How to solve the problem that the verification code is not displayed in thinkphp3.2

Recently, when using ThinkPHP3.2, sometimes we encounter the problem that the verification code is not displayed. How should we solve this situation? This article will share some solutions with you.

First of all, we need to understand the principle of generating verification code. In ThinkPHP, verification codes are generated by instantiating a Verify class, which generates a random verification code image based on specified parameters and saves the verification code value to the session. We can call the verification code generation method through code similar to the following:

$verify = new \Think\Verify();
$verify->entry();

Next, we need to check the relevant configuration options for generating verification codes. In ThinkPHP, the relevant configuration when generating the verification code can be set in the config.php file, for example:

'VERIFY_LENGTH' => 4, // 验证码长度
'VERIFY_IMAGEH' => 45, // 验证码图片高度
'VERIFY_IMAGEW' => 160, // 验证码图片宽度
'VERIFY_FONTFILE' => './Data/Font/elephant.ttf', // 验证码字体文件

If we set the VERIFY_FONTFILE configuration option incorrectly, or the font file does not exist, it may cause verification The code cannot be displayed properly. Therefore, we need to ensure that the value of the VERIFY_FONTFILE configuration option is correct and that the font file exists in the specified location.

If none of the above problems exist, then we need to check whether the GD library extension is enabled in the PHP environment. The GD library is a commonly used image processing library in PHP. If this extension is not turned on, the verification code image cannot be generated. We can check whether the GD library has been opened by executing the phpinfo() function in PHP, for example:

<?php
phpinfo();

Then open the PHP file in the browser and find out whether the gd module is loaded.

Finally, if none of the above problems exist, then we can consider debugging the code to see what happened. For specific methods, please refer to the following code:

$verify = new \Think\Verify();
if (!$verify->check($code)) {
    // 验证码输入有误
    exit($verify->getError());
}

In the above code, we added a debugging code before the verification code verification. If the verification code verification fails, an error message will be output, thus helping us better locate the problem. .

Generally speaking, there are many possibilities for the verification code not being displayed, and we need to investigate one by one to find the specific reason. The above methods only provide some common solutions, I hope they can be helpful to everyone.

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