لقد استكشفنا طبقة الاستضافة وخادم Kestreel في الجزء 2. الآن وصلنا إلى قلب ASP.net orer: Asp.Net enter: Amsterway wail. هذا هو المكان الذي يعيش فيه منطق تطبيقك، حيث يتم معالجة الطلبات، وحيث يتم بناء الردود. فهم البرمجيات الوسيطة هو أساسي لإتقان ASP.Net conrent.
والبرمجيات الوسطى بسيطة جداً في المفهوم -- كل مكون هو دالة التي تقوم بتجهيز طلب HTTP -- حتى الآن قوية بما فيه الكفاية للتعامل مع كل شيء من التوثيق إلى معالجة الخطأ إلى خدمة الملفات. في هذا الجزء، سنستكشف كيفية عمل البرمجيات المتوسطة، وفحص المكونات المدمجة، وتعلّم إنشاء عناصرنا الخاصة.
ملاحظة: هذا جزء من سلسلة من المواد التجريبية (التي تعود إلى الماضي) وهي مزيج من AI وتحريري وتعديلي الخاص.
Amidleware هي البرمجيات التي يتم تجميعها في سلسلة تطبيقات للتعامل مع الطلبات والاستجابات. كل مكون:
فكّر فيها كسلسلة من نداءات الدالة المُعَشّرة، حيث كلّ وسطيّ يلفّ الواحد التالي:
graph LR
A[Request] --> B[Middleware 1]
B --> C[Middleware 2]
C --> D[Middleware 3]
D --> E[Endpoint]
E --> D
D --> C
C --> B
B --> F[Response]
يمكن لكل برنامج وسطي أن:
في جوهره، الواصف الوسيط هو مجرد اقتران مع هذا التوقيع:
public delegate Task RequestDelegate(HttpContext context);
ويتلقى كل برنامج من البرامج الوسيطة ما يلي:
HttpContext context - يتضمن جميع المعلومات المتعلقة بالطلب والردRequestDelegate next -المخطط التالي في خط الأنابيبدعونا نتصور كيف يتدفق الطلب من خلال البرمجيات الوسيطة:
sequenceDiagram
participant Client
participant MW1 as Middleware 1
participant MW2 as Middleware 2
participant MW3 as Middleware 3
participant Endpoint
Client->>MW1: HTTP Request
Note over MW1: Before logic
MW1->>MW2: next()
Note over MW2: Before logic
MW2->>MW3: next()
Note over MW3: Before logic
MW3->>Endpoint: next()
Note over Endpoint: Execute endpoint
Endpoint-->>MW3: Return
Note over MW3: After logic
MW3-->>MW2: Return
Note over MW2: After logic
MW2-->>MW1: Return
Note over MW1: After logic
MW1-->>Client: HTTP Response
النقاط الرئيسية:
next()next()Use()يستخدم النهج المبسط تعبيرات اللامدا:
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.Use(async (context, next) =>
{
// Before the next middleware
Console.WriteLine($"Request: {context.Request.Path}");
var startTime = DateTime.UtcNow;
// Call the next middleware
await next(context);
// After the next middleware
var elapsed = DateTime.UtcNow - startTime;
Console.WriteLine($"Response: {context.Response.StatusCode} ({elapsed.TotalMilliseconds}ms)");
});
app.MapGet("/", () => "Hello World!");
app.Run();
الناتج عند الوصول إلى /:
Request: /
Response: 200 (15.3ms)
Run()Run() إنشاء الطرفية الوسيطة التي تنهي خط الأنابيب:
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.Use(async (context, next) =>
{
Console.WriteLine("This executes");
await next(context);
});
app.Run(async context =>
{
Console.WriteLine("This is terminal - no next() to call");
await context.Response.WriteAsync("End of pipeline");
});
// This never executes because Run() terminates the pipeline
app.Use(async (context, next) =>
{
Console.WriteLine("This never executes");
await next(context);
});
app.Run();
لـ معقّد متوسط استخدام a صنف:
// Middleware class
public class RequestTimingMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<RequestTimingMiddleware> _logger;
public RequestTimingMiddleware(RequestDelegate next, ILogger<RequestTimingMiddleware> logger)
{
_next = next;
_logger = logger;
}
public async Task InvokeAsync(HttpContext context)
{
var sw = Stopwatch.StartNew();
// Store start time in HttpContext.Items for other middleware to access
context.Items["RequestStartTime"] = DateTime.UtcNow;
try
{
await _next(context);
}
finally
{
sw.Stop();
_logger.LogInformation(
"Request {Method} {Path} completed in {ElapsedMs}ms with status {StatusCode}",
context.Request.Method,
