root/branches/cherrypy-2.1/cherrypy/_cputil.py

"""
Copyright (c) 2004, CherryPy Team (team@cherrypy.org)
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, 
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, 
      this list of conditions and the following disclaimer in the documentation 
      and/or other materials provided with the distribution.
    * Neither the name of the CherryPy Team nor the names of its contributors 
      may be used to endorse or promote products derived from this software 
      without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""

"""
A module containing a few utility classes/functions used by CherryPy
"""

import sys
import traceback
import time
import cgi

import cherrypy
from cherrypy.lib import cptools


class EmptyClass:
    """ An empty class """
    pass


def getObjectTrail():
    """ Return all objects from the currenct object to cherrypy """
    root = getattr(cherrypy, 'root', None)
    if root:
        objectTrail = [root]
        # Try object path
        try:
            path = cherrypy.request.objectPath or cherrypy.request.path
        except AttributeError:
            path = '/'
        if path:
            pathList = path.split('/')[1:]
            
            # Successively get objects from the path
            for newObj in pathList:
                try:
                    root = getattr(root, newObj)
                    objectTrail.append(root)
                except AttributeError:
                    break
        
        return objectTrail
    return None

def getSpecialAttribute(name):
    """Return the special attribute. A special attribute is one that
    applies to all of the children from where it is defined, such as
    _cpFilterList."""
    
    # First, we look in the right-most object if this special attribute is implemented.
    # If not, then we try the previous object and so on until we reach cherrypy.root
    # If it's still not there, we use the implementation from this module.
    
    objectList = getObjectTrail()
    if objectList:
        
        objectList.reverse()
        for obj in objectList:
            attr = getattr(obj, name, None)
            if attr != None:
                return attr
    
    try:
        return globals()[name]
    except KeyError:
        msg = "Special attribute %s could not be found" % repr(name)
        raise cherrypy.HTTPError(500, msg)

def getSpecialAttributePath(name):
    """ Return the path to the special attribute """
    objectList = getObjectTrail()
    if objectList:
        pathList = cherrypy.request.objectPath or cherrypy.request.path
        pathList = pathList.split("/")[1:]
        for i in xrange(len(objectList) - 1, -1, -1):
            if hasattr(objectList[i], name):
                return "/" + "/".join(pathList[:i] + [name])
    msg = "Special attribute %s could not be found" % repr(name)
    raise cherrypy.HTTPError(500, msg)


def logtime():
    return '%04d/%02d/%02d %02d:%02d:%02d' % time.localtime(time.time())[:6]

def _cpLogAccess():
    """ Default method for logging access """
    
    tmpl = '%(h)s %(l)s %(u)s [%(t)s] "%(r)s" %(s)s %(b)s'
    s = tmpl % {'h': cherrypy.request.remoteHost,
                'l': '-',
                'u': getattr(cherrypy.request, "login", None) or "-",
                't': logtime(),
                'r': cherrypy.request.requestLine,
                's': cherrypy.response.status.split(" ", 1)[0],
                'b': cherrypy.response.headerMap.get('Content-Length', '') or "-",
                }
    
    if cherrypy.config.get('server.logToScreen', True):
        print s
    
    fname = cherrypy.config.get('server.logAccessFile', '')
    if fname:
        f = open(fname, 'ab')
        f.write(s + '\n')
        f.close()


_log_severity_levels = {0: "INFO", 1: "WARNING", 2: "ERROR"}

def _cpLogMessage(msg, context = '', severity = 0):
    """ Default method for logging messages (error log)"""
    
    level = _log_severity_levels.get(severity, "UNKNOWN")
    s = logtime() + ' ' + context + ' ' + level + ' ' + msg
    
    if cherrypy.config.get('server.logToScreen', True):
        print s
    
    fname = cherrypy.config.get('server.logFile', '')
    #logdir = os.path.dirname(fname)
    #if logdir and not os.path.exists(logdir):
    #    os.makedirs(logdir)
    if fname:
        f = open(fname, 'ab')
        f.write(s + '\n')
        f.close()


_HTTPErrorTemplate = '''<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title>%(status)s</title>
    <style type="text/css">
    #poweredBy {
        margin-top: 20px;
        border-top: 2px solid black;
        font-style: italic;
    }

    #traceback {
        color: red;
    }
    </style>
</head>
    <body>
        <h2>%(status)s</h2>
        <p>%(message)s</p>
        <pre id="traceback">%(traceback)s</pre>
    <div id="poweredBy">
    <span>Powered by <a href="Cherrypy">http://www.cherrypy.org">Cherrypy %(version)s</a></span>
    </div>
    </body>
</html>
'''

def getErrorPage(status, **kwargs):
    """Return an HTML page, containing a pretty error response.
    
