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Provides the core API for Cheetah.
See the docstring in the Template class and the Users' Guide for more information
import sys # used in the error handling code
import re # used to define the internal delims regex
import logging
import string
import os.path
import time # used in the cache refresh code
from random import randrange
import imp
import inspect
import StringIO
import traceback
import pprint
import cgi # Used by .webInput() if the template is a CGI script.
import types
from threading import Lock
except ImportError:
class Lock:
def acquire(self):
def release(self):
filetype = None
if isinstance(sys.version_info[:], tuple):
# Python 2.xx
filetype = types.FileType
def createMethod(func, cls):
return types.MethodType(func, None, cls)
import io
filetype = io.IOBase
def createMethod(func, cls):
return types.MethodType(func, cls)
from Cheetah.Version import convertVersionStringToTuple, MinCompatibleVersionTuple
from Cheetah.Version import MinCompatibleVersion
# Base classes for Template
from Cheetah.Servlet import Servlet
# More intra-package imports ...
from Cheetah.Parser import ParseError, SourceReader
from Cheetah.Compiler import Compiler, DEFAULT_COMPILER_SETTINGS
from Cheetah import ErrorCatchers # for placeholder tags
from Cheetah import Filters # the output filters
from Cheetah.convertTmplPathToModuleName import convertTmplPathToModuleName
from Cheetah.Utils.Misc import checkKeywords # Used in Template.__init__
from Cheetah.Utils.Indenter import Indenter # Used in Template.__init__ and for
# placeholders
from Cheetah.NameMapper import NotFound, valueFromSearchList
from Cheetah.CacheStore import MemoryCacheStore, MemcachedCacheStore
from Cheetah.CacheRegion import CacheRegion
from Cheetah.Utils.WebInputMixin import _Converter, _lookup, NonNumericInputError
from Cheetah.Unspecified import Unspecified
# Decide whether to use the file modification time in file's cache key
__checkFileMtime = True
def checkFileMtime(value):
globals()['__checkFileMtime'] = value
class Error(Exception):
class PreprocessError(Error):
def hashList(l):
hashedList = []
for v in l:
if isinstance(v, dict):
v = hashDict(v)
elif isinstance(v, list):
v = hashList(v)
return hash(tuple(hashedList))
def hashDict(d):
items = sorted(d.items())
hashedList = []
for k, v in items:
if isinstance(v, dict):
v = hashDict(v)
elif isinstance(v, list):
v = hashList(v)
hashedList.append((k, v))
return hash(tuple(hashedList))
def _genUniqueModuleName(baseModuleName):
"""The calling code is responsible for concurrency locking.
if baseModuleName not in sys.modules:
finalName = baseModuleName
finalName = ('cheetah_%s_%s_%s'%(baseModuleName,
str(time.time()).replace('.', '_'),
str(randrange(10000, 99999))))
return finalName
# Cache of a cgi.FieldStorage() instance, maintained by .webInput().
# This is only relavent to templates used as CGI scripts.
_formUsedByWebInput = None
def updateLinecache(filename, src):
import linecache
size = len(src)
mtime = time.time()
lines = src.splitlines()
fullname = filename
linecache.cache[filename] = size, mtime, lines, fullname
class CompileCacheItem(object):
class TemplatePreprocessor(object):
This is used with the preprocessors argument to Template.compile().
See the docstring for Template.compile
** Preprocessors are an advanced topic **
def __init__(self, settings):
self._settings = settings
def preprocess(self, source, file):
"""Create an intermediate template and return the source code
it outputs
settings = self._settings
if not source: # @@TR: this needs improving
if isinstance(file, (str, unicode)): # it's a filename.
f = open(file)
source =
elif hasattr(file, 'read'):
source =
file = None
templateAPIClass = settings.templateAPIClass
possibleKwArgs = [
arg for arg in
if arg not in ('klass', 'source', 'file',)]
compileKwArgs = {}
for arg in possibleKwArgs:
if hasattr(settings, arg):
compileKwArgs[arg] = getattr(settings, arg)
tmplClass = templateAPIClass.compile(source=source, file=file, **compileKwArgs)
tmplInstance = tmplClass(**settings.templateInitArgs)
outputSource = settings.outputTransformer(tmplInstance)
outputFile = None
return outputSource, outputFile
class Template(Servlet):
This class provides a) methods used by templates at runtime and b)
methods for compiling Cheetah source code into template classes.
This documentation assumes you already know Python and the basics of object
oriented programming. If you don't know Python, see the sections of the
Cheetah Users' Guide for non-programmers. It also assumes you have read
about Cheetah's syntax in the Users' Guide.
The following explains how to use Cheetah from within Python programs or via
the interpreter. If you statically compile your templates on the command
line using the 'cheetah' script, this is not relevant to you. Statically
compiled Cheetah template modules/classes (e.g.
MyTemplateClasss) are just like any other Python module or class. Also note,
most Python web frameworks (Webware, Aquarium, mod_python, Turbogears,
CherryPy, Quixote, etc.) provide plugins that handle Cheetah compilation for
There are several possible usage patterns:
1) tclass = Template.compile(src)
t1 = tclass() # or tclass(namespaces=[namespace,...])
t2 = tclass() # or tclass(namespaces=[namespace2,...])
outputStr = str(t1) # or outputStr = t1.aMethodYouDefined()
Template.compile provides a rich and very flexible API via its
optional arguments so there are many possible variations of this
pattern. One example is:
tclass = Template.compile('hello $name from $caller', baseclass=dict)
print tclass(name='world', caller='me')
See the Template.compile() docstring for more details.
2) tmplInstance = Template(src)
# or Template(src, namespaces=[namespace,...])
outputStr = str(tmplInstance) # or outputStr = tmplInstance.aMethodYouDefined(...args...)
Notes on the usage patterns:
usage pattern 1)
This is the most flexible, but it is slightly more verbose unless you
write a wrapper function to hide the plumbing. Under the hood, all
other usage patterns are based on this approach. Templates compiled
this way can #extend (subclass) any Python baseclass: old-style or
new-style (based on object or a builtin type).
usage pattern 2)
This was Cheetah's original usage pattern. It returns an instance,
but you can still access the generated class via
tmplInstance.__class__. If you want to use several different
namespace 'searchLists' with a single template source definition,
you're better off with Template.compile (1).
Limitations (use pattern 1 instead):
- Templates compiled this way can only #extend subclasses of the
new-style 'object' baseclass. Cheetah.Template is a subclass of
'object'. You also can not #extend dict, list, or other builtin
- If your template baseclass' __init__ constructor expects args there
is currently no way to pass them in.