context.Request.Path,
sw.ElapsedMilliseconds,
context.Response.StatusCode
);
}
}
}
// Extension method for convenience
public static class RequestTimingMiddlewareExtensions
{
public static IApplicationBuilder UseRequestTiming(this IApplicationBuilder builder)
{
return builder.UseMiddleware<RequestTimingMiddleware>();
}
}
// Usage
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.UseRequestTiming();
app.MapGet("/", () => "Hello World!");
app.Run();
الناتج:
info: RequestTimingMiddleware[0]
Request GET / completed in 12ms with status 200
الترتيب الذي تضيف فيه مواد متوسطة إلى خط الأنابيب هو أمر حاسم. هذا هو الترتيب الموصى به:
graph TD
A[Exception Handler] --> B[HSTS]
B --> C[HTTPS Redirection]
C --> D[Static Files]
D --> E[Routing]
E --> F[CORS]
F --> G[Authentication]
G --> H[Authorization]
H --> I[Custom Middleware]
I --> J[Session]
J --> K[Response Caching]
K --> L[Response Compression]
L --> M[Endpoints]
لماذا هذا الأمر؟
دعونا نرى هذا في الرمز:
var builder = WebApplication.CreateBuilder(args);
// Add services
builder.Services.AddAuthentication();
builder.Services.AddAuthorization();
builder.Services.AddResponseCaching();
builder.Services.AddResponseCompression();
builder.Services.AddSession();
builder.Services.AddCors();
var app = builder.Build();
// 1. Exception handling (must be first)
if (app.Environment.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/error");
app.UseHsts(); // HTTP Strict Transport Security
}
// 2. HTTPS redirection
app.UseHttpsRedirection();
// 3. Static files (can short-circuit)
app.UseStaticFiles();
// 4. Routing (matches endpoints)
app.UseRouting();
// 5. CORS (after routing, before auth)
app.UseCors();
// 6. Authentication (who are you?)
app.UseAuthentication();
// 7. Authorization (what can you do?)
app.UseAuthorization();
// 8. Custom middleware
app.UseRequestTiming();
// 9. Session
app.UseSession();
// 10. Response caching
app.UseResponseCaching();
// 11. Response compression
app.UseResponseCompression();
// 12. Endpoints
app.MapGet("/", () => "Hello World!");
app.Run();
يُحْصَلُ على الاستثناءاتِ مِنْ البرمجيات الوسيطةِ اللاحقةِ ويُولّدُ ردوداً على الأخطاءِ:
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
// Global exception handler
app.UseExceptionHandler(errorApp =>
{
errorApp.Run(async context =>
{
context.Response.StatusCode = 500;
context.Response.ContentType = "application/json";
var error = context.Features.Get<IExceptionHandlerFeature>();
if (error != null)
{
var ex = error.Error;
await context.Response.WriteAsJsonAsync(new
{
error = new
{
message = ex.Message,
type = ex.GetType().Name,
stackTrace = app.Environment.IsDevelopment() ? ex.StackTrace : null
}
});
}
});
});
// This will be caught by the exception handler
app.MapGet("/error", () =>
{
throw new InvalidOperationException("Something went wrong!");
});
app.MapGet("/", () => "Hello World!");
app.Run();
الاختبار:
$ curl http://localhost:5000/error
{
"error": {
"message": "Something went wrong!",
"type": "InvalidOperationException",
"stackTrace": "..."
}
}
يعمل ثابت ملفات و قصير دوائر خط الأنابيب:
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
// Default: serves files from wwwroot/
app.UseStaticFiles();
// Serve files from additional directory
app.UseStaticFiles(new StaticFileOptions
{
FileProvider = new PhysicalFileProvider(
Path.Combine(builder.Environment.ContentRootPath, "MyStaticFiles")),
RequestPath = "/StaticFiles"
});
// Custom file type (MIME mapping)
var provider = new FileExtensionContentTypeProvider();
provider.Mappings[".myapp"] = "application/x-myapp";
app.UseStaticFiles(new StaticFileOptions
{
ContentTypeProvider = provider
});
// Enable directory browsing (development only!)
