python3/ashd-wsgi3

   1 #!/usr/bin/python3
   2
   3 import sys, os, getopt, threading, logging, time, locale, collections
   4 import ashd.proto, ashd.util, ashd.perf
   5 try:
   6     import pdm.srv
   7 except:
   8     pdm = None
   9
  10 def usage(out):
  11     out.write("usage: ashd-wsgi3 [-hAL] [-m PDM-SPEC] [-p MODPATH] [-l REQLIMIT] HANDLER-MODULE [ARGS...]\n")
  12
  13 reqlimit = 0
  14 modwsgi_compat = False
  15 setlog = True
  16 opts, args = getopt.getopt(sys.argv[1:], "+hALp:l:m:")
  17 for o, a in opts:
  18     if o == "-h":
  19         usage(sys.stdout)
  20         sys.exit(0)
  21     elif o == "-p":
  22         sys.path.insert(0, a)
  23     elif o == "-L":
  24         setlog = False
  25     elif o == "-A":
  26         modwsgi_compat = True
  27     elif o == "-l":
  28         reqlimit = int(a)
  29     elif o == "-m":
  30         if pdm is not None:
  31             pdm.srv.listen(a)
  32 if len(args) < 1:
  33     usage(sys.stderr)
  34     sys.exit(1)
  35 if setlog:
  36     logging.basicConfig(format="ashd-wsgi3(%(name)s): %(levelname)s: %(message)s")
  37 log = logging.getLogger("ashd-wsgi3")
  38
  39 try:
  40     handlermod = __import__(args[0], fromlist = ["dummy"])
  41 except ImportError as exc:
  42     sys.stderr.write("ashd-wsgi3: handler %s not found: %s\n" % (args[0], exc.args[0]))
  43     sys.exit(1)
  44 if not modwsgi_compat:
  45     if not hasattr(handlermod, "wmain"):
  46         sys.stderr.write("ashd-wsgi3: handler %s has no `wmain' function\n" % args[0])
  47         sys.exit(1)
  48     handler = handlermod.wmain(*args[1:])
  49 else:
  50     if not hasattr(handlermod, "application"):
  51         sys.stderr.write("ashd-wsgi3: handler %s has no `application' object\n" % args[0])
  52         sys.exit(1)
  53     handler = handlermod.application
  54
  55 class closed(IOError):
  56     def __init__(self):
  57         super().__init__("The client has closed the connection.")
  58
  59 cwd = os.getcwd()
  60 def absolutify(path):
  61     if path[0] != '/':
  62         return os.path.join(cwd, path)
  63     return path
  64
  65 def unquoteurl(url):
  66     buf = bytearray()
  67     i = 0
  68     while i < len(url):
  69         c = url[i]
  70         i += 1
  71         if c == ord(b'%'):
  72             if len(url) >= i + 2:
  73                 c = 0
  74                 if ord(b'0') <= url[i] <= ord(b'9'):
  75                     c |= (url[i] - ord(b'0')) << 4
  76                 elif ord(b'a') <= url[i] <= ord(b'f'):
  77                     c |= (url[i] - ord(b'a') + 10) << 4
  78                 elif ord(b'A') <= url[i] <= ord(b'F'):
  79                     c |= (url[i] - ord(b'A') + 10) << 4
  80                 else:
  81                     raise ValueError("Illegal URL escape character")
  82                 if ord(b'0') <= url[i + 1] <= ord(b'9'):
  83                     c |= url[i + 1] - ord('0')
  84                 elif ord(b'a') <= url[i + 1] <= ord(b'f'):
  85                     c |= url[i + 1] - ord(b'a') + 10
  86                 elif ord(b'A') <= url[i + 1] <= ord(b'F'):
  87                     c |= url[i + 1] - ord(b'A') + 10
  88                 else:
  89                     raise ValueError("Illegal URL escape character")
  90                 buf.append(c)
  91                 i += 2
  92             else:
  93                 raise ValueError("Incomplete URL escape character")
  94         else:
  95             buf.append(c)
  96     return buf
  97
  98 def dowsgi(req):
  99     env = {}
 100     env["wsgi.version"] = 1, 0
 101     for key, val in req.headers:
 102         env["HTTP_" + key.upper().replace(b"-", b"_").decode("latin-1")] = val.decode("latin-1")
 103     env["SERVER_SOFTWARE"] = "ashd-wsgi/1"
 104     env["GATEWAY_INTERFACE"] = "CGI/1.1"
 105     env["SERVER_PROTOCOL"] = req.ver.decode("latin-1")
 106     env["REQUEST_METHOD"] = req.method.decode("latin-1")
 107     try:
 108         rawpi = unquoteurl(req.rest)
 109     except:
 110         rawpi = req.rest
 111     try:
 112         name, rest, pi = (v.decode("utf-8") for v in (req.url, req.rest, rawpi))
 113         env["wsgi.uri_encoding"] = "utf-8"
 114     except UnicodeError as exc:
 115         name, rest, pi = (v.decode("latin-1") for v in (req.url, req.rest, rawpi))
 116         env["wsgi.uri_encoding"] = "latin-1"
 117     env["REQUEST_URI"] = name
 118     p = name.find('?')