If you need to subclass a dynamically compiled Cheetah class, do something like this:
from Cheetah.Template import Template
T1 = Template.compile('$meth1 #def meth1: this is meth1 in T1')
T2 = Template.compile('#implements meth1\nthis is meth1 redefined in T2', baseclass=T1)
print T1, T1()
print T2, T2()
Note about class and instance attribute names:
Attributes used by Cheetah have a special prefix to avoid confusion with
the attributes of the templates themselves or those of template
Class attributes which are used in class methods look like this:
klass._CHEETAH_useCompilationCache (_CHEETAH_xxx)
Instance attributes look like this:
klass._CHEETAH__globalSetVars (_CHEETAH__xxx with 2 underscores)
# this is used by ._addCheetahPlumbingCodeToClass()
_CHEETAH_requiredCheetahMethods = (
_CHEETAH_requiredCheetahClassMethods = ('subclass',)
_CHEETAH_requiredCheetahClassAttributes = ('cacheRegionClass', 'cacheStore',
'cacheStoreIdPrefix', 'cacheStoreClass')
## the following are used by .compile(). Most are documented in its docstring.
_CHEETAH_cacheModuleFilesForTracebacks = False
_CHEETAH_cacheDirForModuleFiles = None # change to a dirname
_CHEETAH_compileCache = dict() # cache store for compiled code and classes
# To do something other than simple in-memory caching you can create an
# alternative cache store. It just needs to support the basics of Python's
# mapping/dict protocol. E.g.:
# class AdvCachingTemplate(Template):
# _CHEETAH_compileCache = MemoryOrFileCache()
_CHEETAH_compileLock = Lock() # used to prevent race conditions
_CHEETAH_defaultMainMethodName = None
_CHEETAH_compilerSettings = None
_CHEETAH_compilerClass = Compiler
_CHEETAH_compilerInstance = None
_CHEETAH_cacheCompilationResults = True
_CHEETAH_useCompilationCache = True
_CHEETAH_keepRefToGeneratedCode = True
_CHEETAH_defaultBaseclassForTemplates = None
_CHEETAH_defaultClassNameForTemplates = None
# defaults to DEFAULT_COMPILER_SETTINGS['mainMethodName']:
_CHEETAH_defaultMainMethodNameForTemplates = None
_CHEETAH_defaultModuleNameForTemplates = 'DynamicallyCompiledCheetahTemplate'
_CHEETAH_defaultModuleGlobalsForTemplates = None
_CHEETAH_preprocessors = None
_CHEETAH_defaultPreprocessorClass = TemplatePreprocessor
## The following attributes are used by instance methods:
_CHEETAH_generatedModuleCode = None
NonNumericInputError = NonNumericInputError
_CHEETAH_cacheRegionClass = CacheRegion
_CHEETAH_cacheStoreClass = MemoryCacheStore
#_CHEETAH_cacheStoreClass = MemcachedCacheStore
_CHEETAH_cacheStore = None
_CHEETAH_cacheStoreIdPrefix = None
def _getCompilerClass(klass, source=None, file=None):
return klass._CHEETAH_compilerClass
def _getCompilerSettings(klass, source=None, file=None):
return klass._CHEETAH_compilerSettings
def compile(klass, source=None, file=None,
The core API for compiling Cheetah source code into template classes.
This class method compiles Cheetah source code and returns a python
class. You then create template instances using that class. All
Cheetah's other compilation API's use this method under the hood.
Internally, this method a) parses the Cheetah source code and generates
Python code defining a module with a single class in it, b) dynamically
creates a module object with a unique name, c) execs the generated code
in that module's namespace then inserts the module into sys.modules, and
d) returns a reference to the generated class. If you want to get the
generated python source code instead, pass the argument
It caches generated code and classes. See the descriptions of the
arguments'cacheCompilationResults' and 'useCache' for details. This
doesn't mean that templates will automatically recompile themselves when
the source file changes. Rather, if you call Template.compile(src) or
Template.compile(file=path) repeatedly it will attempt to return a
cached class definition instead of recompiling.
Hooks are provided template source preprocessing. See the notes on the
'preprocessors' arg.
If you are an advanced user and need to customize the way Cheetah parses
source code or outputs Python code, you should check out the
compilerSettings argument.
You must provide either a 'source' or 'file' arg, but not both:
- source (string or None)
- file (string path, file-like object, or None)
The rest of the arguments are strictly optional. All but the first
have defaults in attributes of the Template class which can be
overridden in subclasses of this class. Working with most of these is
an advanced topic.
- returnAClass=True
If false, return the generated module code rather than a class.
- compilerSettings (a dict)
Default: Template._CHEETAH_compilerSettings=None
a dictionary of settings to override those defined in
DEFAULT_COMPILER_SETTINGS. These can also be overridden in your
template source code with the #compiler or #compiler-settings
- compilerClass (a class)
Default: Template._CHEETAH_compilerClass=Cheetah.Compiler.Compiler
a subclass of Cheetah.Compiler.Compiler. Mucking with this is a
very advanced topic.
- moduleName (a string)
What to name the generated Python module. If the provided value is
None and a file arg was given, the moduleName is created from the
file path. In all cases if the moduleName provided is already in
sys.modules it is passed through a filter that generates a unique
variant of the name.
- className (a string)
Default: Template._CHEETAH_defaultClassNameForTemplates=None
What to name the generated Python class. If the provided value is
None, the moduleName is use as the class name.
- mainMethodName (a string)
=None (and thus DEFAULT_COMPILER_SETTINGS['mainMethodName'])
What to name the main output generating method in the compiled
template class.
- baseclass (a string or a class)
Default: Template._CHEETAH_defaultBaseclassForTemplates=None
Specifies the baseclass for the template without manually
including an #extends directive in the source. The #extends
directive trumps this arg.
If the provided value is a string you must make sure that a class
reference by that name is available to your template, either by
using an #import directive or by providing it in the arg
If the provided value is a class, Cheetah will handle all the
details for you.
- moduleGlobals (a dict)
Default: Template._CHEETAH_defaultModuleGlobalsForTemplates=None
A dict of vars that will be added to the global namespace of the
module the generated code is executed in, prior to the execution
of that code. This should be Python values, not code strings!
- cacheCompilationResults (True/False)
Default: Template._CHEETAH_cacheCompilationResults=True
Tells Cheetah to cache the generated code and classes so that they
can be reused if Template.compile() is called multiple times with
the same source and options.
- useCache (True/False)
Default: Template._CHEETAH_useCompilationCache=True
Should the compilation cache be used? If True and a previous
compilation created a cached template class with the same source
code, compiler settings and other options, the cached template
class will be returned.
- cacheModuleFilesForTracebacks (True/False)
Default: Template._CHEETAH_cacheModuleFilesForTracebacks=False
In earlier versions of Cheetah tracebacks from exceptions that
were raised inside dynamically compiled Cheetah templates were
opaque because Python didn't have access to a python source file
to use in the traceback:
File "", line 192, in getTextiledContent
content = str(template(searchList=searchList))
File "", line 202, in __str__
File "", line 187, in respond
File "", line 139, in writeBody
ZeroDivisionError: integer division or modulo by zero
It is now possible to keep those files in a cache dir and allow
Python to include the actual source lines in tracebacks and makes
them much easier to understand:
File "", line 192, in getTextiledContent
content = str(template(searchList=searchList))
File "/tmp/CheetahCacheDir/", line 202, in __str__
def __str__(self): return self.respond()
File "/tmp/CheetahCacheDir/", line 187, in respond
File "/tmp/CheetahCacheDir/", line 139, in writeBody
__v = 0/0 # $(0/0)
ZeroDivisionError: integer division or modulo by zero
- cacheDirForModuleFiles (a string representing a dir path)
Default: Template._CHEETAH_cacheDirForModuleFiles=None
See notes on cacheModuleFilesForTracebacks.
- preprocessors
Default: Template._CHEETAH_preprocessors=None
These are used to transform the source code prior to compilation.
They provide a way to use Cheetah as a code generator for Cheetah
code. In other words, you use one Cheetah template to output the
source code for another Cheetah template.
