#!/usr/bin/python -S
import os, sys

real_script = "/var/www/html/aetest/index.cgi"

def main():
    SCRIPT_NAME     = os.environ['SCRIPT_NAME']
    PATH_INFO       = os.environ.get('PATH_INFO', '') or '__index__'
    SCRIPT_FILENAME = os.environ['SCRIPT_FILENAME']
    REQUEST_METHOD  = os.environ['REQUEST_METHOD']

    cache = os.path.join(real_script + "-cache", PATH_INFO.strip("/"))
#   print >>sys.stderr, "cache=%r" % cache
    dep = os.path.join(cache, "_dep")
    cache = os.path.join(cache, "_cache")

    if cache_valid(cache, dep):
        cache = open(cache, "rb").read()
        if REQUEST_METHOD == 'HEAD':
            cache = headers(cache)
        open("hitlog", "a").write("hit  %r %r %r %r\n" % (
            REQUEST_METHOD, PATH_INFO, os.environ.get("QUERY_STRING", None),
            open(dep, "rb").read().split('\0')))
        sys.stdout.write(cache)
    else:
        try:
            os.unlink(cache)
        except os.error:
            pass
        open("hitlog", "a").write("miss %r %r %r %s\n" % (
            REQUEST_METHOD, PATH_INFO, os.environ.get("QUERY_STRING", None),
            reason))
        sys.stdout.write(cache)
        os.execv(real_script, sys.argv)

def headers(x):
    i = x.find("\n\n")
    if i == -1: return x
    return x[:i+2]

def cache_valid(cache, dep):
    global reason
    reason = ""
    if os.environ.get("QUERY_STRING", ""):
        reason = "QUERY_STRING"
        return False
    if os.environ['REQUEST_METHOD'] not in ["HEAD", "GET"]:
        reason = "REQUEST_METHOD"
        return False
    if not os.path.exists(cache):
        resaon = "cache exists"
        return False
    if not os.path.exists(dep):
        reason = "dep exists"
        return False
    deptime = os.stat(dep).st_mtime
    dep = open(dep).read().split('\0')
    for d in dep:
        try:
            dt = os.stat(d).st_mtime
        except os.error:
            reason = "error opening %r" % d
            return False # File no longer exists
        if dt > deptime:
            reason = "mtime %r on %r newer than %r" % (dt, d, deptime)
            return False
    return True

main()

# vim:sw=4:sts=4:et