"""Yet another WSGI micro-framework...""" import cgi, string, new, sys from wsgiref.util import shift_path_info, application_uri __all__ = [ "Page", "form_handler", "HTML", "Text", "Template", "HTTP", "EvalTemplate", "EvalMap", "Method", ] class Method(object): """Turn any object into a method""" def __init__(self, func): self.call = func def __get__(self, ob, typ=None): if ob is None: return self return new.instancemethod(self.call, ob, typ) class HTTP(Method): """Wrapper/decorator that marks an object as an HTTP method""" cls_registry = "http_methods" def form_handler(arg): """Decorator that marks an object as a registered validator""" def decorator(func): func.cls_registry = "form_handlers" func.priority = priority, func.__name__ return func if isinstance(arg, type(form_handler)): priority = 0 return decorator(arg) return decorator text_plain = ('Content-Type', 'text/plain') text_html = ('Content-Type', 'text/html') def get_module(): return sys._getframe(2).f_globals.get('__name__', __name__) sentinel = object() class EvalMap(object): """Object that translates from getitem->getattr""" def __init__(self, page, extra={}, module=__name__): self.page = page self.extra = dict(extra) # always copy, to allow mod by listcomps self.module = module def __setitem__(self, key, value): # needed for listcomp exprs! self.extra[key] = value def __delitem__(self, key): # needed for listcomp exprs! del self.extra[key] def __getitem__(self, key): if key.startswith('(?'): return eval( key[2:].rstrip(')').rstrip('?').strip(), sys.modules[self.module].__dict__, self ) elif key in self.extra: return self.extra[key] else: ob = getattr(self.page, key, sentinel) if ob is not sentinel: return ob g = sys.modules[self.module].__dict__ if key in g: return g[key] if key=='self': return self raise KeyError(key) class EvalTemplate(string.Template): idpattern = r'[_a-z][_a-z0-9]*|\(\?[^?]*\?\)' class Text(Method): """Text template w/string substitution that can be used as a method Note: templates cannot be directly invoked from the web unless they are created with Text.page() or Text.http_method(), or used as a Page's ``body`` attribute. """ cls_registry = None factory = EvalTemplate status = '200 OK' headers = text_plain, resource = caller = None def __init__(self, *args, **kw): kw.setdefault('caller', get_module()) for k, v in kw.items(): if hasattr(type(self),k): setattr(self, k, v) del kw[k] if self.resource: self.options = kw else: self.template = self.factory(*args, **kw) def call(self, page, extra_headers = [], **kw): content = self.render(page, kw) headers = list(self.headers) + extra_headers headers.append(('Content-Length',str(len(content)))) page.start_response(self.status, headers) return [content] def render(self, page, kw={}): if self.resource: from pkg_resources import resource_string body = resource_string(self.caller, self.resource) self.template = self.factory(body, **self.options) self.resource = None return self.template.substitute(EvalMap(page, kw, self.caller)) @classmethod def fragment(cls, *args, **kw): """Template property that returns its rendered body""" return property(cls(caller = get_module(), *args, **kw).render) @classmethod def http_method(cls, *args, **kw): """Template that can be used as an HTTP method (GET, POST, PUT, etc.)""" return cls( caller=get_module(), cls_registry='http_methods', *args, **kw ) @classmethod def method(cls, *args, **kw): """Template method that can be called with keyword arguments""" return Method(cls(caller = get_module(), *args, **kw).render) @classmethod def page(cls, *args, **kw): """Template sub-page (returns a Page subclass w/template as its body) If you supply a `type` keyword argument, that type is used as the base class for the page. The other arguments are used to create the template to be used as the returned class' ``body`` attribute. """ caller = get_module() class _Page(kw.get('type',Page)): body = cls(caller=caller, *args, **kw) return _Page class HTML(Text): """HTML template w/string substitution that can be used as a method Note: templates cannot be directly invoked from the web unless they are created with HTML.page() or HTML.http_method(), or used as a Page's ``body`` attribute. """ headers = text_html, class Template(HTML): """TurboGears/Buffet template that can be used as a method Note: templates cannot be directly invoked from the web unless they are created with Template.page() or Template.http_method(), or used as a Page's ``body`` attribute. """ engine = None resource = property(lambda self:None) # resources can't be used for this def factory(self, templatename, **options): engine, name = templatename.split(':', 1) from pkg_resources import iter_entry_points for ep in iter_entry_points('python.templating.engines',engine): self.engine = ep.load()() break else: raise RuntimeError("Template engine %r is not installed" % (engine,)) return name def render(self, page, kw={}): return self.engine.render( EvalMap(page,kw,self.caller), template=self.template ) class Page(object): """A generic web location""" cls_registry = "sub_pages" http_methods = [] sub_pages = [] body = None class __metaclass__(type): def __init__(cls, name, bases, cdict): for k in dir(cls): v = getattr(cls, k) reg = getattr(v, 'cls_registry', None) if reg: d = cdict.setdefault(reg,[]) d.append(k) setattr(cls, reg, d) def __call__(cls, *args, **kw): self = type.__call__(cls, *args, **kw) return self.go() def __init__(self, environ, start_response, **kw): self.environ = environ self.start_response = start_response cls = type(self) for k, v in kw.items(): getattr(cls,k) # AttributeError here means bad keyword arg setattr(self,k,v) self.setup() # perform any dynamic initialization def HEAD(self): environ['REQUEST_METHOD'] = 'GET' resp = iter(self.invoke_method()) # forward to 'GET' list(resp) # questionable hack to exhaust the response return resp # ensure that .close() gets called, if any def go(self): self.URL = application_uri(self.environ) name = shift_path_info(self.environ) if name: return self.handle_child(name) url = self.URL.rstrip('/') leaf = not self.sub_pages and type(self).handle_child == Page.handle_child if name=='': # trailing / if not leaf or self.environ.get('SCRIPT_NAME')=='/': return self.invoke_method() elif name is None: # no trailing / if leaf: return self.invoke_method() url += '/' # add the trailing / return self.redirect(url) def handle_child(self, name): if name in self.sub_pages: return getattr(self, name)( self.environ, self.start_response, parent=self ) return self.NOT_FOUND() def redirect(self, url): return self.REDIRECT_TO([('Location', url)], url=url) def setup(self): self.errors = [] self.db = getattr(self.parent, 'db', None) parent = None def invoke_method(self): rm = self.environ['REQUEST_METHOD'] if rm=='HEAD' or rm in self.http_methods: return getattr(self, rm)() elif rm=='GET' and self.body is not None: return self.body() elif rm=='POST' and self.form_handlers: return self.POST() methods = set(self.http_methods) # Compute available methods if self.body is not None: methods.add('GET') if 'GET' in methods: methods.add('HEAD') if self.form_handlers: methods.add('POST') return self.METHOD_NOT_ALLOWED([('Allow', ', '.join(methods))]) METHOD_NOT_ALLOWED = Text( "Excellent method!\n" "Alas, my response must be:\n" '"I cannot comply."', status="405 Method not allowed", ) REDIRECT_TO = HTML( '' '' 'Click here', status='302 Found', ) NOT_FOUND = Text( "404 not found\n" "You deserve a kinder note\n" "Than this web haiku!\n", status = '404 Not Found', ) form_handlers = [] form_parsed = False form_data = () form_defaults = {} escape = cgi.escape def get_handlers(self): handlers = [getattr(self,k) for k in self.form_handlers] handlers.sort(key=lambda h: h.priority) return handlers def __getattr__(self, name): """Dynamic attributes from form_data and defaults""" if not name.startswith('_') and name in self.form_data: return self.form_data[name].value if name in self.form_defaults: return self.form_defaults[name] raise AttributeError(name) def parse_form(self): """Ensure that self.form_data contains a FieldStorage, and return it""" if not self.form_parsed: self.form_data = cgi.FieldStorage( self.environ['wsgi.input'], environ=self.environ ) self.form_parsed = True return self.form_data def POST(self): self.parse_form() for handler in self.get_handlers(): response = handler() if response: return response if self.errors: return self.form_failure() else: return self.form_success() # A miserably inadequate attempt at a decent UI... errors_found = HTML.fragment( '' ) show_errors = property(lambda self: self.errors and self.errors_found or '') form_failure = HTML( "" "Sorry, we couldn't process your request\n" "