    status should be an int or a str.
    kwargs will be interpolated into the page template.
    """
    
    code, reason, message = cptools.validStatus(status)
    
    # We can't use setdefault here, because some
    # callers send None for kwarg values.
    if kwargs.get('status') is None:
        kwargs['status'] = "%s %s" % (code, reason)
    if kwargs.get('message') is None:
        kwargs['message'] = message
    if kwargs.get('traceback') is None:
        kwargs['traceback'] = ''
    if kwargs.get('version') is None:
        kwargs['version'] = cherrypy.__version__
    for k, v in kwargs.iteritems():
        if v is None:
            kwargs[k] = ""
        else:
            kwargs[k] = cgi.escape(kwargs[k])
    
    template = _HTTPErrorTemplate
    errorPageFile = cherrypy.config.get('errorPage.%s' % code, '')
    if errorPageFile:
        try:
            template = file(errorPageFile, 'rb').read()
        except:
            m = kwargs['message']
            if m:
                m += "<br />"
            m += ("In addition, the custom error page "
                  "failed:\n<br />%s" % (sys.exc_info()[1]))
            kwargs['message'] = m
    
    return template % kwargs

def formatExc(exc=None):
    """formatExc(exc=None) -> exc (or sys.exc_info if None), formatted."""
    if exc is None:
        exc = sys.exc_info()
    
    if exc == (None, None, None):
        return ""
    return "".join(traceback.format_exception(*exc))

def _cpOnError():
    """ Default _cpOnError method """
    cherrypy.HTTPError(500).set_response()

_cpFilterList = []

# Filters that are always included
from cherrypy.lib.filter import baseurlfilter, cachefilter, \
    decodingfilter, encodingfilter, gzipfilter, logdebuginfofilter, \
    staticfilter, nsgmlsfilter, tidyfilter, \
    xmlrpcfilter, sessionauthenticatefilter, \
    sessionfilter

# this contains the classes for each filter type
# we do not store the instances here because the test
# suite must reinitilize the filters without restarting
# the server
_cpDefaultFilterClasses = {
    'BaseUrlFilter'      : baseurlfilter.BaseUrlFilter,
    'CacheFilter'        : cachefilter.CacheFilter,
    'DecodingFilter'     : decodingfilter.DecodingFilter,
    'EncodingFilter'     : encodingfilter.EncodingFilter,
    'GzipFilter'         : gzipfilter.GzipFilter,
    'LogDebugInfoFilter' : logdebuginfofilter.LogDebugInfoFilter,
    'NsgmlsFilter'       : nsgmlsfilter.NsgmlsFilter,
    'SessionAuthenticateFilter' : sessionauthenticatefilter.SessionAuthenticateFilter,
    'SessionFilter'      : sessionfilter.SessionFilter,
    'StaticFilter'       : staticfilter.StaticFilter,
    'TidyFilter'         : tidyfilter.TidyFilter,
    'XmlRpcFilter'       : xmlrpcfilter.XmlRpcFilter,
}

# this is where the actuall filter instances are first stored
_cpDefaultFilterInstances = {}

# These are in order for a reason!
# They must be strings matching keys in _cpDefaultFilterClasses
__cpDefaultInputFilters = [
    'CacheFilter',
    'LogDebugInfoFilter',
    'BaseUrlFilter',
    'DecodingFilter',
    'SessionFilter',
    'SessionAuthenticateFilter',
    'StaticFilter',
    'NsgmlsFilter',
    'TidyFilter',
    'XmlRpcFilter',
]

__cpDefaultOutputFilters = [
    'XmlRpcFilter',
    'EncodingFilter',
    'TidyFilter',
    'NsgmlsFilter',
    'LogDebugInfoFilter',
    'GzipFilter',
    'SessionFilter',
    'CacheFilter',
]

# these are the lists cp internally uses to access the filters
# they are populated when _cpInitDefaultFilters is called
_cpDefaultInputFilterList  = []
_cpDefaultOutputFilterList = []

