How to post data using node-curl? - node.js

Question

I'm very new to LINUX working with node.js. Its just my 2nd day. I use node-curl for curl request. In the link below I have found example with Get request. Can anybody provide me a Post request example using node-curl.
https://github.com/jiangmiao/node-curl/blob/master/examples/low-level.js

Answer 1

You need to use setopt in order to specify POST options for a cURL request. The options you should start looking at first are CURLOPT_POST and CURLOPT_POSTFIELDS. From the libcurl documentation linked from node-curl:
CURLOPT_POST
A parameter set to 1 tells the library to do a regular HTTP post. This will also make the library use a "Content-Type: application/x-www-form-urlencoded" header. (This is by far the most commonly used POST method).
Use one of CURLOPT_POSTFIELDS or CURLOPT_COPYPOSTFIELDS options to specify what data to post and CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE to set the data size.
Optionally, you can provide data to POST using the CURLOPT_READFUNCTION and CURLOPT_READDATA options but then you must make sure to not set CURLOPT_POSTFIELDS to anything but NULL. When providing data with a callback, you must transmit it using chunked transfer-encoding or you must set the size of the data with the CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE option. To enable chunked encoding, you simply pass in the appropriate Transfer-Encoding header, see the post-callback.c example.
CURLOPT_POSTFIELDS
... [this] should be the full data to post in a HTTP POST operation. You must make sure that the data is formatted the way you want the server to receive it. libcurl will not convert or encode it for you. Most web servers will assume this data to be url-encoded.
This POST is a normal application/x-www-form-urlencoded kind (and libcurl will set that Content-Type by default when this option is used), which is the most commonly used one by HTML forms. See also the CURLOPT_POST. Using CURLOPT_POSTFIELDS implies CURLOPT_POST.
If you want to do a zero-byte POST, you need to set CURLOPT_POSTFIELDSIZE explicitly to zero, as simply setting CURLOPT_POSTFIELDS to NULL or "" just effectively disables the sending of the specified string. libcurl will instead assume that you'll send the POST data using the read callback!
With that information, you should be able add the following options to the low-level example to have it make a POST request:
var fieldsStr = '{}';
curl.setopt('CURLOPT_POST', 1); // true?
curl.setopt('CURLOPT_POSTFIELDS', fieldsStr);
You will need to tweak the contents of fieldsStr to match the format the server is expecting. Per the documentation you may also need to url-encode the data - which should be as simple as using encodeURIComponent according to this post.