Let's talk about the investigation and solutions to the problem of ThinkPHP3 verification code not displaying

In the process of developing using ThinkPHP3, we usually use verification codes to increase the security of the system. However, sometimes we encounter the problem that the verification code does not display. This issue can occur due to different reasons, some possible causes and solutions are described below.

1. The storage path of the verification code image is incorrect

In ThinkPHP3, the verification code image is saved in a temporary directory by default. This directory can be set in the config.php configuration file , for example:

return array(
    'TEMP_PATH' => './Public/temp/',
    //其他配置
);

If the directory does not exist or does not have write permission, the verification code will not be displayed normally. Therefore, we need to check if the directory exists and if it has write permission.

2. Verification code image generation failed

When we need to display the verification code image in the browser, we need to use an Action to generate the verification code image. This Action is usually defined in a controller, for example:

class VerifyAction extends Action {
    public function index(){
        import("ORG.Util.Verify");
        Verify::buildImage();
    }
}

If the verification code image generation fails, it will also cause the verification code to not be displayed normally. We can check the specific cause of this problem by adding logs or debugging information, for example:

class VerifyAction extends Action {
    public function index(){
        import("ORG.Util.Verify");
        $res = Verify::buildImage();
        if(!$res)
            Log::write('验证码图片生成失败');
    }
}

3. Verification code Session saving problem

When we enter the verification code in the browser, we need Compare the value of the verification code with the value saved in the Session to determine whether the input is correct. If the verification code value does not match the value saved in the Session, then we need to regenerate a verification code. Therefore, we need to ensure that the value of the verification code can be correctly saved to the Session, for example:

class VerifyAction extends Action {
    public function index(){
        import("ORG.Util.Verify");
        Verify::buildImage();
        $_SESSION['verify'] = md5(strtolower(trim(Verify::getCode())));
    }
}

In the above code, the value of the verification code is processed through the trim() function, which can remove leading and trailing spaces and Enter character etc. At the same time, encryption is performed through the md5() function to ensure that the value of the verification code cannot be easily guessed.

4. Verification code image URL error

When we use the img tag in the page to display the verification code image, we need to set the correct URL link. If the link is set incorrectly, the verification code will not be displayed properly. We need to make sure that the parameters of the link are set correctly, for example:

<img src="__APP__/Verify/index" onclick="javascript:this.src=&#39;__APP__/Verify/index?&#39;+Math.random();"/>

In the above code, we have used JavaScript to avoid browser caching issues. Every time you click on the verification code image, the verification code image will be refreshed with a random number.

Summary

The above are some reasons and solutions that may cause the ThinkPHP3 verification code to display abnormally. When we encounter this problem, we can investigate and handle it according to the specific situation. By solving this problem, we were able to improve the security of our system while also strengthening our own development skills.

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