X-Git-Url: http://www.dolda2000.com/gitweb/?p=ashd.git;a=blobdiff_plain;f=python3%2Fashd%2Fwsgidir.py;h=4b1e4f0c8ad91bfcdac7f09f8e53105fe07abc98;hp=cc17b9b44ba00ff13f8543a6d902201dc6eef760;hb=b8d56e8f4550642b7798b88abd102ed5158e83be;hpb=c221b22d61df5882462eab41e5c79ae2a3ea9642 diff --git a/python3/ashd/wsgidir.py b/python3/ashd/wsgidir.py index cc17b9b..4b1e4f0 100644 --- a/python3/ashd/wsgidir.py +++ b/python3/ashd/wsgidir.py @@ -1,46 +1,42 @@ """WSGI handler for serving chained WSGI modules from physical files -The WSGI handler in this module examines the SCRIPT_FILENAME variable -of the requests it handles -- that is, the physical file corresponding -to the request, as determined by the webserver -- determining what to -do with the request based on the extension of that file. - -By default, it handles files named `.wsgi' by compiling them into -Python modules and using them, in turn, as chained WSGI handlers, but -handlers for other extensions can be installed as well. - -When handling `.wsgi' files, the compiled modules are cached and -reused until the file is modified, in which case the previous module -is discarded and the new file contents are loaded into a new module in -its place. When chaining such modules, an object named `wmain' is -first looked for and called with no arguments if found. The object it -returns is then used as the WSGI application object for that module, -which is reused until the module is reloaded. If `wmain' is not found, -an object named `application' is looked for instead. If found, it is -used directly as the WSGI application object. +The WSGI handler in this module ensures that the SCRIPT_FILENAME +variable is properly set in every request and points out a file that +exists and is readable. It then dispatches the request in one of two +ways: If the header X-Ash-Python-Handler is set in the request, its +value is used as the name of a handler object to dispatch the request +to; otherwise, the file extension of the SCRIPT_FILENAME is used to +determine the handler object. + +The name of a handler object is specified as a string, which is split +along its last constituent dot. The part left of the dot is the name +of a module, which is imported; and the part right of the dot is the +name of an object in that module, which should be a callable adhering +to the WSGI specification. Alternatively, the module part may be +omitted (such that the name is a string with no dots), in which case +the handler object is looked up from this module. + +By default, this module will handle files with the extensions `.wsgi' +or `.wsgi3' using the `chain' handler, which chainloads such files and +runs them as independent WSGI applications. See its documentation for +details. This module itself contains both an `application' and a `wmain' object. If this module is used by ashd-wsgi(1) or scgi-wsgi(1) so that its wmain function is called, arguments can be specified to it to install handlers for other file extensions. Such arguments take the -form `.EXT=MODULE.HANDLER', where EXT is the file extension to be -handled, and the MODULE.HANDLER string is treated by splitting it -along its last constituent dot. The part left of the dot is the name -of a module which is imported, and the part right of the dot is the -name of an object in that module, which should be a callable adhering -to the WSGI specification. When called, this module will have made -sure that the WSGI environment contains the SCRIPT_FILENAME parameter -and that it is properly working. For example, the argument -`.fpy=my.module.foohandler' can be given to pass requests for `.fpy' -files to the function `foohandler' in the module `my.module' (which -must, of course, be importable). When writing such handler functions, -you will probably want to use the getmod() function in this module. +form `.EXT=HANDLER', where EXT is the file extension to be handled, +and HANDLER is a handler name, as described above. For example, the +argument `.fpy=my.module.foohandler' can be given to pass requests for +`.fpy' files to the function `foohandler' in the module `my.module' +(which must, of course, be importable). When writing such handler +functions, you may want to use the getmod() function in this module. """ -import os, threading, types +import os, threading, types, importlib from . import wsgiutil -__all__ = ["application", "wmain", "getmod", "cachedmod"] +__all__ = ["application", "wmain", "getmod", "cachedmod", "chain"] class cachedmod(object): """Cache entry for modules loaded by getmod() @@ -55,12 +51,11 @@ class cachedmod(object): Additional data attributes can be arbitrarily added for recording any meta-data about the module. """ - def __init__(self, mod, mtime): + def __init__(self, mod = None, mtime = -1): self.lock = threading.Lock() self.mod = mod self.mtime = mtime -exts = {} modcache = {} cachelock = threading.Lock() @@ -87,35 +82,100 @@ def getmod(path): about the module. See its documentation for details. """ sb = os.stat(path) - cachelock.acquire() - try: + with cachelock: if path in modcache: entry = modcache[path] - if sb.st_mtime <= entry.mtime: - return entry + else: + entry = [threading.Lock(), None] + modcache[path] = entry + with entry[0]: + if entry[1] is None or sb.st_mtime > entry[1].mtime: + with open(path, "rb") as f: + text = f.read() + code = compile(text, path, "exec") + mod = types.ModuleType(mangle(path)) + mod.