Contents
The Australian Bureau of Meteorology provides a lot of free useful weather data, as well as regular forecasts, but it is in HTML or plain text format. These scripts try to parse relevant parts of that data out for use elsewhere, with varying levels of success.
Current observations
This script and Python module fetches current weather observations by parsing specially-encoded comments in the automatically-updated report; it has been very reliable. To get the data for a station other than Sydney, just change the STATION_NAME variable (and possibly also REPORT_URL).
1 #!/usr/bin/env python 2 3 # $Id: bom_weather.py,v 1.7 2004/10/26 06:45:04 andrewb Exp $ 4 # script to pull out raw data from Bureau of Meteorology weather observations 5 # andrewb@cse.unsw.edu.au, 2004/10 6 7 import sys, os, urllib, time, getopt 8 from HTMLParser import HTMLParser 9 10 REPORT_URL=ftp://ftp2.bom.gov.au/anon/gen/fwo/IDN65066.html 11 STATION_NAME=Sydney - Observatory Hill 12 MAX_REPORT_AGE=2*60*60 # 2 hours 13 14 15 class BomCommentParser(HTMLParser): 16 def __init__(self): 17 HTMLParser.__init__(self) 18 self.head = None 19 self.unit = None 20 self.data = [] 21 22 def handle_comment(self, data): 23 fields = data.strip().split(',') 24 fields = map(lambda x: x.strip(), fields) 25 26 entrytype = fields[0] 27 if entrytype not in [HEAD, UNIT, DATA]: 28 return # some other comment, we ignore it 29 fields = fields[1:] 30 31 if self.head is None: 32 assert(entrytype == HEAD) 33 self.head = map(lambda x: x.lower(), fields) 34 elif self.unit is None: 35 assert(entrytype == UNIT) 36 assert(len(fields) == len(self.head)) 37 self.unit = fields 38 else: # DATA 39 assert(len(fields) == len(self.head)) 40 dict = {} 41 for i in range(len(fields)): 42 dict[self.head[i]] = fields[i] 43 self.data.append(dict) 44 45 46 class ScreenLog: 47 def __init__(self, fh): 48 self.fh = fh 49 def log(self, msg): 50 self.fh.write(Error: + msg + \n) 51 52 53 class FileLog: 54 def __init__(self, filename): 55 self.fh = open(filename, 'a') 56 def log(self, msg): 57 self.fh.write(time.strftime(%b %d %H:%M:%S ) + msg + \n) 58 59 60 def main(argv): 61 logfilename = None 62 outfilename = None 63 try: 64 opts, args = getopt.getopt(argv[1:], l:) 65 for (opt, arg) in opts: 66 if opt == -l: 67 logfilename = arg 68 assert(len(args) = 1) 69 if len(args) == 1: 70 outfilename = args[0] 71 except: 72 sys.stderr.write(Usage: %s [-l LOGFILE] [FILE]\n % argv[0]) 73 return 1 74 75 try: 76 if (logfilename is not None): 77 log = FileLog(logfilename) 78 else: 79 log = ScreenLog(sys.stderr) 80 except IOError: 81 sys.stderr.write(Error: couldn't append to %s\n % logfilename) 82 return 2 83 84 try: 85 parser = BomCommentParser() 86 fh = urllib.urlopen(REPORT_URL) 87 parser.feed(fh.read()) 88 fh.close() 89 parser.close() 90 except IOError: 91 log.log(failed to fetch report from %s % REPORT_URL) 92 return 2 93 except: 94 log.log(failed to parse report data) 95 return 3 96 97 try: 98 data = None 99 for entry in parser.data: 100 if entry[name] == STATION_NAME: 101 data = entry 102 break 103 assert(data) 104 except: 105 log.log(failed to find data for %s % STATION_NAME) 106 return 3 107 108 try: 109 temperature = round(float(data[temperature])) 110 humidity = round(float(data[relative humidity])) 111 pressure = round(float(data[pressure])) 112 except: 113 log.log(failed to unpack report data) 114 return 3 115 116 try: 117 timestamp = time.mktime(time.strptime(data[time], %Y%m%d:%H%M%S)) 118 now = time.mktime(time.localtime()) 119 if (now timestamp or now - timestamp MAX_REPORT_AGE): 120 log.log(timestamp %s out of range, data[time]) 121 return 4 122 except: 123 log.log(failed to parse timestamp) 124 return 3 125 126 try: 127 if (outfilename is not None): 128 fh = open(outfilename, 'w') 129 else: 130 fh = sys.stdout 131 fh.write(%d\xb0C %d%% %dhPa\n % (temperature, humidity, pressure)) 132 if (outfilename is not None): 133 fh.close() 134 except IOError: 135 log.log(couldn't write to %s % outfilename) 136 return 2 137 138 return 0 139 140 141 if __name__ == __main__: 142 sys.exit(main(sys.argv))
Forecast
This script and Python module attempts to grab the current long or short forecast as well as the minimum and maximum temperatures for Sydney from the published text file. Unfortunately the format of the file seems to be a little variable, so I have had to change the script a few times to handle different formats and try to make it more robust. It could probably be hacked to handle other state forecasts, or return different min/max temperatures.
