#! /usr/bin/env python

# 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()