SourceGenerator 使用姿势（1）：生成代理类，实现简单的AOP - ToB企服应用市场:ToB评测及商务社交产业平台

1 /// <summary>
2 /// Aop 拦截器
3 /// </summary>
4 public interface IAopInterceptor
5 {
6 /// <summary>
7 /// 执行前操作，同步方法调用
8 /// </summary>
9 /// <param name="context"></param>
10 /// <returns></returns>
11 AopContext Before(AopContext context);
12 /// <summary>
13 /// 执行前操作，异步方法调用
14 /// </summary>
15 /// <param name="context"></param>
16 /// <returns></returns>
17 ValueTask<AopContext> BeforeAsync(AopContext context);
18 /// <summary>
19 /// 执行后操作，同步方法调用
20 /// </summary>
21 /// <param name="context"></param>
22 /// <returns></returns>
23 AopContext After(AopContext context);
24 /// <summary>
25 /// 执行后操作，异步方法调用
26 /// </summary>
27 /// <param name="context"></param>
28 /// <returns></returns>
29 ValueTask<AopContext> AfterAsync(AopContext context);
30 /// <summary>
31 /// 执行方法，同步方法调用
32 /// </summary>
33 /// <param name="context"></param>
34 /// <returns></returns>
35 AopContext Next(AopContext context);
36 /// <summary>
37 /// 执行方法，异步方法调用
38 /// </summary>
39 /// <param name="context"></param>
40 /// <returns></returns>
41 ValueTask<AopContext> NextAsync(AopContext context);
42 }

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1 public class AopInterceptor : Attribute, IAopInterceptor
2 {
3 /// <summary>
4 /// 是否执行 Before
5 /// </summary>
6 public bool HasBefore { get; set; }
7 /// <summary>
8 /// 是否执行 After
9 /// </summary>
10 public bool HasAfter { get; set; }
11 /// <summary>
12 /// 是否执行 Aop 的 Next
13 /// </summary>
14 public bool HasAopNext { get; set; }
15 /// <summary>
16 /// 是否执行实际的方法
17 /// </summary>
18 public bool HasActualNext { get; set; }
19
20 /// <summary>
21 /// 默认执行所以方法
22 /// </summary>
23 public AopInterceptor()
24 {
25 HasBefore = true;
26 HasAopNext = true;
27 HasActualNext = true;
28 HasAfter = true;
29 }
30
31 public virtual AopContext Before(AopContext context) => context;
32
33 public virtual async ValueTask<AopContext> BeforeAsync(AopContext context)
34 {
35 await ValueTask.CompletedTask;
36 return context;
37 }
38
39 public virtual AopContext After(AopContext context)
40 {
41 return context.Exception != null ? throw context.Exception : context;
42 }
43
44 public virtual async ValueTask<AopContext> AfterAsync(AopContext context)
45 {
46 if (context.Exception != null)
47 throw context.Exception;
48
49 await ValueTask.CompletedTask;
50 return context;
51 }
52
53 public virtual AopContext Next(AopContext context)
54 {
55 try
56 {
57 context.Invoke();
58 }
59 catch (Exception e)
60 {
61 context.Exception = e;
62 }
63 return context;
64 }
65
66 public virtual async ValueTask<AopContext> NextAsync(AopContext context)
67 {
68 try
69 {
70 context = await context.InvokeAsync();
71 }
72 catch (Exception e)
73 {
74 context.Exception = e;
75 }
76
77 return context;
78 }
79 }

