# THE SOFTWARE.
import sys
-import re
import urlparse
import os
-class InvalidICS(Exception): pass
-class notJoined(Exception): pass
-# RFC5545 and RFC5546 iCalendar registries contain upper case letters
-# and dashes only and are separated from the value by a colon (:)
-icalEntry = re.compile('^[A-Z\-]+:.*')
+class InvalidICS(Exception): pass
+class IncompleteICS(InvalidICS): pass
def lineJoiner(oldcal):
- '''Unfolds a calendar so that items can be parsed'''
+ '''Takes a string containing a calendar and returns an array of its lines'''
- cal = []
+ if not oldcal[0:15] == 'BEGIN:VCALENDAR':
+ raise InvalidICS, "Does not appear to be a valid ICS file"
- # Strip newlines (
- for line in oldcal:
- line = line.rstrip('\r\n')
-
- # Reassemble broken Lines
- if not line:
- if not cal: continue
- else: cal[-1] += '\\n'
- elif line[0] == ' ':
- if not cal: raise InvalidICS, 'First line of ICS must be element'
- line = line[1:len(line)]
- cal[-1] += line
- elif not icalEntry.match(line):
- if not cal: raise InvalidICS, 'First line of ICS must be element'
- cal[-1] += '\\n' + line
- else:
- if cal: cal[-1] += '\r\n'
- cal.append(line)
+ if not 'END:VCALENDAR' in oldcal[-15:-1]:
+ raise IncompleteICS, "File appears to be incomplete"
- cal[-1] += '\r\n'
+ if list(oldcal) == oldcal:
+ oldcal = '\r\n'.join(oldcal)
+
+ oldcal = oldcal.replace('\r\n ', '').replace('\r\n\t','')
+ return oldcal.strip().split('\r\n')
- return cal
def lineFolder(oldcal, length=75):
'''Folds content lines to a specified length, returns a list'''
+ if length > 75:
+ sys.stderr.write('WARN: lines > 75 octets are not RFC compliant\n')
+
cal = []
sl = length - 1
for line in oldcal:
- # Line & line ending line ending fit inside length, do nothing
+ # Line fits inside length, do nothing
if len(line.rstrip()) <= length:
cal.append(line)
else:
- brokenline = [line[0:length] + '\r\n']
+ brokenline = [line[0:length]]
ll = length
- while ll < len(line.rstrip('\r\n')) + 1:
- brokenline.append(' ' + line[ll:sl+ll].rstrip('\r\n') + '\r\n')
+ while ll < len(line) + 1:
+ brokenline.append(line[ll:sl+ll])
ll += sl
- cal += brokenline
+ brokenline = '\r\n '.join(brokenline)
+ cal.append(brokenline)
return cal
-if __name__ == '__main__':
- from optparse import OptionParser
- # If the user passed us a 'stdin' argument, we'll go with that,
- # otherwise we'll try for a url opener
- parser = OptionParser('usage: %prog [options] url')
- parser.add_option('-s', '--stdin', action='store_true', dest='stdin',
- default=False, help='Take a calendar from standard input')
- parser.add_option('-o', '--output', dest='outfile', default='',
- help='Specify output file (defaults to standard output)')
+def splitFields(cal):
+ '''Takes a list of lines in a calendar file and returns a list of tuples
+ as (key, value) pairs'''
- (options, args) = parser.parse_args()
+ ical = [tuple(x.split(':',1)) for x in cal]
- if not args and not options.stdin:
- parser.print_usage()
- sys.exit(0)
- elif not options.stdin:
- url = args[0]
- else:
- url = ''
+ # Check that we got 2 items on every line
+ for line in ical:
+ if not len(line) == 2:
+ raise InvalidICS, "Didn't find a content key on: %s"%(line)
+
+ return ical
+
+
+def joinFields(ical):
+ '''Takes a list of tuples that make up a calendar file and returns it to a
+ list of lines'''
+
+ return [':'.join(x) for x in ical]
- # Work out what url parsers we're going to need based on what the user
- # gave us on the command line - we do like files after all
+
+def getContent(url='',stdin=False):
+ '''Generic content retriever, DO NOT use this function in a CGI script as
+ it can read from the local disk (which you probably don't want it to).
+ '''
+
+ # Special case, if this is a HTTP url, return the data from it using
+ # the HTTP functions which attempt to play a bit nicer.
parsedURL = urlparse.urlparse(url)
- http = 'http' in parsedURL[0]
+ if 'http' in parsedURL[0]: return getHTTPContent(url)
- if not parsedURL[0]: u = False
- else: u = True
+ if stdin:
+ content = sys.stdin.read()
+ return content
+
+ if not parsedURL[0]:
+ try: content = open(os.path.abspath(url),'r').read()
+ except (IOError, OSError), e:
+ sys.stderr.write('%s\n'%e)
+ sys.exit(1)
+ return content
+
+ # If we've survived, use python's generic URL opening library to handle it
+ import urllib2
+ try:
+ res = urllib2.urlopen(url)
+ content = res.read()
+ res.close()
+ except (urllib2.URLError, OSError), e:
+ sys.stderr.write('%s\n'%e)
+ sys.exit(1)
+ return content
+
+
+def getHTTPContent(url='',cache='.httplib2-cache'):
+ '''This function attempts to play nice when retrieving content from HTTP
+ services. It's what you should use in a CGI script.'''
