--- /dev/null
+"""Low-level protocol module for ashd(7)
+
+This module provides primitive functions that speak the raw ashd(7)
+protocol. Primarily, it implements the `req' class that is used to
+represent ashd requests. The functions it provides can also be used to
+create ashd handlers, but unless you require very precise control, the
+ashd.util module provides an easier-to-use interface.
+"""
+
+import os, socket
+from . import htlib
+
+__all__ = ["req", "recvreq", "sendreq"]
+
+class protoerr(Exception):
+ pass
+
+class req(object):
+ """Represents a single ashd request. Normally, you would not
+ create instances of this class manually, but receive them from the
+ recvreq function.
+
+ For the abstract structure of ashd requests, please see the
+ ashd(7) manual page. This class provides access to the HTTP
+ method, raw URL, HTTP version and rest string via the `method',
+ `url', `ver' and `rest' variables respectively. It also implements
+ a dict-like interface for case-independent access to the HTTP
+ headers. The raw headers are available as a list of (name, value)
+ tuples in the `headers' variable.
+
+ For responding, the response socket is available as a standard
+ Python stream object in the `sk' variable. Again, see the ashd(7)
+ manpage for what to receive and transmit on the response socket.
+
+ Note that instances of this class contain a reference to the live
+ socket used for responding to requests, which should be closed
+ when you are done with the request. The socket can be closed
+ manually by calling the close() method on this
+ object. Alternatively, this class implements the resource-manager
+ interface, so that it can be used in `with' statements.
+ """
+
+ def __init__(self, method, url, ver, rest, headers, fd):
+ self.method = method
+ self.url = url
+ self.ver = ver
+ self.rest = rest
+ self.headers = headers
+ self.bsk = socket.fromfd(fd, socket.AF_UNIX, socket.SOCK_STREAM)
+ self.sk = self.bsk.makefile('rwb')
+ os.close(fd)
+
+ def close(self):
+ "Close this request's response socket."
+ self.sk.close()
+ self.bsk.close()
+
+ def __getitem__(self, header):
+ """Find a HTTP header case-insensitively. For example,
+ req["Content-Type"] returns the value of the content-type
+ header regardlessly of whether the client specified it as
+ "Content-Type", "content-type" or "Content-type".
+ """
+ if isinstance(header, str):
+ header = header.encode("ascii")
+ header = header.lower()
+ for key, val in self.headers:
+ if key.lower() == header:
+ return val
+ raise KeyError(header)
+
+ def __contains__(self, header):
+ """Works analogously to the __getitem__ method for checking
+ header presence case-insensitively.
+ """
+ if isinstance(header, str):
+ header = header.encode("ascii")
+ header = header.lower()
+ for key, val in self.headers:
+ if key.lower() == header:
+ return True
+ return False
+
+ def dup(self):
+ """Creates a duplicate of this request, referring to a
+ duplicate of the response socket.
+ """
+ return req(self.method, self.url, self.ver, self.rest, self.headers, os.dup(self.bsk.fileno()))
+
+ def match(self, match):
+ """If the `match' argument matches exactly the leading part of
+ the rest string, this method strips that part of the rest
+ string off and returns True. Otherwise, it returns False
+ without doing anything.
+
+ This can be used for simple dispatching. For example:
+ if req.match("foo/"):
+ handle(req)
+ elif req.match("bar/"):
+ handle_otherwise(req)
+ else:
+ util.respond(req, "Not found", status = "404 Not Found", ctype = "text/plain")
+ """
+ if isinstance(match, str):
+ match = match.encode("utf-8")
+ if self.rest[:len(match)] == match:
+ self.rest = self.rest[len(match):]
+ return True
+ return False
+
+ def __str__(self):
+ def dec(b):
+ return b.decode("ascii", errors="replace")
+ return "\"%s %s %s\"" % (dec(self.method), dec(self.url), dec(self.ver))
+
+ def __enter__(self):
+ return self
+
+ def __exit__(self, *excinfo):
+ self.sk.close()
+ return False
+
+def recvreq(sock = 0):
+ """Receive a single ashd request on the specified socket file
+ descriptor (or standard input if unspecified).
+
+ The returned value is an instance of the `req' class. As per its
+ description, care should be taken to close() the request when
+ done, to avoid leaking response sockets. If end-of-file is
+ received on the socket, None is returned.
+
+ This function may either raise on OSError if an error occurs on
+ the socket, or a ashd.proto.protoerr if the incoming request is
+ invalidly encoded.
+ """
+ data, fd = htlib.recvfd(sock)
+ if fd is None:
+ return None
+ try:
+ parts = data.split(b'\0')[:-1]
+ if len(parts) < 5:
+ raise protoerr("Truncated request")
+ method, url, ver, rest = parts[:4]
+ headers = []
+ i = 4
+ while True:
+ if parts[i] == b"": break
+ if len(parts) - i < 3:
+ raise protoerr("Truncated request")
+ headers.append((parts[i], parts[i + 1]))
+ i += 2
+ return req(method, url, ver, rest, headers, os.dup(fd))
+ finally:
+ os.close(fd)
+
+def sendreq(sock, req):
+ """Encode and send a single request to the specified socket file
+ descriptor using the ashd protocol. The request should be an
+ instance of the `req' class.
+
+ This function may raise an OSError if an error occurs on the
+ socket.
+ """
+ data = b""
+ data += req.method + b'\0'
+ data += req.url + b'\0'
+ data += req.ver + b'\0'
+ data += req.rest + b'\0'
+ for key, val in req.headers:
+ data += key + b'\0'
+ data += val + b'\0'
+ data += b'\0'
+ htlib.sendfd(sock, req.sk.fileno(), data)
Dolda2000 GitWeb / ashd.git / blobdiff