#!/usr/bin/env python
# CGIWrapper.py
# Webware for Python
# See the CGIWrapper.html documentation for more information.
# We first record the starting time, in case we're being run as a CGI script.
from time import time, localtime, gmtime, asctime
serverStartTime = time()
# Some imports
import cgi, os, string, sys, traceback, whrandom
from types import *
if '' not in sys.path:
sys.path.insert(0, '')
try:
import WebUtils
except:
sys.path.append(os.path.abspath('..'))
import WebUtils
from WebUtils.HTMLForException import HTMLForException
import MiscUtils
from MiscUtils.NamedValueAccess import NamedValueAccess
from UserDict import UserDict
# @@ 2000-05-01 ce:
# PROBLEM: For reasons unknown, target scripts cannot import modules of
# the WebUtils package *unless* they are already imported.
# TEMP SOLUTION: Import all the modules.
# TO DO: distill this problem and post to comp.lang.python for help.
# begin
import WebUtils.Cookie
import WebUtils.HTTPStatusCodes
# end
# Beef up UserDict with the NamedValueAccess base class and custom versions of
# hasValueForKey() and valueForKey(). This all means that UserDict's (such as
# os.environ) are key/value accessible. At some point, this probably needs to
# move somewhere else as other Webware components will need this "patch".
# @@ 2000-01-14 ce: move this
#
if not NamedValueAccess in UserDict.__bases__:
UserDict.__bases__ = UserDict.__bases__ + (NamedValueAccess,)
def _UserDict_hasValueForKey(self, key):
return self.has_key(key)
def _UserDict_valueForKey(self, key, default=None):
return self.get(key, default)
setattr(UserDict, 'hasValueForKey', _UserDict_hasValueForKey)
setattr(UserDict, 'valueForKey', _UserDict_valueForKey)
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
class CGIWrapper(NamedValueAccess):
"""
A CGIWrapper executes a target script and provides various services for
the both the script and website developer and administrator.
See the CGIWrapper.html documentation for full information.
"""
## Init ##
def __init__(self):
self._config = self.config()
## Configuration ##
def defaultConfig(self):
"""
Returns a dictionary with the default
configuration. Subclasses could override to customize
the values or where they're taken from.
"""
return {
'ScriptsHomeDir': 'Scripts',
'ChangeDir': 1,
'ExtraPaths': [],
'ExtraPathsIndex': 1,
'LogScripts': 1,
'ScriptLogFilename': 'Scripts.csv',
'ScriptLogColumns': ['environ.REMOTE_ADDR', 'environ.REQUEST_METHOD', 'environ.REQUEST_URI', 'responseSize', 'scriptName', 'serverStartTimeStamp', 'serverDuration', 'scriptDuration', 'errorOccurred'],
'ClassNames': ['', 'Page'],
'ShowDebugInfoOnErrors': 1,
'UserErrorMessage': 'The site is having technical difficulties with this page. An error has been logged, and the problem will be fixed as soon as possible. Sorry!',
'ErrorLogFilename': 'Errors.csv',
'SaveErrorMessages': 1,
'ErrorMessagesDir': 'ErrorMsgs',
'EmailErrors': 0, # be sure to review the following settings when enabling error e-mails
'ErrorEmailServer': 'mail.-.com',
'ErrorEmailHeaders': { 'From': '-@-.com',
'To': ['-@-.com'],
'Reply-to': '-@-.com',
'Content-type': 'text/html',
'Subject': 'Error'
}
}
def configFilename(self):
"""Used by userConfig()."""
return 'Config.dict'
def userConfig(self):
"""
Returns the user config overrides found in the
optional config file, or {} if there is no such
file. The config filename is taken from
configFilename().
"""
try:
file = open(self.configFilename())
except IOError:
return {}
else:
config = eval(file.read())
file.close()
assert type(config) is type({})
return config
def config(self):
"""
Returns the configuration for the wrapper which is a
combination of defaultConfig() and userConfig(). This
method does no caching.
"""
config = self.defaultConfig()
config.update(self.userConfig())
return config
def setting(self, name):
"""Returns the value of a particular setting in the configuration."""
return self._config[name]
## Utilities ##
def makeHeaders(self):
"""Returns a default header dictionary containing {'Content-type': 'text/html'}."""
return {'Content-type': 'text/html'}
def makeFieldStorage(self):
"""Returns a default field storage object created from the cgi module."""
return cgi.FieldStorage()
def enhanceThePath(self):
"""Enhance sys.path according to our configuration."""
extraPathsIndex = self.setting('ExtraPathsIndex')
sys.path[extraPathsIndex:extraPathsIndex] = self.setting('ExtraPaths')
def requireEnvs(self, names):
"""
Checks that given environment variable names exist. If
they don't, a basic HTML error message is printed and
we exit.