if (app.Environment.IsDevelopment())
{
app.UseDirectoryBrowser(new DirectoryBrowserOptions
{
FileProvider = new PhysicalFileProvider(
Path.Combine(builder.Environment.ContentRootPath, "wwwroot")),
RequestPath = "/browse"
});
}
app.Run();
الرسم البياني:
graph TD
A[Request: /css/site.css] --> B{Static Files Middleware}
B -->|File exists| C[Serve file]
C --> D[Return 200]
B -->|File not found| E[Call next middleware]
E --> F[Routing/Endpoints]
F --> G[Return 404]
style C stroke:#10b981,stroke-width:3px
style G stroke:#ef4444,stroke-width:3px
يوثق المستخدم على أساس الطلب:
var builder = WebApplication.CreateBuilder(args);
// Add authentication services
builder.Services.AddAuthentication("Cookies")
.AddCookie("Cookies", options =>
{
options.LoginPath = "/login";
options.LogoutPath = "/logout";
options.ExpireTimeSpan = TimeSpan.FromHours(1);
})
.AddJwtBearer("Bearer", options =>
{
options.TokenValidationParameters = new TokenValidationParameters
{
ValidateIssuer = true,
ValidateAudience = true,
ValidateLifetime = true,
ValidateIssuerSigningKey = true,
ValidIssuer = "https://myapp.com",
ValidAudience = "https://myapp.com",
IssuerSigningKey = new SymmetricSecurityKey(
Encoding.UTF8.GetBytes("your-secret-key-here"))
};
});
var app = builder.Build();
app.UseAuthentication(); // Must be before UseAuthorization()
app.MapGet("/public", () => "Anyone can access this");
app.MapGet("/protected", () => "Only authenticated users can access this")
.RequireAuthorization();
app.MapGet("/login", async (HttpContext context) =>
{
var claims = new[]
{
new Claim(ClaimTypes.Name, "testuser"),
new Claim(ClaimTypes.Email, "[email protected]")
};
var identity = new ClaimsIdentity(claims, "Cookies");
var principal = new ClaimsPrincipal(identity);
await context.SignInAsync("Cookies", principal);
return Results.Ok("Logged in");
});
app.Run();
يحدد ما إذا كان للمستعمل الموثق إذن للوصول إلى مورد ما:
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddAuthentication("Cookies")
.AddCookie("Cookies");
// Configure authorization policies
builder.Services.AddAuthorization(options =>
{
// Policy: Requires specific claim
options.AddPolicy("AdminOnly", policy =>
policy.RequireClaim("role", "admin"));
// Policy: Requires age over 18
options.AddPolicy("Adults", policy =>
policy.RequireAssertion(context =>
{
var ageClaim = context.User.FindFirst("age");
if (ageClaim != null && int.TryParse(ageClaim.Value, out var age))
{
return age >= 18;
}
return false;
}));
// Policy: Combines requirements
options.AddPolicy("AdminOrManager", policy =>
policy.RequireAssertion(context =>
context.User.HasClaim("role", "admin") ||
context.User.HasClaim("role", "manager")));
});
var app = builder.Build();
app.UseAuthentication();
app.UseAuthorization();
// No authorization required
app.MapGet("/public", () => "Public endpoint");
// Requires authentication
app.MapGet("/authenticated", () => "Authenticated endpoint")
.RequireAuthorization();
// Requires specific policy
app.MapGet("/admin", () => "Admin only endpoint")
.RequireAuthorization("AdminOnly");
// Multiple policies
app.MapGet("/restricted", () => "Adults and admins only")
.RequireAuthorization("Adults", "AdminOnly");
app.Run();
تقاسم الموارد:
var builder = WebApplication.CreateBuilder(args);
// Configure CORS policies
builder.Services.AddCors(options =>
{
// Policy 1: Allow all
options.AddPolicy("AllowAll", policy =>
{
policy.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader();
});
// Policy 2: Specific origin
options.AddPolicy("AllowSpecificOrigin", policy =>
{
policy.WithOrigins("https://example.com", "https://app.example.com")
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials(); // Important for cookies/auth
});
// Policy 3: Specific methods and headers
options.AddPolicy("RestrictedAccess", policy =>
{
policy.WithOrigins("https://partner.com")
.WithMethods("GET", "POST")
.WithHeaders("Content-Type", "Authorization")
.WithExposedHeaders("X-Custom-Header")
.SetPreflightMaxAge(TimeSpan.FromMinutes(10));
});
// Default policy
options.AddDefaultPolicy(policy =>
