#! /usr/bin/python2.7
# A simple gopher client.
#
# Usage: gopher [ [selector] host [port] ]
import string
import sys
import os
import socket
# Default selector, host and port
DEF_SELECTOR = ''
DEF_HOST = 'gopher.micro.umn.edu'
DEF_PORT = 70
# Recognized file types
T_TEXTFILE = '0'
T_MENU = '1'
T_CSO = '2'
T_ERROR = '3'
T_BINHEX = '4'
T_DOS = '5'
T_UUENCODE = '6'
T_SEARCH = '7'
T_TELNET = '8'
T_BINARY = '9'
T_REDUNDANT = '+'
T_SOUND = 's'
# Dictionary mapping types to strings
typename = {'0': '<TEXT>', '1': '<DIR>', '2': '<CSO>', '3': '<ERROR>', \
'4': '<BINHEX>', '5': '<DOS>', '6': '<UUENCODE>', '7': '<SEARCH>', \
'8': '<TELNET>', '9': '<BINARY>', '+': '<REDUNDANT>', 's': '<SOUND>'}
# Oft-used characters and strings
CRLF = '\r\n'
TAB = '\t'
# Open a TCP connection to a given host and port
def open_socket(host, port):
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))
return s
# Send a selector to a given host and port, return a file with the reply
def send_request(selector, host, port):
s = open_socket(host, port)
s.send(selector + CRLF)
s.shutdown(1)
return s.makefile('r')
# Get a menu in the form of a list of entries
def get_menu(selector, host, port):
f = send_request(selector, host, port)
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
typechar = line[0]
parts = string.splitfields(line[1:], TAB)
if len(parts) < 4:
print '(Bad line from server: %r)' % (line,)
continue
if len(parts) > 4:
print '(Extra info from server: %r)' % (parts[4:],)
parts.insert(0, typechar)
list.append(parts)
f.close()
return list
# Get a text file as a list of lines, with trailing CRLF stripped
def get_textfile(selector, host, port):
list = []
get_alt_textfile(selector, host, port, list.append)
return list
# Get a text file and pass each line to a function, with trailing CRLF stripped
def get_alt_textfile(selector, host, port, func):
f = send_request(selector, host, port)
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)
f.close()
# Get a binary file as one solid data block
def get_binary(selector, host, port):
f = send_request(selector, host, port)
data = f.read()
f.close()
return data
# Get a binary file and pass each block to a function
def get_alt_binary(selector, host, port, func, blocksize):
f = send_request(selector, host, port)
while 1:
data = f.read(blocksize)
if not data:
break
func(data)
# A *very* simple interactive browser
# Browser main command, has default arguments
def browser(*args):
selector = DEF_SELECTOR
host = DEF_HOST
port = DEF_PORT
n = len(args)
if n > 0 and args[0]:
selector = args[0]
if n > 1 and args[1]:
host = args[1]
if n > 2 and args[2]:
port = args[2]
if n > 3:
raise RuntimeError, 'too many args'
try:
browse_menu(selector, host, port)
except socket.error, msg:
print 'Socket error:', msg
sys.exit(1)
except KeyboardInterrupt:
print '\n[Goodbye]'
# Browse a menu
def browse_menu(selector, host, port):
list = get_menu(selector, host, port)
while 1:
print '----- MENU -----'
print 'Selector:', repr(selector)
print 'Host:', host, ' Port:', port
print
for i in range(len(list)):
item = list[i]
typechar, description = item[0], item[1]
print string.rjust(repr(i+1), 3) + ':', description,
if typename.has_key(typechar):
print typename[typechar]
else:
print '<TYPE=' + repr(typechar) + '>'
print
while 1:
try:
str = raw_input('Choice [CR == up a level]: ')
except EOFError:
print
return
if not str:
return
try:
choice = string.atoi(str)
except string.atoi_error:
print 'Choice must be a number; try again:'
continue
if not 0 < choice <= len(list):
print 'Choice out of range; try again:'
continue
break
item = list[choice-1]
typechar = item[0]
[i_selector, i_host, i_port] = item[2:5]
if typebrowser.has_key(typechar):
browserfunc = typebrowser[typechar]
try:
browserfunc(i_selector, i_host, i_port)
except (IOError, socket.error):
print '***', sys.exc_type, ':', sys.exc_value
else:
print 'Unsupported object type'
# Browse a text file
def browse_textfile(selector, host, port):
x = None
try:
p = os.popen('${PAGER-more}', 'w')
x = SaveLines(p)
get_alt_textfile(selector, host, port, x.writeln)
except IOError, msg:
print 'IOError:', msg
if x:
x.close()
f = open_savefile()
if not f:
return
x = SaveLines(f)
try:
get_alt_textfile(selector, host, port, x.writeln)
print 'Done.'