"""
badNames = []
for name in names:
if not self._environ.has_key(name):
badNames.append(name)
if badNames:
print 'Content-type: text/html\n'
print '<html><body>'
print '<p>ERROR: Missing', string.join(badNames, ', ')
print '</body></html>'
sys.exit(0)
def scriptPathname(self):
"""
Returns the full pathname of the target
script. Scripts that start with an underscore are
special--they run out of the same directory as the CGI
Wrapper and are typically CGI Wrapper support
scripts.
"""
pathname = os.path.split(self._environ['SCRIPT_FILENAME'])[0] # This removes the CGI Wrapper's filename part
filename = self._environ['PATH_INFO'][1:]
ext = os.path.splitext(filename)[1]
if ext=='':
# No extension - we assume a Python CGI script
if filename[0]=='_':
# underscores denote private scripts packaged with CGI Wrapper, such as '_admin.py'
filename = os.path.join(pathname, filename+'.py')
else:
# all other scripts are based in the directory named by the 'ScriptsHomeDir' setting
filename = os.path.join(pathname, self.setting('ScriptsHomeDir'), filename+'.py')
self._servingScript = 1
else:
# Hmmm, some kind of extension like maybe '.html'. Leave out the 'ScriptsHomeDir' and leave the extension alone
filename = os.path.join(pathname, filename)
self._servingScript = 0
return filename
def writeScriptLog(self):
"""
Writes an entry to the script log file. Uses settings
ScriptLogFilename and ScriptLogColumns.
"""
filename = self.setting('ScriptLogFilename')
if os.path.exists(filename):
file = open(filename, 'a')
else:
file = open(filename, 'w')
file.write(string.join(self.setting('ScriptLogColumns'), ',')+'\n')
values = []
for column in self.setting('ScriptLogColumns'):
value = self.valueForName(column)
if type(value) is FloatType:
value = '%0.2f' % value # might need more flexibility in the future
else:
value = str(value)
values.append(value)
file.write(string.join(values, ',')+'\n')
file.close()
def version(self):
return '0.2'
## Exception handling ##
def handleException(self, excInfo):
"""
Invoked by self when an exception occurs in the target
script. <code>excInfo</code> is a sys.exc_info()-style
tuple of information about the exception.
"""
self._scriptEndTime = time() # Note the duration of the script and time of the exception
self.logExceptionToConsole()
self.reset()
print self.htmlErrorPage(showDebugInfo=self.setting('ShowDebugInfoOnErrors'))
fullErrorMsg = None
if self.setting('SaveErrorMessages'):
fullErrorMsg = self.htmlErrorPage(showDebugInfo=1)
filename = self.saveHTMLErrorPage(fullErrorMsg)
else:
filename = ''
self.logExceptionToDisk(filename)
if self.setting('EmailErrors'):
if fullErrorMsg is None:
fullErrorMsg = self.htmlErrorPage(showDebugInfo=1)
self.emailException(fullErrorMsg)
def logExceptionToConsole(self, stderr=sys.stderr):
"""
Logs the time, script name and traceback to the
console (typically stderr). This usually results in
the information appearing in the web server's error
log. Used by handleException().
"""
# stderr logging
stderr.write('[%s] [error] CGI Wrapper: Error while executing script %s\n' % (
asctime(localtime(self._scriptEndTime)), self._scriptPathname))
traceback.print_exc(file=stderr)
def reset(self):
"""
Used by handleException() to clear out the current CGI
output results in preparation of delivering an HTML
error message page. Currently resets headers and
deletes cookies, if present.
"""
# Set headers to basic text/html. We don't want stray headers from a script that failed.
headers = {'Content-Type': 'text/html'}
# Get rid of cookies, too
if self._namespace.has_key('cookies'):
del self._namespace['cookies']
def htmlErrorPage(self, showDebugInfo=1):
"""
Returns an HTML page explaining that there is an
error. There could be more options in the future so
using named arguments (e.g., 'showDebugInfo=1') is
recommended. Invoked by handleException().
"""
html = ['''
<html>
<title>Error</title>
<body fgcolor=black bgcolor=white>
%s
<p> %s''' % (htTitle('Error'), self.setting('UserErrorMessage'))]
if self.setting('ShowDebugInfoOnErrors'):
html.append(self.htmlDebugInfo())
html.append('</body></html>')
return string.join(html, '')
def htmlDebugInfo(self):
"""
Return HTML-formatted debugging information about the
current exception. Used by handleException().
