python: Always properly close request handlers when exiting.

[ashd.git] / python3 / scgi-wsgi3

#!/usr/bin/python3

import sys, os, getopt, logging, collections
import socket
import ashd.scgi, ashd.perf, ashd.serve
try:
    import pdm.srv
except:
    pdm = None

def usage(out):
    out.write("usage: scgi-wsgi3 [-hAL] [-m PDM-SPEC] [-p MODPATH] [-T [HOST:]PORT] HANDLER-MODULE [ARGS...]\n")

sk = None
modwsgi_compat = False
setlog = True
opts, args = getopt.getopt(sys.argv[1:], "+hALp:T:m:")
for o, a in opts:
    if o == "-h":
        usage(sys.stdout)
        sys.exit(0)
    elif o == "-p":
        sys.path.insert(0, a)
    elif o == "-L":
        setlog = False
    elif o == "-T":
        sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sk.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        p = a.rfind(":")
        if p < 0:
            bindhost = "localhost"
            bindport = int(a)
        else:
            bindhost = a[:p]
            bindport = int(a[p + 1:])
        sk.bind((bindhost, bindport))
        sk.listen(32)
    elif o == "-A":
        modwsgi_compat = True
    elif o == "-m":
        if pdm is not None:
            pdm.srv.listen(a)
if len(args) < 1:
    usage(sys.stderr)
    sys.exit(1)
if setlog:
    logging.basicConfig(format="scgi-wsgi3(%(name)s): %(levelname)s: %(message)s")

if sk is None:
    # This is suboptimal, since the socket on stdin is not necessarily
    # AF_UNIX, but Python does not seem to offer any way around it,
    # that I can find.
    sk = socket.fromfd(0, socket.AF_UNIX, socket.SOCK_STREAM)

try:
    handlermod = __import__(args[0], fromlist = ["dummy"])
except ImportError as exc:
    sys.stderr.write("scgi-wsgi3: handler %s not found: %s\n" % (args[0], exc.args[0]))
    sys.exit(1)
if not modwsgi_compat:
    if not hasattr(handlermod, "wmain"):
        sys.stderr.write("scgi-wsgi3: handler %s has no `wmain' function\n" % args[0])
        sys.exit(1)
    handler = handlermod.wmain(*args[1:])
else:
    if not hasattr(handlermod, "application"):
        sys.stderr.write("scgi-wsgi3: handler %s has no `application' object\n" % args[0])
        sys.exit(1)
    handler = handlermod.application

def mkenv(head, sk):
    try:
        env = ashd.scgi.decodehead(head, "utf-8")
        env["wsgi.uri_encoding"] = "utf-8"
    except UnicodeError:
        env = ashd.scgi.decodehead(head, "latin-1")
        env["wsgi.uri_encoding"] = "latin-1"
    env["wsgi.version"] = 1, 0
    if "HTTP_X_ASH_PROTOCOL" in env:
        env["wsgi.url_scheme"] = env["HTTP_X_ASH_PROTOCOL"]
    elif "HTTPS" in env:
        env["wsgi.url_scheme"] = "https"
    else:
        env["wsgi.url_scheme"] = "http"
    env["wsgi.input"] = sk
    env["wsgi.errors"] = sys.stderr
    env["wsgi.multithread"] = True
    env["wsgi.multiprocess"] = False
    env["wsgi.run_once"] = False
    return env

def recode(thing):
    if isinstance(thing, collections.ByteString):
        return thing
    else:
        return str(thing).encode("latin-1")

reqhandler = ashd.serve.freethread()

class request(ashd.serve.wsgirequest):
    def __init__(self, *, sk, **kw):
        super().__init__(**kw)
        self.sk = sk.dup()

    def mkenv(self):
        fsk = self.sk.dup().makefile("rwb")
        try:
            return mkenv(ashd.scgi.readhead(fsk), fsk)
        finally:
            fsk.close()

    def handlewsgi(self, env, startreq):
        return handler(env, startreq)

    def fileno(self):
        return self.sk.fileno()

    def writehead(self, status, headers):
        w = self.buffer.extend
        w(b"Status: " + recode(status) + b"\n")
        for nm, val in headers:
            w(recode(nm) + b": " + recode(val) + b"\n")
        w(b"\n")

    def flush(self):
        try:
            ret = self.sk.send(self.buffer, socket.MSG_DONTWAIT)
            self.buffer[:ret] = b""
        except IOError:
            raise ashd.serve.closed()

    def close(self):
        self.sk.close()

try:
    while True:
        nsk, addr = sk.accept()
        try:
            reqhandler.handle(request(sk=nsk, handler=reqhandler))
        finally:
            nsk.close()
finally:
    reqhandler.close()