{
policy.WithOrigins("https://trustedsite.com")
.AllowAnyMethod()
.AllowAnyHeader();
});
});
var app = builder.Build();
app.UseRouting();
// Apply CORS globally
app.UseCors("AllowSpecificOrigin");
// Or apply per endpoint
app.MapGet("/api/data", () => new { data = "Hello" })
.RequireCors("AllowAll");
app.MapGet("/api/restricted", () => new { data = "Restricted" })
.RequireCors("RestrictedAccess");
app.Run();
سعة طلب الطيران:
sequenceDiagram
participant Browser
participant CORS as CORS Middleware
participant Endpoint
Browser->>CORS: OPTIONS /api/data<br/>(Preflight Request)
Note over Browser,CORS: Origin: https://example.com<br/>Access-Control-Request-Method: POST<br/>Access-Control-Request-Headers: Content-Type
Note over CORS: Check CORS policy
alt Policy allows
CORS-->>Browser: 204 No Content<br/>Access-Control-Allow-Origin: https://example.com<br/>Access-Control-Allow-Methods: POST<br/>Access-Control-Allow-Headers: Content-Type
Browser->>CORS: POST /api/data<br/>(Actual Request)
CORS->>Endpoint: Forward request
Endpoint-->>CORS: Response
CORS-->>Browser: Response + CORS headers
else Policy denies
CORS-->>Browser: 403 Forbidden
end
عناصر الاستجابة لتحسين الأداء:
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddResponseCaching();
var app = builder.Build();
app.UseResponseCaching();
// Cache this endpoint
app.MapGet("/cached", (HttpContext context) =>
{
context.Response.Headers.CacheControl = "public,max-age=60"; // Cache for 60 seconds
return $"Generated at {DateTime.UtcNow:HH:mm:ss}";
});
// Don't cache this
app.MapGet("/no-cache", (HttpContext context) =>
{
context.Response.Headers.CacheControl = "no-cache";
return $"Generated at {DateTime.UtcNow:HH:mm:ss}";
});
// Conditional caching
app.MapGet("/data", (HttpContext context, string? cache) =>
{
if (cache == "yes")
{
context.Response.Headers.CacheControl = "public,max-age=30";
}
return new
{
timestamp = DateTime.UtcNow,
data = "Some data"
};
});
app.Run();
الاختبار:
# First request - generates response and caches it
$ curl -i http://localhost:5000/cached
Date: Mon, 15 Jan 2024 10:30:00 GMT
Cache-Control: public,max-age=60
Generated at 10:30:00
# Second request within 60 seconds - served from cache
$ curl -i http://localhost:5000/cached
Date: Mon, 15 Jan 2024 10:30:00 GMT # Same time!
Cache-Control: public,max-age=60
Age: 15 # Cache age in seconds
Generated at 10:30:00 # Same response!
يضغط على استجابات الحد من النطاق الترددي:
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddResponseCompression(options =>
{
options.EnableForHttps = true; // Enable for HTTPS (be aware of CRIME attack)
// Providers (order matters - tried in sequence)
options.Providers.Add<BrotliCompressionProvider>();
options.Providers.Add<GzipCompressionProvider>();
// MIME types to compress
options.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(
new[] { "application/json", "text/plain", "text/css", "application/javascript" });
});
// Configure compression levels
builder.Services.Configure<BrotliCompressionProviderOptions>(options =>
{
options.Level = CompressionLevel.Fastest; // Fastest, Optimal, SmallestSize
});
builder.Services.Configure<GzipCompressionProviderOptions>(options =>
{
options.Level = CompressionLevel.Optimal;
});
var app = builder.Build();
app.UseResponseCompression();
app.MapGet("/large", () =>
{
// Generate large response
var data = string.Join("", Enumerable.Repeat("Hello World! ", 1000));
return Results.Text(data, "text/plain");
});
app.Run();
الاختبار:
# Without compression
$ curl -H "Accept-Encoding:" http://localhost:5000/large
# Response: ~13KB
# With gzip
$ curl -H "Accept-Encoding: gzip" http://localhost:5000/large
# Response: ~100 bytes (compressed)
# Header: Content-Encoding: gzip
# With brotli (better compression)
$ curl -H "Accept-Encoding: br" http://localhost:5000/large
# Response: ~60 bytes (compressed)
# Header: Content-Encoding: br
يضيف معرفا فريدا لكل طلب من طلبات التعقب:
public class RequestIdMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<RequestIdMiddleware> _logger;
