module documentation

Standardized versions of various cool and/or strange things that you can do with Python's reflection capabilities.

Class QueueMethod I represent a method that doesn't exist yet.
Exception InvalidName The given name is not a dot-separated list of Python objects.
Exception ModuleNotFound The module associated with the given name doesn't exist and it can't be imported.
Exception ObjectNotFound The object associated with the given name doesn't exist and it can't be imported.
Function accumulateClassDict Accumulate all attributes of a given name in a class hierarchy into a single dictionary.
Function accumulateClassList Accumulate all attributes of a given name in a class hierarchy into a single list.
Function accumulateMethods Given an object obj, add all methods that begin with prefix.
Function addMethodNamesToDict This goes through classObj (and its bases) and puts method names starting with 'prefix' in 'dict' with a value of 1. if baseClass isn't None, methods will only be added if classObj is-a baseClass
Function filenameToModuleName Convert a name in the filesystem to the name of the Python module it is.
Function findInstances Undocumented
Function fullFuncName Undocumented
Function fullyQualifiedName Return the fully qualified name of a module, class, method or function. Classes and functions need to be module level ones to be correctly qualified.
Function getClass Return the class or type of object 'obj'.
Function isLike Undocumented
Function isOfType Undocumented
Function isSame Undocumented
Function modgrep Undocumented
Function namedAny Retrieve a Python object by its fully qualified name from the global Python module namespace. The first part of the name, that describes a module, will be discovered and imported. Each subsequent part of the name is treated as the name of an attribute of the object specified by all of the name which came before it...
Function namedModule Return a module given its name.
Function namedObject Get a fully named module-global object.
Function objgrep objgrep finds paths between start and goal.
Function prefixedMethodNames Given a class object classObj, returns a list of method names that match the string prefix.
Function prefixedMethods Given an object obj, returns a list of method objects that match the string prefix.
Function qual Return full import path of a class.
Function requireModule Try to import a module given its name, returning default value if ImportError is raised during import.
Function safe_repr Returns a string representation of an object, or a string containing a traceback, if that object's __repr__ raised an exception.
Function safe_str Returns a string representation of an object, or a string containing a traceback, if that object's __str__ raised an exception.
Variable RegexType Undocumented
Exception _NoModuleFound No module was found because none exists.
Function _determineClass Undocumented
Function _determineClassName Undocumented
Function _importAndCheckStack Import the given name as a module, then walk the stack to determine whether the failure was the module not existing, or some code in the module (for example a dependent import) failing. This can be helpful to determine whether any actual application code was run...
Function _safeFormat Helper function for safe_repr and safe_str.
def accumulateClassDict(classObj, attr, adict, baseClass=None): (source)

Accumulate all attributes of a given name in a class hierarchy into a single dictionary.

Assuming all class attributes of this name are dictionaries. If any of the dictionaries being accumulated have the same key, the one highest in the class hierarchy wins. (XXX: If "highest" means "closest to the starting class".)

Ex:

  class Soy:
    properties = {"taste": "bland"}

  class Plant:
    properties = {"colour": "green"}

  class Seaweed(Plant):
    pass

  class Lunch(Soy, Seaweed):
    properties = {"vegan": 1 }

  dct = {}

  accumulateClassDict(Lunch, "properties", dct)

  print(dct)

{"taste": "bland", "colour": "green", "vegan": 1}

def accumulateClassList(classObj, attr, listObj, baseClass=None): (source)

Accumulate all attributes of a given name in a class hierarchy into a single list.

Assuming all class attributes of this name are lists.

def accumulateMethods(obj, dict, prefix='', curClass=None): (source)

Given an object obj, add all methods that begin with prefix.

Parameters
objAn arbitrary object to collect methods from.
dict:dictA dict which will be updated with the results of the accumulation. Items are added to this dictionary, with method names as keys and corresponding instance method objects as values.
prefix:strA native string giving a prefix. Each method of obj with a name which begins with this prefix will be returned.
curClassThe class in the inheritance hierarchy at which to start collecting methods. Collection proceeds up. To collect all methods from obj, do not pass a value for this parameter.
Returns
None
def addMethodNamesToDict(classObj, dict, prefix, baseClass=None): (source)

This goes through classObj (and its bases) and puts method names starting with 'prefix' in 'dict' with a value of 1. if baseClass isn't None, methods will only be added if classObj is-a baseClass

If the class in question has the methods 'prefix_methodname' and 'prefix_methodname2', the resulting dict should look something like: {"methodname": 1, "methodname2": 1}.

Parameters
classObjA class object from which to collect method names.
dict:dictA dict which will be updated with the results of the accumulation. Items are added to this dictionary, with method names as keys and 1 as values.
prefix:strA native string giving a prefix. Each method of classObj (and base classes of classObj) with a name which begins with this prefix will be returned.
baseClassA class object at which to stop searching upwards for new methods. To collect all method names, do not pass a value for this parameter.
Returns
None
def filenameToModuleName(fn): (source)

Convert a name in the filesystem to the name of the Python module it is.

This is aggressive about getting a module name back from a file; it will always return a string. Aggressive means 'sometimes wrong'; it won't look at the Python path or try to do any error checking: don't use this method unless you already know that the filename you're talking about is a Python module.

