commit 12fe309124e0f2099716db600fa0e5d68fac30b3 Author: David Fifield david@bamsoftware.com Date: Fri Jul 13 04:07:31 2012 -0700

Parse input commands. --- facilitator | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 66 insertions(+), 1 deletions(-)

diff --git a/facilitator b/facilitator index 16782cc..90fb1d8 100755 --- a/facilitator +++ b/facilitator @@ -114,6 +114,65 @@ def format_addr(addr): else: return u"%s:%d" % (host, port)

+def skip_space(pos, line): + """Skip a (possibly empty) sequence of space characters (the ASCII character + '\x20' exactly). Returns a pair (pos, num_skipped).""" + begin = pos + while pos < len(line) and line[pos] == "\x20": + pos += 1 + return pos, pos - begin + +TOKEN_CHARS = set("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-") +def get_token(pos, line): + begin = pos + while pos < len(line) and line[pos] in TOKEN_CHARS: + pos += 1 + if begin == pos: + raise ValueError("No token found at position %d" % pos) + return pos, line[begin:pos] + +def get_quoted_string(pos, line): + chars = [] + if not (pos < len(line) and line[pos] == '"'): + raise ValueError("Expected '"' at beginning of quoted string.") + pos += 1 + while pos < len(line) and line[pos] != '"': + if line[pos] == '\': + pos += 1 + if not (pos < len(line)): + raise ValueError("End of line after backslash in quoted string") + chars.append(line[pos]) + pos += 1 + if not (pos < len(line) and line[pos] == '"'): + raise ValueError("Expected '"' at end of quoted string.") + pos += 1 + return pos, "".join(chars) + +def parse_command(line): + """A line is a command followed by zero or more key-value pairs. Like so: + COMMAND KEY="VALUE" KEY=""ESCAPED" VALUE" + Values must be quoted. Any byte value may be escaped with a backslash. + Returns a pair: (COMMAND, ((KEY1, VALUE1), (KEY2, VALUE2), ...)). + """ + pos = 0 + pos, skipped = skip_space(pos, line) + pos, command = get_token(pos, line) + + pairs = [] + while True: + pos, skipped = skip_space(pos, line) + if not (pos < len(line)): + break + if skipped == 0: + raise ValueError("Expected space before key-value pair") + pos, key = get_token(pos, line) + if not (pos < len(line) and line[pos] == '='): + raise ValueError("No '=' found after key") + pos += 1 + pos, value = get_quoted_string(pos, line) + pairs.append((key, value)) + return command, tuple(pairs) + class Handler(SocketServer.StreamRequestHandler): def __init__(self, *args, **kwargs): self.deadline = time.time() + CLIENT_TIMEOUT @@ -165,7 +224,13 @@ class Handler(SocketServer.StreamRequestHandler): except socket.error, e: log("socket error after reading %d lines: %s" % (num_lines, str(e))) break - print "line", repr(line) + self.handle_line(line) + + def handle_line(self, line): + if not (len(line) > 0 and line[-1] == '\n'): + raise ValueError("No newline at end of string returned by readline") + command, pairs = parse_command(line[:-1]) + print command, pairs

class Server(SocketServer.ThreadingMixIn, SocketServer.TCPServer): allow_reuse_address = True