"""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 = '<'
_names = dir()
_type_to_name_map = {}
def type_to_name(gtype):
"""Map all file types to strings; unknown types become TYPE='x'."""
global _type_to_name_map
if _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'
def send_selector(selector, host, port = 0):
"""Send a selector to a given host and port, return a file with the reply."""
import socket
import string
if not port:
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('rb')
def send_query(selector, query, host, port = 0):
"""Send a selector and a query string."""
return send_selector(selector + '\t' + query, host, port)
def path_to_selector(path):
"""Takes a path as returned by urlparse and returns the appropriate selector."""
if path=="/":
return "/"
else:
return path[2:] # Cuts initial slash and data type identifier
def path_to_datatype_name(path):
"""Takes a path as returned by urlparse and maps it to a string.
See section 3.4 of RFC 1738 for details."""
if path=="/":
# No way to tell, although "INDEX" is likely
return "TYPE='unknown'"
else:
return type_to_name(path[1])
# The following functions interpret the data returned by the gopher
# server according to the expected type, e.g. textfile or directory
def get_directory(f):
"""Get a directory in the form of a list of entries."""
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:',
print parts[4:], ')'
else:
parts.append('')
parts.insert(0, gtype)
list.append(parts)
return list
def get_textfile(f):
"""Get a text file as a list of lines, with trailing CRLF stripped."""
list = []
get_alt_textfile(f, list.append)
return list
def get_alt_textfile(f, func):
"""Get a text file and pass each line to a function, with trailing CRLF stripped."""
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)
def get_binary(f):
"""Get a binary file as one solid data block."""
data = f.read()
return data
def get_alt_binary(f, func, blocksize):
"""Get a binary file and pass each block to a function."""
while 1:
data = f.read(blocksize)
if not data:
break
func(data)
def test():
"""Trivial test program."""
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()
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