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Chris Pollett > Old Classes > PIC40 ( Print View ) Lecture Notes-PDF Spring '01 Ad: Enrollment info Course Info:
Practice Exams: PIC: |
HW4 Solutions Page
<html>
<!--
Filename: p40hw4file1.html
Purpose: This file is the main document for our Toy Search Engine
site. It gives the opportunity to the user to search
the engine for an entry. It also has a link to the add a
page document (p40hw4file4.php).
-->
<head>
<title>Toy Search Engine</title>
<meta http-equiv="Content-Type" content="text/html;
charset=iso-8859-1" />
<meta name="Authors" content="Christopher Pollett" />
<meta name="keywords" content="search engine" />
</head>
<body text="#000000" bgcolor="#99FFCC" link="#0000EE" vlink="#551A8B"
alink="#FF0000">
<h1 style="text-align:center">Toy Search Engine
</h1>
<!--The SSI that follows checks if the searchdb directory
exists. If not it creates it. In the event that this document
was accessed as the action of the add a page document's
(p40hw4file4.php's) form, the SSI below adds the URL
and description to the appropriate DBMS in the searchdb.
It then prints out if this was successful.
-->
<!--#exec cgi="p40hw4file2.cgi" -->
<!-- Now we have the search form described in the purpose of this document.
-->
<form method="GET"
action="http://www.math.ucla.edu/~cpollett/hw4/p40hw4file1.php">
<div style="text-align:center">
<table border="0" cellpadding="0" >
<tr>
<td valign="center">Search database for a single keyword:
</td>
<td valign="bottom">
<input type="text" name="searchfield" size="15" maxlength="80" />
</td>
<td valign="bottom">
<input type="submit" name="submit1" value="Submit" />
</td>
</tr>
</table>
</form>
<!-- If this document was called as the action of the above form,
then the next SSI checks the DBMs in the searchdb to see
if there are any matches.
-->
<!--#exec cgi="p40hw4file3.cgi" -->
<br />
<a href="p40hw4file4.php" >Add a page to the database.</a>
<p>
This page was last modified <!--#flastmod file="p40hw4file1.php"-->.</p>
</div>
</body>
</html>
#!/usr/local/bin/perl
#
# Filename: p40hw4file2.cgi
#
# Purpose: This script is used by the Toy Search Engine to
# associate a URL description pair with a list of
# keywords. It is also called by the p40hw1file1.php
# document to create the searchdb directory if it doesn't exist.
#
require "subparseform.lib";
Parse_Form();
#
# Begin Main Section
#
print "Content-type: text/html\n\n";
if(!$formdata{submit2})
{CheckDir();} # if submit2 doesn't exist we check if need to create
# searchdb
else
{AddPage();} # add URL description pairs to appropriate DBMs.
#
# End Main Section
#
#
# Function: CheckDir
#
# Purpose: creates the searchdb directory if it doesn't exist
#
sub CheckDir()
{
if(-d "searchdb") {return;}
mkdir("searchdb",0755);
}
#
# Function: AddPage
#
# Purpose: adds URL description row to a DBM hash for each keyword
# passed in the keywords form variable.
#
sub AddPage()
{
my @keywords= split(/\s/,$formdata{keywords}); #get list of keywords
foreach $word (@keywords) #now add URL description row to
#each keyword's DBM.
{
dbmopen(%urlTable,"searchdb/$word",0755);
$urlTable{$formdata{url}}=$formdata{description};
dbmclose(%urlTable);
}
print "<p>URL added to appropriate DBMs.</p>\n";
}
#!/usr/local/bin/perl
#
# Filename: p40hw4file3.cgi
#
# Purpose: This script presents the results a Toy Engine Search
# on a given keyword.
#
require "subparseform.lib";
Parse_Form();
print "Content-type: text/html\n\n";
if(!$formdata{searchfield})
{return;} #if the searchfield variable is not set
#then we haven't searched for anything yet so stop
#
# Now we check if the keyword exists as a DBM hash in the searchdb.
# If not print no matches. Otherwise, we open that hash and print
# the URL description pairs listed there.
#
if(-e "searchdb/$formdata{searchfield}.dir")
{
dbmopen(%urlTable,"searchdb/$formdata{searchfield}",0755);
print "<table>\n";
#
# The next while loop prints out the URL description pairs.
#
while( ($key, $value) = each(%urlTable))
{
print "<tr><td>\n";
print "<a href=\"$key\">$key</a>\n";
print "</td><tr><td>\n";
print "Description:<br />\n$value\n";
print "<br /><br /></td></tr>\n";
}
print "</table>\n";
dbmclose(%urlTable);
}
else
{
print "<p>Sorry, no matches.</p>\n";
}
<html>
<!--
Filename: p40hw4file4.php
Purpose: This document provides a form that allows the user
to associate a new URL description pair to a list of
keywords in th Toy Search Engine.