+
+ try:
+ import httplib2
+ except ImportError:
+ import urllib2
+
+ if not url: return ''
- if not options.stdin and http:
- try:
- import httplib2
- except ImportError:
- import urllib2
-
- # Try and play nice with HTTP servers unless something goes wrong. We don't
- # really care about this cache (A lot of ics files seem to be generated with
- # php which hates caching with a passion).
- h = False
if 'httplib2' in sys.modules:
try: h = httplib2.Http('.httplib2-cache')
except OSError: h = httplib2.Http()
+ else: h = False
- # Load urllib2 if this is not a stdin
- if not options.stdin and (not http or not 'httplib2' in sys.modules):
- import urllib2
+ try:
+ if h: content = h.request(url)[1]
+ return content
+ except ValueError, e:
+ sys.stderr.write('%s\n'%e)
+ sys.exit(1)
try:
- content = u and (h and h.request(url)[1] or urllib2.urlopen(url).read())
- except (ValueError, urllib2.URLError), e:
+ content = urllib2.urlopen(url).read()
+ return content
+ except (urllib2.URLError, OSError), e:
sys.stderr.write('%s\n'%e)
sys.exit(1)
- if not u and not options.stdin:
- try: content = open(os.path.abspath(url),'r').read()
+ return ''
+
+
+def generateRules():
+ '''Attempts to load a series of rules into a list'''
+ try:
+ import parserrules
+ except ImportError:
+ return []
+
+ rules = [getattr(parserrules, rule) for rule in dir(parserrules) if callable(getattr(parserrules, rule))]
+ return rules
+
+
+def applyRules(ical, rules=[], verbose=False):
+ 'Runs a series of rules on the lines in ical and mangles its output'
+
+ for rule in rules:
+ output = []
+ if rule.__doc__ and verbose:
+ print(rule.__doc__)
+ for line in ical:
+ try:
+ out = rule(line[0],line[1])
+ except TypeError, e:
+ output.append(line)
+ print(e)
+ continue
+
+ # Drop lines that are boolean False
+ if not out and not out == None: continue
+
+ # If the rule did something and is a tuple or a list we'll accept it
+ # otherwise, pay no attention to the man behind the curtain
+ try:
+ if tuple(out) == out or list(out) == out and len(out) == 2:
+ output.append(tuple(out))
+ else:
+ output.append(line)
+ except TypeError, e:
+ output.append(line)
+
+ ical = output
+
+ return ical
+
+
+def writeOutput(cal, outfile=''):
+ '''Takes a list of lines and outputs to the specified file'''
+
+ if not cal:
+ sys.stderr.write('Refusing to write out an empty file')
+ sys.exit(0)
+
+ if not outfile:
+ out = sys.stdout
+ else:
+ try:
+ out = open(outfile, 'w')
except (IOError, OSError), e:
sys.stderr.write('%s\n'%e)
sys.exit(1)
- if options.stdin:
- content = sys.stdin.read()
+ if cal[-1]: cal.append('')
+
+ out.write('\r\n'.join(cal))
+
+ if not out == sys.stdout:
+ out.close()
+
+
+if __name__ == '__main__':
+ from optparse import OptionParser
+ # If the user passed us a 'stdin' argument, we'll go with that,
+ # otherwise we'll try for a url opener
+
+ parser = OptionParser('usage: %prog [options] url')
+ parser.add_option('-s', '--stdin', action='store_true', dest='stdin',
+ default=False, help='Take a calendar from standard input')
+ parser.add_option('-v', '--verbose', action='store_true', dest='verbose',
+ default=False, help='Be verbose when rules are being applied')
+ parser.add_option('-o', '--output', dest='outfile', default='',
+ help='Specify output file (defaults to standard output)')
- # RFC5545 and RFC5546 New calendars should be generated UTF-8 and we need to
- # be able to read ANSI as well. This should take care of us.
- content = unicode(content, encoding='utf-8')
+ (options, args) = parser.parse_args()
+
+ if not args and not options.stdin:
+ parser.print_usage()
+ sys.exit(0)
+ elif not options.stdin:
+ url = args[0]
+ else:
+ url = ''
- #return content
+ content = getContent(url, options.stdin)
+ cal = lineJoiner(content)
+ ical = applyRules(splitFields(cal), generateRules(), options.verbose)
+ output = lineFolder(joinFields(ical))
+ writeOutput(output, options.outfile)
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