# initilize the default filters
def _cpInitDefaultFilters():
    global _cpDefaultInputFilterList, _cpDefaultOutputFilterList
    global _cpDefaultFilterInstances
    _cpDefaultInputFilterList  = []
    _cpDefaultOutputFilterList = []
    _cpDefaultFilterInstances = {}
    
    for filterName in __cpDefaultInputFilters:
        filterClass = _cpDefaultFilterClasses[filterName]
        filterInstance = _cpDefaultFilterInstances[filterName] = filterClass()
        _cpDefaultInputFilterList.append(filterInstance)
    
    for filterName in __cpDefaultOutputFilters:
        filterClass = _cpDefaultFilterClasses[filterName]
        filterInstance = _cpDefaultFilterInstances.setdefault(filterName, filterClass())
        _cpDefaultOutputFilterList.append(filterInstance)

def _cpInitUserDefinedFilters():
    filtersRoot = cherrypy.config.get('server.filtersRoot', [])
    inputFiltersDict = cherrypy.config.get('server.inputFiltersDict', {})
    outputFiltersDict = cherrypy.config.get('server.outputFiltersDict', {})
    
    if len(filtersRoot) == 0:
        return

    sys.path.extend(filtersRoot)
        
    for filterName, filterClassname in inputFiltersDict.items():
        filterModule = __import__(filterName, globals(),  locals(), [])
        filterClass = getattr(filterModule, filterClassname, None)
        filterInstance = filterClass()
        _cpDefaultInputFilterList.append(filterInstance)

    for filterName, filterClassname in outputFiltersDict.items():
        filterModule = __import__(filterName, globals(),  locals(), [])
        filterClass = getattr(filterModule, filterClassname, None)
        filterInstance = filterClass()
        _cpDefaultOutputFilterList.append(filterInstance)

    # Avoid pollution of the system path
    for path in filtersRoot:
        sys.path.remove(path)


# public domain "unrepr" implementation, found on the web and then improved.
import compiler

def getObj(s):
    s = "a=" + s
    p = compiler.parse(s)
    return p.getChildren()[1].getChildren()[0].getChildren()[1]


class UnknownType(Exception):
    
    # initialize the built-in filters 
    for n in xrange(len(_cpDefaultInputFilterList)):
        try:
            _cpDefaultInputFilterList[n] = _cpDefaultInputFilterList[n]()
        except:
            pass
    
    for n in xrange(len(_cpDefaultOutputFilterList)):
        try:
            _cpDefaultOutputFilterList[n] = _cpDefaultOutputFilterList[n]()
        except:
            pass


class Builder:
    
    def build(self, o):
        m = getattr(self, 'build_' + o.__class__.__name__, None)
        if m is None:
            raise UnknownType(o.__class__.__name__)
        return m(o)
    
    def build_List(self, o):
        return map(self.build, o.getChildren())
    
    def build_Const(self, o):
        return o.value
    
    def build_Dict(self, o):
        d = {}
        i = iter(map(self.build, o.getChildren()))
        for el in i:
            d[el] = i.next()
        return d
    
    def build_Tuple(self, o):
        return tuple(self.build_List(o))
    
    def build_Name(self, o):
        if o.name == 'None':
            return None
        if o.name == 'True':
            return True
        if o.name == 'False':
            return False
        
        # See if the Name is a package or module
        try:
            return modules(o.name)
        except ImportError:
            pass
        
        raise UnknownType(o.name)
    
    def build_Add(self, o):
        real, imag = map(self.build_Const, o.getChildren())
        try:
            real = float(real)
        except TypeError:
            raise UnknownType('Add')
        if not isinstance(imag, complex) or imag.real != 0.0:
            raise UnknownType('Add')
        return real+imag
    
    def build_Getattr(self, o):
        parent = self.build(o.expr)
        return getattr(parent, o.attrname)


def unrepr(s):
    if not s:
        return s
    try:
        return Builder().build(getObj(s))
    except:
        raise cherrypy.WrongUnreprValue(repr(s))

def modules(modulePath):
    """Load a module and retrieve a reference to that module."""
    try:
        mod = sys.modules[modulePath]
        if mod is None:
            raise KeyError()
    except KeyError:
        # The last [''] is important.
        mod = __import__(modulePath, globals(), locals(), [''])
    return mod

def attributes(fullAttributeName):
    """Load a module and retrieve an attribute of that module."""
    
    # Parse out the path, module, and attribute
    lastDot = fullAttributeName.rfind(u".")
    attrName = fullAttributeName[lastDot + 1:]
    modPath = fullAttributeName[:lastDot]
    
    aMod = modules(modPath)
    # Let an AttributeError propagate outward.
    try:
        attr = getattr(aMod, attrName)
    except AttributeError:
        raise AttributeError("'%s' object has no attribute '%s'"
                             % (modPath, attrName))
    
    # Return a reference to the attribute.
    return attr