Parameters
fnA filesystem path to a module or package; bytes on Python 2, bytes or unicode on Python 3.
Returns
strA hopefully importable module name.
def findInstances(start, t): (source)

Undocumented

def fullFuncName(func): (source)

Undocumented

def fullyQualifiedName(obj): (source)

Return the fully qualified name of a module, class, method or function. Classes and functions need to be module level ones to be correctly qualified.

Returns
str.Undocumented
def getClass(obj): (source)

Return the class or type of object 'obj'.

def isLike(a, b): (source)

Undocumented

def isOfType(start, goal): (source)

Undocumented

def isSame(a, b): (source)

Undocumented

def modgrep(goal): (source)

Undocumented

def namedAny(name): (source)

Retrieve a Python object by its fully qualified name from the global Python module namespace. The first part of the name, that describes a module, will be discovered and imported. Each subsequent part of the name is treated as the name of an attribute of the object specified by all of the name which came before it. For example, the fully-qualified name of this object is 'twisted.python.reflect.namedAny'.

Parameters
name:strThe name of the object to return.
Returns
the Python object identified by 'name'.
Raises
InvalidNameIf the name is an empty string, starts or ends with a '.', or is otherwise syntactically incorrect.
ModuleNotFoundIf the name is syntactically correct but the module it specifies cannot be imported because it does not appear to exist.
ObjectNotFoundIf the name is syntactically correct, includes at least one '.', but the module it specifies cannot be imported because it does not appear to exist.
AttributeErrorIf an attribute of an object along the way cannot be accessed, or a module along the way is not found.
def namedModule(name): (source)

Return a module given its name.

def namedObject(name): (source)

Get a fully named module-global object.

def objgrep(start, goal, eq=isLike, path='', paths=None, seen=None, showUnknowns=0, maxDepth=None): (source)

objgrep finds paths between start and goal.

Starting at the python object start, we will loop over every reachable reference, tring to find the python object goal (i.e. every object candidate for whom eq(candidate, goal) is truthy), and return a list of str, where each str is Python syntax for a path between start and goal.

Since this can be slightly difficult to visualize, here's an example:

    >>> class Holder:
    ...     def __init__(self, x):
    ...         self.x = x
    ...
    >>> start = Holder({"irrelevant": "ignore",
    ...                 "relevant": [7, 1, 3, 5, 7]})
    >>> for path in objgrep(start, 7):
    ...     print("start" + path)
    start.x['relevant'][0]
    start.x['relevant'][4]

This can be useful, for example, when debugging stateful graphs of objects attached to a socket, trying to figure out where a particular connection is attached.

Parameters
startThe object to start looking at.
goalThe object to search for.
eqA 2-argument predicate which takes an object found by traversing references starting at start, as well as goal, and returns a boolean.
pathThe prefix of the path to include in every return value; empty by default.
pathsThe result object to append values to; a list of strings.
seenA dictionary mapping ints (object IDs) to objects already seen.
showUnknownsif true, print a message to stdout when encountering objects that objgrep does not know how to traverse.
maxDepthThe maximum number of object references to attempt traversing before giving up. If an integer, limit to that many links, if None, unlimited.
Returns
A list of strings representing python object paths starting at start and terminating at goal.
def prefixedMethodNames(classObj, prefix): (source)

Given a class object classObj, returns a list of method names that match the string prefix.

Parameters
classObjA class object from which to collect method names.
prefix:strA native string giving a prefix. Each method with a name which begins with this prefix will be returned.
Returns
list of strA list of the names of matching methods of classObj (and base classes of classObj).
def prefixedMethods(obj, prefix=''): (source)

Given an object obj, returns a list of method objects that match the string prefix.

Parameters
objAn arbitrary object from which to collect methods.
prefix:strA native string giving a prefix. Each method of obj with a name which begins with this prefix will be returned.
Returns
listA list of the matching method objects.
def qual(clazz: type[object]) -> str: (source)

Return full import path of a class.

def requireModule(name, default=None): (source)

Try to import a module given its name, returning default value if ImportError is raised during import.

Parameters
name:str.Module name as it would have been passed to import.
defaultValue returned in case ImportError is raised while importing the module.
Returns
Module or default value.
def safe_repr(o): (source)

Returns a string representation of an object, or a string containing a traceback, if that object's __repr__ raised an exception.

Parameters
oAny object.
Returns
strUndocumented
def safe_str(o: object) -> str: (source)

Returns a string representation of an object, or a string containing a traceback, if that object's __str__ raised an exception.

Parameters
o:objectAny object.
Returns
strUndocumented
RegexType = (source)

Undocumented

def _determineClass(x): (source)

Undocumented

def _determineClassName(x): (source)

Undocumented

def _importAndCheckStack(importName): (source)

Import the given name as a module, then walk the stack to determine whether the failure was the module not existing, or some code in the module (for example a dependent import) failing. This can be helpful to determine whether any actual application code was run. For example, to distiguish administrative error (entering the wrong module name), from programmer error (writing buggy code in a module that fails to import).

Parameters
importName:strThe name of the module to import.
Raises
Exceptionif something bad happens. This can be any type of exception, since nobody knows what loading some arbitrary code might do.
_NoModuleFoundif no module was found.
def _safeFormat(formatter: types.FunctionType | type[str], o: object) -> str: (source)

Helper function for safe_repr and safe_str.

Called when repr or str fail. Returns a string containing info about o and the latest exception.

Parameters
formatter:typestr or repr.
o:objectAny object.
Returns
strA string containing information about o and the raised exception.