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1 /// <summary>
2 /// Aop 上下文
3 /// </summary>
4 public struct AopContext
5 {
6 /// <summary>
7 /// 是否是异步
8 /// </summary>
9 public bool IsTask { get; private set; }
10 /// <summary>
11 /// 是否有返回值
12 /// </summary>
13 public bool HasReturnValue { get; private set; }
14 /// <summary>
15 /// 方法输入参数
16 /// </summary>
17 public Dictionary<string, dynamic> MethodInputParam { get; private set; }
18
19 /// <summary>
20 /// 实际方法执行结果，可能是 Task
21 /// </summary>
22 public Func<dynamic> ActualMethod { get; set; }
23 /// <summary>
24 /// 返回值，具体的值
25 /// </summary>
26 public dynamic ReturnValue { get; set; }
27 /// <summary>
28 /// 异常信息
29 /// </summary>
30 public Exception Exception { get; set; }
31 /// <summary>
32 /// IServiceProvider
33 /// </summary>
34 public IServiceProvider ServiceProvider { get; private set; }
35
36 /// <summary>
37 /// 初始化
38 /// </summary>
39 /// <param name="serviceProvider"></param>
40 /// <param name="methodInputParam"></param>
41 /// <param name="isTask"></param>
42 /// <param name="hasReturnValue"></param>
43 /// <param name="actualMethod"></param>
44 public AopContext(IServiceProvider serviceProvider, Dictionary<string, dynamic> methodInputParam, bool isTask, bool hasReturnValue, Func<dynamic> actualMethod) : this()
45 {
46 ServiceProvider = serviceProvider;
47 MethodInputParam = methodInputParam;
48 IsTask = isTask;
49 HasReturnValue = hasReturnValue;
50 ActualMethod = actualMethod;
51 }
52
53 /// <summary>
54 /// 执行实际方法异步
55 /// </summary>
56 /// <returns></returns>
57 public async ValueTask<AopContext> InvokeAsync()
58 {
59 if (ActualMethod == null)
60 return this;
61
62 if (HasReturnValue)
63 {
64 ReturnValue = await ActualMethod();
65 return this;
66 }
67
68 await ActualMethod();
69 return this;
70 }
71
72 /// <summary>
73 /// 执行实际方法同步
74 /// </summary>
75 /// <returns></returns>
76 public void Invoke()
77 {
78 if (ActualMethod == null)
79 return;
80
81 //特殊处理同步且没有返回值，用 Task.Run 包装
82 if (!IsTask && !HasReturnValue)
83 ActualMethod.Invoke().GetAwaiter().GetResult();
84 else
85 ReturnValue = ActualMethod.Invoke();
86 }
87 }

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1 /// <summary>
2 /// 常规服务，执行所有方法
3 /// </summary>
4 public class SampleAttribute : AopInterceptor
5 {
6 /// <summary>执行前操作，同步方法调用</summary>
7 /// <param name="context"></param>
8 /// <returns></returns>
9 public override AopContext Before(AopContext context)
10 {
11 Console.WriteLine("Before...");
12 return base.Before(context);
13 }
14
15 /// <summary>执行前操作，异步方法调用</summary>
16 /// <param name="context"></param>
17 /// <returns></returns>
18 public override ValueTask<AopContext> BeforeAsync(AopContext context)
19 {
20 Console.WriteLine("BeforeAsync...");
21 return base.BeforeAsync(context);
22 }
23
24 public override AopContext After(AopContext context)
25 {
26 Console.WriteLine("After...");
27 return context;
28 }
29
30 /// <summary>执行后操作，异步方法调用</summary>
31 /// <param name="context"></param>
32 /// <returns></returns>
33 public override ValueTask<AopContext> AfterAsync(AopContext context)
34 {
35 Console.WriteLine("AfterAsync...");
36 return base.AfterAsync(context);
37 }
38
39 /// <summary>执行方法，同步方法调用</summary>
40 /// <param name="context"></param>
41 /// <returns></returns>
42 public override AopContext Next(AopContext context)
43 {
44 Console.WriteLine("Next...");
45 return base.Next(context);
46 }
47
48 /// <summary>执行方法，异步方法调用</summary>
49 /// <param name="context"></param>
50 /// <returns></returns>
51 public override ValueTask<AopContext> NextAsync(AopContext context)
52 {
53 Console.WriteLine("NextAsync...");
54 return base.NextAsync(context);
55 }
56 }

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1 public interface ITestService
2 {
3 [Sample]
4 DateTime SampleSync();
5
6 [Sample]
7 ValueTask<DateTime> SampleAsync();
8 }

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1 public class TestService : ITestService
2 {
3
4 public virtual DateTime SampleSync()
5 {
6 return DateTime.Now;
7 }
8
9 public virtual async ValueTask<DateTime> SampleAsync()
10 {
11 await ValueTask.CompletedTask;
12 return DateTime.Now;
13 }
14 }

