# Methoden fuer die einzelnen HTTP requests gibt es bereits (allerdins ohne exception handling)

# moegliche aufrufe:

# normaler aufruf:
http_REQ(http_GET, someurl)

# aufruf mit eigenem error handler:
hdl = HTTPError_Handler('404', 'not found', some_method, some_arguments)
f = http_REQ(http_GET, someurl, hdl)

def http_REQ(kind, url, custom_handlers = None, text = True, run = True, debug = False):
    """ do safe HTTP request
        kind:             kind of request (e.g. GET, PUT, POST...); has to be passed a method-object
        url:              url
        custom_handlers:  custom error handles (optional)
        text, run, debug: print text, run method, print debug output
    """
    try:
        return kind(url)
    except urllib2.HTTPError, e:
        err = HTTPError(e)
        if custom_handlers:
            #TODO: support for more handlers...
            err.setHandler(custom_handlers)
        print err
        if text:
            print err.current.text
        if run:
            err.current.runerr()
        if debug:
            print err.errObj
            print err.errObj.read()
        return None

class HTTPError:
    """handle HTTP Errors"""

    def __init__(self, errObj):
        self.errObj = errObj
        self.current = None
        self.handlers = {}
        # create some standard error handlers:
        self.handlers['403'] = HTTPError_Handler('403', 'permission denied', None)
        self.handlers['404'] = HTTPError_Handler('404', 'no such file or package or project', None)
        self.handlers['500'] = HTTPError_Handler('500', 'internal server error', None)
        self.handlers['unknown'] = HTTPError_Handler(str(self.errObj.code), 'unknown error', None)

        self.findHandler()

    def findHandler(self):
        """check if we can handle the current error"""
        if self.handlers.has_key(str(self.errObj.code)):
            self.current = self.handlers[str(self.errObj.code)]
        else:
            self.current = self.handlers['unknown']

    def setHandler(self, hdl):
        """set a custom handler"""
        self.handlers[hdl.errCode] = hdl
        self.findHandler()

    def __str__(self):
        r = []
        r.append('HTTPError: %d' % self.errObj.code)
        r.append(' active handlers: %d' % len(self.handlers))
        r.append(' self.current: %s' % self.current)
        return '\n'.join(r)

class HTTPError_Handler:
    def __init__(self, errCode, text, method, *args):
        """ errCode: the HTTP error code
            text:    description of the error (which can be printed to the user)
            method:  method which should be invoked
            *args:   arguments which should be passed to the method
        """
        self.errCode = errCode
        self.text = text
        self.run = method
        self.run_args = args

    def runerr(self):
        if self.run != None:
            self.run(*self.run_args)

    def __str__(self):
        return 'HTTPError_Handler for \'' + self.errCode + '\' errors'