javascript - Ajax实现的长轮询如何才能不阻塞同一时间内页面的其他Ajax请求(同域请求)呢?
长轮询的实现是用xmlhttprequest递归得到的,页面一旦加入了这种轮询方式,其他地方的ajax请求就没反应了,比如滚动到页底自动加载新文章。查了资料,据说HTTP 1.1是不允许同一时间客户端向同一服务器建立2个http连接。如何解决?
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长轮询的实现是用xmlhttprequest递归得到的,页面一旦加入了这种轮询方式,其他地方的ajax请求就没反应了,比如滚动到页底自动加载新文章。查了资料,据说HTTP 1.1是不允许同一时间客户端向同一服务器建立2个http连接。如何解决?
据说HTTP 1.1是不允许同一时间客户端向同一服务器建立2个http连接
这个说法不对
实际上是不能并发访问同一个站点使用了session的页面,因为访问A页面时,session被锁住了,B页面要等A页面结束释放锁才能被执行。解决方法就是不用session,或者session使用后立刻释放(php 使用session_write_close释放session锁)
回过一次了,再回一次
直接终止轮询返回当前结果(轮询结果,可能为空),发起其他地方的ajax请求,得到结果,然后再开个轮询呗(可能我这想法太naive了),或者改需求哈哈。
其实用轮询的方式实现server push(一般都是这个作用吧?),不如用socket,不过好像其标准还不是太清晰。具体请google,对了昨天还看到个有人分享的文章:消息推送机制技术设计
递归一个LongPolling,在开启第二个请求时,第一个请求的连接已经被关闭了。那实际上就还有一个可用的通道。只要保证后端对应的数据服务返回足够快,那么一个信道也可以不block。
至于别的方案么,绕个圈子JSONP,Flash XML Socket/Websocket,某些Ajax放在别的域下,然后配置server的CORS,或者iframe什么的。
讲一下ifame的数据提交方式
用iframe实际上是用form提交数据的方式,把数据提交给一个iframe,然后返回一个页面在iframe中,页面中是一段js代码
例如
<code><script type="text/javascript"> window.parent.method(data); </script> </code>
用这种方式把数据提交到后台进行处理,在低版本浏览器中,通常使用此方法,上传图片
在当前页面中,要在window对象下定义一个全局对象或方式,可以使用
window.parent
来调用此方法使用iframe来提交数据,要与后端进行约定,在前端所执行的js方法。 一般数据提交不建议使用iframe方式。还是ajax较为方使
能不能把长轮询改下请求方式,在客户端使用js定时去请求服务器端,服务器端设置响应的时间。到了设置的时间就去响应。仿照队列,前后端都排好队。先来的先服务。

Setting session cookie parameters in PHP can be achieved through the session_set_cookie_params() function. 1) Use this function to set parameters, such as expiration time, path, domain name, security flag, etc.; 2) Call session_start() to make the parameters take effect; 3) Dynamically adjust parameters according to needs, such as user login status; 4) Pay attention to setting secure and httponly flags to improve security.

The main purpose of using sessions in PHP is to maintain the status of the user between different pages. 1) The session is started through the session_start() function, creating a unique session ID and storing it in the user cookie. 2) Session data is saved on the server, allowing data to be passed between different requests, such as login status and shopping cart content.

How to share a session between subdomains? Implemented by setting session cookies for common domain names. 1. Set the domain of the session cookie to .example.com on the server side. 2. Choose the appropriate session storage method, such as memory, database or distributed cache. 3. Pass the session ID through cookies, and the server retrieves and updates the session data based on the ID.

HTTPS significantly improves the security of sessions by encrypting data transmission, preventing man-in-the-middle attacks and providing authentication. 1) Encrypted data transmission: HTTPS uses SSL/TLS protocol to encrypt data to ensure that the data is not stolen or tampered during transmission. 2) Prevent man-in-the-middle attacks: Through the SSL/TLS handshake process, the client verifies the server certificate to ensure the connection legitimacy. 3) Provide authentication: HTTPS ensures that the connection is a legitimate server and protects data integrity and confidentiality.

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.


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