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1#! /usr/bin/env python
2
3# A simple gopher client.
4#
5# Usage: gopher [ [selector] host [port] ]
6
7import string
8import sys
9import os
10import socket
11
12# Default selector, host and port
13DEF_SELECTOR = ''
14DEF_HOST     = 'gopher.micro.umn.edu'
15DEF_PORT     = 70
16
17# Recognized file types
18T_TEXTFILE  = '0'
19T_MENU      = '1'
20T_CSO       = '2'
21T_ERROR     = '3'
22T_BINHEX    = '4'
23T_DOS       = '5'
24T_UUENCODE  = '6'
25T_SEARCH    = '7'
26T_TELNET    = '8'
27T_BINARY    = '9'
28T_REDUNDANT = '+'
29T_SOUND     = 's'
30
31# Dictionary mapping types to strings
32typename = {'0': '<TEXT>', '1': '<DIR>', '2': '<CSO>', '3': '<ERROR>', \
33        '4': '<BINHEX>', '5': '<DOS>', '6': '<UUENCODE>', '7': '<SEARCH>', \
34        '8': '<TELNET>', '9': '<BINARY>', '+': '<REDUNDANT>', 's': '<SOUND>'}
35
36# Oft-used characters and strings
37CRLF = '\r\n'
38TAB = '\t'
39
40# Open a TCP connection to a given host and port
41def open_socket(host, port):
42    if not port:
43        port = DEF_PORT
44    elif type(port) == type(''):
45        port = string.atoi(port)
46    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
47    s.connect((host, port))
48    return s
49
50# Send a selector to a given host and port, return a file with the reply
51def send_request(selector, host, port):
52    s = open_socket(host, port)
53    s.send(selector + CRLF)
54    s.shutdown(1)
55    return s.makefile('r')
56
57# Get a menu in the form of a list of entries
58def get_menu(selector, host, port):
59    f = send_request(selector, host, port)
60    list = []
61    while 1:
62        line = f.readline()
63        if not line:
64            print '(Unexpected EOF from server)'
65            break
66        if line[-2:] == CRLF:
67            line = line[:-2]
68        elif line[-1:] in CRLF:
69            line = line[:-1]
70        if line == '.':
71            break
72        if not line:
73            print '(Empty line from server)'
74            continue
75        typechar = line[0]
76        parts = string.splitfields(line[1:], TAB)
77        if len(parts) < 4:
78            print '(Bad line from server: %r)' % (line,)
79            continue
80        if len(parts) > 4:
81            print '(Extra info from server: %r)' % (parts[4:],)
82        parts.insert(0, typechar)
83        list.append(parts)
84    f.close()
85    return list
86
87# Get a text file as a list of lines, with trailing CRLF stripped
88def get_textfile(selector, host, port):
89    list = []
90    get_alt_textfile(selector, host, port, list.append)
91    return list
92
93# Get a text file and pass each line to a function, with trailing CRLF stripped
94def get_alt_textfile(selector, host, port, func):
95    f = send_request(selector, host, port)
96    while 1:
97        line = f.readline()
98        if not line:
99            print '(Unexpected EOF from server)'
100            break
101        if line[-2:] == CRLF:
102            line = line[:-2]
103        elif line[-1:] in CRLF:
104            line = line[:-1]
105        if line == '.':
106            break
107        if line[:2] == '..':
108            line = line[1:]
109        func(line)
110    f.close()
111
112# Get a binary file as one solid data block
113def get_binary(selector, host, port):
114    f = send_request(selector, host, port)
115    data = f.read()
116    f.close()
117    return data
118
119# Get a binary file and pass each block to a function
120def get_alt_binary(selector, host, port, func, blocksize):
121    f = send_request(selector, host, port)
122    while 1:
123        data = f.read(blocksize)
124        if not data:
125            break
126        func(data)
127
128# A *very* simple interactive browser
129
130# Browser main command, has default arguments
131def browser(*args):
132    selector = DEF_SELECTOR
133    host = DEF_HOST
134    port = DEF_PORT
135    n = len(args)
136    if n > 0 and args[0]:
137        selector = args[0]
138    if n > 1 and args[1]:
139        host = args[1]
140    if n > 2 and args[2]:
141        port = args[2]
142    if n > 3:
143        raise RuntimeError, 'too many args'
144    try:
145        browse_menu(selector, host, port)
146    except socket.error, msg:
147        print 'Socket error:', msg
148        sys.exit(1)
149    except KeyboardInterrupt:
150        print '\n[Goodbye]'
151
152# Browse a menu
153def browse_menu(selector, host, port):
154    list = get_menu(selector, host, port)
155    while 1:
156        print '----- MENU -----'
157        print 'Selector:', repr(selector)
158        print 'Host:', host, ' Port:', port
159        print
160        for i in range(len(list)):
161            item = list[i]
162            typechar, description = item[0], item[1]
163            print string.rjust(repr(i+1), 3) + ':', description,
164            if typename.has_key(typechar):
165                print typename[typechar]
166            else:
167                print '<TYPE=' + repr(typechar) + '>'
168        print
169        while 1:
170            try:
171                str = raw_input('Choice [CR == up a level]: ')
172            except EOFError:
173                print
174                return
175            if not str:
176                return
177            try:
178                choice = string.atoi(str)
179            except string.atoi_error:
180                print 'Choice must be a number; try again:'
181                continue
182            if not 0 < choice <= len(list):
183                print 'Choice out of range; try again:'
184                continue
185            break
186        item = list[choice-1]
187        typechar = item[0]
188        [i_selector, i_host, i_port] = item[2:5]
189        if typebrowser.has_key(typechar):
190            browserfunc = typebrowser[typechar]
191            try:
192                browserfunc(i_selector, i_host, i_port)
193            except (IOError, socket.error):
194                print '***', sys.exc_type, ':', sys.exc_value
195        else:
196            print 'Unsupported object type'
197
198# Browse a text file
199def browse_textfile(selector, host, port):
200    x = None
201    try:
202        p = os.popen('${PAGER-more}', 'w')
203        x = SaveLines(p)
204        get_alt_textfile(selector, host, port, x.writeln)
205    except IOError, msg:
206        print 'IOError:', msg
207    if x:
208        x.close()
209    f = open_savefile()
210    if not f:
211        return
212    x = SaveLines(f)
213    try:
214        get_alt_textfile(selector, host, port, x.writeln)
215        print 'Done.'
