当我们要使用先在php.ini里增加一行引用:extension=php_gd2.dll
重启apache。做一个测试页 var_dump(gd_info());输出数据表明PHP GD库引用成功。
表单auth.html
<ol class="dp-xml"> <li class="alt"><span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span></span></font></strong><span> </span></span></li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">head</span><span class="tag">></span></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">meta</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">http-equiv</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'Content-Type'</font></span><span> </span><span class="attribute"><font color="#ff0000">content</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'text/html; charset=utf-8'</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">title</span><span class="tag">></span></span></font></strong><span>验证码</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">title</span><span class="tag">></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span></font></strong><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">h1</span><span class="tag">></span></span></font></strong><span>请输入验证码</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">h1</span><span class="tag">></span></font></strong><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">form</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">action</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"check_auth.php"</font></span><span> </span><span class="attribute"><font color="#ff0000">method</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"post"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><span class="tag-name">input</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">name</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"auth"</font></span><span> </span><span class="attribute"><font color="#ff0000">type</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"text"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class=""> <span> </span><strong><font color="#006699"><span class="tag"><span class="tag-name">img</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">src</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"auth.php"</font></span><span> </span><span class="attribute"><font color="#ff0000">border</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"0"</font></span><span> </span><span class="tag"><strong><font color="#006699">/></font></strong></span><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><span class="tag-name">input</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">type</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"submit"</font></span><span> </span><span class="attribute"><font color="#ff0000">value</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"提交"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">form</span><span class="tag">></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span></font></strong><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span> </li> </ol>
PHP GD库生成验证码 auth.php
<ol class="dp-xml"> <li class="alt"><span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">php</span></font></strong><span> </span></span></li> <li class=""><span> session_start(); </span></li> <li class="alt"><span> header("Content-type:image/png"); </span></li> <li class=""><span> </span></li> <li class="alt"> <span> $</span><span class="attribute"><font color="#ff0000">img_width</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">100</font></span><span>; </span> </li> <li class=""> <span> $</span><span class="attribute"><font color="#ff0000">img_height</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">20</font></span><span>; </span> </li> <li class="alt"><span> </span></li> <li class=""><span> srand(microtime()*100000); </span></li> <li class="alt"> <span> for($</span><span class="attribute"><font color="#ff0000">i</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">0</font></span><span>;$i</span><strong><font color="#006699"><span class="tag"><span class="tag-name">4</span></span></font></strong><span>;$i++) </span> </li> <li class=""><span> { </span></li> <li class="alt"> <span> $</span><span class="attribute"><font color="#ff0000">new_number.</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">dechex</font></span><span>(rand(0,15)); </span> </li> <li class=""><span> } </span></li> <li class="alt"><span> </span></li> <li class=""><span> $_SESSION[check_auth]=$new_number; </span></li> <li class="alt"> <span> $</span><span class="attribute"><font color="#ff0000">new_number</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">imageCreate</font></span><span>($img_width,$img_height);//创建图象 </span> </li> <li class=""><span> ImageColorAllocate($new_number,255,255,255); //设置背景色为白色 </span></li> <li class="alt"><span> </span></li> <li class=""> <span> for($</span><span class="attribute"><font color="#ff0000">i</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">0</font></span><span>;$i</span><strong><font color="#006699"><span class="tag"><span class="tag-name">strlen</span></span></font></strong><span>($_SESSION[check_auth]);$i++) </span> </li> <li class="alt"><span> { </span></li> <li class=""> <span> $</span><span class="attribute"><font color="#ff0000">font</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">mt_rand</font></span><span>(3,5); </span> </li> <li class="alt"> <span> $</span><span class="attribute"><font color="#ff0000">x</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">mt_rand</font></span><span>(1,8) + $img_width*$i/4; </span> </li> <li class=""> <span> $</span><span class="attribute"><font color="#ff0000">y</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">mt_rand</font></span><span>(1,$img_height/4); </span> </li> <li class="alt"> <span> $</span><span class="attribute"><font color="#ff0000">color</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">imageColorAllocate</font></span><span>($new_number,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200));//设置字符颜色 </span> </li> <li class=""><span> imageString($new_number,$font,$x,$y,$_SESSION[check_auth][$i],$color);//输出字符 </span></li> <li class="alt"><span> } </span></li> <li class=""><span> </span></li> <li class="alt"><span> ImagePng($new_number); </span></li> <li class=""><span> ImageDestroy($new_number); </span></li> <li class="alt"> <span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span> </li> </ol>
PHP GD库提交页面 check_auth.php
<ol class="dp-xml"> <li class="alt"><span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">php</span></font></strong><span> </span></span></li> <li class=""><span> session_start(); </span></li> <li class="alt"> <span> $</span><span class="attribute"><font color="#ff0000">auth</font></span><span>=$_POST['auth']; </span> </li> <li class=""><span> </span></li> <li class="alt"><span> if(empty($auth)) </span></li> <li class=""><span> { </span></li> <li class="alt"><span> echo '错误:验证码不能为空'; </span></li> <li class=""><span> die; </span></li> <li class="alt"><span> } </span></li> <li class=""><span> </span></li> <li class="alt"> <span> if($</span><span class="attribute"><font color="#ff0000">auth</font></span><span>==$_SESSION['check_auth']) </span> </li> <li class=""><span> { </span></li> <li class="alt"><span> echo '正确'; </span></li> <li class=""><span> } </span></li> <li class="alt"><span> else </span></li> <li class=""><span> { </span></li> <li class="alt"><span> echo '错误:验证码输入错误'; </span></li> <li class=""><span> } </span></li> <li class="alt"> <span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span> </li> </ol>
以上就是本文所介绍的PHP GD库生成验证码的相关知识,希望对大家有所帮助。

