《Web开发基础-基础知识》由会员分享，可在线阅读，更多相关《Web开发基础-基础知识（30页珍藏版）》请在金锄头文库上搜索。
1、Web开发基础赵刚本课程内容摘要 网站开发基础知识 网站环境构建 管理和配置网站 HTML Google January 1996 Chinese First Connection with Internet：Chinese Academics Net, by Computer Applying Technology Institute of Beijing1986， First email, Sep. 14 1987, from CATIB,“Across the Great Wall we can reach every corner in the world” Chinese First
2、 Full Internet Connection：NCFC (National Computing and Networking Facility of China) 1994 Baidu1999；Taobao 2003 essential of web development8Key aspects of the Internet Internet is for freedom of information internet Vs. Internet subnetworks can stand on their own computers can dynamically join and
3、leave the network built on open standards; anyone can create a new device lack of centralized control (mostly) everyone can use it with simple, commonly available softwareessential of web development9Layered architectureThe internet uses a layered hardware/software architecture (OSI model): physical
4、 layer: devices such as coaxial cables, fiber-optic lines, modems data link layer: basic hardware protocols (Ethernet, Wi-Fi, DSL, ATM, PPP) network / internet layer: basic software protocol (IP) transport layer: add reliability to network layer (TCP, UDP) application layer: implements specific comm
5、unication for each kind of program (HTTP, POP3/IMAP, SSH, FTP) essential of web development10Internet Protocol (IP)the IP is the underlying system of communication for all data (packets) sent across the internet. each device has a 32-bit IP address as four 8-bit numbers (0- 255) find out your intern
6、et IP address: find out your local IP address: in a terminal, type: ipconfig (Windows) or ifconfig (Mac/Linux) IP v4 vs. IP v6 (32-b vs. 128-b)essential of web development11Transmission Control Protocol (TCP)adds multiple, guaranteed message delivery on top of IP multiplexing: multiple programs usi
7、ng the same IP address port: a number given to each program or service 80: Web browser (443 for secure browsing) 25: email 22: ssh 21: ftp more common ports some programs (QQ, games, streaming media programs) use simpler UDP protocol instead of TCP find out ports used: in a terminal, using netstat (
8、Windows) command using CurrPortsessential of web development12Web servers and browsers Web server: software that listens for Web page requests part of Windows) C/S Vs B/S model Web browser: fetches/displays documents from Web servers Microsoft Internet Explorer (IE) Mozilla Firefox Apple Safari Goog
9、le Chrome Operaessential of web development13Domain Name System (DNS) a set of servers that map written names to IP addresses Example: 219.143.204.38 using Windows command nslookup to find out IP address many systems maintain a local cache called a host file Windows: C:Windowssystem32driversetchost
10、s Mac: /private/etc/hosts Linux: /etc/hostsessential of web development14Uniform Resource Locator (URL) an identifier for the location of a document on a web site a basic URL: http:/www.aw- protocol host path upon entering this URL into the browser, it would: ask the DNS server for the IP address of
11、 www.aw- connect to that IP address at port 80 ask the server to GET /info/regesstepp/index.html display the resulting page on the screenessential of web development15More advanced URLs anchor: jumps to a given section of a web page http:/ fetches index.html then jumps down to part of the page label
12、ed downloads port: for web servers on ports other than the default 80 http:/:8080/ query string: a set of parameters passed to a web program http:/ 10 parameter q is set to “miserable+failure“ parameter start is set to 10essential of web development16Hypertext Transport Protocol (HTTP)HTTP is the fo
13、undation of data communication for the World Wide Web. the set of commands understood by a web server and sent from a browser some HTTP commands (your browser sends these internally): GET filename : download POST filename : send a web form response PUT filename : upload DELETE filename : remove enti
14、ty HEAD filename : only status information, not entire content essential of web development17HTTP error codes when something goes wrong, the web server returns a special “error code“ number to the browser, possibly followed by an HTML document common error codes: 200 OK 301-303 page has moved (perma
15、nently or temporarily) 403 you are forbidden to access this page 404 page not found 500 internal server errorcomplete listessential of web development18Terms Internet Service Provider enterprises or organizations who provide Internet access to you, who? please identify your ISPs Web Hosting provide a place for consumers to store pag