The major expected use cases are:
a) 'compile-time caching' aka 'partial template binding',
wherein an intermediate Cheetah template is used to output
the source for the final Cheetah template. The intermediate
template is a mix of a modified Cheetah syntax (the
'preprocess syntax') and standard Cheetah syntax. The
preprocessor syntax is executed at compile time and outputs
Cheetah code which is then compiled in turn. This approach
allows one to completely soft-code all the elements in the
template which are subject to change yet have it compile to
extremely efficient Python code with everything but the
elements that must be variable at runtime (per browser
request, etc.) compiled as static strings. Examples of this
usage pattern will be added to the Cheetah Users' Guide.
The'preprocess syntax' is just Cheetah's standard one with
alternatives for the $ and # tokens:
e.g. '@' and '%' for code like this
@aPreprocessVar $aRuntimeVar
%if aCompileTimeCondition then yyy else zzz
%% preprocessor comment
#if aRunTimeCondition then aaa else bbb
## normal comment
b) adding #import and #extends directives dynamically based on
the source
If preprocessors are provided, Cheetah pipes the source code
through each one in the order provided. Each preprocessor should
accept the args (source, file) and should return a tuple (source,
The argument value should be a list, but a single non-list value
is acceptable and will automatically be converted into a list.
Each item in the list will be passed through
Template._normalizePreprocessor(). The items should either match
one of the following forms:
- an object with a .preprocess(source, file) method
- a callable with the following signature:
source, file = f(source, file)
or one of the forms below:
- a single string denoting the 2 'tokens' for the preprocess
syntax. The tokens should be in the order (placeholderToken,
directiveToken) and should separated with a space:
e.g. '@ %'
klass = Template.compile(src, preprocessors='@ %')
# or
klass = Template.compile(src, preprocessors=['@ %'])
- a dict with the following keys or an object with the
following attributes (all are optional, but nothing will
happen if you don't provide at least one):
- tokens: same as the single string described above. You can
also provide a tuple of 2 strings.
- searchList: the searchList used for preprocess $placeholders
- compilerSettings: used in the compilation of the intermediate
- templateAPIClass: an optional subclass of `Template`
- outputTransformer: a simple hook for passing in a callable
which can do further transformations of the preprocessor
output, or do something else like debug logging. The
default is str().
+ any keyword arguments to Template.compile which you want to
provide for the compilation of the intermediate template.
klass = Template.compile(src,
preprocessors=[ dict(tokens='@ %', searchList=[...]) ] )
errmsg = "arg '%s' must be %s"
if not isinstance(source, (types.NoneType, basestring)):
raise TypeError(errmsg % ('source', 'string or None'))
if not isinstance(file, (types.NoneType, basestring, filetype)):
raise TypeError(errmsg %
('file', 'string, file-like object, or None'))
if baseclass is Unspecified:
baseclass = klass._CHEETAH_defaultBaseclassForTemplates
if isinstance(baseclass, Template):
baseclass = baseclass.__class__
if not isinstance(baseclass, (types.NoneType, basestring, type)):
raise TypeError(errmsg % ('baseclass', 'string, class or None'))
if cacheCompilationResults is Unspecified:
cacheCompilationResults = klass._CHEETAH_cacheCompilationResults
if not isinstance(cacheCompilationResults, (int, bool)):
raise TypeError(errmsg % ('cacheCompilationResults', 'boolean'))
if useCache is Unspecified:
useCache = klass._CHEETAH_useCompilationCache
if not isinstance(useCache, (int, bool)):
raise TypeError(errmsg % ('useCache', 'boolean'))
if compilerSettings is Unspecified:
compilerSettings = klass._getCompilerSettings(source, file) or {}
if not isinstance(compilerSettings, dict):
raise TypeError(errmsg % ('compilerSettings', 'dictionary'))
if compilerClass is Unspecified:
compilerClass = klass._getCompilerClass(source, file)
if preprocessors is Unspecified:
preprocessors = klass._CHEETAH_preprocessors
if keepRefToGeneratedCode is Unspecified:
keepRefToGeneratedCode = klass._CHEETAH_keepRefToGeneratedCode
if not isinstance(keepRefToGeneratedCode, (int, bool)):
raise TypeError(errmsg % ('keepReftoGeneratedCode', 'boolean'))
if not isinstance(moduleName, (types.NoneType, basestring)):
raise TypeError(errmsg % ('moduleName', 'string or None'))
__orig_file__ = None
if not moduleName:
if file and isinstance(file, basestring):
moduleName = convertTmplPathToModuleName(file)
__orig_file__ = file
moduleName = klass._CHEETAH_defaultModuleNameForTemplates
if className is Unspecified:
className = klass._CHEETAH_defaultClassNameForTemplates
if not isinstance(className, (types.NoneType, basestring)):
raise TypeError(errmsg % ('className', 'string or None'))
className = re.sub(r'^_+([^0-9])',r'\1', className or moduleName)
if mainMethodName is Unspecified:
mainMethodName = klass._CHEETAH_defaultMainMethodNameForTemplates
if not isinstance(mainMethodName, (types.NoneType, basestring)):
raise TypeError(errmsg % ('mainMethodName', 'string or None'))
if moduleGlobals is Unspecified:
moduleGlobals = klass._CHEETAH_defaultModuleGlobalsForTemplates
if cacheModuleFilesForTracebacks is Unspecified:
cacheModuleFilesForTracebacks = klass._CHEETAH_cacheModuleFilesForTracebacks
if not isinstance(cacheModuleFilesForTracebacks, (int, bool)):
raise TypeError(errmsg %
('cacheModuleFilesForTracebacks', 'boolean'))
if cacheDirForModuleFiles is Unspecified:
cacheDirForModuleFiles = klass._CHEETAH_cacheDirForModuleFiles
if not isinstance(cacheDirForModuleFiles, (types.NoneType, basestring)):
raise TypeError(errmsg %
('cacheDirForModuleFiles', 'string or None'))
## handle any preprocessors
if preprocessors:
origSrc = source
source, file = klass._preprocessSource(source, file, preprocessors)
## compilation, using cache if requested/possible
baseclassValue = None
baseclassName = None
if baseclass:
if isinstance(baseclass, basestring):
baseclassName = baseclass
elif isinstance(baseclass, type):
# @@TR: should soft-code this
baseclassName = 'CHEETAH_dynamicallyAssignedBaseClass_'+baseclass.__name__
baseclassValue = baseclass
cacheHash = None
cacheItem = None
if source or isinstance(file, basestring):
compilerSettingsHash = None
if compilerSettings:
compilerSettingsHash = hashDict(compilerSettings)
moduleGlobalsHash = None
if moduleGlobals:
moduleGlobalsHash = hashDict(moduleGlobals)
fileHash = None
if file:
fileHash = str(hash(file))
if globals()['__checkFileMtime']:
fileHash += str(os.path.getmtime(file))