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1 public sealed class TestService_Aop : TestService
2 {
3 private readonly IServiceProvider _serviceProvider0;
4 public TestService_Aop(IServiceProvider serviceProvider0)
5 {
6 _serviceProvider0 = serviceProvider0;
7 }
8
9 public override DateTime SampleSync()
10 {
11 var aopContext = new AopContext(_serviceProvider0,
12 new Dictionary<string, dynamic>() { },
13 false,
14 true,
15 null);
16
17 var aopInterceptor0 = _serviceProvider0.GetRequiredService<SampleAttribute>();
18 if (aopInterceptor0.HasBefore) aopContext = aopInterceptor0.Before(aopContext);
19 if (aopInterceptor0.HasAopNext)
20 {
21 if (aopInterceptor0.HasActualNext)
22 {
23 aopContext.ActualMethod = () => base.SampleSync();
24 }
25 aopContext = aopInterceptor0.Next(aopContext);
26 }
27 else
28 {
29 if (aopInterceptor0.HasActualNext)
30 {
31 aopContext.ReturnValue = base.SampleSync();
32 }
33 }
34 if (aopInterceptor0.HasAfter) aopContext = aopInterceptor0.After(aopContext);
35
36 return aopContext.ReturnValue;
37 }
38
39 public override async ValueTask<DateTime> SampleAsync()
40 {
41 var aopContext = new AopContext(_serviceProvider0,
42 new Dictionary<string, dynamic>() { },
43 true,
44 true,
45 null);
46
47 var aopInterceptor0 = _serviceProvider0.GetRequiredService<SampleAttribute>();
48 if (aopInterceptor0.HasBefore) aopContext = await aopInterceptor0.BeforeAsync(aopContext);
49 if (aopInterceptor0.HasAopNext)
50 {
51 if (aopInterceptor0.HasActualNext)
52 {
53 aopContext.ActualMethod = () => base.SampleAsync();
54 }
55 aopContext = await aopInterceptor0.NextAsync(aopContext);
56 }
57 else
58 {
59 if (aopInterceptor0.HasActualNext)
60 {
61 aopContext.ReturnValue = await base.SampleAsync();
62 }
63 }
64 if (aopInterceptor0.HasAfter) aopContext = await aopInterceptor0.AfterAsync(aopContext);
65
66 return aopContext.ReturnValue;
67 }
68 }

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<ItemGroup>
<PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.3.1" PrivateAssets="all" />
<PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
</ItemGroup>

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1 /// <summary>
2 /// 代码生成器
3 /// </summary>
4 [Generator]
5 public class AopGenerator : ISourceGenerator
6 {
7 /// <summary>
8 /// 初始化
9 /// </summary>
10 /// <param name="context"></param>
11 public void Initialize(GeneratorInitializationContext context)
12 {
13 //Debugger.Launch();
14
15 context.RegisterForSyntaxNotifications(() => new AopSyntaxReceiver());
16 }
17
18 /// <summary>
19 /// 执行
20 /// </summary>
21 /// <param name="context"></param>
22 public void Execute(GeneratorExecutionContext context)
23 {
24 if (context.SyntaxReceiver is AopSyntaxReceiver receiver)
25 {
26 var aopMateData = receiver
27 .FindAopInterceptor() // 查找所有的拦截器
28 .GetAopMetaData(context.Compilation); //根据拦截器找到所有的类或方法，获取元数据，包含所有接口、实现类、所有属性、所有方法
29
30 var builders = aopMateData
31 .GetAopCodeBuilderMetaData() //获取用于构建代码的元数据，过滤出需要的数据
32 .Select(i => new AopCodeBuilder(i))
33 .Distinct()
34 .ToList();
35 //开始生成代码
36 foreach (var builder in builders)
37 {
38 context.AddSource(builder.SourceCodeName, builder.ToSourceText());
39 }
40 }
41 }
42 }

