Web Programming Week 1

1. Web ProgrammingWeek 1 Old Dominion University Department of Computer Science CS 418/518 Fall 2010 Martin Klein <mklein@cs.odu.edu> 8/31/10

2. Goals • We will learn to work in the LAMP environment: PHP - PHP: Hypertext Preprocessor PHP - PHP: Hypertext Preprocessor PHP - PHP: Hypertext Preprocessor PHP - PHP: Hypertext Preprocessor . . .

3. No MS Environments!

4. Goals • Demonstrate LAMP proficiency with a semester long project based on a bulletin board system. • Some examples: • http://tt.tennis-warehouse.com/ • http://boards.caazone.com/ • http://www.fordfe.com/ • http://www.techsideline.com/forums.htm

5. Prerequisites • I assume you know: • how to program in some (imperative) language • basic Internet/WWW concepts • basic HTML • basic relational database concepts

6. Who Should Take This Class? • This class will cover breadth, not depth • If you want to learn more about: • System administration • CS 454/554 Network Management • HTTP • CS 495/595 Web Server Design • databases • CS 450/550 Database Concepts • CS 419/519 Internet Databases • and many others…. • Java • CS 695 Java & XML

7. Mandatory 1st Class of the Semester Slide • This is a programming class! • I assume you know how to program • your grade will be determined solely on your program’s performance on 4 different checkpoints through the semester • Attendance is not mandatory • But don’t waste your and my time! • You will work in teams of 1 or 2 • (grad + undergrad teams are possible) • Pick teams wisely • teams will exist by mutual consent only • at any time, teams can split up, but no new teams will be formed after the first assignment is due • ex-team members will have access to their shared code base

8. Mandatory 1st Class of the Semester Slide #2 • Important URLs • http://www.cs.odu.edu/~mklein/teaching/cs518-f10/ • http://groups.google.com/group/cs518-f10 • Class homepage: • Readings are listed under the day they are expected to be completed • assignments are listed under the day they will be demoed in class (attendance) • each group will give a 3-4 minute status report the week before an assignment is due! (attendance) • All development will be done on a shared Linux machine • mln-web.cs.odu.edu • TA: tbd

9. Grading, aka Mandatory 1st Class of the Semester Slide #3 • 4 programs, 23 points each • 17 points for functional requirements • 3 points voted on by other groups for aesthetic appeal • 3 points for in-class status report the week prior to the assignment’s due date • 8 remaining points come from each group asking or answering 8 technical questions about the assignments on the email list • no points for duplicate questions or answers!

10. request = (method, URI, version, “MIME-like” message) response = (version, success/error code, “MIME-like” message) HTTP Operation Origin Server Client

11. Lots of HTTP Methods… • GET, HEAD • TRACE • for debugging • OPTIONS • what methods are defined on this URI? • DELETE • rarely supported for most URIs • PUT • also rarely supported • unix semantics: % echo “hello world” > temp.txt • POST • commonly supported • unix semantics: % echo “hello world” | spell • Want to learn more? read RFC-2616 • http://www.ietf.org/rfc/rfc2616.txt

12. Talking to HTTP servers… mk$ curl --head www.cs.odu.edu/~mklein/ HTTP/1.1 200 OK Date: Wed, 13 Jan 2010 15:36:09 GMT Server: Apache/2.2.14 (Unix) DAV/2 PHP/5.2.11 Last-Modified: Mon, 11 Jan 2010 01:38:15 GMT ETag: "640e2a-552-47cd9974d0fd9" Accept-Ranges: bytes Content-Length: 1362 Content-Type: text/html “curl” is convenient, but speaking raw HTTP is more fun… mk$ curl --head www.google.com/ HTTP/1.1 200 OK Date: Wed, 13 Jan 2010 15:43:10 GMT Expires: -1 Cache-Control: private, max-age=0 Content-Type: text/html; charset=ISO-8859-1 Set-Cookie: PREF=ID=93c27673a367c338:TM=1263397390:LM=1263397390:S=akzlDIbyLg9rjmww; expires=Fri, 13-Jan-2012 15:43:10 GMT; path=/; domain=.google.com Server: gws Transfer-Encoding: chunked

13. GET mk$ telnet www.cs.odu.edu 80 Trying 128.82.4.2... Connected to xenon.cs.odu.edu. Escape character is '^]'. GET /~mklein/index.html HTTP/1.1 Connection: close Host: www.cs.odu.edu HTTP/1.1 200 OK Date: Wed, 13 Jan 2010 14:51:57 GMT Server: Apache/2.2.14 (Unix) DAV/2 PHP/5.2.11 Last-Modified: Mon, 11 Jan 2010 01:38:15 GMT ETag: "640e2a-552-47cd9974d0fd9" Accept-Ranges: bytes Content-Length: 1362 Connection: close Content-Type: text/html <html> <head><title>Martin Klein -- Old Dominion University</title></head> <body> … [lots of html deleted] … </html> Connection closed by foreign host. Request (ends w/ CRLF) Response

14. HEAD mk$ telnet www.cs.odu.edu 80 Trying 128.82.4.2... Connected to xenon.cs.odu.edu. Escape character is '^]'. HEAD /~mklein/index.html HTTP/1.1 Connection: close Host: www.cs.odu.edu HTTP/1.1 200 OK Date: Wed, 13 Jan 2010 15:46:43 GMT Server: Apache/2.2.14 (Unix) DAV/2 PHP/5.2.11 Last-Modified: Mon, 11 Jan 2010 01:38:15 GMT ETag: "640e2a-552-47cd9974d0fd9" Accept-Ranges: bytes Content-Length: 1362 Connection: close Content-Type: text/html Connection closed by foreign host.

