python/ashd/scgi.py

   1 import sys
   2 import threading
   3
   4 class protoerr(Exception):
   5     pass
   6
   7 class closed(IOError):
   8     def __init__(self):
   9         super(closed, self).__init__("The client has closed the connection.")
  10
  11 def readns(sk):
  12     hln = 0
  13     while True:
  14         c = sk.read(1)
  15         if c == ':':
  16             break
  17         elif c >= '0' or c <= '9':
  18             hln = (hln * 10) + (ord(c) - ord('0'))
  19         else:
  20             raise protoerr, "Invalid netstring length byte: " + c
  21     ret = sk.read(hln)
  22     if sk.read(1) != ',':
  23         raise protoerr, "Non-terminated netstring"
  24     return ret
  25
  26 def readhead(sk):
  27     parts = readns(sk).split('\0')[:-1]
  28     if len(parts) % 2 != 0:
  29         raise protoerr, "Malformed headers"
  30     ret = {}
  31     i = 0
  32     while i < len(parts):
  33         ret[parts[i]] = parts[i + 1]
  34         i += 2
  35     return ret
  36
  37 class reqthread(threading.Thread):
  38     def __init__(self, sk, handler):
  39         super(reqthread, self).__init__(name = "SCGI request handler")
  40         self.bsk = sk.dup()
  41         self.sk = self.bsk.makefile("r+")
  42         self.handler = handler
  43
  44     def run(self):
  45         try:
  46             head = readhead(self.sk)
  47             self.handler(head, self.sk)
  48         finally:
  49             self.sk.close()
  50             self.bsk.close()
  51
  52 def handlescgi(sk, handler):
  53     t = reqthread(sk, handler)
  54     t.start()
  55
  56 def servescgi(socket, handler):
  57     while True:
  58         nsk, addr = socket.accept()
  59         try:
  60             handlescgi(nsk, handler)
  61         finally:
  62             nsk.close()
  63
  64 def wrapwsgi(handler):
  65     def handle(head, sk):
  66         env = dict(head)
  67         env["wsgi.version"] = 1, 0
  68         if "HTTP_X_ASH_PROTOCOL" in env:
  69             env["wsgi.url_scheme"] = env["HTTP_X_ASH_PROTOCOL"]
  70         elif "HTTPS" in env:
  71             env["wsgi.url_scheme"] = "https"
  72         else:
  73             env["wsgi.url_scheme"] = "http"
  74         env["wsgi.input"] = sk
  75         env["wsgi.errors"] = sys.stderr
  76         env["wsgi.multithread"] = True
  77         env["wsgi.multiprocess"] = False
  78         env["wsgi.run_once"] = False
  79
  80         resp = []
  81         respsent = []
  82
  83         def flushreq():
  84             if not respsent:
  85                 if not resp:
  86                     raise Exception, "Trying to write data before starting response."
  87                 status, headers = resp
  88                 respsent[:] = [True]
  89                 try:
  90                     sk.write("Status: %s\n" % status)
  91                     for nm, val in headers:
  92                         sk.write("%s: %s\n" % (nm, val))
  93                     sk.write("\n")
  94                 except IOError:
  95                     raise closed()
  96
  97         def write(data):
  98             if not data:
  99                 return
 100             flushreq()
 101             try:
 102                 sk.write(data)
 103                 sk.flush()
 104             except IOError:
 105                 raise closed()
 106
 107         def startreq(status, headers, exc_info = None):
 108             if resp:
 109                 if exc_info:                # Interesting, this...
 110                     try:
 111                         if respsent:
 112                             raise exc_info[0], exc_info[1], exc_info[2]
 113                     finally:
 114                         exc_info = None     # CPython GC bug?
 115                 else:
 116                     raise Exception, "Can only start responding once."
 117             resp[:] = status, headers
 118             return write
 119
 120         respiter = handler(env, startreq)
 121         try:
 122             try:
 123                 for data in respiter:
 124                     write(data)
 125                 if resp:
 126                     flushreq()
 127             except closed:
 128                 pass
 129         finally:
 130             if hasattr(respiter, "close"):
 131                 respiter.close()
 132     return handle