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/// <summary>
/// 语法接收器
/// </summary>
sealed class AopSyntaxReceiver : ISyntaxReceiver
{
private const string GeneratorTagName = "AopInterceptor"; //所有拦截器需要继承的基类
private const string IgnoreAttribute = "IgnoreAopAttribute"; //忽略aop
/// <summary>
/// 类列表
/// </summary>
private readonly List<ClassDeclarationSyntax> _classSyntaxList = new List<ClassDeclarationSyntax>();
/// <summary>
/// 接口列表
/// </summary>
private readonly List<InterfaceDeclarationSyntax> _interfaceSyntaxList = new List<InterfaceDeclarationSyntax>();
/// <summary>
/// 所有的AopInterceptor
/// </summary>
public List<string> AopAttributeList = new List<string>();
/// <summary>
/// 所有的AopInterceptor
/// </summary>
public List<ClassMetaData> AopAttributeClassMetaDataList = new List<ClassMetaData>();
/// <summary>
/// 访问语法树
/// </summary>
/// <param name="syntaxNode"></param>
void ISyntaxReceiver.OnVisitSyntaxNode(SyntaxNode syntaxNode)
{
if (syntaxNode is InterfaceDeclarationSyntax interfaceSyntax)
{
this._interfaceSyntaxList.Add(interfaceSyntax);
}
if (syntaxNode is ClassDeclarationSyntax classSyntax)
{
this._classSyntaxList.Add(classSyntax);
}
}
//其他代码........
}

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1 /// <summary>
2 /// 找出所有 AopInterceptor
3 /// </summary>
4 /// <returns></returns>
5 public AopSyntaxReceiver FindAopInterceptor()
6 {
7 foreach (var classSyntax in this._classSyntaxList)
8 {
9 var root = classSyntax.SyntaxTree.GetRoot();
10 var classesWithAttribute = root
11 .DescendantNodes()
12 .OfType<ClassDeclarationSyntax>()
13 .ToList();
14
15 if (!classesWithAttribute.Any())
16 continue;
17
18 foreach (var classDeclarationSyntax in classesWithAttribute)
19 {
20 if (classDeclarationSyntax.BaseList == null)
21 continue;
22
23 foreach (BaseTypeSyntax baseTypeSyntax in classDeclarationSyntax.BaseList.Types)
24 {
25 if (baseTypeSyntax.ToString().Trim() == GeneratorTagName)
26 {
27 AopAttributeList.Add(classDeclarationSyntax.Identifier.Text);
28
29 var meta = GetClassMetaData(classSyntax);
30 if (meta != null && AopAttributeClassMetaDataList.All(d => d.Name != meta.Name))
31 AopAttributeClassMetaDataList.Add(meta);
32 }
33 }
34 }
35 }
36
37 AopAttributeList = AopAttributeList.Distinct().ToList();
38
39 return this;
40 }

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1 /// <summary>
2 /// 获取所有打了标记的接口和类
3 /// </summary>
4 /// <param name="compilation"></param>
5 /// <returns></returns>
6 public AopMetaData GetAopMetaData(Compilation compilation)
7 {
8 var result = new AopMetaData(AopAttributeList, IgnoreAttribute, new List<InterfaceMetaData>(), new List<ClassMetaData>());
9
10 if (!AopAttributeList.Any())
11 return result;
12
13 //处理接口
14 foreach (var classSyntax in this._interfaceSyntaxList)
15 {
16 var root = classSyntax.SyntaxTree.GetRoot();
17 var interfaceWithAttribute = root
18 .DescendantNodes()
19 .OfType<InterfaceDeclarationSyntax>()
20 .ToList();
21
22 if (!interfaceWithAttribute.Any())
23 continue;
24
25 //处理接口
26 foreach (var interfaceDeclaration in interfaceWithAttribute)
27 {
28 var namespaceName = interfaceDeclaration.FindParent<NamespaceDeclarationSyntax>().Name.ToString();
29 var className = interfaceDeclaration.Identifier.Text;
30 var properties = interfaceDeclaration.DescendantNodes().OfType<PropertyDeclarationSyntax>().ToList();
31 var methodSyntaxs = interfaceDeclaration.DescendantNodes().OfType<MethodDeclarationSyntax>().ToList();
32
33 //属性集合
34 var props = properties.Select(d => new PropertyMetaData(d.Identifier.Text, d.GetAttributeMetaData())).ToList();
35 //方法集合
36 var methods = methodSyntaxs.Select(GetMethodMetaData).ToList();
37
38 var interfaceMetaData = new InterfaceMetaData(namespaceName, className, interfaceDeclaration.GetAttributeMetaData(), props, methods);
39 if (interfaceMetaData.MethodMetaData.Any() && !result.InterfaceMetaDataList.Exists(d => d.Equals(interfaceMetaData)))
40 result.InterfaceMetaDataList.Add(interfaceMetaData);
41 }
42 }
43
44 //处理类
45 foreach (var classSyntax in this._classSyntaxList)
46 {
47 var root = classSyntax.SyntaxTree.GetRoot();
48 var classesWithAttribute = root
49 .DescendantNodes()
50 .OfType<ClassDeclarationSyntax>()
51 .ToList();
52
53 if (!classesWithAttribute.Any())
54 continue;
55
56 foreach (var classDeclaration in classesWithAttribute)
57 {
58 var classMetaData = GetClassMetaData(classDeclaration);
59 if (classMetaData == null)
60 continue;
61
62 if (AopAttributeList.Contains(classMetaData.Name))
63 continue;
64
65 if (classMetaData.MethodMetaData.Any() && !result.ClassMetaDataList.Exists(d => d.Equals(classMetaData)))
66 result.ClassMetaDataList.Add(classMetaData);
67 }
68 }
69
70 result.AopAttributeClassMetaDataList = AopAttributeClassMetaDataList;
71
72 return result;
73 }

