#! /usr/bin/env python
# A simple gopher client.
#
# Usage: gopher [ [selector] host [port] ]
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 = int(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 = line[1:].split(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 as 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(repr(i+1).rjust(3) + ':', description, end=' ')
if typechar in typename:
print(typename[typechar])
else:
print('<TYPE=' + repr(typechar) + '>')
print()
while 1:
try:
str = input('Choice [CR == up a level]: ')
except EOFError:
print()
return
if not str:
return
try:
choice = int(str)
except ValueError:
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 typechar in typebrowser:
browserfunc = typebrowser[typechar]
try:
browserfunc(i_selector, i_host, i_port)
except (IOError, socket.error):
t, v, tb = sys.exc_info()
print('***', t, ':', v)
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 as 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 as msg:
print('IOError:', msg)
x.close()
def raw_input(prompt):
sys.stdout.write(prompt)
sys.stdout.flush()
return sys.stdin.readline()
# 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 = input('Query [CR == up a level]: ')
except EOFError:
print()
break
query = query.strip()
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 = input( \
'Save as file [CR == don\'t save; |pipeline or ~user/... OK]: ')
except EOFError:
print()
return None
savefile = savefile.strip()
if not savefile:
return None
if savefile[0] == '|':
cmd = savefile[1:].strip()
try:
p = os.popen(cmd, 'w')
except IOError as 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 as 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 = int(sys.argv[2])
selector = ''
host = sys.argv[1]
except ValueError:
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()
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