Reflection Helper - Python

A module that makes reflection easier in Python, based on the C# System.Reflection library

Installation

Use pip3 install ReflectionHelper to install the module. (Python3.7+)

Usage

Import the module using

from ReflectionHelper import *

The module adds 4 new functions to the type class.

-GetField

-GetFields

-GetMethod

-GetMethods

Classes

MemberInfo

A parent class storing the datas of the reflected values

FieldInfo

Inherits MemberInfo

A class storing the reflected field

Methods

GetValue

Gets the value of the field

Returns: object

Parameter	Type	Description	Default value
cl	The type of the class the field was reflected from or None	An instance of the class if the field is private; None, instance or the type of the class if the field is static

SetValue

Sets the value of the field

Parameter	Type	Description	Default value
cl	The type of the class the field was reflected from or None	An instance of the class if the field is private; None, instance or the type of the class if the field is static
value	object	Sets the value of the field in the type to value

Variables

Variable	Type	Description
Name	str	The name of the field

MethodInfo

Inherits MemberInfo

A class storing the reflected method

Methods

Invoke

Runs the method and returns its result (or None if it doesn't have a result)

Returns: object

Parameter	Type	Description	Default value
cl	The type of the class the method was reflected from or None	An instance of the class if the method is private; None, instance or the type of the class if the field is static
arr	List of object	The parameters to call the method with (see example below)

InvokeAsync

Asyncronous

Awaits the method and returns its result (or None if it doesn't have a result)

Returns object

Parameter	Type	Description	Default value
cl	The type of the class the method was reflected from or None	An instance of the class if the method is private; None, instance or the type of the class if the field is static
arr	List of object	The parameters to call the method with (see example below)

GetParameters

Gets the parameters of the reflected method.

Returns: List of ParameterInfo

Parameter	Type	Description	Default value
enableSelf	bool	If it's true, the self parameter will be returned too (if present)	False

Variables

Variable	Type	Description
Name	str	The name of the method
ReturnType	type	The type of the returned value
IsStatic	bool	True if the method is static, otherwise false
IsAsync	bool	True if the method is asyncronous, otherwise false

ParameterInfo

A class storing the informations of a parameter

Printing it will write the type of the parameter.

Variables

Variable	Type	Description
Name	str	The name of the parameter
ParameterType	type	The type of the parameter
Position	int	The position of the parameter when calling the method (going from 0)
Default	object	The default value of the parameter (None if it doesn't have)
HasDefault / Optional	bool	True if the parameter has a default value, false if it doesn't

Functions

GetField

Gets a specified field of the type

Returns: FieldInfo if the field is present or forceEmpty is true, otherwise None

Parameter	Type	Description	Default value
name	str	The name of the field to get
forceEmpty	bool	See description below	False

forceEmpty

Python doesn't store the private fields (self.var) before the class gets initialized.

If forceEmpty is false, using type.GetField(str) on a private filed will return None. But if it's true, it will still return a FieldInfo based on the name, but when you try to get the value of it and the field doesn't exist in the given class, it will raise an ArgumentError.

You can alternatively use GetField(class, str) to with a pre-initialized class to get the private field.

GetFields

Gets all the fields of the type.

Returns: List of FieldInfo

This function has no parameters.

Again, this only returns static variables of the specified type. If you want to get all the private ones too, use GetFields(class) with a pre-initialized class

GetMethod

Gets the specified method of the type

Returns: MethodInfo if the method is present, otherwise None

Parameter	Type	Description	Default value
name	str	The name of the method to get

GetMethods

Gets all the methods of the type-

Returns: List of MethodInfo

This function has no parameters.

Examples

Getting a static field's value

Example 1.

from ReflectionHelper import *

class Ex:
    f = 0

Field = Ex.GetField("f")
print(Field.GetValue(None))
#Output: 0

Example 2.

from ReflectionHelper import *

class Ex:
    f = 0

Inst = Ex()
Field = type(Inst).GetField("f")
print(Field.GetValue(None))
#Output: 0

Getting a private field's value

Example 1.

from ReflectionHelper import *

class Ex:
    def __init__(self, val):
        self.f = val

Field = Ex.GetField("f", True)
Inst = Ex("Yay")
print(Field.GetValue(Inst))
#Output: Yay

Example 2.

from ReflectionHelper import *

class Ex:
    def __init__(self, val):
        self.f = val

Inst = Ex("Yay")
Field = GetField(Inst, "f")
print(Field.GetValue(Inst))
#Output: Yay

Multiple instances

from ReflectionHelper import *

class Ex:
    def __init__(self, val):
        self.f = val

Inst1 = Ex("First")
Inst2 = Ex("Second")
Field = Ex.GetField("f", True)
print(Field.GetValue(Inst1), Field.GetValue(Inst2))
#Output: First Second

Setting a field's value

from ReflectionHelper import *

class Ex:
    def __init__(self, val):
        self.f = val

Inst = Ex("Before")
Field = Ex.GetField("f", True)
print(Field.GetValue(Inst))
Field.SetValue(Inst, "After")
print(Field.GetValue(Inst))
#Output:
#Before
#After

Invoking method

from ReflectionHelper import *

class Ex:
    def M(p1, p2):
        print(f"First parameter: {p1}; Second parameter: {p2}")

Method = Ex.GetMethod("M")
Method.Invoke(None, ["H", "I"])
#Output: First parameter: H; Second parameter: I

Invoking async method

from ReflectionHelper import *
import asyncio

class Ex:
    def __init__(self, seconds):
        self.s = seconds

    async def M(self, returnVal):
        await asyncio.sleep(self.s)
        return returnVal

Method = Ex.GetMethod("M")
Inst = Ex(5)
print(asyncio.run(Method.InvokeAsync(Inst, ["Returned"])))
#Output after waiting 5 seconds: Returned

Get parameters of method

from ReflectionHelper import *

class Ex:
    def M(p1: int, p2: bool, p3, p4 = "Def") -> list:
        return [p1, p2, p3, p4]

Parameters = Ex.GetMethod("M").GetParameters()
for parameter in Parameters:
    print(f'Parameter data: name is {parameter.Name}, type is {parameter.ParameterType}, position in method is {parameter.Position}, default value is {parameter.Default}')

#Output
#Parameter data: name is p1, type is <class 'int'>, position in method is 0, default value is None
#Parameter data: name is p2, type is <class 'bool'>, position in method is 1, default value is None
#Parameter data: name is p3, type is None, position in method is 2, default value is None
#Parameter data: name is p4, type is None, position in method is 3, default value is Def