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c:\python24\lib \ gopherlib.py



0001 """Gopher protocol client interface."""
0002 
0003 __all__ = ["send_selector","send_query"]
0004 
0005 # Default selector, host and port
0006 DEF_SELECTOR = '1/'
0007 DEF_HOST     = 'gopher.micro.umn.edu'
0008 DEF_PORT     = 70
0009 
0010 # Recognized file types
0011 A_TEXT       = '0'
0012 A_MENU       = '1'
0013 A_CSO        = '2'
0014 A_ERROR      = '3'
0015 A_MACBINHEX  = '4'
0016 A_PCBINHEX   = '5'
0017 A_UUENCODED  = '6'
0018 A_INDEX      = '7'
0019 A_TELNET     = '8'
0020 A_BINARY     = '9'
0021 A_DUPLICATE  = '+'
0022 A_SOUND      = 's'
0023 A_EVENT      = 'e'
0024 A_CALENDAR   = 'c'
0025 A_HTML       = 'h'
0026 A_TN3270     = 'T'
0027 A_MIME       = 'M'
0028 A_IMAGE      = 'I'
0029 A_WHOIS      = 'w'
0030 A_QUERY      = 'q'
0031 A_GIF        = 'g'
0032 A_HTML       = 'h'          # HTML file
0033 A_WWW        = 'w'          # WWW address
0034 A_PLUS_IMAGE = ':'
0035 A_PLUS_MOVIE = ';'
0036 A_PLUS_SOUND = '<'
0037 
0038 
0039 _names = dir()
0040 _type_to_name_map = {}
0041 def type_to_name(gtype):
0042     """Map all file types to strings; unknown types become TYPE='x'."""
0043     global _type_to_name_map
0044     if _type_to_name_map=={}:
0045         for name in _names:
0046             if name[:2] == 'A_':
0047                 _type_to_name_map[eval(name)] = name[2:]
0048     if gtype in _type_to_name_map:
0049         return _type_to_name_map[gtype]
0050     return 'TYPE=%r' % (gtype,)
0051 
0052 # Names for characters and strings
0053 CRLF = '\r\n'
0054 TAB = '\t'
0055 
0056 def send_selector(selector, host, port = 0):
0057     """Send a selector to a given host and port, return a file with the reply."""
0058     import socket
0059     if not port:
0060         i = host.find(':')
0061         if i >= 0:
0062             host, port = host[:i], int(host[i+1:])
0063     if not port:
0064         port = DEF_PORT
0065     elif type(port) == type(''):
0066         port = int(port)
0067     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
0068     s.connect((host, port))
0069     s.sendall(selector + CRLF)
0070     s.shutdown(1)
0071     return s.makefile('rb')
0072 
0073 def send_query(selector, query, host, port = 0):
0074     """Send a selector and a query string."""
0075     return send_selector(selector + '\t' + query, host, port)
0076 
0077 def path_to_selector(path):
0078     """Takes a path as returned by urlparse and returns the appropriate selector."""
0079     if path=="/":
0080         return "/"
0081     else:
0082         return path[2:] # Cuts initial slash and data type identifier
0083 
0084 def path_to_datatype_name(path):
0085     """Takes a path as returned by urlparse and maps it to a string.
0086     See section 3.4 of RFC 1738 for details."""
0087     if path=="/":
0088         # No way to tell, although "INDEX" is likely
0089         return "TYPE='unknown'"
0090     else:
0091         return type_to_name(path[1])
0092 
0093 # The following functions interpret the data returned by the gopher
0094 # server according to the expected type, e.g. textfile or directory
0095 
0096 def get_directory(f):
0097     """Get a directory in the form of a list of entries."""
0098     entries = []
0099     while 1:
0100         line = f.readline()
0101         if not line:
0102             print '(Unexpected EOF from server)'
0103             break
0104         if line[-2:] == CRLF:
0105             line = line[:-2]
0106         elif line[-1:] in CRLF:
0107             line = line[:-1]
0108         if line == '.':
0109             break
0110         if not line:
0111             print '(Empty line from server)'
0112             continue
0113         gtype = line[0]
0114         parts = line[1:].split(TAB)
0115         if len(parts) < 4:
0116             print '(Bad line from server: %r)' % (line,)
0117             continue
0118         if len(parts) > 4:
0119             if parts[4:] != ['+']:
0120                 print '(Extra info from server:',
0121                 print parts[4:], ')'
0122         else:
0123             parts.append('')
0124         parts.insert(0, gtype)
0125         entries.append(parts)
0126     return entries
0127 
0128 def get_textfile(f):
0129     """Get a text file as a list of lines, with trailing CRLF stripped."""
0130     lines = []
0131     get_alt_textfile(f, lines.append)
0132     return lines
0133 
0134 def get_alt_textfile(f, func):
0135     """Get a text file and pass each line to a function, with trailing CRLF stripped."""
0136     while 1:
0137         line = f.readline()
0138         if not line:
0139             print '(Unexpected EOF from server)'
0140             break
0141         if line[-2:] == CRLF:
0142             line = line[:-2]
0143         elif line[-1:] in CRLF:
0144             line = line[:-1]
0145         if line == '.':
0146             break
0147         if line[:2] == '..':
0148             line = line[1:]
0149         func(line)
0150 
0151 def get_binary(f):
0152     """Get a binary file as one solid data block."""
0153     data = f.read()
0154     return data
0155 
0156 def get_alt_binary(f, func, blocksize):
0157     """Get a binary file and pass each block to a function."""
0158     while 1:
0159         data = f.read(blocksize)
0160         if not data:
0161             break
0162         func(data)
0163 
0164 def test():
0165     """Trivial test program."""
0166     import sys
0167     import getopt
0168     opts, args = getopt.getopt(sys.argv[1:], '')
0169     selector = DEF_SELECTOR
0170     type = selector[0]
0171     host = DEF_HOST
0172     if args:
0173         host = args[0]
0174         args = args[1:]
0175     if args:
0176         type = args[0]
0177         args = args[1:]
0178         if len(type) > 1:
0179             type, selector = type[0], type
0180         else:
0181             selector = ''
0182             if args:
0183                 selector = args[0]
0184                 args = args[1:]
0185         query = ''
0186         if args:
0187             query = args[0]
0188             args = args[1:]
0189     if type == A_INDEX:
0190         f = send_query(selector, query, host)
0191     else:
0192         f = send_selector(selector, host)
0193     if type == A_TEXT:
0194         lines = get_textfile(f)
0195         for item in lines: print item
0196     elif type in (A_MENU, A_INDEX):
0197         entries = get_directory(f)
0198         for item in entries: print item
0199     else:
0200         data = get_binary(f)
0201         print 'binary data:', len(data), 'bytes:', repr(data[:100])[:40]
0202 
0203 # Run the test when run as script
0204 if __name__ == '__main__':
0205     test()
0206 

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