# @@TR: find some way to create a cacheHash that is consistent
# between process restarts. It would allow for caching the
# compiled module on disk and thereby reduce the startup time
# for applications that use a lot of dynamically compiled
# templates.
cacheHash = ''.join([str(v) for v in
#@@TR: should add some logging to this
outputEncoding = 'ascii'
compiler = None
if useCache and cacheHash and cacheHash in klass._CHEETAH_compileCache:
cacheItem = klass._CHEETAH_compileCache[cacheHash]
generatedModuleCode = cacheItem.code
compiler = compilerClass(source, file,
settings=(compilerSettings or {}))
if commandlineopts:
generatedModuleCode = compiler.getModuleCode()
outputEncoding = compiler.getModuleEncoding()
if not returnAClass:
# This is a bit of a hackish solution to make sure we're setting the proper
# encoding on generated code that is destined to be written to a file
if not outputEncoding == 'ascii':
generatedModuleCode = generatedModuleCode.split('\n')
generatedModuleCode.insert(1, '# -*- coding: %s -*-' % outputEncoding)
generatedModuleCode = '\n'.join(generatedModuleCode)
return generatedModuleCode.encode(outputEncoding)
if cacheItem:
cacheItem.lastCheckoutTime = time.time()
return cacheItem.klass
uniqueModuleName = _genUniqueModuleName(moduleName)
__file__ = uniqueModuleName+'.py' # relative file path with no dir part
if cacheModuleFilesForTracebacks:
if not os.path.exists(cacheDirForModuleFiles):
raise Exception('%s does not exist'%cacheDirForModuleFiles)
__file__ = os.path.join(cacheDirForModuleFiles, __file__)
# @@TR: might want to assert that it doesn't already exist
open(__file__, 'w').write(generatedModuleCode)
# @@TR: should probably restrict the perms, etc.
mod = types.ModuleType(str(uniqueModuleName))
if moduleGlobals:
for k, v in moduleGlobals.items():
setattr(mod, k, v)
mod.__file__ = __file__
if __orig_file__ and os.path.exists(__orig_file__):
# this is used in the WebKit filemonitoring code
mod.__orig_file__ = __orig_file__
if baseclass and baseclassValue:
setattr(mod, baseclassName, baseclassValue)
co = compile(generatedModuleCode, __file__, 'exec')
exec(co, mod.__dict__)
except SyntaxError, e:
parseError = genParserErrorFromPythonException(
source, file, generatedModuleCode, exception=e)
updateLinecache(__file__, generatedModuleCode)
e.generatedModuleCode = generatedModuleCode
raise e
raise parseError
except Exception, e:
updateLinecache(__file__, generatedModuleCode)
e.generatedModuleCode = generatedModuleCode
sys.modules[uniqueModuleName] = mod
templateClass = getattr(mod, className)
if (cacheCompilationResults
and cacheHash
and cacheHash not in klass._CHEETAH_compileCache):
cacheItem = CompileCacheItem()
cacheItem.cacheTime = cacheItem.lastCheckoutTime = time.time()
cacheItem.code = generatedModuleCode
cacheItem.klass = templateClass
templateClass._CHEETAH_isInCompilationCache = True
klass._CHEETAH_compileCache[cacheHash] = cacheItem
templateClass._CHEETAH_isInCompilationCache = False
if keepRefToGeneratedCode or cacheCompilationResults:
templateClass._CHEETAH_generatedModuleCode = generatedModuleCode
# If we have a compiler object, let's set it to the compiler class
# to help the directive analyzer code
if compiler:
templateClass._CHEETAH_compilerInstance = compiler
return templateClass
def subclass(klass, *args, **kws):
"""Takes the same args as the .compile() classmethod and returns a
template that is a subclass of the template this method is called from.
T1 = Template.compile(' foo - $meth1 - bar\n#def meth1: this is T1.meth1')
T2 = T1.subclass('#implements meth1\n this is T2.meth1')
kws['baseclass'] = klass
if isinstance(klass, Template):
templateAPIClass = klass
templateAPIClass = Template
return templateAPIClass.compile(*args, **kws)
def _preprocessSource(klass, source, file, preprocessors):
"""Iterates through the .compile() classmethod's preprocessors argument
and pipes the source code through each each preprocessor.
It returns the tuple (source, file) which is then used by
Template.compile to finish the compilation.
if not isinstance(preprocessors, (list, tuple)):
preprocessors = [preprocessors]
for preprocessor in preprocessors:
preprocessor = klass._normalizePreprocessorArg(preprocessor)
source, file = preprocessor.preprocess(source, file)
return source, file
def _normalizePreprocessorArg(klass, arg):
"""Used to convert the items in the .compile() classmethod's
preprocessors argument into real source preprocessors. This permits the
use of several shortcut forms for defining preprocessors.
if hasattr(arg, 'preprocess'):
return arg
elif hasattr(arg, '__call__'):
class WrapperPreprocessor:
def preprocess(self, source, file):
return arg(source, file)
return WrapperPreprocessor()
class Settings(object):
placeholderToken = None
directiveToken = None
settings = Settings()
if isinstance(arg, str) or isinstance(arg, (list, tuple)):
settings.tokens = arg
elif isinstance(arg, dict):
for k, v in arg.items():
setattr(settings, k, v)
settings = arg
settings = klass._normalizePreprocessorSettings(settings)
return klass._CHEETAH_defaultPreprocessorClass(settings)
def _normalizePreprocessorSettings(klass, settings):
settings.keepRefToGeneratedCode = True
def normalizeSearchList(searchList):
if not isinstance(searchList, (list, tuple)):
searchList = [searchList]
return searchList
def normalizeTokens(tokens):
if isinstance(tokens, str):
return tokens.split() # space delimited string e.g.'@ %'
elif isinstance(tokens, (list, tuple)):
return tokens
raise PreprocessError('invalid tokens argument: %r'%tokens)
if hasattr(settings, 'tokens'):
settings.directiveToken) = normalizeTokens(settings.tokens)
if (not getattr(settings, 'compilerSettings', None)
and not getattr(settings, 'placeholderToken', None) ):
raise TypeError(
'Preprocessor requires either a "tokens" or a "compilerSettings" arg.'
' Neither was provided.')
if not hasattr(settings, 'templateInitArgs'):
settings.templateInitArgs = {}
if 'searchList' not in settings.templateInitArgs:
if not hasattr(settings, 'searchList') and hasattr(settings, 'namespaces'):
settings.searchList = settings.namespaces
elif not hasattr(settings, 'searchList'):
settings.searchList = []
settings.templateInitArgs['searchList'] = settings.searchList
settings.templateInitArgs['searchList'] = (
if not hasattr(settings, 'outputTransformer'):
settings.outputTransformer = unicode
if not hasattr(settings, 'templateAPIClass'):
class PreprocessTemplateAPIClass(klass): pass
settings.templateAPIClass = PreprocessTemplateAPIClass
if not hasattr(settings, 'compilerSettings'):
settings.compilerSettings = {}
return settings
def _updateSettingsWithPreprocessTokens(
klass, compilerSettings, placeholderToken, directiveToken):
if (placeholderToken and 'cheetahVarStartToken' not in compilerSettings):
compilerSettings['cheetahVarStartToken'] = placeholderToken
if directiveToken:
if 'directiveStartToken' not in compilerSettings:
compilerSettings['directiveStartToken'] = directiveToken
if 'directiveEndToken' not in compilerSettings:
compilerSettings['directiveEndToken'] = directiveToken
if 'commentStartToken' not in compilerSettings:
compilerSettings['commentStartToken'] = directiveToken*2
if 'multiLineCommentStartToken' not in compilerSettings:
compilerSettings['multiLineCommentStartToken'] = (
if 'multiLineCommentEndToken' not in compilerSettings:
compilerSettings['multiLineCommentEndToken'] = (
if 'EOLSlurpToken' not in compilerSettings:
compilerSettings['EOLSlurpToken'] = directiveToken
def _addCheetahPlumbingCodeToClass(klass, concreteTemplateClass):
"""If concreteTemplateClass is not a subclass of Cheetah.Template, add
the required cheetah methods and attributes to it.
