Node.js http.ServerResponse.headersSent用法及代码示例

httpServerResponse.headersSent是HTTP模块内的ServerResponse类的内置应用程序编程接口，用于检查标头是否已发送。

用法:

const response.headersSent

参数：此属性不接受任何参数作为参数。

返回值：当且仅当发送标头时，此属性返回true，否则返回false。

范例1：Filename-index.js

Javascript

// Node.js program to demonstrate the   
// response.headersSent() method 
  
// Importing http module  
var http = require('http'); 
  
// Setting up PORT  
const PORT = process.env.PORT || 3000; 
  
// Creating http Server  
var httpServer = http.createServer( 
    function (request, response) { 
  
    // Checking if response header is sent or not 
    // by using headersSent method 
    const value = response.headersSent; 
  
    // Display result by using end() method 
    response.end("Headers have been sent:"
                   + value, 'utf8', () => { 
        console.log("displaying the result..."); 
  
        httpServer.close(() => { 
            console.log("server is closed") 
        }) 
    }); 
}); 
  
// Listening to http Server  
httpServer.listen(PORT, () => { 
    console.log("Server is running at port 3000..."); 
});

使用以下命令运行index.js文件：

node index.js

输出：

Server is running at port 3000...
displaying the result...
server is closed

现在打开浏览器并转到http：//localhost：3000 /，您将看到以下输出：

Headers have been sent:false

示例2：Filename-index.js

Javascript

// Node.js program to demonstrate the   
// response.headersSent() method 
  
// Importing http module  
var http = require('http'); 
  
// Request and response handler  
const httpHandlers = (request, response) => { 
  
    // Checking if response header is sent or not 
    // by using headersSent method 
    const value = response.headersSent; 
  
    // Display result by using end() method 
    response.end("Headers have been sent:"
                      + value, 'utf8', () => { 
        console.log("displaying the result..."); 
  
        httpServer.close(() => { 
            console.log("server is closed") 
        }) 
    }); 
}; 
  
// Creating http Server  
var httpServer = http.createServer( 
    httpHandlers).listen(3000, () => { 
    console.log("Server is running at port 3000..."); 
});

使用以下命令运行index.js文件：

node index.js

输出：

Server is running at port 3000...
displaying the result...
server is closed

现在打开浏览器并转到http：//localhost：3000 /，您将看到以下输出：

Headers have been sent:false

参考： https://nodejs.org/dist/latest-v12.x/docs/api/http.html#http_response_headerssent

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注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 Node.js http.ServerResponse.headersSent Property。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。