__file__ = path + exec(code, mod.__dict__) + entry[1] = cachedmod(mod, sb.st_mtime) + return entry[1] + +class handler(object): + def __init__(self): + self.lock = threading.Lock() + self.handlers = {} + self.exts = {} + self.addext("wsgi", "chain") + self.addext("wsgi3", "chain") + + def resolve(self, name): + with self.lock: + if name in self.handlers: + return self.handlers[name] + p = name.rfind('.') + if p < 0: + return globals()[name] + mname = name[:p] + hname = name[p + 1:] + mod = importlib.import_module(mname) + ret = getattr(mod, hname) + self.handlers[name] = ret + return ret - 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, mod.__dict__) - entry = cachedmod(mod, sb.st_mtime) - modcache[path] = entry - return entry - finally: - cachelock.release() + def addext(self, ext, handler): + self.exts[ext] = self.resolve(handler) + + def handle(self, env, startreq): + if not "SCRIPT_FILENAME" in env: + return wsgiutil.simpleerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.") + path = env["SCRIPT_FILENAME"] + if not os.access(path, os.R_OK): + return wsgiutil.simpleerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.") + if "HTTP_X_ASH_PYTHON_HANDLER" in env: + handler = self.resolve(env["HTTP_X_ASH_PYTHON_HANDLER"]) + else: + base = os.path.basename(path) + p = base.rfind('.') + if p < 0: + return wsgiutil.simpleerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.") + ext = base[p + 1:] + if not ext in self.exts: + return wsgiutil.simpleerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.") + handler = self.exts[ext] + return handler(env, startreq) + +def wmain(*argv): + """Main function for ashd(7)-compatible WSGI handlers + + Returns the `application' function. If any arguments are given, + they are parsed according to the module documentation. + """ + ret = handler() + for arg in argv: + if arg[0] == '.': + p = arg.index('=') + ret.addext(arg[1:p], arg[p + 1:]) + return ret.handle def chain(env, startreq): + """Chain-loading WSGI handler + + This handler loads requested files, compiles them and loads them + into their own modules. The compiled modules are cached and reused + until the file is modified, in which case the previous module is + discarded and the new file contents are loaded into a new module + in its place. When chaining such modules, an object named `wmain' + is first looked for and called with no arguments if found. The + object it returns is then used as the WSGI application object for + that module, which is reused until the module is reloaded. If + `wmain' is not found, an object named `application' is looked for + instead. If found, it is used directly as the WSGI application + object. + """ path = env["SCRIPT_FILENAME"] mod = getmod(path) entry = None if mod is not None: - mod.lock.acquire() - try: + with mod.lock: if hasattr(mod, "entry"): entry = mod.entry else: @@ -124,46 +184,8 @@ def chain(env, startreq): elif hasattr(mod.mod, "application"): entry = mod.mod.application mod.entry = entry - finally: - mod.lock.release() if entry is not None: return entry(env, startreq) return wsgiutil.simpleerror(env, startreq, 500, "Internal Error", "Invalid WSGI handler.") -exts["wsgi"] = chain -exts["wsgi3"] = chain - -def addext(ext, handler): - p = handler.rindex('.') - mname = handler[:p] - hname = handler[p + 1:] - mod = __import__(mname, fromlist = ["dummy"]) - exts[ext] = getattr(mod, hname) - -def application(env, startreq): - """WSGI handler function - - Handles WSGI requests as per the module documentation. - """ - if not "SCRIPT_FILENAME" in env: - return wsgiutil.simpleerror(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.simpleerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.") - ext = base[p + 1:] - if not ext in exts: - return wsgiutil.simpleerror(env, startreq, 500, "Internal Error", "The server is erroneously configured.") - return(exts[ext](env, startreq)) - -def wmain(*argv): - """Main function for ashd(7)-compatible WSGI handlers - Returns the `application' function. If any arguments are given, - they are parsed according to the module documentation. - """ - for arg in argv: - if arg[0] == '.': - p = arg.index('=') - addext(arg[1:p], arg[p + 1:]) - return application +application = handler().handle