With the continuous development of Internet technology, we need to implement more and more multi-request functions when developing web applications. In the development mode where the front and back ends are separated, the front-end page needs to send multiple requests to the back-end to obtain different data or implement different operations. In PHP development, we can use an excellent framework - ThinkPHP to achieve this goal.
This article will introduce in detail how to use the ThinkPHP framework to implement multi-request functionality.
1. What is multiple requests?
Multiple requests means that in a web application, a page or a function needs to send multiple requests to the backend to obtain different data or implement different operations. The implementation of multiple requests usually relies on JavaScript technology and AJAX technology.
2. The principle of multi-request implementation in ThinkPHP
In ThinkPHP, we can use AJAX technology to implement the multi-request function. AJAX (Asynchronous JavaScript and XML) is a technology that uses JavaScript technology to send asynchronous requests to the server and receive responses. When sending a request using AJAX technology, the Web page does not need to be refreshed, nor does it need to reload the entire page, but only the part that needs to be updated needs to be updated.
ThinkPHP framework provides a convenient AJAX request method, which handles asynchronous requests through the index method of the AjaxController class, which returns a response in JSON data format. We can handle multiple requests in the index method and return multiple JSON format data.
3. Implementation steps of ThinkPHP multiple requests
php think make:controller AjaxController
The following is a simple example. We get a list of students and use the index method to return data in JSON format:
// applicationindexcontrollerAjaxController.php namespace appindexcontroller; use thinkController; use thinkDb; class AjaxController extends Controller { public function index() { // 获取学生列表 $students = Db::table('student')->select(); // 返回 JSON 格式的数据 return json($students); } }
The following is a simple example. We send a request to AjaxController and display the data on the page after getting the data:
// index.html <script> var xhr = new XMLHttpRequest(); xhr.open('GET', '/index/ajax/index', true); // 发送异步请求 xhr.onreadystatechange = function() { if(xhr.readyState === 4 && xhr.status === 200) { var data = JSON.parse(xhr.responseText); // 获取后台返回的 JSON 数据 // 将数据显示在页面上 for(var i = 0; i < data.length; i++) { var tr = document.createElement('tr'); var td1 = document.createElement('td'); var td2 = document.createElement('td'); td1.innerHTML = data[i].name; td2.innerHTML = data[i].age; tr.appendChild(td1); tr.appendChild(td2); document.getElementById('studentList').appendChild(tr); } } } xhr.send(); </script> <table id="studentList"> <thead> <tr> <th>姓名</th> <th>年龄</th> </tr> </thead> <tbody> </tbody> </table>
In the above code, we send a request to AjaxController Send a GET request and listen to readyState and status events. When the readyState attribute value becomes 4, it indicates that the request has been completed, and the status attribute value is 200, which indicates that the request was successful. At this time, you can obtain the JSON data returned by the background through the responseText attribute, and then dynamically display the data on the page.
Through the above three steps, we can implement the multi-request function in the ThinkPHP framework. In actual development, we can process multiple requests in the index method according to specific needs, and return multiple JSON format data to the front-end page.
4. Summary
This article introduces how to implement the multi-request function in the ThinkPHP framework. By using AJAX technology, we can make multiple requests to the backend and get responses without reloading the page. In actual development, we can further optimize the implementation of multiple requests based on specific needs, such as using efficient database query methods and sending requests in reasonable groups.
In actual development, multiple requests are a very common requirement. Mastering the multi-request implementation method in the ThinkPHP framework can help us develop web applications more efficiently.
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