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1 private ClassMetaData? GetClassMetaData(ClassDeclarationSyntax classDeclaration)
2 {
3 var namespaceName = classDeclaration.FindParent<NamespaceDeclarationSyntax>().Name.ToString();
4 var className = classDeclaration.Identifier.Text;
5 var properties = classDeclaration.DescendantNodes().OfType<PropertyDeclarationSyntax>().ToList();
6 var methodSyntaxs = classDeclaration.DescendantNodes().OfType<MethodDeclarationSyntax>().ToList();
7
8 //属性集合
9 var props = properties.Select(d => new PropertyMetaData(d.Identifier.Text, d.GetAttributeMetaData())).ToList();
10 //方法集合
11 var methods = methodSyntaxs.Select(GetMethodMetaData).ToList();
12 //实现的接口集合
13 var interfaces = classDeclaration.BaseList?.ToString().Split(':').Last().Trim().Split(',').Where(d => d.Split('.').Last().StartsWith("I")).ToList() ?? new List<string>();
14 //using 引用
15 var usingDirectiveSyntax = classDeclaration.Parent?.Parent == null ? new SyntaxList<UsingDirectiveSyntax>() : ((CompilationUnitSyntax)classDeclaration.Parent.Parent).Usings;
16 var usings = usingDirectiveSyntax.Select(d => d.ToString()).ToList();
17
18 //构造函数
19 var constructorDictionary = new List<KeyValueModel>();
20 foreach (var memberDeclarationSyntax in classDeclaration.Members)
21 {
22 if (memberDeclarationSyntax.Kind().ToString() == "ConstructorDeclaration")
23 {
24 //constructorDictionary = memberDeclarationSyntax.DescendantNodes().OfType<ParameterSyntax>().ToDictionary(d => d.GetFirstToken().Text, d => d.GetLastToken().Text);
25 constructorDictionary = memberDeclarationSyntax.DescendantNodes().OfType<ParameterSyntax>().Select(d => new KeyValueModel(d.Type?.ToString(), d.Identifier.Text)).ToList();
26 break;
27 }
28 }
29
30 return new ClassMetaData(namespaceName, className, classDeclaration.GetAttributeMetaData(), props, methods, interfaces, constructorDictionary, usings);
31 }

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1 private MethodMetaData GetMethodMetaData(MethodDeclarationSyntax methodDeclarationSyntax)
2 {
3 var param = new List<KeyValueModel>();
4 var properties = methodDeclarationSyntax.DescendantNodes().OfType<ParameterListSyntax>().FirstOrDefault()?.DescendantNodes().OfType<ParameterSyntax>().ToList() ?? new List<ParameterSyntax>();
5 foreach (var parameterSyntax in properties)
6 {
7 var type = parameterSyntax?.Type?.ToString();
8 var name = parameterSyntax?.Identifier.Text;
9 if (type != null && name != null)
10 param.Add(new KeyValueModel(type, name));
11 }
12
13 var returnValue = methodDeclarationSyntax.ReturnType.ToString();
14
15 return new MethodMetaData(methodDeclarationSyntax.Identifier.Text,
16 methodDeclarationSyntax.GetAttributeMetaData(), returnValue, param, methodDeclarationSyntax.Modifiers.ToString());
17 }