"""
html = ['''
%s
<p> <i>%s</i>
''' % (htTitle('Traceback'), self._scriptPathname)]
html.append(HTMLForException())
html.extend([
htTitle('Misc Info'),
htDictionary({
'time': asctime(localtime(self._scriptEndTime)),
'filename': self._scriptPathname,
'os.getcwd()': os.getcwd(),
'sys.path': sys.path
}),
htTitle('Fields'), htDictionary(self._fields),
htTitle('Headers'), htDictionary(self._headers),
htTitle('Environment'), htDictionary(self._environ, {'PATH': ';'}),
htTitle('Ids'), htTable(osIdTable(), ['name', 'value'])])
return string.join(html, '')
def saveHTMLErrorPage(self, html):
"""
Saves the given HTML error page for later viewing by
the developer, and returns the filename used. Invoked
by handleException().
"""
filename = os.path.join(self.setting('ErrorMessagesDir'), self.htmlErrorPageFilename())
f = open(filename, 'w')
f.write(html)
f.close()
return filename
def htmlErrorPageFilename(self):
"""Construct a filename for an HTML error page, not including the 'ErrorMessagesDir' setting."""
return 'Error-%s-%s-%d.html' % (
os.path.split(self._scriptPathname)[1],
string.join(map(lambda x: '%02d' % x, localtime(self._scriptEndTime)[:6]), '-'),
whrandom.whrandom().randint(10000, 99999))
# @@ 2000-04-21 ce: Using the timestamp & a random number is a poor technique for filename uniqueness, but this works for now
def logExceptionToDisk(self, errorMsgFilename='', excInfo=None):
"""
Writes a tuple containing (date-time, filename,
pathname, exception-name, exception-data,error report
filename) to the errors file (typically 'Errors.csv')
in CSV format. Invoked by handleException().
"""
if not excInfo:
excInfo = sys.exc_info()
logline = (
asctime(localtime(self._scriptEndTime)),
os.path.split(self._scriptPathname)[1],
self._scriptPathname,
str(excInfo[0]),
str(excInfo[1]),
errorMsgFilename)
filename = self.setting('ErrorLogFilename')
if os.path.exists(filename):
f = open(filename, 'a')
else:
f = open(filename, 'w')
f.write('time,filename,pathname,exception name,exception data,error report filename\n')
f.write(string.join(logline, ','))
f.write('\n')
f.close()
def emailException(self, html, excInfo=None):
# Construct the message
if not excInfo:
excInfo = sys.exc_info()
headers = self.setting('ErrorEmailHeaders')
msg = []
for key in headers.keys():
if key!='From' and key!='To':
msg.append('%s: %s\n' % (key, headers[key]))
msg.append('\n')
msg.append(html)
msg = string.join(msg, '')
# dbg code, in case you're having problems with your e-mail
# open('error-email-msg.text', 'w').write(msg)
# Send the message
import smtplib
server = smtplib.SMTP(self.setting('ErrorEmailServer'))
server.set_debuglevel(0)
server.sendmail(headers['From'], headers['To'], msg)
server.quit()
## Serve ##
def serve(self, environ=os.environ):
# Record the time
if globals().has_key('isMain'):
self._serverStartTime = serverStartTime
else:
self._serverStartTime = time()
self._serverStartTimeStamp = asctime(localtime(self._serverStartTime))
# Set up environment
self._environ = environ
# Ensure that filenames and paths have been provided
self.requireEnvs(['SCRIPT_FILENAME', 'PATH_INFO'])
# Set up the namespace
self._headers = self.makeHeaders()
self._fields = self.makeFieldStorage()
self._scriptPathname = self.scriptPathname()
self._scriptName = os.path.split(self._scriptPathname)[1]
# @@ 2000-04-16 ce: Does _namespace need to be an ivar?
self._namespace = {
'headers': self._headers,
'fields': self._fields,
'environ': self._environ,
'wrapper': self,
# 'WebUtils': WebUtils # @@ 2000-05-01 ce: Resolve.
}
info = self._namespace.copy()
