Handling Form Submissions in ThinkPHP: POST vs GET and Using the I Method

In ThinkPHP, common form submission methods include the POST and GET methods.

The POST method is more secure because GET parameters appear in the URL, potentially exposing sensitive information such as usernames and passwords.

To rewrite the add method, first check whether the request is a POST; if it is, process the form submission, otherwise display the template.

ThinkPHP provides several constants for request type detection, such as IS_POST (true when the request is POST), IS_GET , IS_AJAX , IS_CGI , IS_PUT , and others.

For receiving data, instead of using $_POST directly, ThinkPHP offers the I() helper method, which can retrieve input from any source (post, get, request, put, etc.) and automatically applies htmlspecialchars to mitigate SQL injection.

The I() method takes a variable type (e.g., 'post.' ) and a variable name; if the filtered value becomes an empty string, a default value can be supplied.

To receive an entire array of inputs, omit the variable name, for example I('get.') will return all GET parameters as an array.

Below is a complete PHP example demonstrating these concepts:

<?php
public function add(){
    if(IS_POST){
        //处理表单提交
        $post = I('post.');
        //实例化模型
        $model = M('Dept');
        $result = $model->add($post);
        //判断返回值
        if($result){
            //添加成功
            $this->success('添加成功',U('showList'),5);
        }else{
            $this->error('添加失败');
        }
    }else{
        //实例化模型
        $model = M('Dept');
        //查询操作
        $data = $model->where('pid = 0')->select();
        //变量分配
        $this->assign('data',$data);
        //展示模板
        $this->display();
    }
}
?>