65 lines
2.4 KiB
C#
65 lines
2.4 KiB
C#
using System.Threading.RateLimiting;
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using Microsoft.AspNetCore.RateLimiting;
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namespace Backend.Gateway;
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public static class GatewayServiceCollectionExtensions
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{
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public const string CorsPolicyName = "DefaultCorsPolicy";
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public static IServiceCollection AddApiGateway(
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this IServiceCollection services,
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IConfiguration configuration)
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{
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services.Configure<CorsOptions>(configuration.GetSection(CorsOptions.SectionName));
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services.Configure<RateLimitOptions>(configuration.GetSection(RateLimitOptions.SectionName));
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var corsSettings = configuration.GetSection(CorsOptions.SectionName).Get<CorsOptions>()
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?? new CorsOptions();
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var rateLimitSettings = configuration.GetSection(RateLimitOptions.SectionName).Get<RateLimitOptions>()
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?? new RateLimitOptions();
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services.AddCors(options => options.AddPolicy(CorsPolicyName, policy =>
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{
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if (corsSettings.AllowedOrigins.Length == 0)
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{
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return;
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}
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policy.WithOrigins(corsSettings.AllowedOrigins)
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.AllowAnyHeader()
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.AllowAnyMethod();
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}));
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services.AddRateLimiter(options =>
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{
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options.RejectionStatusCode = StatusCodes.Status429TooManyRequests;
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options.GlobalLimiter = CreateGlobalLimiter(rateLimitSettings);
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});
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services.Configure<RouteOptions>(options => options.LowercaseUrls = true);
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return services;
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}
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// Health checks are exempt so that infrastructure probes are never throttled.
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private static PartitionedRateLimiter<HttpContext> CreateGlobalLimiter(RateLimitOptions settings) =>
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PartitionedRateLimiter.Create<HttpContext, string>(context =>
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{
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if (context.Request.Path.StartsWithSegments(ApiRoutes.Health))
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{
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return RateLimitPartition.GetNoLimiter("health");
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}
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var partitionKey = context.Connection.RemoteIpAddress?.ToString() ?? "unknown";
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return RateLimitPartition.GetFixedWindowLimiter(partitionKey, _ => new FixedWindowRateLimiterOptions
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{
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PermitLimit = settings.PermitLimit,
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Window = TimeSpan.FromSeconds(settings.WindowSeconds),
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QueueLimit = settings.QueueLimit,
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QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
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});
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});
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}
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