public RequestIdMiddleware(RequestDelegate next, ILogger<RequestIdMiddleware> logger)
{
_next = next;
_logger = logger;
}
public async Task InvokeAsync(HttpContext context)
{
// Check if request already has an ID (from client)
var requestId = context.Request.Headers["X-Request-ID"].FirstOrDefault()
?? Guid.NewGuid().ToString();
// Add to response headers
context.Response.Headers["X-Request-ID"] = requestId;
// Store in HttpContext for other middleware/endpoints to access
context.Items["RequestId"] = requestId;
// Use scope for structured logging
using (_logger.BeginScope(new Dictionary<string, object>
{
["RequestId"] = requestId
}))
{
_logger.LogInformation("Processing request {RequestId}", requestId);
await _next(context);
_logger.LogInformation("Completed request {RequestId}", requestId);
}
}
}
مُرفق مُز
public class ApiKeyMiddleware
{
private readonly RequestDelegate _next;
private readonly IConfiguration _configuration;
private const string API_KEY_HEADER = "X-API-Key";
public ApiKeyMiddleware(RequestDelegate next, IConfiguration configuration)
{
_next = next;
_configuration = configuration;
}
public async Task InvokeAsync(HttpContext context)
{
// Skip authentication for public endpoints
if (context.Request.Path.StartsWithSegments("/public"))
{
await _next(context);
return;
}
// Check for API key in header
if (!context.Request.Headers.TryGetValue(API_KEY_HEADER, out var providedKey))
{
context.Response.StatusCode = 401;
await context.Response.WriteAsJsonAsync(new { error = "API Key is missing" });
return;
}
// Validate API key (in production, check against database)
var validApiKey = _configuration["ApiKey"];
if (providedKey != validApiKey)
{
context.Response.StatusCode = 403;
await context.Response.WriteAsJsonAsync(new { error = "Invalid API Key" });
return;
}
// Set user identity based on API key
var claims = new[] { new Claim("ApiKey", providedKey!) };
var identity = new ClaimsIdentity(claims, "ApiKey");
context.User = new ClaimsPrincipal(identity);
await _next(context);
}
}
طلبات حدود لـ عنوان:
public class RateLimitingMiddleware
{
private readonly RequestDelegate _next;
private readonly IMemoryCache _cache;
private readonly int _requestLimit;
private readonly TimeSpan _timeWindow;
public RateLimitingMiddleware(
RequestDelegate next,
IMemoryCache cache,
int requestLimit = 100,
int timeWindowSeconds = 60)
{
_next = next;
_cache = cache;
_requestLimit = requestLimit;
_timeWindow = TimeSpan.FromSeconds(timeWindowSeconds);
}
public async Task InvokeAsync(HttpContext context)
{
var clientIp = context.Connection.RemoteIpAddress?.ToString() ?? "unknown";
var cacheKey = $"RateLimit_{clientIp}";
// Get current request count
var requestCount = _cache.GetOrCreate(cacheKey, entry =>
{
entry.AbsoluteExpirationRelativeToNow = _timeWindow;
return 0;
});
if (requestCount >= _requestLimit)
{
context.Response.StatusCode = 429; // Too Many Requests
context.Response.Headers["Retry-After"] = _timeWindow.TotalSeconds.ToString();
await context.Response.WriteAsJsonAsync(new
{
error = "Rate limit exceeded",
retryAfter = _timeWindow.TotalSeconds
});
return;
}
// Increment request count
_cache.Set(cacheKey, requestCount + 1, _timeWindow);
// Add rate limit headers
context.Response.Headers["X-RateLimit-Limit"] = _requestLimit.ToString();
context.Response.Headers["X-RateLimit-Remaining"] = (_requestLimit - requestCount - 1).ToString();
context.Response.Headers["X-RateLimit-Reset"] = DateTimeOffset.UtcNow.Add(_timeWindow).ToUnixTimeSeconds().ToString();
await _next(context);
}
}
// Usage
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddMemoryCache();
var app = builder.Build();
app.UseMiddleware<RateLimitingMiddleware>(100, 60); // 100 requests per 60 seconds
app.Run();
الاختبار:
# First request - OK
$ curl -i http://localhost:5000/api/data
HTTP/1.1 200 OK
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 99
X-RateLimit-Reset: 1705318860
# After 100 requests
$ curl -i http://localhost:5000/api/data
HTTP/1.1 429 Too Many Requests
Retry-After: 60
