bosh comet ajax

本文介绍了BOSH(双向流过同步HTTP)和Comet两种技术。BOSH是一种高效的双向HTTP传输协议,避免了轮询并减少了延迟,在即时通讯应用中广泛使用。Comet则允许服务器主动推送数据到浏览器,通过长时间保持HTTP连接实现这一目标。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

Bidirectional-streams Over Synchronous HTTP (BOSH) is a transport protocol that emulates a bidirectional stream between two entities (such as a client and a server) by using multiple synchronous HTTP request/response pairs without requiring the use of polling or asynchronouschunking.

For applications that require both “push” and “pull” communications, BOSH is significantly more bandwidth-efficient and responsive than most other bidirectional HTTP-based transport protocols and the techniques known as AJAX. BOSH achieves this efficiency and low latency by avoiding HTTP polling, yet it does so without resorting to chunked HTTP responses as is done in the technique known as Comet. To date, BOSH has been used mainly as a transport for traffic exchanged between Jabber/XMPP clients and servers (e.g., to facilitate connections from web clients and from mobile clients on intermittent networks). However, BOSH is not tied solely to XMPP and can be used for other kinds of traffic, as well.

For "push", a BOSH client starts an HTTP request, but the server postpones sending a reply until it has data to send.[1] After receiving a reply, the client immediately makes another request on the same HTTP connection, so the server can always send data to the client without waiting for the client to poll. If while waiting for a reply the client needs to send data to the server, it opens a second HTTP connection. There are at most two HTTP connections open at a time, one on which the server can send data as a reply and one on which the client can send data as a POST.

It is a draft standard of the XMPP Standards Foundation.

The related standard XMPP Over BOSH defines how BOSH may be used to transport XMPP stanzas. The result is an HTTP binding for XMPP communications that is intended to be used in situations where a device or client is unable to maintain a long-lived TCP connection to an XMPP server.




Comet is a web application model in which a long-held HTTP request allows a web server to push data to a browser, without the browser explicitly requesting it.[1][2] Comet is an umbrella term, encompassing multiple techniques for achieving this interaction. All these methods rely on features included by default in browsers, such as JavaScript, rather than on non-default plugins. The Comet approach differs from the original model of the web, in which a browser requests a complete web page at a time.[3]

The use of Comet techniques in web development predates the use of the word Comet as a neologism for the collective techniques. Comet is known by several other names, including Ajax Push,[4][5] Reverse Ajax,[6] Two-way-web,[7] HTTP Streaming,[7] and HTTP server push[8] among others.[9]




Ajax (also AJAX/ˈæks/; an acronym for Asynchronous JavaScript and XML)[1] is a group of interrelated web development techniques used on the client-side to create asynchronous web applications. With Ajax, web applications can send data to, and retrieve data from, a serverasynchronously (in the background) without interfering with the display and behavior of the existing page. Data can be retrieved using the XMLHttpRequest object. Despite the name, the use of XML is not required (JSON is often used instead. See AJAJ), and the requests do not need to be asynchronous.[2]

Ajax is not a single technology, but a group of technologies. HTML and CSS can be used in combination to mark up and style information. The DOM is accessed with JavaScript to dynamically display, and allow the user to interact with, the information presented. JavaScript and the XMLHttpRequest object provide a method for exchanging data asynchronously between browser and server to avoid full page reloads






评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值