This is called on each new template class after it has been compiled.
If concreteTemplateClass is not a subclass of Cheetah.Template but
already has method with the same name as one of the required cheetah
methods, this will skip that method.
for methodname in klass._CHEETAH_requiredCheetahMethods:
if not hasattr(concreteTemplateClass, methodname):
method = getattr(Template, methodname)
newMethod = createMethod(method.im_func, concreteTemplateClass)
setattr(concreteTemplateClass, methodname, newMethod)
for classMethName in klass._CHEETAH_requiredCheetahClassMethods:
if not hasattr(concreteTemplateClass, classMethName):
meth = getattr(klass, classMethName)
setattr(concreteTemplateClass, classMethName, classmethod(meth.im_func))
for attrname in klass._CHEETAH_requiredCheetahClassAttributes:
attrname = '_CHEETAH_'+attrname
if not hasattr(concreteTemplateClass, attrname):
attrVal = getattr(klass, attrname)
setattr(concreteTemplateClass, attrname, attrVal)
if (not hasattr(concreteTemplateClass, '__str__')
or concreteTemplateClass.__str__ is object.__str__):
mainMethNameAttr = '_mainCheetahMethod_for_'+concreteTemplateClass.__name__
mainMethName = getattr(concreteTemplateClass, mainMethNameAttr, None)
if mainMethName:
def __str__(self):
rc = getattr(self, mainMethName)()
if isinstance(rc, unicode):
return rc.encode('utf-8')
return rc
def __unicode__(self):
return getattr(self, mainMethName)()
elif (hasattr(concreteTemplateClass, 'respond')
and concreteTemplateClass.respond!=Servlet.respond):
def __str__(self):
rc = self.respond()
if isinstance(rc, unicode):
return rc.encode('utf-8')
return rc
def __unicode__(self):
return self.respond()
def __str__(self):
rc = None
if hasattr(self, mainMethNameAttr):
rc = getattr(self, mainMethNameAttr)()
elif hasattr(self, 'respond'):
rc = self.respond()
rc = super(self.__class__, self).__str__()
if isinstance(rc, unicode):
return rc.encode('utf-8')
return rc
def __unicode__(self):
if hasattr(self, mainMethNameAttr):
return getattr(self, mainMethNameAttr)()
elif hasattr(self, 'respond'):
return self.respond()
return super(self.__class__, self).__unicode__()
__str__ = createMethod(__str__, concreteTemplateClass)
__unicode__ = createMethod(__unicode__, concreteTemplateClass)
setattr(concreteTemplateClass, '__str__', __str__)
setattr(concreteTemplateClass, '__unicode__', __unicode__)
def __init__(self, source=None,
namespaces=None, searchList=None,
# use either or. They are aliases for the same thing.
filter='RawOrEncodedUnicode', # which filter from Cheetah.Filters
compilerSettings=Unspecified, # control the behaviour of the compiler
_globalSetVars=None, # used internally for #include'd templates
_preBuiltSearchList=None # used internally for #include'd templates
"""a) compiles a new template OR b) instantiates an existing template.
Read this docstring carefully as there are two distinct usage patterns.
You should also read this class' main docstring.
a) to compile a new template:
t = Template(source=aSourceString)
# or
t = Template(file='some/path')
# or
t = Template(file=someFileObject)
# or
namespaces = [{'foo':'bar'}]
t = Template(source=aSourceString, namespaces=namespaces)
# or
t = Template(file='some/path', namespaces=namespaces)
print t
b) to create an instance of an existing, precompiled template class:
## i) first you need a reference to a compiled template class:
tclass = Template.compile(source=src) # or just Template.compile(src)
# or
tclass = Template.compile(file='some/path')
# or
tclass = Template.compile(file=someFileObject)
# or
# if you used the command line compiler or have Cheetah's ImportHooks
# installed your template class is also available via Python's
# standard import mechanism:
from ACompileTemplate import AcompiledTemplate as tclass
## ii) then you create an instance
t = tclass(namespaces=namespaces)
# or
t = tclass(namespaces=namespaces, filter='RawOrEncodedUnicode')
print t
for usage pattern a)
If you are compiling a new template, you must provide either a
'source' or 'file' arg, but not both:
- source (string or None)
- file (string path, file-like object, or None)
Optional args (see below for more) :
- compilerSettings
Default: Template._CHEETAH_compilerSettings=None
a dictionary of settings to override those defined in
Cheetah.Template.DEFAULT_COMPILER_SETTINGS and the Users' Guide
for details.
You can pass the source arg in as a positional arg with this usage
pattern. Use keywords for all other args.
for usage pattern b)
Do not use positional args with this usage pattern, unless your
template subclasses something other than Cheetah.Template and you
want to pass positional args to that baseclass. E.g.:
dictTemplate = Template.compile('hello $name from $caller', baseclass=dict)
tmplvars = dict(name='world', caller='me')
print dictTemplate(tmplvars)
This usage requires all Cheetah args to be passed in as keyword args.
optional args for both usage patterns:
- namespaces (aka 'searchList')
Default: None
an optional list of namespaces (dictionaries, objects, modules,
etc.) which Cheetah will search through to find the variables
referenced in $placeholders.
If you provide a single namespace instead of a list, Cheetah will
automatically convert it into a list.
NOTE: Cheetah does NOT force you to use the namespaces search list
and related features. It's on by default, but you can turn if off
using the compiler settings useSearchList=False or
- filter
Default: 'EncodeUnicode'
Which filter should be used for output filtering. This should
either be a string which is the name of a filter in the
'filtersLib' or a subclass of Cheetah.Filters.Filter. . See the
Users' Guide for more details.
- filtersLib
Default: Cheetah.Filters
A module containing subclasses of Cheetah.Filters.Filter. See the
Users' Guide for more details.
- errorCatcher
Default: None
This is a debugging tool. See the Users' Guide for more details.
Do not use this or the #errorCatcher diretive with live
production systems.
Do NOT mess with the args _globalSetVars or _preBuiltSearchList!
errmsg = "arg '%s' must be %s"
errmsgextra = errmsg + "\n%s"
if not isinstance(source, (types.NoneType, basestring)):
raise TypeError(errmsg % ('source', 'string or None'))
if not isinstance(file, (types.NoneType, basestring, filetype)):
raise TypeError(errmsg %
('file', 'string, file open for reading, or None'))
if not isinstance(filter, (basestring, types.TypeType)) and not \
(isinstance(filter, type) and issubclass(filter, Filters.Filter)):
raise TypeError(errmsgextra %
('filter', 'string or class',
'(if class, must be subclass of Cheetah.Filters.Filter)'))
if not isinstance(filtersLib, (basestring, types.ModuleType)):
raise TypeError(errmsgextra %
('filtersLib', 'string or module',
'(if module, must contain subclasses of Cheetah.Filters.Filter)'))
if not errorCatcher is None:
err = True
if isinstance(errorCatcher, (basestring, types.TypeType)):
err = False
if isinstance(errorCatcher, type) and \
issubclass(errorCatcher, ErrorCatchers.ErrorCatcher):
err = False
if err:
raise TypeError(errmsgextra %
('errorCatcher', 'string, class or None',
'(if class, must be subclass of Cheetah.ErrorCatchers.ErrorCatcher)'))
if compilerSettings is not Unspecified:
if not isinstance(compilerSettings, types.DictType):
raise TypeError(errmsg %
('compilerSettings', 'dictionary'))
if source is not None and file is not None:
raise TypeError("you must supply either a source string or the" +
" 'file' keyword argument, but not both")