216    except IOError, msg:
217        print 'IOError:', msg
218    x.close()
219
220# Browse a search index
221def browse_search(selector, host, port):
222    while 1:
223        print '----- SEARCH -----'
224        print 'Selector:', repr(selector)
225        print 'Host:', host, ' Port:', port
226        print
227        try:
228            query = raw_input('Query [CR == up a level]: ')
229        except EOFError:
230            print
231            break
232        query = string.strip(query)
233        if not query:
234            break
235        if '\t' in query:
236            print 'Sorry, queries cannot contain tabs'
237            continue
238        browse_menu(selector + TAB + query, host, port)
239
240# "Browse" telnet-based information, i.e. open a telnet session
241def browse_telnet(selector, host, port):
242    if selector:
243        print 'Log in as', repr(selector)
244    if type(port) <> type(''):
245        port = repr(port)
246    sts = os.system('set -x; exec telnet ' + host + ' ' + port)
247    if sts:
248        print 'Exit status:', sts
249
250# "Browse" a binary file, i.e. save it to a file
251def browse_binary(selector, host, port):
252    f = open_savefile()
253    if not f:
254        return
255    x = SaveWithProgress(f)
256    get_alt_binary(selector, host, port, x.write, 8*1024)
257    x.close()
258
259# "Browse" a sound file, i.e. play it or save it
260def browse_sound(selector, host, port):
261    browse_binary(selector, host, port)
262
263# Dictionary mapping types to browser functions
264typebrowser = {'0': browse_textfile, '1': browse_menu, \
265        '4': browse_binary, '5': browse_binary, '6': browse_textfile, \
266        '7': browse_search, \
267        '8': browse_telnet, '9': browse_binary, 's': browse_sound}
268
269# Class used to save lines, appending a newline to each line
270class SaveLines:
271    def __init__(self, f):
272        self.f = f
273    def writeln(self, line):
274        self.f.write(line + '\n')
275    def close(self):
276        sts = self.f.close()
277        if sts:
278            print 'Exit status:', sts
279
280# Class used to save data while showing progress
281class SaveWithProgress:
282    def __init__(self, f):
283        self.f = f
284    def write(self, data):
285        sys.stdout.write('#')
286        sys.stdout.flush()
287        self.f.write(data)
288    def close(self):
289        print
290        sts = self.f.close()
291        if sts:
292            print 'Exit status:', sts
293
294# Ask for and open a save file, or return None if not to save
295def open_savefile():
296    try:
297        savefile = raw_input( \
298    'Save as file [CR == don\'t save; |pipeline or ~user/... OK]: ')
299    except EOFError:
300        print
301        return None
302    savefile = string.strip(savefile)
303    if not savefile:
304        return None
305    if savefile[0] == '|':
306        cmd = string.strip(savefile[1:])
307        try:
308            p = os.popen(cmd, 'w')
309        except IOError, msg:
310            print repr(cmd), ':', msg
311            return None
312        print 'Piping through', repr(cmd), '...'
313        return p
314    if savefile[0] == '~':
315        savefile = os.path.expanduser(savefile)
316    try:
317        f = open(savefile, 'w')
318    except IOError, msg:
319        print repr(savefile), ':', msg
320        return None
321    print 'Saving to', repr(savefile), '...'
322    return f
323
324# Test program
325def test():
326    if sys.argv[4:]:
327        print 'usage: gopher [ [selector] host [port] ]'
328        sys.exit(2)
329    elif sys.argv[3:]:
330        browser(sys.argv[1], sys.argv[2], sys.argv[3])
331    elif sys.argv[2:]:
332        try:
333            port = string.atoi(sys.argv[2])
334            selector = ''
335            host = sys.argv[1]
336        except string.atoi_error:
337            selector = sys.argv[1]
338            host = sys.argv[2]
339            port = ''
340        browser(selector, host, port)
341    elif sys.argv[1:]:
342        browser('', sys.argv[1])
343    else:
344        browser()
345
346# Call the test program as a main program
347test()
348