-->
<head>
<title>Toy Search Engine -- add a page</title>
<meta http-equiv="Content-Type" content="text/html;
charset=iso-8859-1" />
<meta name="Authors" content="Christopher Pollett" />
<meta name="keywords" content="search engine" />
</head>
<body text="#000000" bgcolor="#99FFCC" link="#0000EE" vlink="#551A8B"
alink="#FF0000">
<div style="text-align:center">
<h1>Toy Search Engine -- add a page
</h1>
<!-- The action of the form on this page is p40hw4file1.html;
however, the page is actually added by the cgi script
p40hw4file2.cgi which is exec'd as an SSI in
p40hw4file1.php
-->
<form method="GET"
action="http://www.math.ucla.edu/~cpollett/hw4/p40hw4file1.php">
<table border="0" cellpadding="0" >
<tr>
<td>Enter a list of space separated keywords:</td>
</tr>
<tr>
<td>
<input type="text" name="keywords" size="40" maxlength="120" />
<br /> <br />
</td>
</tr>
<tr><td>Enter a URL:</td></tr>
<tr>
<td>
<input type="text" name="url" size="40" maxlength="120" />
<br /> <br />
</td>
</tr>
<tr><td valign="top">Enter a description:</td></tr>
<tr><td><textarea name="description" cols="40" rows="10">
</textarea></td>
</tr>
</table>
<input type="submit" name="submit2" value="Submit" />
<input type="reset" name="Reset" />
</form>
<p>
This page was last modified <!--#flastmod file="p40hw4file4.php"-->.
</p>
</div>
</body>
</html>
#!/usr/local/bin/perl
#
# Name: NClock HW3 Bonus solutions
#
# Purpose: A simple PERL clock which sync's with the NIST atomic clock
# or any internet clock which uses the RFC 867 time protocol.
# Command line arguments: timezone, width, height, clockSite, sync frequency
#
# Example Uses: >NClock --- starts a 150x150 clock on PST using time-a.nist.gov
# syncing every 60 seconds.
#
# >NClock -5 200 300 time-b.nist.gov 30
# --- starts a 200x300 clock on EST using time-b.nist.gov
# syncing every 30 seconds
#
# Author: Chris Pollett
#
#
# includes
#
use Tk;
use Socket;
#
# Globals
#
$PI=3.1415926535; # beloved constant
$zoneOffset = ($ARGV[0]) ? $ARGV[0] : -8; # timezones from Greenwich Mean Time
$clockSizeX = ($ARGV[1]) ? $ARGV[1] : 150; #clock width
$clockSizeY = ($ARGV[2]) ? $ARGV[2] : 150; #clock height
$syncClock = ($ARGV[3]) ? $ARGV[3] : "time-a.nist.gov"; #atomic clock to connect to
$syncFreq = ($ARGV[4]) ? $ARGV[4] : 300; # number of seconds between contacting atomic clock
$secCount=0; #counter used to tell when to resync with atomic clock
#
# Main Loop
#
$mw = MainWindow->new;
$mw->geometry("$clockSizeX"."x"."$clockSizeY");
$menu = $mw->Menu(-tearoff =>'0',
-menuitems => [
[ 'command' => "Greenwich",
-command=>sub{$zoneOffset = 0; $secCount=0;}],
[ 'command' => "Maritime",
-command=>sub{$zoneOffset = -4; $secCount=0;}],
[ 'command' => "Eastern",
-command=>sub{$zoneOffset = -5; $secCount=0;}],
[ 'command' => "Central",
-command=>sub{$zoneOffset = -6; $secCount=0;}],
[ 'command' => "Mountain",
-command=>sub{$zoneOffset = -7; $secCount=0;}],
[ 'command' => "Pacific",
-command=>sub{$zoneOffset = -8; $secCount=0;}]
]);
$mw->bind("<Button-3>", sub{ $menu->Popup(-popover =>'cursor');});
$canvas = $mw->Canvas(-background => "white",
-height => $clockSizeX,
-width => $clockSizeY);
$canvas->pack(); #canvas on which clock drawn
$mw->repeat(1000,\&ReDraw);
MainLoop;
#
# Name: ReDraw($frame, $canvas);
#
# Purpose: computes current time (sync'd with atomic clock every $syncFreq seconds)
# then draws clock based on this time
#
sub ReDraw
{
#
#get size of current window and resize clock accordingly
#
($clockSizeX,$clockSizeY)=split(/[x|+]/,$mw->geometry());
$canvas->configure(-height => $clockSizeY,
-width => $clockSizeX);
#
# Now either sync with NIST time or assume a second has passed
# and update time accordingly
#
if($secCount== 0)