Sorry, we couldn't process your request

\n" "

We encountered some difficulties with your input:

" "$errors_found\n" "

If you would please use your browser's BACK button to go back and " "correct these problems, we'd appreciate it. Thanks for your help!" "

" ) form_success = Text( "Oops. Someone forgot to create a template or method here." ) db = None # DBAPI database connection object def db_connect(self): """Override this in a subclass to return a DBAPI connection object""" raise NotImplementedError def cursor(self, *args, **kw): """Create and return a cursor (after optionally running a query on it) If positional arguments are supplied, they're passed to the cursor's ``execute()`` method. If keyword arguments are supplied, they are used to set cursor attributes prior to the ``execute()`` (if applicable). """ db = self.db if db is None: db = self.db = self.db_connect() cursor = db.cursor() for k, v in kw.items(): setattr(cursor, k, v) if args: cursor.execute(*args) return cursor def query(self, *args, **kw): csr = self.cursor(*args, **kw) return (Row(csr,r) for rows in iter(csr.fetchmany,[]) for r in rows) class Row(object): """Easy-access dict/object wrapper for DBAPI row tuples""" def __init__(self, cursor, row): self.__dict__ = dict(zip([d[0]for d in cursor.description], row)) class TestForm(Page): """A stupid example to test the framework""" form_defaults = dict(name='Joey', animal='Dog', email='joe@dog.com') body = form_failure = HTML(""" What is your favorite animal ? $show_errors
What is your name ?
What is your favorite animal ?
What is your email address ?
""") form_success = Text("Hey Joe!") @form_handler def check_joe(self): if self.name!='Joe': self.errors.append("Hey, you're not Joe!") errors_found = HTML.fragment( "

Please correct the following problems:

" '' ) class TestContainer(Page): body = HTML(""" Silly test of WebHaiku """) a = Text.page("Hello world!") b = TestForm c = Page # placeholder TestContainer.c = TestContainer # allow some depth to the test...