Transcript Web server
159.339 Quick Tour of the Web LECTURE Technologies: The BIG picture A bird’s eye view of the different web technologies that we shall explore and study. Client-Server Client Web browser 159.339 requests an Internet resource by specifying a URL and providing input via HTTP encoded strings OS •Usually we want to open an HTML file from some website, but we can also open a program alternatively. HTML supports Javascript, DOM, CSS, HTML Events Client-Server Client Web browser 159.339 requests an Internet resource by specifying a URL and providing input via HTTP encoded strings Server os Web server os Internet Network Core Client-Server Client Web browser 159.339 Server-side program works out the necessary business logic and dynamically builds an HTML response. Server os Web server os Internet Client-Server Client Web browser 159.339 Server-side program sends back output as HTML using HTTP as transport mechanism Server Web server Internet Client-Server Client Web browser 159.339 Client-side program (Internet Explorer, Firefox) displays the HTML output • HTML text • Graphics • Streaming video/audio • XML Server Web server Internet Our own webserver 159.339 •Our codes might be embedded into an HTML, or viceversa. It may generate an HTML on its own as well. Server Web server My codes HTML MySQL Client Operating System Web browser Internet PHP Xitami Webserver • free, fast and open source professional web server, written in ANSI C • Server supports HTTP/1.0, FTP, CGI/1.1, SSI protocols • Security: basic authentication per directory, FTP access rights per user and per directory • Deployment: installs ready-to-run, portable to Windows, OS/2, Unix, OpenVMS, fully portable web sites and web applications; • Performance: internal multithreading engine, fast even on slower systems • Configuration: editable config files, or through a web-based administration interface (WBA) Documentation: http://legacy.imatix.com/html/xitami/ 159.339 159.339 Simple CGI Demonstration Let’s have a look at a very simple program (CGI) running in the server side CGI - The executable file generated out of a C program. Step 1. Run your webserver. Step 2. Using a browser, request for the HTML file containing our program from the server. Warning! You should specify the port number used by your webserver! HTTP Protocol 159.339 HTTP and TCP/IP 159.339 • Webserver supports HTTP. • HTTP compliancy is implemented using TCP/IP components. Server Web server My codes HTTP HTML MySQL Client Operating System Web browser TCP/IP Internet PHP Network Core 159.339 What’s in the network core? Server Web server My codes HTTP HTML MySQL Client Operating System Web browser TCP/IP Internet PHP Validating HTML Client Web browser 159.339 How to validate your HTML and CSS files? We want to write HTML pages + CSS files that are interoperable across many platforms (OS + web browser combination) Server Web server http://www.w3.org/QA/Tools/ Editor What editor can we use to assist us in writing PHP, Javascript, HTML, CSS files, etc.? phpDesigner Personal Edition • a free editor for your web-development. • rapid fast and full-featured PHP editor and PHP IDE with built-in HTML, CSS and JavaScript editors and FTP/SFTP! Link: http://www.mpsoftware.dk/ 159.339 PuTTY 159.339 Using a simple tool called PuTTY, examine the HTTP protocol in action when a web client interacts with your webserver (Xitami, running in your own machine). PuTTY is a free implementation of Telnet and SSH for Windows and Unix platforms, along with an xterm terminal emulator. It is written and maintained primarily by Simon Tatham. What is the IP address of your machine? Ipconfig /all Is your server running properly? What was the server’s response? Which port number is open? netstat -anop TCP http://surf11.com/entry/176/command-to-show-open-tcp-ports-windows What’s next? 159.339 We shall be looking at all the details of prominent internet programming languages and technology but we shall study how to write HTML and CSS documents first. Next meeting, I shall provide a good background on the nuts and bolts of the internet so that you may have knowledge of the essential protocols that will be interacting with our web server. Servlets 159.339 CLIENT Servlets run inside a Web Container - the component of the web server that runs and interacts with servlets Servlets 159.339 HTML, WML, XML CLIENT Servlets run inside a Web Container - the component of the web server that runs and interacts with servlets Servlet is running on the server listening for requests When a request comes in, a new thread is generated by the web container. NetBeans •Servlets go into a specific directory structure. •NetBeans will create that for you. • Compile, load, deploy your servlets. Link: http://netbeans.org/downloads/ 159.339 JSP 159.339 JSP encourages you to: – Separate the (Java) code that creates the content from the (HTML) code that presents it – Have different members of your team work on the HTML layout and do the Java programming JSP vs. Competing tech.159.339 • JSP vs PHP – Much richer language for the dynamic part – Better tool support – More resource efficient • JSP vs pure servlets – More convenient to create HTML – Can use standard tools – Divide and conquer • JSP vs client-side Javascript – You control the server, not the client • JSP vs .NET – Open standards: Portable to multiple servers and operating systems • JSP vs static HTML – Obvious!