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 0
X-RateLimit-Reset: 1705318860
{"error":"Rate limit exceeded","retryAfter":60}
بإمكانك أن تفرع خط الأنابيب بناءً على الشروط التالية:
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
// Map: Creates a branch based on path prefix
app.Map("/api", apiApp =>
{
apiApp.UseMiddleware<ApiKeyMiddleware>();
apiApp.MapGet("/data", () => new { data = "API data" });
});
// MapWhen: Creates a branch based on custom condition
app.MapWhen(
context => context.Request.Headers.ContainsKey("X-Custom-Header"),
customApp =>
{
customApp.Use(async (context, next) =>
{
context.Response.Headers["X-Custom-Response"] = "Matched!";
await next(context);
});
customApp.MapGet("/special", () => "Special endpoint");
});
// UseWhen: Rejoins the main pipeline after the branch
app.UseWhen(
context => context.Request.Path.StartsWithSegments("/admin"),
adminApp =>
{
adminApp.Use(async (context, next) =>
{
// Log admin access
Console.WriteLine("Admin area accessed");
await next(context);
});
});
app.MapGet("/", () => "Main pipeline");
app.Run();
المصوِّر المفرع:
graph TD
A[Request] --> B{Path?}
B -->|/api/*| C[API Branch]
B -->|/admin/*| D[Admin Branch UseWhen]
B -->|Other| E[Main Pipeline]
C --> F[API Key Middleware]
F --> G[API Endpoints]
G --> Z1[Response]
D --> H[Admin Logging]
H --> I[Rejoin Main Pipeline]
I --> J[Main Pipeline Continues]
J --> Z2[Response]
E --> K[Main Endpoints]
K --> Z3[Response]
وينبغي أن تكون لكل برنامج من البرامج الوسيطة مسؤولية واحدة:
// ❌ Bad: Doing too much
public class BadMiddleware
{
public async Task InvokeAsync(HttpContext context)
{
// Authentication
// Authorization
// Logging
// Rate limiting
// Response modification
// ... too much!
}
}
// ✅ Good: Single responsibility
public class AuthenticationMiddleware { /* Only authentication */ }
public class LoggingMiddleware { /* Only logging */ }
public class RateLimitingMiddleware { /* Only rate limiting */ }
public class SafeMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<SafeMiddleware> _logger;
public SafeMiddleware(RequestDelegate next, ILogger<SafeMiddleware> logger)
{
_next = next;
_logger = logger;
}
public async Task InvokeAsync(HttpContext context)
{
try
{
await _next(context);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in middleware");
// Don't swallow exceptions - let exception handler middleware handle them
throw;
}
}
}
لا تعدل الإجابة بعد أن تبدأ:
public class ResponseSafeMiddleware
{
private readonly RequestDelegate _next;
public ResponseSafeMiddleware(RequestDelegate next)
{
_next = next;
}
public async Task InvokeAsync(HttpContext context)
{
// Good: Check before modifying
if (!context.Response.HasStarted)
{
context.Response.Headers["X-Custom-Header"] = "Value";
}
await _next(context);
// Bad: Response might have already started
// context.Response.Headers["X-After-Header"] = "Value"; // This might throw!
// ✅ Good: Check first
if (!context.Response.HasStarted)
{
context.Response.Headers["X-After-Header"] = "Value";
}
}
}
public class DIAwareMiddleware
{
private readonly RequestDelegate _next;
// Singleton services injected in constructor
private readonly ILogger<DIAwareMiddleware> _logger;
public DIAwareMiddleware(RequestDelegate next, ILogger<DIAwareMiddleware> logger)
{
_next = next;
_logger = logger;
}
// Scoped/Transient services injected in InvokeAsync
public async Task InvokeAsync(HttpContext context, IMyService myService)
{
// myService is scoped to this request
var data = await myService.GetDataAsync();
await _next(context);
}
}
next()app.Use() لـ بوصة سطر لـ بوصة خط وسط و فئات لـ معقّد وسطMap() وقد عقد مؤتمراً بشأن MapWhen()Response.HasStarted أولاً - مقدمة قبلInvokeAsync()فهم البرمجيات الوسيطة يعطيك السيطرة الكاملة على كيفية معالجة الطلبات، وكل شاغل شامل - من قطع الأشجار إلى التوثيق إلى المنطق التجاري المخصص - يمكن التعامل معه ببراعة كبرمجيات متوسطة.
الاستمرار في الجزء الرابع: تحديد المسارات والنقاط النهائية لمعرفة كيفية مطابقة الطلبات مع نقاط النهاية وكيفية عمل نظام التوجيه.
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