## Do superclass initialization.
super(Template, self).__init__()
## Do required version check
if not hasattr(self, '_CHEETAH_versionTuple'):
mod = sys.modules[self.__class__.__module__]
compiledVersion = mod.__CHEETAH_version__
compiledVersionTuple = convertVersionStringToTuple(compiledVersion)
if compiledVersionTuple < MinCompatibleVersionTuple:
raise AssertionError(
'This template was compiled with Cheetah version'
' %s. Templates compiled before version %s must be recompiled.'%(
compiledVersion, MinCompatibleVersion))
except AssertionError:
## Setup instance state attributes used during the life of template
## post-compile
if searchList:
for namespace in searchList:
if isinstance(namespace, dict):
intersection = self.Reserved_SearchList & set(namespace.keys())
warn = False
if intersection:
warn = True
if isinstance(compilerSettings, dict) and compilerSettings.get('prioritizeSearchListOverSelf'):
warn = False
if warn:''' The following keys are members of the Template class and will result in NameMapper collisions! ''')''' > %s ''' % ', '.join(list(intersection)))''' Please change the key's name or use the compiler setting "prioritizeSearchListOverSelf=True" to prevent the NameMapper from using ''')''' the Template member in place of your searchList variable ''')
searchList=searchList, namespaces=namespaces,
filter=filter, filtersLib=filtersLib,
## Now, compile if we're meant to
if (source is not None) or (file is not None):
self._compile(source, file, compilerSettings=compilerSettings)
def generatedModuleCode(self):
"""Return the module code the compiler generated, or None if no
compilation took place.
return self._CHEETAH_generatedModuleCode
def generatedClassCode(self):
"""Return the class code the compiler generated, or None if no
compilation took place.
return self._CHEETAH_generatedModuleCode[
self._CHEETAH_generatedModuleCode.find('\nclass '):
self._CHEETAH_generatedModuleCode.find('\n## END CLASS DEFINITION')]
def searchList(self):
"""Return a reference to the searchlist
return self._CHEETAH__searchList
def errorCatcher(self):
"""Return a reference to the current errorCatcher
return self._CHEETAH__errorCatcher
## cache methods ##
def _getCacheStore(self):
if not self._CHEETAH__cacheStore:
if self._CHEETAH_cacheStore is not None:
self._CHEETAH__cacheStore = self._CHEETAH_cacheStore
# @@TR: might want to provide a way to provide init args
self._CHEETAH__cacheStore = self._CHEETAH_cacheStoreClass()
return self._CHEETAH__cacheStore
def _getCacheStoreIdPrefix(self):
if self._CHEETAH_cacheStoreIdPrefix is not None:
return self._CHEETAH_cacheStoreIdPrefix
return str(id(self))
def _createCacheRegion(self, regionID):
return self._CHEETAH_cacheRegionClass(
def getCacheRegion(self, regionID, cacheInfo=None, create=True):
cacheRegion = self._CHEETAH__cacheRegions.get(regionID)
if not cacheRegion and create:
cacheRegion = self._createCacheRegion(regionID)
self._CHEETAH__cacheRegions[regionID] = cacheRegion
return cacheRegion
def getCacheRegions(self):
"""Returns a dictionary of the 'cache regions' initialized in a
Each #cache directive block or $*cachedPlaceholder is a separate 'cache
# returns a copy to prevent users mucking it up
return self._CHEETAH__cacheRegions.copy()
def refreshCache(self, cacheRegionId=None, cacheItemId=None):
"""Refresh a cache region or a specific cache item within a region.
if not cacheRegionId:
for cacheRegion in self.getCacheRegions().itervalues():
cregion = self._CHEETAH__cacheRegions.get(cacheRegionId)
if not cregion:
if not cacheItemId: # clear the desired region and all its cacheItems
else: # clear one specific cache of a specific region
cache = cregion.getCacheItem(cacheItemId)
if cache:
## end cache methods ##
def shutdown(self):
"""Break reference cycles before discarding a servlet.
self._CHEETAH__searchList = None
self.__dict__ = {}
## utility functions ##
def getVar(self, varName, default=Unspecified, autoCall=True):
"""Get a variable from the searchList. If the variable can't be found
in the searchList, it returns the default value if one was given, or
raises NameMapper.NotFound.
return valueFromSearchList(self.searchList(), varName.replace('$', ''), autoCall)
except NotFound:
if default is not Unspecified:
return default
def varExists(self, varName, autoCall=True):
"""Test if a variable name exists in the searchList.
valueFromSearchList(self.searchList(), varName.replace('$', ''), autoCall)
return True
except NotFound:
return False
hasVar = varExists
def i18n(self, message,
"""This is just a stub at this time.
plural = the plural form of the message
n = a sized argument to distinguish between single and plural forms
id = msgid in the translation catalog
domain = translation domain
source = source lang
target = a specific target lang
comment = a comment to the translation team
See the following for some ideas
Other notes:
- There is no need to replicate the i18n:name attribute from plone / PTL,
as cheetah placeholders serve the same purpose
return message
def getFileContents(self, path):
"""A hook for getting the contents of a file. The default
implementation just uses the Python open() function to load local files.
This method could be reimplemented to allow reading of remote files via
various protocols, as PHP allows with its 'URL fopen wrapper'
fp = open(path, 'r')
output =
return output
def runAsMainProgram(self):
"""Allows the Template to function as a standalone command-line program
for static page generation.
Type 'python --help to see what it's capabable of.
from TemplateCmdLineIface import CmdLineIface
## internal methods -- not to be called by end-users
def _initCheetahInstance(self,
filter='RawOrEncodedUnicode', # which filter from Cheetah.Filters
"""Sets up the instance attributes that cheetah templates use at
This is automatically called by the __init__ method of compiled
Note that the names of instance attributes used by Cheetah are prefixed
with '_CHEETAH__' (2 underscores), where class attributes are prefixed
with '_CHEETAH_' (1 underscore).
if getattr(self, '_CHEETAH__instanceInitialized', False):
if namespaces is not None:
assert searchList is None, (
'Provide "namespaces" or "searchList", not both!')
