Editing Using curl to test POST data

[[Category:Web Development]]
== Basic request passing variables as POST ==

Use `--data` or `-d` option to pass variables to the page.

<syntaxhighlight lang="bash">
$ curl -d "user=mylogin&pass=mypass&foo=bar&biz=bash" http://www.mydomain.com/mypage/
</syntaxhighlight>

== Request using basic authentication ==

Use `--user` or `-u` option.

<syntaxhighlight lang="bash">
$ curl -u mylogin:mypass -d "user=mylogin&pass=mypass&foo=bar&biz=bash" http://www.mydomain.com/mypage/
</syntaxhighlight>

== Request using Windows integrated authentication ==

Add `--ntlm` option.

<syntaxhighlight lang="bash">
$ curl -u mylogin:mypass --ntlm -d "user=mylogin&pass=mypass&foo=bar&biz=bash" http://www.mydomain.com/mypage/
</syntaxhighlight>

== Special characters in username or password ==

Escape special characters with back slash.

<syntaxhighlight lang="bash">
$ curl -u mylogin:myp\&ss --ntlm -d "user=mylogin&pass=mypass&foo=bar&biz=bash" http://www.mydomain.com/mypage/
</syntaxhighlight>

== Storing arguments in a text file ==

Content of file, saved as `curlargs.txt`:
<syntaxhighlight lang="bash">
-d foo=bar&biz=bash http://localhost/mytestpage.html
</syntaxhighlight>

Run curl using contents of <code>curlargs.txt</code> (in a bash shell):

<syntaxhighlight lang="bash">
$ cat curlargs.txt | xargs -n3 curl
</syntaxhighlight>

== Sending request headers ==

<syntaxhighlight lang="powershell">
> curl -H "X-MyHeader: 123" www.google.com
</syntaxhighlight>

The argument is either `-H` or `--header` followed by header name, colon, and header value.

For example, to send an Accept request-header for JSON data: `-H "Accept: application/json"`.

To view the request that is sent add the `-v` option to `curl`.

== Handling quotes in POST data ==

'''Problem:''' The value of the `-d` or `--data` argument (typically a JSON string) contains either a single or double quote: 
<syntaxhighlight lang="bash">
# Error is thrown when it hits the first quote in the ''title'' string.
curl -d '{ "id": "6650", "title": "A record title containing 'quotes'."}' http://mydomain.com/path/to/page/
</syntaxhighlight>

'''Solution:''' Use the `@` character to read the data from a separate file.

Curl arguments stored in `curargs.txt`:
<pre>
-d @jsondata.txt http://mydomain.com/path/to/page/
</pre>
Contents of `jsondata.txt`:
<pre>
{ "id": "6650", "title": "A record title containing 'quotes'."}
</pre>
Then pass the contents of the two files to curl with
<syntaxhighlight lang="bash">
$ cat curlargs.txt | xargs -n3 curl
</syntaxhighlight>

== Sending POST requests to Django projects ==

Because of [https://docs.djangoproject.com/en/dev/ref/contrib/csrf/ Cross Site Request Forgery protection] in Django, POST requests have to include a CSRF token generated by the Django app. 

It's not really practical or safe to generate the token so it can be used with `curl`. 

Instead right above the Django view that is being called, place an CSRF exemption:
<syntaxhighlight lang="python">
from django.views.decorators.csrf import csrf_exempt

@csrf_exempt
def my_view(request):
    return HttpResponse('Hello world')
</syntaxhighlight>

It's possible to pass the token with `curl`: 

<syntaxhighlight lang="bash">
curl
 -X POST
 -d "email=test@test.com&a=1&csrfmiddlewaretoken=<inserttoken>"
 --cookie "csrftoken=[as above]"
 http://127.0.0.1:8083/registrations/register/
</syntaxhighlight>

It's also possible to use `--header "X-CSRFToken: <token>"` instead of including it in the form data.

== Following redirects ==

<syntaxhighlight lang="bash">
$ curl -L -X POST -d "foo=bar&biz=bash" http://dev-server.com
</syntaxhighlight>

* `-L` '''location''' Tells `curl` to reattempt the get if the server reports that the page is at a different location (`301` and `302` responses)
* `-X POST` Explicitly use the POST method (as opposed to the `-d` option which implicitly uses POST.<ref>[http://man.cx/curl curl man page]</ref> (man.cx manual pages)

This happens with Symfony, which sends a `301` response with its controllers.<ref>[http://stackoverflow.com/a/22654902 php curl post request to symfony2 app shows an empty ParameterBag] (Stackoverflow)</ref>,<ref>[http://www.recursion.org/2011/11/18/following-redirects-with-curl Following Redirects with Curl] (recursion.org blog)</ref>

<p class="alert-warning">N.B. This did not work on the first attempt with Symfony. Not sure if it's not a solution, or if I was doing something wrong.</p>

== Notes ==
<references />