is Tcl driven (it's running AOLserver!) I thought it'd be fun to build An HTTP Robot in Tcl to automate searching for an A-Z route. Previously I'd downloaded data from the 1990 US Census containing (among other things) a list of cities & states and stuck it in database. In this data only two states, Ohio & Illinois had cities beginning with each letter of the alphabet.I decided I'd give my HTTP robot a city and state as command line input (and that I'd start with the Z-cities in each state) and have it query mapquest (recursively) between each city and all the cities whose names start with the proceeding letter of the alphabet. I figured it'd be a reasonable starting algorithm.Here is the Tcl code:
package require nstcl
nstcl::load_driver solid
nstcl::configure_pool solid mapquest 1 "tcp localhost 1314" user pass
namespace import nstcl::*
proc mapquest {1c 1s 2c 2s} {
set url http://www.mapquest.com/directions/main.adp?go=1
foreach field [list 1c 1s 2c 2s] {
append url &$field=[ns_urlencode [set $field]]
}
set html [ns_striphtml [ns_geturl $url]]
set RE {(?i)Total\s+Distance:\s+([0-9,.]+)\s+mile}
if {[regexp $RE $html => miles]} {
return $miles
}
}
proc neighbor {from state} {ohio
set letter [format %c [expr [scan $from %c] -1]]
set SQL "
select city
from zt_citiescolumbus
where city like '$letter%' and
state = '$state'"
db_foreach city $SQL {hershey
set distance [mapquest $from $state $city $state]pa
if {[string is double -strict $distance] &&
(![info exists shortest(mileage)] ||
$shortest(mileage) > $distance)} {
set shortest(mileage) $distance
set shortest(city) $city
}
}
if {[info exists shortest(mileage)]} {
puts [join [list $shortest(city) $shortest(mileage)] \t]
return [expr {$shortest(mileage) +
[neighbor $shortest(city) $state]}]
} else {
# either we reached a disconnect where mapquest didn't
# recognize any of our cities, or we're at A and
# there are no cities whose names begin with @ in our
# database :^)
return 0.00
}
}
set from [string toupper [lindex $argv 0]]
set state [string toupper [lindex $argv 1]]
puts $from
puts "Total Distance: [format %0.2f [neighbor $from $state]]"The best results (formatted for the Wiki)? For Illinois:
- Alexis 29.55
- Biggsville 16.69
- Carman 10.73
- Dallas City 22.71
- Elvaston 38.97
- Fowler 17.95
- Golden 15.32
- Huntsville 23.79
- Industry 55.16
- Jacksonville 74.37
- Kenney 23.42
- Lincoln 14.85
- Middletown 6.27
- New Holland 28.73
- Oakford 108.85
- Payson 15.30
- Quincy 322.91
- Rosiclare 32.78
- Simpson 44.77
- Tamms 7.47
- Ullin 121.50
- Vernon 63.11
- Wayne City 24.66
- Xenia 62.81
- Yale 141.191
- Zeigler 1,324.58 total
- Arcanum 49.02
- Bellbrook 17.67
- Cedarville 23.60
- Dayton 23.39
- Enon 9.56
- Fairborn 62.65
- Grove City 14.06
- Hilliard 23.41
- Irwin 89.18
- Junction City 41.21
- Kingston 53.94
- Leesburg 19.83
- Midland 12.08
- New Vienna 35.47
- Oregonia 64.11
- Piqua 25.33
- Quincy 37.02
- Russia 23.59
- Sidney 26.31
- Tipp City 40.65
- Urbana 37.78
- Vandalia 12.93
- West Milton 37.43
- Xenia 9.19
- Yellow Springs 41.32
- Zanesfield 830.73 total
[Anyone know whether Mapquest offers a WS interface? I wouldn't expect so ...]
Category Geography
