Showing Or Saving An Image Retrieved Via cURL

As a developer cURL can be a very handy for numerous reasons. In my case I have used it for my plugin Twitter Stream, but here we are going to look at a little tip I stumbled across while playing with cURL.

cURL is used to make a connection to an external source to retrieve the content at the source. What most people new to cURL don’t realize is that it can be used to retrieve any content, including images.

Piping Output from One Command to Another

Piping allows the user to do several fantastic thing by combining utilities. I will cover only very basic uses for piping. I most commonly use the pipe command, |, to pipe text that is output from one command through the grep command to search for text.
 
Examples:

See if a program, centericq, is running:$ ps ax | grep centericq 25824 pts/2 S 0:18 centericq Count the number of files in a directory (nl counts things):$ ls | nl 1 #.emacs# 2 BitchX 3 Outcast double cd.lst 4 bm.shader 5 bmtexturesbase.pk3 If my memory serves using RPM to check if a package is installed:$ rpm -qa | grep package_name A more advance example:$ cat /etc/passwd | awk -F: '{print $1 "\t" $6}' | sort > ./users This sequence takes the information if the file passwd, pipes it to awk, which takes the first and sixth fields (the user name and home directory respectively), pipes these fields separated by a tab ("\t") to sort, which sorts the list alphabetically, and puts it into a file called users.

PHP POST Upload File Using CURL

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<?php     $data = array (                 'type' => 'direct',                 'userfile[]' => '@c:\Apache Server Doc Folder\picture.jpg',                 'private' => '0', );     $curl = curl_init(); curl_setopt($curl, CURLOPT_URL, "http://www.url.com/upload.php"); curl_setopt($curl, CURLOPT_VERBOSE, true); curl_setopt($curl, CURLOPT_POST, true); curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true); curl_setopt($curl, CURLOPT_POSTFIELDS, $data); $result = curl_exec($curl); curl_close($curl);   ?>

And there is a reference for POST JSON here :

http://www.lornajane.net/posts/2011/posting-json-data-with-php-curl

Login with cURL and PHP

By Ryan at ifupdown.com:

Social networking websites often ask you to see if any of your email contacts are already using the service. They ask for your email and password and then connect to your email account and read through your contacts. In this post, I’ll provide the code that you can use to connect and log in via a login form. This isn’t going to be on the logging into gmail caliber though, it’s a simple demonstration of cURL and PHP.

A couple notes before we start though. I’ve always hated the non-object oriented methods that cURL used to set options. So I wrote a little wrapper class for cURL and will be in along with the code file. It should be fairly easy to follow along. To begin with, we need a really simple login form. I mean, dead simple.