Towards a standard access mechanism for URLs.

1 files changed, 195 insertions, 0 deletions

diff --git a/Lib/gopherlib.py b/Lib/gopherlib.py
new file mode 100644
index 0000000..71413ba
--- /dev/null
+++ b/Lib/gopherlib.py
@@ -0,0 +1,195 @@
+# Gopher protocol client interface
+
+import string
+
+# Default selector, host and port
+DEF_SELECTOR = '1/'
+DEF_HOST     = 'gopher.micro.umn.edu'
+DEF_PORT     = 70
+
+# Recognized file types
+A_TEXT       = '0'
+A_MENU       = '1'
+A_CSO        = '2'
+A_ERROR      = '3'
+A_MACBINHEX  = '4'
+A_PCBINHEX   = '5'
+A_UUENCODED  = '6'
+A_INDEX      = '7'
+A_TELNET     = '8'
+A_BINARY     = '9'
+A_DUPLICATE  = '+'
+A_SOUND      = 's'
+A_EVENT      = 'e'
+A_CALENDAR   = 'c'
+A_HTML       = 'h'
+A_TN3270     = 'T'
+A_MIME       = 'M'
+A_IMAGE      = 'I'
+A_WHOIS      = 'w'
+A_QUERY      = 'q'
+A_GIF        = 'g'
+A_HTML       = 'h'			# HTML file
+A_WWW        = 'w'			# WWW address
+A_PLUS_IMAGE = ':'
+A_PLUS_MOVIE = ';'
+A_PLUS_SOUND = '<'
+
+
+# Function mapping all file types to strings; unknown types become TYPE='x'
+_names = dir()
+_type_to_name_map = None
+def type_to_name(gtype):
+	global _type_to_name_map
+	if not _type_to_name_map:
+		for name in _names:
+			if name[:2] == 'A_':
+				_type_to_name_map[eval(name)] = name[2:]
+	if _type_to_name_map.has_key(gtype):
+		return _type_to_name_map[gtype]
+	return 'TYPE=' + `gtype`
+
+# Names for characters and strings
+CRLF = '\r\n'
+TAB = '\t'
+
+# Send a selector to a given host and port, return a file with the reply
+def send_selector(selector, host, *args):
+	import socket
+	import string
+	if args:
+		if args[1:]: raise TypeError, 'too many args'
+		port = args[0]
+	else:
+		port = None
+		i = string.find(host, ':')
+		if i >= 0:
+			host, port = host[:i], string.atoi(host[i+1:])
+	if not port:
+		port = DEF_PORT
+	elif type(port) == type(''):
+		port = string.atoi(port)
+	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+	s.connect(host, port)
+	s.send(selector + CRLF)
+	s.shutdown(1)
+	return s.makefile('r')
+
+# Send a selector and a query string
+def send_query(selector, query, host, *args):
+	return apply(send_selector, (selector + '\t' + query, host) + args)
+
+# The following functions interpret the data returned by the gopher
+# server according to the expected type, e.g. textfile or directory
+
+# Get a directory in the form of a list of entries
+def get_directory(f):
+	import string
+	list = []
+	while 1:
+		line = f.readline()
+		if not line:
+			print '(Unexpected EOF from server)'
+			break
+		if line[-2:] == CRLF:
+			line = line[:-2]
+		elif line[-1:] in CRLF:
+			line = line[:-1]
+		if line == '.':
+			break
+		if not line:
+			print '(Empty line from server)'
+			continue
+		gtype = line[0]
+		parts = string.splitfields(line[1:], TAB)
+		if len(parts) < 4:
+			print '(Bad line from server:', `line`, ')'
+			continue
+		if len(parts) > 4:
+			if parts[4:] != ['+']:
+			    print '(Extra info from server:', parts[4:], ')'
+		else:
+			parts.append('')
+		parts.insert(0, gtype)
+		list.append(parts)
+	return list
+
+# Get a text file as a list of lines, with trailing CRLF stripped
+def get_textfile(f):
+	list = []
+	get_alt_textfile(f, list.append)
+	return list
+
+# Get a text file and pass each line to a function, with trailing CRLF stripped
+def get_alt_textfile(f, func):
+	while 1:
+		line = f.readline()
+		if not line:
+			print '(Unexpected EOF from server)'
+			break
+		if line[-2:] == CRLF:
+			line = line[:-2]
+		elif line[-1:] in CRLF:
+			line = line[:-1]
+		if line == '.':
+			break
+		if line[:2] == '..':
+			line = line[1:]
+		func(line)
+
+# Get a binary file as one solid data block
+def get_binary(f):
+	data = f.read()
+	return data
+
+# Get a binary file and pass each block to a function
+def get_alt_binary(f, func, blocksize):
+	while 1:
+		data = f.read(blocksize)
+		if not data:
+			break
+		func(data)
+
+# Trivial test program
+def test():
+	import sys
+	import getopt
+	opts, args = getopt.getopt(sys.argv[1:], '')
+	selector = DEF_SELECTOR
+	type = selector[0]
+	host = DEF_HOST
+	port = DEF_PORT
+	if args:
+		host = args[0]
+		args = args[1:]
+	if args:
+		type = args[0]
+		args = args[1:]
+		if len(type) > 1:
+			type, selector = type[0], type
+		else:
+			selector = ''
+			if args:
+				selector = args[0]
+				args = args[1:]
+		query = ''
+		if args:
+			query = args[0]
+			args = args[1:]
+	if type == A_INDEX:
+		f = send_query(selector, query, host)
+	else:
+		f = send_selector(selector, host)
+	if type == A_TEXT:
+		list = get_textfile(f)
+		for item in list: print item
+	elif type in (A_MENU, A_INDEX):
+		list = get_directory(f)
+		for item in list: print item
+	else:
+		data = get_binary(f)
+		print 'binary data:', len(data), 'bytes:', `data[:100]`[:40]
+
+# Run the test when run as script
+if __name__ == '__main__':
+	test()