 119     if p >= 0:
 120         env["QUERY_STRING"] = name[p + 1:]
 121         name = name[:p]
 122     else:
 123         env["QUERY_STRING"] = ""
 124     if name[-len(rest):] == rest:
 125         # This is the same hack used in call*cgi.
 126         name = name[:-len(rest)]
 127     if name == "/":
 128         # This seems to be normal CGI behavior, but see callcgi.c for
 129         # details.
 130         pi = "/" + pi
 131         name = ""
 132     env["SCRIPT_NAME"] = name
 133     env["PATH_INFO"] = pi
 134     for src, tgt in [("HTTP_HOST", "SERVER_NAME"), ("HTTP_X_ASH_PROTOCOL", "wsgi.url_scheme"),
 135                      ("HTTP_X_ASH_SERVER_ADDRESS", "SERVER_ADDR"), ("HTTP_X_ASH_SERVER_PORT", "SERVER_PORT"),
 136                      ("HTTP_X_ASH_ADDRESS", "REMOTE_ADDR"), ("HTTP_X_ASH_PORT", "REMOTE_PORT"),
 137                      ("HTTP_CONTENT_TYPE", "CONTENT_TYPE"), ("HTTP_CONTENT_LENGTH", "CONTENT_LENGTH")]:
 138         if src in env: env[tgt] = env[src]
 139     for key in ["HTTP_CONTENT_TYPE", "HTTP_CONTENT_LENGTH"]:
 140         # The CGI specification does not strictly require this, but
 141         # many actualy programs and libraries seem to.
 142         if key in env: del env[key]
 143     if "X-Ash-Protocol" in req and req["X-Ash-Protocol"] == b"https": env["HTTPS"] = "on"
 144     if "X-Ash-File" in req: env["SCRIPT_FILENAME"] = absolutify(req["X-Ash-File"].decode(locale.getpreferredencoding()))
 145     env["wsgi.input"] = req.sk
 146     env["wsgi.errors"] = sys.stderr
 147     env["wsgi.multithread"] = True
 148     env["wsgi.multiprocess"] = False
 149     env["wsgi.run_once"] = False
 150
 151     resp = []
 152     respsent = []
 153
 154     def recode(thing):
 155         if isinstance(thing, collections.ByteString):
 156             return thing
 157         else:
 158             return str(thing).encode("latin-1")
 159
 160     def flushreq():
 161         if not respsent:
 162             if not resp:
 163                 raise Exception("Trying to write data before starting response.")
 164             status, headers = resp
 165             respsent[:] = [True]
 166             buf = bytearray()
 167             buf += b"HTTP/1.1 " + recode(status) + b"\n"
 168             for nm, val in headers:
 169                 buf += recode(nm) + b": " + recode(val) + b"\n"
 170             buf += b"\n"
 171             try:
 172                 req.sk.write(buf)
 173             except IOError:
 174                 raise closed()
 175
 176     def write(data):
 177         if not data:
 178             return
 179         flushreq()
 180         try:
 181             req.sk.write(data)
 182             req.sk.flush()
 183         except IOError:
 184             raise closed()
 185
 186     def startreq(status, headers, exc_info = None):
 187         if resp:
 188             if exc_info:                # Interesting, this...
 189                 try:
 190                     if respsent:
 191                         raise exc_info[1]
 192                 finally:
 193                     exc_info = None     # CPython GC bug?
 194             else:
 195                 raise Exception("Can only start responding once.")
 196         resp[:] = status, headers
 197         return write
 198
 199     with ashd.perf.request(env) as reqevent:
 200         try:
 201             respiter = handler(env, startreq)
 202             try:
 203                 for data in respiter:
 204                     write(data)
 205                 if resp:
 206                     flushreq()
 207             finally:
 208                 if hasattr(respiter, "close"):
 209                     respiter.close()
 210         except closed:
 211             pass
 212         if resp:
 213             reqevent.response(resp)
 214
 215 flightlock = threading.Condition()
 216 inflight = 0
 217
 218 class reqthread(threading.Thread):
 219     def __init__(self, req):
 220         super().__init__(name = "Request handler")
 221         self.req = req.dup()
 222
 223     def run(self):
 224         global inflight
 225         try:
 226             with flightlock:
 227                 if reqlimit != 0:
 228                     start = time.time()
 229                     while inflight >= reqlimit:
 230                         flightlock.wait(10)
 231                         if time.time() - start > 10:
 232                             os.abort()
 233                 inflight += 1
 234             try:
 235                 dowsgi(self.req)
 236             finally:
 237                 with flightlock:
 238                     inflight -= 1
 239                     flightlock.notify()
 240         except:
 241             log.error("exception occurred in handler thread", exc_info=True)
 242         finally:
 243             self.req.close()
 244             sys.stderr.flush()
 245
 246 def handle(req):
 247     reqthread(req).start()
 248
 249 ashd.util.serveloop(handle)