python/ashd-wsgi3

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