Asp Forum - Re: [SOLUTION] Current Temperature (#68

Ross Bamford

2/26/2006 3:15:00 PM

I wanted to allow UK postcodes, and I've had some mad insomnia the past
couple of nights. This is some of the nastiest code I've written in a
long time, which is pretty liberating if I'm honest...

====[CUT HERE]====
#!/usr/local/bin/ruby
# Run a query for temperature based on place name or UK Postcode.
#
# Uses the BBC weather service (data from the MET office).
# See: http://www.bbc.co.u...
#
require 'net/http'
require 'uri'

unless $0 == __FILE__
raise LoadError, "You don't wanna require this..."
end

if ARGV.detect { |e| e =~ /--?h(elp)?/ }
puts <<-EOM

Syntax: ruby weather.rb [-h] [-f] [-x] [-a[select-ids]] search query

Options:

-h Show this help text.
-f Display temperatures in degrees Farenheit (default: Celsius)
-x Show eXtended report.
-a[ids] Automatically select [ids] where a search returns multiple
results. Avoids user input at runtime. Examples:

-a - Show temperature for all results
-a1 - Show the first result
-a'1 3' - Show results 1 and 3

Search Query:

The search query is constructed from all non-option arguments, and
may be one of:

* UK postcode (partial or full)
* UK town
* UK or International city
* Country

Examples:

ruby weather.rb -f ilkeston - Temp in farenheit for Ilkeston, UK
ruby weather.rb -a76 italy - Celsius temp in Rome, Italy
ruby weather.rb -a3 de7 - Celsius in Derby, UK
ruby weather.rb london - Temp in interactively-selected result
for query 'london'
ruby weather.rb -f -x -a new york - Extended report in Farenheit for all
'new york' results

EOM
exit(1)
end

RESULT_TITLE = /5 Day Forecast in (\w+) for ([^<]+)<\/title>/
MULTI_RESULT_TITLE = /Weather Centre - Search Results<\/title>/
NO_LOCS = /No locations were found for "([^"]*)"/
FIVEDAY = /5day.shtml/

# Extract result from multiple result page
EX_RESULT = /<a href="\/weather\/5day(?:_f)?.shtml\?([^"]*)" class="seasonlink"><strong>([^<]*)(?:<\/strong>)?<\/a>/

# Extract from 5day result page
EX_OVERVIEW = /">(\w+)<\/span>\s*\d+<abbr title="Temperature/
EX_TEMP = /(\d+)\s*\<abbr title="Temperature in degrees[^"]*"\>/
EX_WIND = /<br \/>(\w+) \((\d+) <abbr title="Miles per/
EX_HUMIDITY = /title="Relative humid[^:]*: (\d+)/
EX_PRESSURE = /title="Pressure in[^:]*: ([^<]+)/
EX_VISIBILITY = /Visibility<\/strong>: ([^<]+)/

# validate input
SELECT_INPUT = /^([Aa]|\d+(\s*\d+)*)$/

FARENHEIT = if ARGV.include? '-f'
ARGV.reject! { |e| e == '-f' }
true
end
AUTOSELECT = if ARGV.detect(&asp = lambda { |e| e =~ /-a([Aa]|\d+(?:\s*\d+)*)?/ })
a = $1 || 'A'
ARGV.reject!(&asp)
a
end
EXTMODE = if ARGV.include? '-x'
ARGV.reject! { |e| e == '-x' }
true
end

# Fetch and process a single URI (either search, results or 5day)
def fetch_process(uri)
case r = fetch(uri)
when Net::HTTPSuccess
process_result(r.body)
else
r.error!
end
end

# Actually fetches data from the web. All results ultimately come from
# 5day pages (new_search.pl redirects us there). We handle redirects
# here and also do URL rewriting to support Farenheit mode.
def fetch(uri_str, limit = 10)
raise ArgumentError, 'HTTP redirect too deep' if limit == 0

if FARENHEIT and uri_str =~ FIVEDAY
uri_str = uri_str.dup
uri_str[FIVEDAY] = '5day_f.shtml'
end

response = Net::HTTP.get_response(URI.parse(uri_str))
case response
when Net::HTTPSuccess then response
when Net::HTTPRedirection then fetch(response['location'], limit - 1)
else
response.error!
end
end

# Collects multiple results from a "Search Results" page into an
# array of arrays e.g [["Some Place", "id=3309"], ["Etc", "id=2002"]]
def collect_results(body)
a = []
body.scan(EX_RESULT) { |s| a << [$2, $1] }
a
end

# The main result processing function. This handles all responses.
# If it's given a single result (a 5day page) it extracts and outputs
# the current temp. If it's a multi result page, the results are
# extracted and the user selects from them, with the resulting URL
# (a 5day) then passed to fetch_process to handle the fetch and pass
# the result back here.
def process_result(body)
if body =~ RESULT_TITLE
# this is a result
units, place = $1, $2
if body =~ EX_TEMP
temp = $1
out = if EXTMODE
overview = ((m = EX_OVERVIEW.match(body)) ? m[1] : '?')
wind_dir, wind_speed = ((m = EX_WIND.match(body)) ? m[1,2] : ['?','?'])
humidity = ((m = EX_HUMIDITY.match(body)) ? m[1] : '?')
pressure = ((m = EX_PRESSURE.match(body)) ? m[1] : '?')
visibility = ((m = EX_VISIBILITY.match(body)) ? m[1] : '?')

"\n#{place}\n" +
" Temp : #{temp} degrees #{units}\n" +
" Wind : #{wind_dir} (#{wind_speed} mph)\n" +
" Humidity (%) : #{humidity}\n" +
" Pressure (mB): #{pressure.chop}\n" +
" Visibility : #{visibility}"
else
"#{place} - #{temp} degrees #{units}"
end

puts out
else
puts "No data for #{place}"
end
elsif body =~ MULTI_RESULT_TITLE
# multiple or no result
if body =~ NO_LOCS
puts "No locations matched '#{$1}'"
else
a = collect_results(body)

if a.length > 0
unless n = AUTOSELECT
puts "Multiple results:\n"
puts " [0]\tCancel"
a.each_with_index do |e,i|
puts " [#{i+1}]\t#{e.first}"
end

puts " [A]\tAll\n\n"

begin
print "Select (separate with spaces): "
n = STDIN.gets.chomp
end until n =~ SELECT_INPUT
end

if n != '0' # 0 is cancel
n.split(' ').inject([]) do |ary,i|
if i.upcase == 'A'
ary + a.map { |e| e.last }
else
ary << a[i.to_i - 1].last
end
end.each do |id|
fetch_process("http://www.bbc.co.u...5day.shtml?#{id}")
end
end
else
puts "No usable results found"
end
end
else
puts "Unknown location"
end
end

def display_temp(q)
fetch_process("http://www.bbc.co.uk/cgi-perl/weather/search/new_search.pl?sear...{q}")
end

display_temp(URI.encode(ARGV.empty? ? 'ilkeston' : ARGV.join(' ')))

--
Ross Bamford - rosco@roscopeco.REMOVE.co.uk

comp.lang.ruby

Re: [SOLUTION] Current Temperature (#68

Ross Bamford

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