searchList = namespaces
if searchList is not None and not isinstance(searchList, (list, tuple)):
searchList = [searchList]
self._CHEETAH__globalSetVars = {}
if _globalSetVars is not None:
# this is intended to be used internally by Nested Templates in #include's
self._CHEETAH__globalSetVars = _globalSetVars
if _preBuiltSearchList is not None:
# happens with nested Template obj creation from #include's
self._CHEETAH__searchList = list(_preBuiltSearchList)
# create our own searchList
self._CHEETAH__searchList = [self._CHEETAH__globalSetVars, self]
if searchList is not None:
if isinstance(compilerSettings, dict) and compilerSettings.get('prioritizeSearchListOverSelf'):
self._CHEETAH__searchList = searchList + self._CHEETAH__searchList
self._CHEETAH__cheetahIncludes = {}
self._CHEETAH__cacheRegions = {}
self._CHEETAH__indenter = Indenter()
# @@TR: consider allowing simple callables as the filter argument
self._CHEETAH__filtersLib = filtersLib
self._CHEETAH__filters = {}
if isinstance(filter, basestring):
filterName = filter
klass = getattr(self._CHEETAH__filtersLib, filterName)
klass = filter
filterName = klass.__name__
self._CHEETAH__currentFilter = self._CHEETAH__filters[filterName] = klass(self).filter
self._CHEETAH__initialFilter = self._CHEETAH__currentFilter
self._CHEETAH__errorCatchers = {}
if errorCatcher:
if isinstance(errorCatcher, basestring):
errorCatcherClass = getattr(ErrorCatchers, errorCatcher)
elif isinstance(errorCatcher, type):
errorCatcherClass = errorCatcher
self._CHEETAH__errorCatcher = ec = errorCatcherClass(self)
self._CHEETAH__errorCatchers[errorCatcher.__class__.__name__] = ec
self._CHEETAH__errorCatcher = None
self._CHEETAH__initErrorCatcher = self._CHEETAH__errorCatcher
if not hasattr(self, 'transaction'):
self.transaction = None
self._CHEETAH__instanceInitialized = True
self._CHEETAH__isBuffering = False
self._CHEETAH__isControlledByWebKit = False
self._CHEETAH__cacheStore = None
if self._CHEETAH_cacheStore is not None:
self._CHEETAH__cacheStore = self._CHEETAH_cacheStore
def _compile(self, source=None, file=None, compilerSettings=Unspecified,
moduleName=None, mainMethodName=None):
"""Compile the template. This method is automatically called by
Template.__init__ it is provided with 'file' or 'source' args.
if compilerSettings is Unspecified:
compilerSettings = self._getCompilerSettings(source, file) or {}
mainMethodName = mainMethodName or self._CHEETAH_defaultMainMethodName
self._fileMtime = None
self._fileDirName = None
self._fileBaseName = None
if file and isinstance(file, basestring):
file = self.serverSidePath(file)
self._fileMtime = os.path.getmtime(file)
self._fileDirName, self._fileBaseName = os.path.split(file)
self._filePath = file
templateClass = self.compile(source, file,
if not self.__class__ == Template:
# Only propogate attributes if we're in a subclass of
# Template
for k, v in self.__class__.__dict__.iteritems():
if not v or k.startswith('__'):
## Propogate the class attributes to the instance
## since we're about to obliterate self.__class__
## (see: cheetah.Tests.Tepmlate.SubclassSearchListTest)
setattr(self, k, v)
self.__class__ = templateClass
# must initialize it so instance attributes are accessible
if not hasattr(self, 'transaction'):
self.transaction = None
def _handleCheetahInclude(self, srcArg, trans=None, includeFrom='file', raw=False):
"""Called at runtime to handle #include directives.
_includeID = srcArg
if _includeID not in self._CHEETAH__cheetahIncludes:
if not raw:
if includeFrom == 'file':
source = None
if isinstance(srcArg, basestring):
if hasattr(self, 'serverSidePath'):
file = path = self.serverSidePath(srcArg)
file = path = os.path.normpath(srcArg)
file = srcArg ## a file-like object
source = srcArg
file = None
# @@TR: might want to provide some syntax for specifying the
# Template class to be used for compilation so compilerSettings
# can be changed.
compiler = self._getTemplateAPIClassForIncludeDirectiveCompilation(source, file)
nestedTemplateClass = compiler.compile(source=source, file=file)
nestedTemplate = nestedTemplateClass(_preBuiltSearchList=self.searchList(),
# Set the inner template filters to the initial filter of the
# outer template:
# this is the only really safe way to use
# filter='WebSafe'.
nestedTemplate._CHEETAH__initialFilter = self._CHEETAH__initialFilter
nestedTemplate._CHEETAH__currentFilter = self._CHEETAH__initialFilter
self._CHEETAH__cheetahIncludes[_includeID] = nestedTemplate
if includeFrom == 'file':
path = self.serverSidePath(srcArg)
self._CHEETAH__cheetahIncludes[_includeID] = self.getFileContents(path)
self._CHEETAH__cheetahIncludes[_includeID] = srcArg
if not raw:
def _getTemplateAPIClassForIncludeDirectiveCompilation(self, source, file):
"""Returns the subclass of Template which should be used to compile
#include directives.
This abstraction allows different compiler settings to be used in the
included template than were used in the parent.
if issubclass(self.__class__, Template):
return self.__class__
return Template
## functions for using templates as CGI scripts
def webInput(self, names, namesMulti=(), default='', src='f',
defaultInt=0, defaultFloat=0.00, badInt=0, badFloat=0.00, debug=False):
"""Method for importing web transaction variables in bulk.
This works for GET/POST fields both in Webware servlets and in CGI
scripts, and for cookies and session variables in Webware servlets. If
you try to read a cookie or session variable in a CGI script, you'll get
a RuntimeError. 'In a CGI script' here means 'not running as a Webware
servlet'. If the CGI environment is not properly set up, Cheetah will
act like there's no input.
The public method provided is:
def webInput(self, names, namesMulti=(), default='', src='f',
defaultInt=0, defaultFloat=0.00, badInt=0, badFloat=0.00, debug=False):
This method places the specified GET/POST fields, cookies or session
variables into a dictionary, which is both returned and put at the
beginning of the searchList. It handles:
* single vs multiple values
* conversion to integer or float for specified names
* default values/exceptions for missing or bad values
* printing a snapshot of all values retrieved for debugging
All the 'default*' and 'bad*' arguments have 'use or raise' behavior,
meaning that if they're a subclass of Exception, they're raised. If
they're anything else, that value is substituted for the missing/bad
The simplest usage is:
#silent $webInput(['choice'])
dic = self.webInput(['choice'])
Both these examples retrieves the GET/POST field 'choice' and print it.
If you leave off the'#silent', all the values would be printed too. But
a better way to preview the values is
#silent $webInput(['name'], $debug=1)
because this pretty-prints all the values inside HTML <PRE> tags.
** KLUDGE: 'debug' is supposed to insert into the template output, but it
wasn't working so I changed it to a'print' statement. So the debugging
output will appear wherever standard output is pointed, whether at the
terminal, in a Webware log file, or whatever. ***
Since we didn't specify any coversions, the value is a string. It's a
'single' value because we specified it in 'names' rather than
'namesMulti'. Single values work like this:
* If one value is found, take it.
* If several values are found, choose one arbitrarily and ignore the rest.
* If no values are found, use or raise the appropriate 'default*' value.
Multi values work like this:
* If one value is found, put it in a list.
* If several values are found, leave them in a list.
* If no values are found, use the empty list ([]). The 'default*'
arguments are *not* consulted in this case.
Example: assume 'days' came from a set of checkboxes or a multiple combo
box on a form, and the user chose'Monday', 'Tuesday' and 'Thursday'.
#silent $webInput([], ['days'])
The days you chose are: #slurp
#for $day in $days
$day #slurp
#end for
dic = self.webInput([], ['days'])
write('The days you chose are: ')
for day in dic['days']:
write(day + ' ')
Both these examples print: 'The days you chose are: Monday Tuesday Thursday'.
