将代码注入所有没有自定义属性的方法和属性的最简单方法 [英] Easiest way to inject code to all methods and properties that don't have a custom attribute

问题描述

AOP 有很多问题和答案http://en.wikipedia.org/wiki/.NET_Framework" rel="nofollow">.NET 在 StackOverflow 上，经常提到 PostSharp 和其他第三方产品.所以在 .NET 和 C# 世界中似乎有相当多的 AOP 选项.但是每个都有自己的限制，在下载了有前途的 PostSharp 我在他们的文档中发现方法必须是虚拟的"才能注入代码(参见 ChrisWue 的回答和我的评论 - 我想虚拟约束一定是在其中一个竞争者身上).我没有进一步调查这个陈述的准确性，但它的分类让我回到 StackOverflow.

所以我想得到这个非常具体的问题的答案:

我想注入简单if (some-condition) Console.WriteLine"样式代码到每个方法和属性(静态、密封、内部、虚拟、非- 虚拟，无所谓)在我没有自定义注释的项目中，以便在运行时动态测试我的软件.注入的代码不应保留在发布版本中，它仅用于开发期间的动态测试(与线程相关).

最简单的方法是什么?我偶然发现了 Mono.Cecil，它看起来很理想，只是你似乎必须编写代码你想注入 IL.这不是一个大问题，很容易使用 Mono.Cecil 来获得用 C# 编写的代码的 IL 版本.但是，如果有更简单的东西，最好甚至内置到 .NET 中(我仍然使用 .NET 3.5)，我想知道.[更新:如果建议的工具不是 .NET Framework 的一部分，最好是开源的，比如 Mono.Cecil，或者免费提供]

解决方案

我能够用 Mono.Cecil 解决这个问题.我仍然对它的易学性、易用性和强大功能感到惊讶.几乎完全没有文档并没有改变这一点.

这些是我使用的 3 个文档来源:

• static-method-interception-in-net-with-c-and-monocecil
• 迁移到 0.9
• 源代码本身

第一个链接提供了一个非常温和的介绍，但由于它描述了旧版本的 Cecil - 并且在此期间发生了很大变化 - 第二个链接非常有助于将介绍翻译成 Cecil 0.9.开始后，源代码(也未记录在案)非常宝贵，并回答了我遇到的每一个问题 - 可能是关于 .NET 平台的一般问题，但我敢肯定，网上有大量有关这方面的书籍和材料.

我现在可以获取 DLL 或 EXE 文件，对其进行修改，然后将其写回磁盘.我唯一还没有做的事情是弄清楚如何保留调试信息 - 文件名、行号等.目前在写入 DLL 或 EXE 文件后会丢失.我的背景不是 .NET，所以我在这里猜测，我的猜测是我需要查看 mono.cecil.pdb 来解决这个问题.以后的某个地方 - 现在对我来说并不是那么重要.我正在创建这个 EXE 文件，运行该应用程序 - 它是一个复杂的 GUI 应用程序，经过多年的发展，包含了你期望在这样一个软件中找到的所有包袱 - 它会检查事物并记录错误我.

这是我的代码的要点:

DefaultAssemblyResolver assemblyResolver = new DefaultAssemblyResolver();//因此它不会抱怨找不到与我们要修补的 dll/exe 位于同一目录中的程序集assemblyResolver.AddSearchDirectory(assemblyDirectory);var readerParameters = new ReaderParameters { AssemblyResolver = assemblyResolver };AssemblyDefinition assembly = AssemblyDefinition.ReadAssembly(assemblyFilename, readerParameters);foreach(在 assembly.Modules 中的 var moduleDefinition){foreach(ModuleDefinitionRocks.GetAllTypes(moduleDefinition) 中的变量类型){foreach(type.Methods 中的 var 方法){if (!HasAttribute("MyCustomAttribute", method.method.CustomAttributes){ILProcessor ilProcessor = method.Body.GetILProcessor();ilProcessor.InsertBefore(method.Body.Instructions.First(), ilProcessor.Create(OpCodes.Call, threadCheckerMethod));//...private static bool HasAttribute(string attributeName, IEnumerable customAttributes){返回 GetAttributeByName(attributeName, customAttributes) != null;}私有静态 CustomAttribute GetAttributeByName(string attributeName, IEnumerable customAttributes){foreach(customAttributes 中的 var 属性)if (attribute.AttributeType.FullName == attributeName)返回属性；返回空；}

如果有人知道如何更简单地完成这项工作，我仍然对答案感兴趣，我不会将其标记为解决方案 - 除非没有更简单的解决方案出现.

