Getting started with curl

Remarks#

This section provides an overview of what curl is, and why a developer might want to use it.

It should also mention any large subjects within curl, and link out to the related topics. Since the Documentation for curl is new, you may need to create initial versions of those related topics.

Transfer data using curl

cURL is the name of the project which depicts: ‘Client for URLs’ and also be called as Client URL Request Library

it combines two separate packages: curl and libcurl.

1. curl is a command line tool used to get documents/files from or send documents to a server, using any of the supported protocols: DICT, FILE, FTP, FTPS, Gopher, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMTP, SMTPS, Telnet and TFTP.

2. libcurl is the underlying library curl uses to do the actual networking and transfer work. libcurl is used by thousands of services, applications and devices and very often through one of the “language bindings” that allows programmers of higher level languages to access its powers.

Using curl in PHP to fetch data

<?php
 
    $ch = curl_init(); //curl handler init

    curl_setopt($ch,CURLOPT_URL,"https://www.google.com/search?q=curl");
    curl_setopt($ch,CURLOPT_RETURNTRANSFER,true);// set optional params
    curl_setopt($ch,CURLOPT_HEADER, false); 
 
    $result=curl_exec($ch);
 
    curl_close($ch);
 
    echo $result;
?>

Using curl through the command line

Show curl version:

curl --version

GET a remote resource and have it displayed in the terminal:

curl https://stackoverflow.com

GET a remote resource and save it in a local file:

curl -o file https://stackoverflow.com

Add headers to response:

curl -i https://stackoverflow.com

Output only headers:

curl -I https://stackoverflow.com

Use the libcurl easy C API to get a remote resource

#include <stdio.h>
#include <curl/curl.h>

int main(void)
{
  CURL *curl;
  CURLcode res;

  curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* example.com is redirected, so we tell libcurl to follow redirection */
    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);

    /* Perform the request, res will get the return code */
    res = curl_easy_perform(curl);
    /* Check for errors */
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(res));

    /* always cleanup */
    curl_easy_cleanup(curl);
  }
  return 0;
}