By default, missing strings are replaced by '' and missing/bad numbers
by zero. (A'bad number' means the converter raised an exception for
it, usually because of non-numeric characters in the value.) This
mimics Perl/PHP behavior, and simplifies coding for many applications
where missing/bad values *should* be blank/zero. In those relatively
few cases where you must distinguish between empty-string/zero on the
one hand and missing/bad on the other, change the appropriate
'default*' and 'bad*' arguments to something like:
* None
* another constant value
* $NonNumericInputError/self.NonNumericInputError
* $ValueError/ValueError
(NonNumericInputError is defined in this class and is useful for
distinguishing between bad input vs a TypeError/ValueError thrown for
some other rason.)
Here's an example using multiple values to schedule newspaper
deliveries. 'checkboxes' comes from a form with checkboxes for all the
days of the week. The days the user previously chose are preselected.
The user checks/unchecks boxes as desired and presses Submit. The value
of 'checkboxes' is a list of checkboxes that were checked when Submit
was pressed. Our task now is to turn on the days the user checked, turn
off the days he unchecked, and leave on or off the days he didn't
dic = self.webInput([], ['dayCheckboxes'])
wantedDays = dic['dayCheckboxes'] # The days the user checked.
for day, on in self.getAllValues():
if not on and wantedDays.has_key(day):
# ... Set a flag or insert a database record ...
elif on and not wantedDays.has_key(day):
# ... Unset a flag or delete a database record ...
'source' allows you to look up the variables from a number of different
'f' fields (CGI GET/POST parameters)
'c' cookies
's' session variables
'v' 'values', meaning fields or cookies
In many forms, you're dealing only with strings, which is why the
'default' argument is third and the numeric arguments are banished to
the end. But sometimes you want automatic number conversion, so that
you can do numeric comparisions in your templates without having to
write a bunch of conversion/exception handling code. Example:
#silent $webInput(['name', 'height:int'])
$name is $height cm tall.
#if $height >= 300
Wow, you're tall!
Pshaw, you're short.
#end if
dic = self.webInput(['name', 'height:int'])
name = dic[name]
height = dic[height]
write('%s is %s cm tall.' % (name, height))
if height > 300:
write('Wow, you're tall!')
write('Pshaw, you're short.')
To convert a value to a number, suffix ':int' or ':float' to the name.
The method will search first for a 'height:int' variable and then for a
'height' variable. (It will be called 'height' in the final
dictionary.) If a numeric conversion fails, use or raise 'badInt' or
'badFloat'. Missing values work the same way as for strings, except the
default is 'defaultInt' or 'defaultFloat' instead of 'default'.
If a name represents an uploaded file, the entire file will be read into
memory. For more sophistocated file-upload handling, leave that name
out of the list and do your own handling, or wait for
This only in a subclass that also inherits from Webware's Servlet or
HTTPServlet. Otherwise you'll get an AttributeError on 'self.request'.
EXCEPTIONS: ValueError if 'source' is not one of the stated characters.
TypeError if a conversion suffix is not ':int' or ':float'.
FUTURE EXPANSION: a future version of this method may allow source
cascading; e.g., 'vs' would look first in 'values' and then in session
Author: Mike Orr <>
License: This software is released for unlimited distribution under the
terms of the MIT license. See the LICENSE file.
Version: $Revision: 1.186 $
Start Date: 2002/03/17
Last Revision Date: $Date: 2008/03/10 04:48:11 $
src = src.lower()
isCgi = not self._CHEETAH__isControlledByWebKit
if isCgi and src in ('f', 'v'):
global _formUsedByWebInput
if _formUsedByWebInput is None:
_formUsedByWebInput = cgi.FieldStorage()
source, func = 'field', _formUsedByWebInput.getvalue
elif isCgi and src == 'c':
raise RuntimeError("can't get cookies from a CGI script")
elif isCgi and src == 's':
raise RuntimeError("can't get session variables from a CGI script")
elif isCgi and src == 'v':
source, func = 'value', self.request().value
elif isCgi and src == 's':
source, func = 'session', self.request().session().value
elif src == 'f':
source, func = 'field', self.request().field
elif src == 'c':
source, func = 'cookie', self.request().cookie
elif src == 'v':
source, func = 'value', self.request().value
elif src == 's':
source, func = 'session', self.request().session().value
raise TypeError("arg 'src' invalid")
sources = source + 's'
converters = {
'': _Converter('string', None, default, default ),
'int': _Converter('int', int, defaultInt, badInt ),
'float': _Converter('float', float, defaultFloat, badFloat), }
#pprint.pprint(locals()); return {}
dic = {} # Destination.
for name in names:
k, v = _lookup(name, func, False, converters)
dic[k] = v
for name in namesMulti:
k, v = _lookup(name, func, True, converters)
dic[k] = v
# At this point, 'dic' contains all the keys/values we want to keep.
# We could split the method into a superclass
# method for Webware/WebwareExperimental and a subclass for Cheetah.
# The superclass would merely 'return dic'. The subclass would
# 'dic = super(ThisClass, self).webInput(names, namesMulti, ...)'
# and then the code below.
if debug:
print("<PRE>\n" + pprint.pformat(dic) + "\n</PRE>\n\n")
self.searchList().insert(0, dic)
return dic
T = Template # Short and sweet for debugging at the >>> prompt.
Template.Reserved_SearchList = set(dir(Template))
def genParserErrorFromPythonException(source, file, generatedPyCode, exception):
#print dir(exception)
filename = isinstance(file, (str, unicode)) and file or None
sio = StringIO.StringIO()
traceback.print_exc(1, sio)
formatedExc = sio.getvalue()
if hasattr(exception, 'lineno'):
pyLineno = exception.lineno
pyLineno = int('[ \t]*File.*line (\d+)', formatedExc).group(1))
lines = generatedPyCode.splitlines()
prevLines = [] # (i, content)
for i in range(1, 4):
if pyLineno-i <=0:
prevLines.append( (pyLineno+1-i, lines[pyLineno-i]) )
nextLines = [] # (i, content)
for i in range(1, 4):
if not pyLineno+i < len(lines):
nextLines.append( (pyLineno+i, lines[pyLineno+i]) )
report = 'Line|Python Code\n'
report += '----|-------------------------------------------------------------\n'
while prevLines:
lineInfo = prevLines.pop()
report += "%(row)-4d|%(line)s\n"% {'row':lineInfo[0], 'line':lineInfo[1]}
if hasattr(exception, 'offset'):
report += ' '*(3+(exception.offset or 0)) + '^\n'
while nextLines:
lineInfo = nextLines.pop()
report += "%(row)-4d|%(line)s\n"% {'row':lineInfo[0], 'line':lineInfo[1]}
message = [
"Error in the Python code which Cheetah generated for this template:",
cheetahPosMatch ='line (\d+), col (\d+)', formatedExc)
if cheetahPosMatch:
lineno = int(
col = int(
#if hasattr(exception, 'offset'):
# col = exception.offset
message.append('\nHere is the corresponding Cheetah code:\n')
lineno = None
col = None
cheetahPosMatch ='line (\d+), col (\d+)',
'\n'.join(lines[max(pyLineno-2, 0):]))
if cheetahPosMatch:
lineno = int(
col = int(
message.append('\nHere is the corresponding Cheetah code.')
message.append('** I had to guess the line & column numbers,'
' so they are probably incorrect:\n')
message = '\n'.join(message)
reader = SourceReader(source, filename=filename)
return ParseError(reader, message, lineno=lineno, col=col)
# vim: shiftwidth=4 tabstop=4 expandtab