{
$time = connectNIST();
($hour,$minute,$second) =split(/:/,$time);
$hour =($hour+$zoneOffset)%24;
$ampm = ($hour<12)? "am" : "pm";
$hour %=12;
}
else
{
$second = ($second+1)%60;
if($second == 0)
{
$minute = ($minute+1)%60;
if($minute == 0)
{$hour = ($hour+1)%12;}
}
}
#update title of clock then redraw clock face then sync update counter
if (length($second)<2) {$second = "0$second";}
if (length($minute)<2) {$minute = "0$minute";}
$time = $hour.":".$minute.":".$second.$ampm;
$mw->title($time);
DrawClock($clockSizeX, $clockSizeY, $hour, $minute, $second);
$secCount= ($secCount+1)%$syncFreq;
}
#
# Name: DrawClock($clockSizeX, $clockSizeY, $hour, $minute, $second)
#
# Purpose: Draws the picture of an analog clock according to the size
# and time parameters passed
#
sub DrawClock
{
#time to angle conversions
$secondAng = $_[4]/30*$PI-$PI/2;
$minuteAng = $_[3]/30*$PI+($secondAng+$PI/2)/60-$PI/2;
$hourAng = $_[2]/6*$PI+($minuteAng+$PI/2)/12-$PI/2;
#calculate border around clock and clock dimensions
my $offSetX = $_[0]/15;
my $offSetY = $_[1]/15;
my $diameterX = $_[0]-2*$offSetX;
my $diameterY = $_[1]-2*$offSetY;
my $radiusX = $diameterX/2;
my $radiusY = $diameterY/2;
my $centerX = $radiusX +$offSetX;
my $centerY = $radiusY +$offSetY;
#starting and ending positions of tick marks
my $startTickX;
my $startTickY;
my $endTickX;
my $endTickY;
#lengths of ticks and of hands
my $tickScaling = .85;
my $secScaling = .85;
my $minScaling = .75;
my $hourScaling = .5;
#
#Clear screen & draw face
#
$canvas->delete("all");
$canvas->createOval( $offSetX, $offSetY,
$diameterX+$offSetX,
$diameterY+$offSetY,
-width=>($offSetX+$offSetY)/4,
-outline=>"black");
#
#Draw Ticks
#
$tickWidth = ($offSetX+$offSetY)/8;
for($theta=0; $theta< 2*$PI; $theta+= $PI/6)
{
$endTickX= $radiusX*cos($theta);
$endTickY= $radiusY*sin($theta);
$startTickX= $tickScaling*$endTickX;
$startTickY= $tickScaling*$endTickY;
$canvas->createLine($centerX+$startTickX,
$centerY+$startTickY,
$centerX+$endTickX,
$centerY+$endTickY,
-fill=>"black",
-width=>$tickWidth);
}
#
#Draw Hour and Minutes then Seconds
#
$canvas->createLine($centerX+$hourScaling*$radiusX*cos($hourAng),
$centerY+$hourScaling*$radiusY*sin($hourAng),
$centerX,
$centerY,
$centerX+$minScaling*$radiusX*cos($minuteAng),
$centerY+$minScaling*$radiusY*sin($minuteAng),
-fill=>"blue",
-width=>$tickWidth,
-joinstyle=>"bevel");
$canvas->createLine($centerX+$secScaling*$radiusX*cos($secondAng),
$centerY+$secScaling*$radiusY*sin($secondAng),
$centerX,
$centerY,
-fill=>"red",
-width=>$tickWidth/2,
-joinstyle=>"bevel");
}
#
# TCP Stuff
#
#
# Name: openTCP
#
# Purpose: given a stream, an internet address name, and a port opens a TCP
# connection to that port. (Taken essentially from Client Web Programming Perl
# book)
#
sub openTCP
{
my ($FS, $dest, $port) = @_;
my $protocol = getprotobyname('tcp');
socket($FS, PF_INET, SOCK_STREAM, $protocol);
my $sin =sockaddr_in($port, inet_aton($dest));
connect($FS,$sin) || return undef;
my $old_fh = select($FS);
$| =1;
select($old_fh);
return 1;
}
#
# Name: connectNist
#
# Purpose: connects to a RFC-867 clock $syncClock grab its time string
# and return hour, minute, second substring.
#
sub connectNIST
{
my @time;
my $timeString;
#
#connect to nist using RFC-867 protocol
#get there time string and close connection
#
if(openTCP(F,$syncClock, 13) == undef)
{
print "Error connecting to server.\n";
exit(-1);
}
$timeString="";
$timeString .= $_ while (<F>);
close(F);
@time = split(/\s/, $timeString);
return $time[3]; # return only hour:minute:second part of string
}
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