except IOError, msg:
print 'IOError:', msg
x.close()
# Browse a search index
def browse_search(selector, host, port):
while 1:
print '----- SEARCH -----'
print 'Selector:', repr(selector)
print 'Host:', host, ' Port:', port
print
try:
query = raw_input('Query [CR == up a level]: ')
except EOFError:
print
break
query = string.strip(query)
if not query:
break
if '\t' in query:
print 'Sorry, queries cannot contain tabs'
continue
browse_menu(selector + TAB + query, host, port)
# "Browse" telnet-based information, i.e. open a telnet session
def browse_telnet(selector, host, port):
if selector:
print 'Log in as', repr(selector)
if type(port) <> type(''):
port = repr(port)
sts = os.system('set -x; exec telnet ' + host + ' ' + port)
if sts:
print 'Exit status:', sts
# "Browse" a binary file, i.e. save it to a file
def browse_binary(selector, host, port):
f = open_savefile()
if not f:
return
x = SaveWithProgress(f)
get_alt_binary(selector, host, port, x.write, 8*1024)
x.close()
# "Browse" a sound file, i.e. play it or save it
def browse_sound(selector, host, port):
browse_binary(selector, host, port)
# Dictionary mapping types to browser functions
typebrowser = {'0': browse_textfile, '1': browse_menu, \
'4': browse_binary, '5': browse_binary, '6': browse_textfile, \
'7': browse_search, \
'8': browse_telnet, '9': browse_binary, 's': browse_sound}
# Class used to save lines, appending a newline to each line
class SaveLines:
def __init__(self, f):
self.f = f
def writeln(self, line):
self.f.write(line + '\n')
def close(self):
sts = self.f.close()
if sts:
print 'Exit status:', sts
# Class used to save data while showing progress
class SaveWithProgress:
def __init__(self, f):
self.f = f
def write(self, data):
sys.stdout.write('#')
sys.stdout.flush()
self.f.write(data)
def close(self):
print
sts = self.f.close()
if sts:
print 'Exit status:', sts
# Ask for and open a save file, or return None if not to save
def open_savefile():
try:
savefile = raw_input( \
'Save as file [CR == don\'t save; |pipeline or ~user/... OK]: ')
except EOFError:
print
return None
savefile = string.strip(savefile)
if not savefile:
return None
if savefile[0] == '|':
cmd = string.strip(savefile[1:])
try:
p = os.popen(cmd, 'w')
except IOError, msg:
print repr(cmd), ':', msg
return None
print 'Piping through', repr(cmd), '...'
return p
if savefile[0] == '~':
savefile = os.path.expanduser(savefile)
try:
f = open(savefile, 'w')
except IOError, msg:
print repr(savefile), ':', msg
return None
print 'Saving to', repr(savefile), '...'
return f
# Test program
def test():
if sys.argv[4:]:
print 'usage: gopher [ [selector] host [port] ]'
sys.exit(2)
elif sys.argv[3:]:
browser(sys.argv[1], sys.argv[2], sys.argv[3])
elif sys.argv[2:]:
try:
port = string.atoi(sys.argv[2])
selector = ''
host = sys.argv[1]
except string.atoi_error:
selector = sys.argv[1]
host = sys.argv[2]
port = ''
browser(selector, host, port)
elif sys.argv[1:]:
browser('', sys.argv[1])
else:
browser()
# Call the test program as a main program
test()