# Set up sys.stdout to be captured as a string. This allows scripts
# to set CGI headers at any time, which we then print prior to
# printing the main output. This also allows us to skip on writing
# any of the script's output if there was an error.
#
# This technique was taken from Andrew M. Kuchling's Feb 1998
# WebTechniques article.
#
self._realStdout = sys.stdout
sys.stdout = StringIO()
# Change directories if needed
if self.setting('ChangeDir'):
origDir = os.getcwd()
os.chdir(os.path.split(self._scriptPathname)[0])
else:
origDir = None
# A little more setup
self._errorOccurred = 0
self._scriptStartTime = time()
# Run the target script
try:
if self._servingScript:
execfile(self._scriptPathname, self._namespace)
for name in self.setting('ClassNames'):
if name=='':
name = os.path.splitext(self._scriptName)[0]
if self._namespace.has_key(name): # our hook for class-oriented scripts
print self._namespace[name](info).html()
break
else:
self._headers = { 'Location': os.path.split(self._environ['SCRIPT_NAME'])[0] + self._environ['PATH_INFO'] }
# Note the end time of the script
self._scriptEndTime = time()
self._scriptDuration = self._scriptEndTime - self._scriptStartTime
except:
# Note the end time of the script
self._scriptEndTime = time()
self._scriptDuration = self._scriptEndTime - self._scriptStartTime
self._errorOccurred = 1
# Not really an error, if it was sys.exit(0)
excInfo = sys.exc_info()
if excInfo[0]==SystemExit:
code = excInfo[1].code
if code==0 or code==None:
self._errorOccurred = 0
# Clean up
if self._errorOccurred:
if origDir:
os.chdir(origDir)
origDir = None
# Handle exception
self.handleException(sys.exc_info())
self.deliver()
# Restore original directory
if origDir:
os.chdir(origDir)
# Note the duration of server processing (as late as we possibly can)
self._serverDuration = time() - self._serverStartTime
# Log it
if self.setting('LogScripts'):
self.writeScriptLog()
def deliver(self):
"""Deliver the HTML, whether it came from the script being served, or from our own error reporting."""
# Compile the headers & cookies
headers = StringIO()
for header, value in self._headers.items():
headers.write("%s: %s\n" % (header, value))
if self._namespace.has_key('cookies'):
headers.write(str(self._namespace['cookies']))
headers.write('\n')
# Get the string buffer values
headersOut = headers.getvalue()
stdoutOut = sys.stdout.getvalue()
# Compute size
self._responseSize = len(headersOut) + len(stdoutOut)
# Send to the real stdout
self._realStdout.write(headersOut)
self._realStdout.write(stdoutOut)
# Some misc functions
def htTitle(name):
return '''
<p> <br> <table border=0 cellpadding=4 cellspacing=0 bgcolor=#A00000> <tr> <td>
<font face="Tahoma, Arial, Helvetica" color=white> <b> %s </b> </font>
</td> </tr> </table>''' % name
def htDictionary(dict, addSpace=None):
"""Returns an HTML string with a <table> where each row is a key-value pair."""
keys = dict.keys()
keys.sort()
html = ['<table width=100% border=0 cellpadding=2 cellspacing=2 bgcolor=#F0F0F0>']
for key in keys:
value = dict[key]
if addSpace!=None and addSpace.has_key(key):
target = addSpace[key]
value = string.join(string.split(value, target), '%s '%target)
html.append('<tr> <td> %s </td> <td> %s </td> </tr>\n' % (key, value))
html.append('</table>')
return string.join(html, '')
def osIdTable():
"""
Returns a list of dictionaries contained id information such
as uid, gid, etc., all obtained from the os module. Dictionary
keys are 'name' and 'value'.
"""
funcs = ['getegid', 'geteuid', 'getgid', 'getpgrp', 'getpid', 'getppid', 'getuid']
table = []
for funcName in funcs:
if hasattr(os, funcName):
value = getattr(os, funcName)()
table.append({'name': funcName, 'value': value})
return table
def htTable(listOfDicts, keys=None):
"""
The listOfDicts parameter is expected to be a list of
dictionaries whose keys are always the same. This function
returns an HTML string with the contents of the table. If
keys is None, the headings are taken from the first row in
alphabetical order. Returns an empty string if listOfDicts is
none or empty.
Deficiencies: There's no way to influence the formatting or to
use column titles that are different than the keys.
"""
if not listOfDicts:
return ''
if keys is None:
keys = listOfDicts[0].keys()
keys.sort()
s = '<table border=0 cellpadding=2 cellspacing=2 bgcolor=#F0F0F0>\n<tr>'
for key in keys:
s = '%s<td><b>%s</b></td>' % (s, key)
s = s + '</tr>\n'
for row in listOfDicts:
s = s + '<tr>'
for key in keys:
s = '%s<td>%s</td>' % (s, row[key])
s = s + '</tr>\n'
s = s + '</table>'
return s
def main():
stdout = sys.stdout
try:
wrapper = CGIWrapper()
wrapper.serve()
except:
# There is already a fancy exception handler in the CGIWrapper for
# uncaught exceptions from target scripts. However, we should also
# catch exceptions here that might come from the wrapper, including
# ones generated while it's handling exceptions.
import traceback
sys.stderr.write('[%s] [error] CGI Wrapper: Error while executing script (unknown)\n' % (
asctime(localtime(time()))))
sys.stderr.write('Error while executing script\n')
traceback.print_exc(file=sys.stderr)
output = apply(traceback.format_exception, sys.exc_info())
output = string.join(output, '')
output = string.replace(output, '&', '&')
output = string.replace(output, '<', '<')
output = string.replace(output, '>', '>')
stdout.write('''Content-type: text/html
<html><body>
<p>ERROR
<p><pre>%s</pre>
</body></html>\n''' % output)
if __name__=='__main__':
isMain = 1
main()