Added a SCGI-WSGI gateway for Python.

diff --git a/python/.gitignore b/python/.gitignore
new file mode 100644 (file)
index 0000000..0d20b64
--- /dev/null
+++ b/python/.gitignore
@@ -0,0 +1 @@
+*.pyc

diff --git a/python/ashd/__init__.py b/python/ashd/__init__.py
new file mode 100644 (file)
index 0000000..e69de29

diff --git a/python/ashd/scgi.py b/python/ashd/scgi.py
new file mode 100644 (file)
index 0000000..9357e9d
--- /dev/null
+++ b/python/ashd/scgi.py
@@ -0,0 +1,113 @@
+import sys
+import threading
+
+class protoerr(Exception):
+    pass
+
+def readns(sk):
+    hln = 0
+    while True:
+        c = sk.read(1)
+        if c == ':':
+            break
+        elif c >= '0' or c <= '9':
+            hln = (hln * 10) + (ord(c) - ord('0'))
+        else:
+            raise protoerr, "Invalid netstring length byte: " + c
+    ret = sk.read(hln)
+    if sk.read(1) != ',':
+        raise protoerr, "Non-terminated netstring"
+    return ret
+
+def readhead(sk):
+    parts = readns(sk).split('\0')[:-1]
+    if len(parts) % 2 != 0:
+        raise protoerr, "Malformed headers"
+    ret = {}
+    i = 0
+    while i < len(parts):
+        ret[parts[i]] = parts[i + 1]
+        i += 2
+    return ret
+
+class reqthread(threading.Thread):
+    def __init__(self, sk, handler):
+        super(reqthread, self).__init__(name = "SCGI request handler")
+        self.sk = sk.dup().makefile("r+")
+        self.handler = handler
+
+    def run(self):
+        try:
+            head = readhead(self.sk)
+            self.handler(head, self.sk)
+        finally:
+            self.sk.close()
+
+def handlescgi(sk, handler):
+    t = reqthread(sk, handler)
+    t.start()
+
+def servescgi(socket, handler):
+    while True:
+        nsk, addr = socket.accept()
+        try:
+            handlescgi(nsk, handler)
+        finally:
+            nsk.close()
+
+def wrapwsgi(handler):
+    def handle(head, sk):
+        env = dict(head)
+        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
+
+        resp = []
+        respsent = []
+
+        def write(data):
+            if not data:
+                return
+            if not respsent:
+                if not resp:
+                    raise Exception, "Trying to write data before starting response."
+                status, headers = resp
+                respsent[:] = [True]
+                sk.write("Status: %s\n" % status)
+                for nm, val in headers:
+                    sk.write("%s: %s\n" % (nm, val))
+                sk.write("\n")
+            sk.write(data)
+            sk.flush()
+
+        def startreq(status, headers, exc_info = None):
+            if resp:
+                if exc_info:                # Interesting, this...
+                    try:
+                        if respsent:
+                            raise exc_info[0], exc_info[1], exc_info[2]
+                    finally:
+                        exc_info = None     # CPython GC bug?
+                else:
+                    raise Exception, "Can only start responding once."
+            resp[:] = status, headers
+            return write
+
+        respiter = handler(env, startreq)
+        try:
+            for data in respiter:
+                write(data)
+            write("")
+        finally:
+            if hasattr(respiter, "close"):
+                respiter.close()
+    return handle

