Linux下cURL使用教程之四：curl基本使用实例

本篇主要结合编写的PHP程序实例对上篇curl基本使用进行具体说明。

环境搭建

HTTP服务器

建议Ubuntu+Apache+PHP，方便简洁:

sudo apt-get install apache2 php5

即可。

网页

以下为测试使用的服务器端代码，全部使用php实现。

curldemo.php，用于输出User-Agent、Referer、Cookie信息：

<html>
<head>
<title>
PHP Demo for curl basic usage By Stackeye
</title>
</head>
<body>
<?php
    echo "<strong>User-Agent:</strong><br>".$_SERVER['HTTP_USER_AGENT']."<br>\n";
    if(isset($_SERVER['HTTP_REFERER']))
    {
        echo "<strong>Referer:</strong><br>".$_SERVER['HTTP_REFERER']."<br>\n";
    }
    if(isset($_COOKIE['user']))
    {
        echo "<strong>Cookie:</strong><br>user=".$_COOKIE['user']."<br>\n";
        setcookie("user","",time()-1);
    }
?>
<br><br><br>
<a href="http://www.stackeye.com" target="_blank">Stackeye's Blog</a>
</body>
</html>

curlfollow.php，设置cookie后跳转至curldemo.php（使用js跳转，curl不会执行js函数，因此只有在浏览器中才会自动跳转）：
<?php
setcookie("user","Stackeye");
echo "<script>window.location =\"curldemo.php\";</script>";
?>
curl301.php，重定向至curldemo.php（header重定向后Referer字段为空，设置的cookie也不保存）：
<?php
Header( "HTTP/1.1 301 Moved Permanently" ) ;
Header( "Location: curldemo.php" );
?>

curldeny.php，对User-Agent/Referer/cookie有严格要求，才会显示最终内容：

<html>
<head>
<title>
CurlDeny-PHP Demo for curl basic usage By Stackeye
</title>
</head>
<body>
	I'll deny all http requests,<br>
	except your User-agent contains "Mozilla/4.0",<br>
	your referer contains "www.baidu.com",<br>
	and your cookie user is "Stackeye"!<br>
	If you succeed,you will see "You finally get it"!<br><br>
<?php
    if(strpos($_SERVER['HTTP_USER_AGENT'],"Mozilla/4.0")!==false)
    {
    	echo "<strong>User-Agent:</strong><br>".$_SERVER['HTTP_USER_AGENT']."<br>\n";
    	if(isset($_SERVER['HTTP_REFERER'])
         &&strpos($_SERVER['HTTP_REFERER'],"www.stackeye.com")!==false)
    	{
    		echo "<strong>Referer:</strong><br>".$_SERVER['HTTP_REFERER']."<br>\n";
    		if(isset($_COOKIE['user'])&&strcmp($_COOKIE['user'],"Stackeye")==0)
    		{
    	      echo "<strong>Cookie:</strong><br>user=".$_COOKIE['user']."<br>\n";
            setcookie("user","",time()-1);
            echo "You finally get it!<br>\n";
    		}
    		else
    		    echo "\n<br><br>I'm sorry but you are so close!<br>\n";
    	}
    	else
    	    echo "\n<br><br>I'm sorry but you are so close!<br>\n";
    }
    else
        echo "\n<br><br>I'm sorry but you are so close!<br>\n" ;
?>
<br>
<a href="http://www.stackeye.com" target="_blank">Stackeye's Blog</a>
</body>
</html>

setcookie.php，设置cookie的user字段，用以访问curldeny.php:

<html>
<head>
<title>
SetCookie-PHP Demo for curl basic usage By Stackeye
</title>
</head>
<body>
	I just set the cookie,<br> 
	with which you can get the curldeny.php.<br><br>
<?php
    setcookie("user","Stackeye");
?>
<br>
<a href="http://www.stackeye.com" target="_blank">Stackeye's Blog</a>
</body>
</html>

以上PHP文件放入服务器根目录下即可（Ubuntu+Apache下默认为/var/www）。以下默认服务器地址为本机127.0.0.1。

curl访问任务

使用curl命令完成如下任务。

1. 伪装成Firefox访问curldemo.php

curl -s -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curldemo.html http://127.0.0.1/curldemo.php

保存的html文件可以用浏览器打开查看。

2. 伪装来源页面为www.stackeye.com访问curldemo.php

curl -s -o curlex.html -e http://www.stackeye.com http://127.0.0.1/curldemo.php

3. 伪装成Firefox访问curlfollow.php，并保存cookie文件

然后使用保存的cookie文件，伪装成firefox，访问curldemo.php

curl -s -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curlfollow.html -D cookie001.txt http://127.0.0.1/curlfollow.php
curl -s -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curldemo.html -D cookie002.txt -b cookie001.txt http://127.0.0.1/curldemo.php

curldemo.html将显示user的值为Stackeye。

4. 伪装成Firefox并直接使用cookie值访问curldemo.php

cookie中user值为Stackeye，pass值为password

curl -s -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curldemo.html -D cookie002.txt -b “user=Stackeye;pass=password” \
http://127.0.0.1/curldemo.php

curldemo.html将显示user的值为Stackeye，pass值为password。

5. 不自动跟踪重定向访问curl301.php

curl -v -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curl301.html http://127.0.0.1/curl301.php

因为此时curl301.html文件内容为空，我们只能通过-v查看具体内容。
可以看到curl只访问了curl301.php

6. 自动跟踪重定向访问curl301.php

curl -s -L -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curl301.html http://127.0.0.1/curl301.php

此时打开curl301.html会看到curldemo.php的内容，说明curl自动根据重定向去访问了curldemo.php。

7. 访问setcookie.php和curldeny.php，使curldeny.php显示“You finally get it!”

curl -s -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o setcookie.html -D cookie001.txt http://127.0.0.1/setcookie.php
curl -s -A "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" \
-o curldeny.html -e http://www.adeploy.com -D cookie002.txt -b cookie001.txt \
http://127.0.0.1/curldeny.php

打开curldeny.html文件，可看到“You finally get it!”信息。

总结

本篇主要是针对curl基本用法的实例以加深理解和掌握。实际操作中，登陆、发帖等操作还会用到提交表单相关操作，下篇将进行讲解。