Dynamic Proxy

Relevant source files

• src/Audit.DynamicProxy/Audit.DynamicProxy.csproj
• src/Audit.DynamicProxy/README.md
• src/Audit.EntityFramework.Core/Audit.EntityFramework.Core.csproj
• src/Audit.EntityFramework/Audit.EntityFramework.csproj
• src/Audit.Mvc/Audit.Mvc.csproj
• src/Audit.Mvc/README.md
• src/Audit.NET.MongoDB/Audit.NET.MongoDB.csproj
• src/Audit.NET.MongoDB/README.md
• src/Audit.NET.MySql/Audit.NET.MySql.csproj
• src/Audit.NET.Redis/Audit.NET.Redis.csproj
• src/Audit.NET.SqlServer/Audit.NET.SqlServer.csproj
• src/Audit.NET.SqlServer/README.md
• src/Audit.NET.Udp/Audit.NET.Udp.csproj
• src/Audit.NET/Audit.NET.csproj
• src/Audit.WCF/Audit.WCF.csproj
• src/Audit.WCF/README.md
• src/Audit.WebApi/Audit.WebApi.csproj
• src/Audit.WebApi/README.md

Purpose and Scope

This page documents Audit.DynamicProxy, a library that enables non-invasive auditing of class instances without modifying their source code. It uses Castle DynamicProxy to intercept method calls and property accesses, automatically generating audit events for operations performed on proxied instances.

For other application integration patterns, see:

• MediatR Integration for auditing CQRS commands and queries
• Azure Functions Integration for auditing serverless functions
• File System Monitoring for auditing file system changes

Key Characteristics:

• No source code modifications required
• Intercepts method calls, property accessors, and event handlers
• Supports both synchronous and asynchronous operations
• Provides detailed operation metadata including arguments and return values

Sources: src/Audit.DynamicProxy/README.md1-10

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Architecture Overview

Diagram: Dynamic Proxy Architecture

The proxy pattern creates a wrapper object that implements the same interface (or inherits from the same class) as the target, intercepting all method calls before forwarding them to the real instance.

Sources: src/Audit.DynamicProxy/README.md23-91 src/Audit.DynamicProxy/Audit.DynamicProxy.csproj1-54

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Creating Audit Proxies

The AuditProxy.Create Method

The entry point for creating auditable proxies is the static factory method:

T AuditProxy.Create<T>(T instance, InterceptionSettings settings = null)

Type Parameter T Constraints:

Proxy Type	Description	Limitations
Interface	Generates interface proxy	Only interface members are intercepted (Recommended)
Class	Generates class proxy	Only virtual members are intercepted

Sources: src/Audit.DynamicProxy/README.md74-91

Interface Proxy Example

Diagram: Interface Proxy Implementation

Usage Pattern:

The proxied instance can be used as a drop-in replacement for the real instance, with all interface method calls automatically audited.

Sources: src/Audit.DynamicProxy/README.md29-55

Class Proxy Example

For class proxies, only virtual members can be intercepted:

Sources: src/Audit.DynamicProxy/README.md84-86

Conditional Proxy Creation

Sources: src/Audit.DynamicProxy/README.md57-72

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Configuration

InterceptionSettings Class

The InterceptionSettings class provides fine-grained control over proxy behavior:

Diagram: InterceptionSettings Class Structure

Sources: src/Audit.DynamicProxy/README.md92-105

Configuration Options

Property	Type	Default	Description
EventType	string	"{class}.{method}"	Event type identifier with placeholders
IgnoreProperties	bool	false	Skip logging property getters/setters
IgnoreEvents	bool	false	Skip logging event attach/detach
MethodFilter	Func<MethodInfo, bool>	null	Fine-grained method inclusion filter
AuditDataProvider	AuditDataProvider	Global	Instance-specific data provider

EventType Placeholders:

• {class}: Replaced with class name
• {method}: Replaced with method name

Sources: src/Audit.DynamicProxy/README.md96-104

Configuration Examples

Basic Configuration:

Advanced Filtering:

Sources: src/Audit.DynamicProxy/README.md92-105

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Filtering and Exclusion

AuditIgnore Attribute

The AuditIgnore attribute provides declarative exclusion of members, arguments, or return values from audit logging:

Diagram: AuditIgnore Attribute Application

Sources: src/Audit.DynamicProxy/README.md106-134

Usage Examples

Method Exclusion:

Argument Exclusion:

Return Value Exclusion:

Sources: src/Audit.DynamicProxy/README.md109-133

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Customization and Lifecycle Hooks

Accessing the Current Audit Scope

The static property AuditProxy.CurrentScope provides access to the AuditScope associated with the currently executing proxied method:

Diagram: Current Scope Access Flow

Sources: src/Audit.DynamicProxy/README.md136-162

Thread Safety and Async Considerations

Important: AuditProxy.CurrentScope is thread-static and must be accessed from the same thread as the executing operation:

• ✅ Safe: Access before any await in async methods
• ❌ Unsafe: Access after await (continuation may run on different thread)

Example:

Sources: src/Audit.DynamicProxy/README.md136-162

Custom Fields and Comments

Sources: src/Audit.DynamicProxy/README.md143-161

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Output Structure

Event Data Model

Diagram: Output Event Object Model

Sources: src/Audit.DynamicProxy/README.md180-211

AuditInterceptEvent Fields

Field	Type	Description
ClassName	string	Name of the class containing the method
MethodName	string	Name of the audited method
IsAsync	boolean	Whether the method is async
AsyncStatus	string	Final task status: Canceled, Faulted, RanToCompletion
InstanceQualifiedName	string	Assembly-qualified type name
MethodSignature	string	Complete method signature
PropertyName	string	Property name (for property accessors)
EventName	string	Event name (for event handlers)
Arguments	array	Input and output parameter values
Success	boolean	Whether operation completed successfully
Exception	string	Exception details if thrown
Result	object	Return value of the method

Sources: src/Audit.DynamicProxy/README.md186-199

AuditInterceptArgument Fields

Field	Type	Description
Index	int	Argument index in parameter list
Name	string	Parameter name
Type	string	Parameter type name
Value	object	Input argument value
OutputValue	object	Output value for ref/out parameters

Sources: src/Audit.DynamicProxy/README.md201-211

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Output Samples

Successful Async Method Call

Sources: src/Audit.DynamicProxy/README.md215-251

Failed Async Method Call

Sources: src/Audit.DynamicProxy/README.md253-290

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Integration Patterns

Repository Pattern Integration

Diagram: Repository Pattern with Audit Proxy

Implementation:

Sources: src/Audit.DynamicProxy/README.md29-55

Dependency Injection Integration

When using dependency injection, create the proxy in the service registration:

This pattern ensures all injected instances are automatically audited without modifying consuming code.

Sources: src/Audit.WebApi/README.md504-508

Service Layer Auditing

Diagram: Multi-Layer Auditing Pattern

This pattern can be combined with other Audit.NET extensions:

• Use Web API Integration to audit controller actions
• Use Dynamic Proxy to audit service method calls
• Use Entity Framework Integration to audit data changes

Sources: src/Audit.WebApi/README.md504-508

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Package Information

NuGet Package

Package Name: Audit.DynamicProxy

Dependencies:

• Audit.NET (core library)
• Castle.Core version 5.1.1

Target Frameworks:

• .NET Framework 4.6.2
• .NET Standard 2.0
• .NET 6.0

Sources: src/Audit.DynamicProxy/Audit.DynamicProxy.csproj1-54

Installation

PM> Install-Package Audit.DynamicProxy

Sources: src/Audit.DynamicProxy/README.md14-18

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Key Implementation Classes

Class	Location	Purpose
AuditProxy	Audit.DynamicProxy	Static factory for creating proxied instances
AuditInterceptor	Audit.DynamicProxy	Implements Castle IInterceptor for method interception
InterceptionSettings	Audit.DynamicProxy	Configuration for proxy behavior
AuditInterceptEvent	Audit.DynamicProxy	Event data model for intercepted operations
AuditInterceptArgument	Audit.DynamicProxy	Represents method arguments in audit events

Sources: src/Audit.DynamicProxy/README.md1-301 src/Audit.DynamicProxy/Audit.DynamicProxy.csproj1-54