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public List<AopCodeBuilderMetaData> GetAopCodeBuilderMetaData()
{
//就近原则，方法 > 类 > 接口方法 > 接口
var list = new List<AopCodeBuilderMetaData>();
foreach (var classMetaData in ClassMetaDataList.Where(d => !AopAttributeList.Contains(d.Name)))
{
////必须要可重写方法放出错误
//if (classMetaData.MethodMetaData.All(d => !d.CanOverride))
// continue;
var methods = new List<MethodMetaData>();
var classHasIgnore = classMetaData.HasIgnore(IgnoreAttribute);
//实现的接口
classMetaData.Usings.Add(classMetaData.NameSpace);
classMetaData.InterfaceMetaData = InterfaceMetaDataList.Where(d => classMetaData.Interfaces.Contains(d.Key)
|| classMetaData.Interfaces.SelectMany(t => classMetaData.Usings.Select(u => $"{u.Replace("using ", "").Replace(";", "")}.{t.Split('.').Last()}")).Contains(d.Key)).ToList();
classMetaData.Usings.Remove(classMetaData.NameSpace);
//按照就近原则过滤
//foreach (var methodMetaData in classMetaData.MethodMetaData.Where(d => d.CanOverride))
foreach (var methodMetaData in classMetaData.MethodMetaData)
{
//忽略
if (methodMetaData.AttributeMetaData.HasIgnore(IgnoreAttribute))
continue;
//类方法标记
var methodAttrs = methodMetaData.AttributeMetaData.GetAopAttributes(AopAttributeList);
if (methodAttrs.Any())
{
methodMetaData.AttributeMetaData.Clear();
methodMetaData.AttributeMetaData.AddRange(methodAttrs);
methods.Add(methodMetaData);
continue;
}
//类标记
if (classHasIgnore)
continue;
var classAttr = classMetaData.AttributeMetaData.GetAopAttribute(AopAttributeList);
if (classAttr != null)
{
methodMetaData.AttributeMetaData.Clear();
methodMetaData.AttributeMetaData.Add(classAttr);
methods.Add(methodMetaData);
continue;
}
//接口标记
if (!classMetaData.Interfaces.Any())
continue;
//接口方法忽略
if (classMetaData.InterfaceMetaData.Any(d => d.MethodMetaData.FirstOrDefault(m => m.Key == methodMetaData.Key)?.AttributeMetaData.HasIgnore(IgnoreAttribute) == true))
continue;
//接口方法标记
var interfaceMethodAttr = classMetaData.InterfaceMetaData.Select(d => d.MethodMetaData.FirstOrDefault(m => m.Key == methodMetaData.Key)?.AttributeMetaData.GetAopAttribute(AopAttributeList))
.FirstOrDefault(d => d != null);
if (interfaceMethodAttr != null)
{
methodMetaData.AttributeMetaData.Clear();
methodMetaData.AttributeMetaData.Add(interfaceMethodAttr);
methods.Add(methodMetaData);
continue;
}
//接口标记
var interfaceAttr = classMetaData.InterfaceMetaData.Where(d => d.MethodMetaData.Any(d => d.Key == methodMetaData.Key)).Select(d => d.AttributeMetaData.GetAopAttribute(AopAttributeList))
.FirstOrDefault(d => d != null);
if (interfaceAttr != null)
{
methodMetaData.AttributeMetaData.Clear();
methodMetaData.AttributeMetaData.Add(interfaceAttr);
methods.Add(methodMetaData);
continue;
}
}
if (methods.Any())
list.Add(new AopCodeBuilderMetaData(classMetaData.NameSpace, classMetaData.Name, methods, classMetaData.Constructor, classMetaData.Usings, classMetaData.InterfaceMetaData));
}
return list;
}

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