diff --git a/python/ashd/wsgidir.py b/python/ashd/wsgidir.py
new file mode 100644 (file)
index 0000000..037544d
--- /dev/null
+++ b/python/ashd/wsgidir.py
@@ -0,0 +1,62 @@
+import os, threading, types
+import wsgiutil
+
+exts = {}
+modcache = {}
+cachelock = threading.Lock()
+
+def mangle(path):
+    ret = ""
+    for c in path:
+        if c.isalnum():
+            ret += c
+        else:
+            ret += "_"
+    return ret
+
+def getmod(path):
+    sb = os.stat(path)
+    cachelock.acquire()
+    try:
+        if path in modcache:
+            mod, mtime = modcache[path]
+            if sb.st_mtime <= mtime:
+                return mod
+        f = open(path)
+        try:
+            text = f.read()
+        finally:
+            f.close()
+        code = compile(text, path, "exec")
+        mod = types.ModuleType(mangle(path))
+        mod.__file__ = path
+        exec code in mod.__dict__
+        modcache[path] = mod, sb.st_mtime
+        return mod
+    finally:
+        cachelock.release()
+
+def chain(path, env, startreq):
+    mod = getmod(path)
+    if hasattr(mod, "wmain"):
+        return (mod.wmain())(env, startreq)
+    elif hasattr(mod, "application"):
+        return mod.application(env, startreq)
+    return wsgi.simpleerror(env, startreq, 500, "Internal Error", "Invalid WSGI handler.")
+exts["wsgi"] = chain
+
+def application(env, startreq):
+    if not "SCRIPT_FILENAME" in env:
+        return wsgiutil.simplerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.")
+    path = env["SCRIPT_FILENAME"]
+    base = os.path.basename(path)
+    p = base.rfind('.')
+    if p < 0 or not os.access(path, os.R_OK):
+        return wsgiutil.simplerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.")
+    ext = base[p + 1:]
+    if not ext in exts:
+        return wsgiutil.simplerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.")
+    return(exts[ext](path, env, startreq))
+
+def wmain(argv):
+    return application

diff --git a/python/ashd/wsgiutil.py b/python/ashd/wsgiutil.py
new file mode 100644 (file)
index 0000000..b947407
--- /dev/null
+++ b/python/ashd/wsgiutil.py
@@ -0,0 +1,29 @@
+def htmlquote(text):
+    ret = ""
+    for c in text:
+        if c == '&':
+            ret += "&"
+        elif c == '<':
+            ret += "&lt;"
+        elif c == '>':
+            ret += "&gt;"
+        elif c == '"':
+            ret += "&quot;"
+        else:
+            ret += c
+    return ret
+
+def simpleerror(env, startreq, code, title, msg):
+    buf = """<?xml version="1.0" encoding="US-ASCII"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
+<head>
+<title>%s</title>
+</head>
+<body>
+<h1>%s</h1>
+<p>%s</p>
+</body>
+</html>""" % (title, title, htmlquote(msg))
+    startreq("%i %s" % (code, title), [("Content-Type", "text/html"), ("Content-Length", str(len(buf)))])
+    return [buf]

diff --git a/python/scgi-wsgi b/python/scgi-wsgi
new file mode 100755 (executable)
index 0000000..944ed39
--- /dev/null
+++ b/python/scgi-wsgi
@@ -0,0 +1,58 @@
+#!/usr/bin/python
+
+import sys, os, getopt
+import socket
+import ashd.scgi
+
+def usage(out):
+    out.write("usage: scgi-wsgi [-hA] [-p MODPATH] [-T [HOST:]PORT] HANDLER-MODULE [ARGS...]\n")
+
+sk = None
+modwsgi_compat = False
+opts, args = getopt.getopt(sys.argv[1:], "+hAp:T:")
+for o, a in opts:
+    if o == "-h":
+        usage(sys.stdout)
+        sys.exit(0)
+    elif o == "-p":
+        sys.path.append(0, a)
+    elif o == "-T":
+        sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        p = a.rfind(":")
+        if p < 0:
+            bindhost = "hostname"
+            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
+if len(args) < 1:
+    usage(sys.stderr)
+    sys.exit(1)
+
+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, exc:
+    sys.stderr.write("scgi-wsgi: handler %s not found: %s\n" % (args[0], exc.message))
+    sys.exit(1)
+if not modwsgi_compat:
+    if not hasattr(handlermod, "wmain"):
+        sys.stderr.write("scgi-wsgi: 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-wsgi: handler %s has no `application' object\n" % args[0])
+        sys.exit(1)
+    handler = handlermod.application
+
+ashd.scgi.servescgi(sk, ashd.scgi.wrapwsgi(handler))