使用数据库存储会话的主要优势包括持久性、可扩展性和安全性。1.持久性:即使服务器重启,会话数据也能保持不变。2.可扩展性:适用于分布式系统,确保会话数据在多服务器间同步。3.安全性:数据库提供加密存储,保护敏感信息。

在PHP中实现自定义会话处理可以通过实现SessionHandlerInterface接口来完成。具体步骤包括:1)创建实现SessionHandlerInterface的类,如CustomSessionHandler;2)重写接口中的方法(如open,close,read,write,destroy,gc)来定义会话数据的生命周期和存储方式;3)在PHP脚本中注册自定义会话处理器并启动会话。这样可以将数据存储在MySQL、Redis等介质中,提升性能、安全性和可扩展性。

SessionID是网络应用程序中用来跟踪用户会话状态的机制。1.它是一个随机生成的字符串,用于在用户与服务器之间的多次交互中保持用户的身份信息。2.服务器生成并通过cookie或URL参数发送给客户端,帮助在用户的多次请求中识别和关联这些请求。3.生成通常使用随机算法保证唯一性和不可预测性。4.在实际开发中,可以使用内存数据库如Redis来存储session数据,提升性能和安全性。

在无状态环境如API中管理会话可以通过使用JWT或cookies来实现。1.JWT适合无状态和可扩展性,但大数据时体积大。2.Cookies更传统且易实现,但需谨慎配置以确保安全性。

要保护应用免受与会话相关的XSS攻击,需采取以下措施:1.设置HttpOnly和Secure标志保护会话cookie。2.对所有用户输入进行输出编码。3.实施内容安全策略(CSP)限制脚本来源。通过这些策略,可以有效防护会话相关的XSS攻击,确保用户数据安全。

优化PHP会话性能的方法包括:1.延迟会话启动,2.使用数据库存储会话,3.压缩会话数据,4.管理会话生命周期,5.实现会话共享。这些策略能显着提升应用在高并发环境下的效率。

thesession.gc_maxlifetimesettinginphpdeterminesthelifespanofsessiondata,setInSeconds.1)它'sconfiguredinphp.iniorviaini_set().2)abalanceIsiseededeedeedeedeedeedeedto to to avoidperformance andununununununexpectedLogOgouts.3)

在PHP中,可以使用session_name()函数配置会话名称。具体步骤如下:1.使用session_name()函数设置会话名称,例如session_name("my_session")。2.在设置会话名称后,调用session_start()启动会话。配置会话名称可以避免多应用间的会话数据冲突,并增强安全性,但需注意会话名称的唯一性、安全性、长度和设置时机。


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