CGI II: Cookies & Stuff Web Programming

HTTP Cookie Mechanism to store/retrieve information on the HTTP client Web server sends a “cookie” in HTTP response header cookie is stored as text file (not executable) on the client’s local drive cookie is included in subsequent HTTP request headers until expiration Syntax HTTP Response Cookie is created & sent from Web Server to Web Client (e.g., Internet Explorer) Set-Cookie: NAME=VALUE; expires=DATE; domain=DOMAIN_NAME; path=PATH e.g. Set-Cookie: user=kiyang; expires=Thursday, 09-Dec-10 11:11:22 GMT; domain= kiyang.kmu.ac.kr; path=/~kiyang/teaching HTTP Request Cookie is returned from Web Client to Web Server Cookie: NAME1=VALUE1; NAME2=VALUE2; .. e.g. Cookie: user=kiyang; Web Programming

Cookies with CGI.pm Setting Cookies Getting Cookies $cookie = cookie ( -name => “WP-cookie”, -value => “$cookieID”, -path=> “/teaching/WP/f10’, -expires=>’+24h’); print header (-cookie=>$cookie); Getting Cookies $cookie_value = cookie (‘cookie-name’);  Example: Form Form CGI CGI (sending cookie) CGI (checking cookie) Web Programming

Fetching Web Pages Using LWP::Simple #!/usr/bin/perl use LWP::Simple; $url= http://widit.knu.ac.kr/~kiyang/hello.htm; $body= get($url); print $body; Example script Web Programming

Fetching Web Pages Using WWW-Mechanize use WWW::Mechanize; $url= "http://widit.kmu.ac.kr/~kiyang/hello.htm"; # Create a mechanize object my $mech = WWW::Mechanize->new( autocheck => 1 ); # Fetch a page $mech->get($url); print $mech->content; # Fetch a page into a file $mech->get($url,":content_file"=>"hello.htm"); # Get links @links= $mech->links(); # @links: array of link object foreach $link(@links) { my($url,$text,$absurl)= ($link->url(), $link->text, $link->url_abs()); print “$url, $text, $absurl\n”; } # Find links $link= $mech->find_link(url_abs_regex=>qr|^http://ella.slis.indiana.edu|); $page= $mech->follow_link(url_abs_regex=>qr|^http://ella.slis.indiana.edu|); @pages= $mech->follow_all_links(url_abs_regex=>qr|^http://ella.slis.indiana.edu|); Mechanized Spider Example: HTML, CGI S517 Session 13, SLIS-IU

CGI Examples Email Webpage Fetch File Upload Simple Search HTML form CGI Webpage Fetch File Upload Simple Search Advanced Search S517 Session 10, SLIS-IU

Reference/Pointer A reference Syntax a pointer to something (e.g. array, hash) a variable that refer to other variables contain a memory address of data good for working with large data structures creating complex data structures Syntax to create a reference $ptr1= \$scalar; $ptr2= \@array; $ptr3= \%hash; $ptr4= [1, 2, 3]; $ptr5= { k1=>v1, k2=>v2} to get the value Variable (i.e. scalar, array, hash) $$ptr1; @$ptr2; %$ptr3; Element of array/hash $$ptr2[0]; $$ptr3{0}; $ptr2->[0]; $ptr3->{0}; S517 Session 12, IU-SLIS

Multi-dimensional Arrays Using anonymous arrays $array = [ [id1,pw1], [id2,pw2], [id3,pw3] ]; for ($i=0; $i<=2; $i++) { for ($j=0; $j<=1; $j++) { print “$array -> [i][j]\n”; } Using array references @a1= (id1,pw1); @a2= (id2,pw2); @a3= (id3,pw3); @array = (\@a1, \@a2, \@a3); # array of array pointers for ($i=0; $i<=2; $i++) { $ptr= $array[$i]; print “@$ptr\n”; Examples: #1, #2, #3, #4, #5 S517 Session 12, IU-SLIS