15. POST • Typically the result of HTML “Forms” • http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4 • Two types of values in the client’s “Content-type” request header: • application/x-www-form-urlencoded   • (original & default) • multipart/form-data • introduced in RFC-1867; allows file upload • http://www.ietf.org/rfc/rfc1867.txt

16. HTML Examples <FORM action="http://server.com/cgi/handle" enctype= "application/x-www-form-urlencoded" method="post"> <P> What is your name? <INPUT type="text" name="submit-name"><BR> <INPUT type="submit" value="Send"> <INPUT type="reset"> </FORM> <FORM action="http://server.com/cgi/handle" enctype="multipart/form-data" method="post"> <P> What is your name? <INPUT type="text" name="submit-name"><BR> What files are you sending? <INPUT type="file" name="files"> <BR> <INPUT type="submit" value="Send"> <INPUT type="reset"> </FORM> based on examples from: http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4

17. application/x-www-form-urlencoded POST /~mklein/foo.cgi HTTP/1.1 Host: www.cs.odu.edu Connection: close Referer: http://www.cs.odu.edu/~mklein/fromhere.html User-Agent: CS 595-s10 Automatic Testing Program Content-type: application/x-www-form-urlencoded Content-Length: 134 action=restore&manufacturer=ford&model=fairlane+500XL &year=1966&status=modified&engine=427+sideoiler &transmission=4+speed+toploader functionally the same as (modulo a possible 414 response): GET /~mklein/foo.cgi?action=restore&manufacturer=ford&model=fairlane+500XL &year=1966&status=modified&engine=427+sideoiler&transmission=4+speed+toploader HTTP/1.1 Host: www.cs.odu.edu Connection: close Referer: http://www.cs.odu.edu/~mklein/fromhere.html User-Agent: CS 595-s10 Automatic Testing Program

18. POST /~mklein/foo.cgi HTTP/1.1 Host: www.cs.odu.edu Connection: close Referer: http://www.cs.odu.edu/~mklein/fromhere.html User-Agent: CS 595-s10 Automatic Testing Program Content-type: multipart/form-data; boundary=----------0xKhTmLbOuNdArY Content-Length: 698 ------------0xKhTmLbOuNdArY Content-Disposition: form-data; name=”action" restore ------------0xKhTmLbOuNdArY Content-Disposition: form-data; name=”manufacturer" ford ------------0xKhTmLbOuNdArY Content-Disposition: form-data; name=”model" fairlane 500xl ------------0xKhTmLbOuNdArY Content-Disposition: form-data; name=”year" 1966 ------------0xKhTmLbOuNdArY Content-Disposition: form-data; name=”picture"; filename="fairlane.txt" Content-Type: text/plain ______________ // \\ ---------//--------------\\------- | __ __ | |--/ \--------------------/ \---| \__/ \__/ ------------0xKhTmLbOuNdArY-- multipart/form-data(with file upload) note the “--” to indicate the end

19. Response Codes from section 6.1.1 of RFC 2616 - 1xx: Informational - Request received, continuing process - 2xx: Success - The action was successfully received, understood, and accepted - 3xx: Redirection - Further action must be taken in order to complete the request - 4xx: Client Error - The request contains bad syntax or cannot be fulfilled - 5xx: Server Error - The server failed to fulfill an apparently valid request

20. GET /foo HTTP/1.1 HTTP/1.1 200 OK foo foo HTML, PDF, etc. foo foo PHP, ASP, JSP foo foo Java, Javascript But Few Web Resources Are Static Files… Origin Server Client foo

21. Server Side Processing Mnemonic CODE HTML html code html code “Traditional” CGI (e.g. Perl) PHP

22. Let’s Look at Some Basic PHP http://mln-web.cs.odu.edu/~mklein/code/

23. WWW History If you want to know more, read a book (irony intentional)

24. PHP Helper (one of many)

25. Who Should NOT Take This Class? • Students not able to/not willing to learn how to code • Students not willing to work in groups • Students not willing to work on and solve complex problems

26. To Do for Next Time… • Subscribe to the class email list • Log in to: mln-web.cs.odu.edu (I will send email to the class list when the accounts are ready) • uid/passwds same as *.cs.odu.edu machines • don’t have a *.cs.odu.edu acct? get one: https://sysweb.cs.odu.edu/online/ • MySQL login == linux login; passwd = (to be determined) • Start reading & practicing in your own public_html directory on the cs machines • Email me your group info! If you’re not in a group by 11:59 PM Sept 07 2010, you’re working alone.

27. “And Now For Something Completely Different” • Weekly “Trivia of the Day” • Question: “What happened today x years ago?” • Main but not exclusive source: Wikipedia • Price: