large portion is about PHP/CURL) but there’s also a significant amount of tags for questions where curl is only used to do something and that other something is actually what the question is about. And ‘libcurl’ is used as a separate tag and is often used independently of the ‘curl’ one. libcurl is tagged on almost 2,000 questions.

curl-symbolBut still. 25,000 questions. Wow.

I visit that site every so often and answer to some questions but I often end up feeling a great “distance” between me and questions there, and I have a hard time to bridge that gap. Also, stackoverflow the site and the format isn’t really suitable for debugging or solving problems within curl so I often end up trying to get the user move over to file an issue on curl’s github page or discuss the curl problem on a mailing list instead. Forums more suitable for plenty of back-and-forth before the solution or fix is figured out.

Now, any bets for how long it takes until we reach 100K questions?