There are a a lot of questions and answers around AOP in .NET here on Stack Overflow, often mentioning PostSharp and other third-party products. So there seems to be quite a range of AOP optons in the .NET and C# world. But each of those has their restrictions, and after downloading the promising PostSharp I found in their documentation that 'methods have to be virtual' in order to be able to inject code (edit: see ChrisWue's answer and my comment - the virtual constraint must have been on one of the contenders, I suppose). I haven't investigated the accuracy of this statement any further, but it's categoricality made me return back to Stack Overflow.

So I'd like to get an answer to this very specific question:

I want to inject simple "if (some-condition) Console.WriteLine" style code to every method and property (static, sealed, internal, virtual, non-virtual, doesn't matter) in my project that does not have a custom annotation, in order to dynamically test my software at run-time. This injected code should not remain in the release build, it is just meant for dynamic testing (thread-related) during development.

What's the easiest way to do this? I stumbled upon Mono.Cecil, which looks ideal, except that you seem to have to write the code that you want to inject in IL. This isn't a huge problem, it's easy to use Mono.Cecil to get an IL version of code written in C#. But nevertheless, if there was something simpler, ideally even built into .NET (I'm still on .NET 3.5), I'd like to know. [Update: If the suggested tool is not part of the .NET Framework, it would be nice if it was open-source, like Mono.Cecil, or freely available]

解决方案

I was able to solve the problem with Mono.Cecil. I am still amazed how easy to learn, easy to use, and powerful it is. The almost complete lack of documentation did not change that.

These are the 3 sources of documentation I used:

• static-method-interception-in-net-with-c-and-monocecil
• Migration to 0.9
• the source code itself

The first link provides a very gentle introduction, but as it describes an older version of Cecil - and much has changed in the meantime - the second link was very helpful in translating the introduction to Cecil 0.9. After getting started, the (also not documented) source code was invaluable and answered every question I had - expect perhaps those about the .NET platform in general, but there's tons of books and material on that somewhere online I'm sure.

I can now take a DLL or EXE file, modify it, and write it back to disk. The only thing that I haven't done yet is figuring out how to keep debugging information - file name, line number, etc. currently get lost after writing the DLL or EXE file. My background isn't .NET, so I'm guessing here, and my guess would be that I need to look at mono.cecil.pdb to fix that. Somewhere later - it's not that super important for me right now. I'm creating this EXE file, run the application - and it's a complex GUI application, grown over many years with all the baggage you would expect to find in such a piece of, ahem, software - and it checks things and logs errors for me.

Here's the gist of my code:

DefaultAssemblyResolver assemblyResolver = new DefaultAssemblyResolver();
// so it won't complain about not finding assemblies sitting in the same directory as the dll/exe we are going to patch
assemblyResolver.AddSearchDirectory(assemblyDirectory);
var readerParameters = new ReaderParameters { AssemblyResolver = assemblyResolver };

AssemblyDefinition assembly = AssemblyDefinition.ReadAssembly(assemblyFilename, readerParameters);

foreach (var moduleDefinition in assembly.Modules)
{
    foreach (var type in ModuleDefinitionRocks.GetAllTypes(moduleDefinition))
    {
        foreach (var method in type.Methods)
        {
            if (!HasAttribute("MyCustomAttribute", method.method.CustomAttributes)
            {
              ILProcessor ilProcessor = method.Body.GetILProcessor();
              ilProcessor.InsertBefore(method.Body.Instructions.First(), ilProcessor.Create(OpCodes.Call, threadCheckerMethod));
// ...

private static bool HasAttribute(string attributeName, IEnumerable<CustomAttribute> customAttributes)
{
    return GetAttributeByName(attributeName, customAttributes) != null;
}

private static CustomAttribute GetAttributeByName(string attributeName, IEnumerable<CustomAttribute> customAttributes)
{
    foreach (var attribute in customAttributes)
        if (attribute.AttributeType.FullName == attributeName)
            return attribute;
    return null;
}

If someone knows an easier way how to get this done, I'm still interested in an answer and I won't mark this as the solution - unless no easier solutions show up.

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