document.write(‘Toggle line numbers<\/a>‘);
1 #!/usr/bin/env python 2 3 # $Id: bom_forecast.py,v 1.9 2006-12-05 22:11:41 andrewb Exp $ 4 # script to grab bureau of meteorology forecast for sydney 5 # andrewb@cse.unsw.edu.au, 2004/10 6 7 import sys, os, urllib, time, getopt 8 from bom_weather import FileLog, ScreenLog 9 10 FORECAST_URL=ftp://ftp2.bom.gov.au/anon/gen/fwo/IDN10064.txt 11 FORECAST_LOCN=City 12 13 14 def long_forecast(lines, minmax): 15 day = time.strftime(%A).lower() 16 para = None 17 for line in lines: 18 if para == None: 19 if line.strip().lower().startswith(forecast for + day): 20 para = [] 21 else: 22 if line == or line.startswith(Precis:): 23 break 24 else: 25 para.append(line) 26 27 forecast = .join(para) 28 try: 29 if minmax: 30 forecast += Max %d % minmax[1] 31 except ValueError: 32 pass # no max temperature 33 return forecast 34 35 def short_forecast(lines): 36 for line in lines: 37 if line.startswith(Precis:): 38 return .join(line.split(':',1)[1].split()).strip(.) 39 raise RuntimeError(Couldn't parse short forecast) 40 41 def get_minmax(lines): 42 found = False 43 seen_forecast = False 44 min = max = None 45 prevword = None 46 for line in lines: 47 if line.startswith(Forecast for): 48 # if we see this twice, it means that the min/max temps are 49 # for tomorrow's forecast and not today's, so don't return them 50 if seen_forecast: 51 return None 52 seen_forecast = True 53 words = line.split() 54 for word in words: 55 if found: 56 try: 57 n = int(word) 58 if prevword.lower().startswith('min'): 59 min = n 60 elif prevword.lower().startswith('max'): 61 max = n 62 except ValueError: 63 pass 64 if max: 65 return min, max 66 prevword = word 67 elif word == FORECAST_LOCN + :: 68 found = True 69 prevword = None 70 return None, None 71 72 def fetch_forecast(do_long_forecast): 73 fh = urllib.urlopen(FORECAST_URL) 74 lines = map(str.strip, fh.readlines()) 75 minmax = get_minmax(lines) 76 if (do_long_forecast): 77 forecast = long_forecast(lines, minmax) 78 else: 79 forecast = short_forecast(lines) 80 if minmax: 81 forecast = forecast + ( %d % minmax[1]) 82 fh.close() 83 return forecast 84 85 def main(argv): 86 logfilename = None 87 outfilename = None 88 do_long_forecast = False 89 try: 90 opts, args = getopt.getopt(argv[1:], fl:) 91 for (opt, arg) in opts: 92 if opt == -l: 93 logfilename = arg 94 elif opt == -f: 95 do_long_forecast = True 96 assert(len(args) = 1) 97 if len(args) == 1: 98 outfilename = args[0] 99 except: 100 sys.stderr.write(Usage: %s [-l LOGFILE] [-f] [FILE]\n % argv[0]) 101 return 1 102 103 try: 104 if (logfilename is not None): 105 log = FileLog(logfilename) 106 else: 107 log = ScreenLog(sys.stderr) 108 except IOError: 109 sys.stderr.write(Error: couldn't append to %s\n % logfilename) 110 return 2 111 112 try: 113 forecast = fetch_forecast(do_long_forecast) 114 except IOError: 115 log.log(failed to fetch forecast from %s % FORECAST_URL) 116 return 2 117 except: 118 log.log(failed to parse forecast data) 119 return 3 120 121 # fridge hack for very short forecasts 122 if (len(forecast) = 6): 123 forecast = Forecast: + forecast 124 125 try: 126 if (outfilename is not None): 127 fh = open(outfilename, 'w') 128 else: 129 fh = sys.stdout 130 fh.write(forecast + \n) 131 if (outfilename is not None): 132 fh.close() 133 except IOError: 134 log.log(couldn't write to %s % outfilename) 135 return 2 136 137 return 0 138 139 140 if __name__ == __main__: 141 sys.exit(main(sys.argv))
Slimserver Weather Display
This is unlikely to be useful for many people, but it shows how to use the bom_forecast module in another script. It connects to a running SlimServer (on which the CLI must be enabled) and displays the latest weather forecast for a specified duration. I run it from a cron job to have the weather forecast displayed on my Squeezebox when I wake up.
document.write(‘Toggle line numbers<\/a>‘);
1 #!/usr/bin/python 2 3 import sys, socket, urllib 4 from optparse import OptionParser 5 import bom_forecast 6 7 class SlimCLI: 8 def __init__(self, host, port=9090): 9 self.sock = socket.socket() 10 self.sock.connect((host, port)) 11 12 def cmd(self, command, args = [], player = None): 13 if player != None: 14 line = player + 15 else: 16 line = 17 line += command 18 for arg in args: 19 line += + urllib.quote(str(arg)) 20 self.sock.sendall(line + \n) 21 buf = self.sock.recv(4096) 22 line = buf.splitlines()[0] 23 return map(urllib.unquote, line.split()) 24 25 def close(self): 26 self.sock.sendall(exit\n) 27 self.sock.close() 28 29 def parse_args(): 30 p = OptionParser() 31 p.add_option('-m', type='int', dest='mins', default=30, 32 help='time (in minutes) to display weather, default: 30') 33 return p.parse_args() 34 35 def main(): 36 opts, args = parse_args() 37 forecast = bom_forecast.fetch_forecast(True) 38 cli = SlimCLI(localhost) 39 cli.cmd(display, [Today's weather forecast, forecast, opts.mins * 60]) 40 cli.close() 41 42 if __name__ == __main__: 43 main()
