Ocelot與路由共存

引言

在Asp.Net Core中使用了Ocelot做網關之後，其自身的Api路由就不起作用了，尋了許久的解決方法，終於找到一個，主要是使用MapWhen判斷Ocelot的配置是否符合，是則走轉發路由，否則走自身路由，步驟如下：

1.先創建以下類

using Ocelot.Configuration.Repository;
using Ocelot.DownstreamRouteFinder.Finder;
using Ocelot.Middleware;

namespace GateWay.Extensions
{
    public static class OcelotExtensions
    {
        public static IApplicationBuilder UseOcelotWhenRouteMatch(this IApplicationBuilder app)
            => UseOcelotWhenRouteMatch(app, new OcelotPipelineConfiguration());

        public static IApplicationBuilder UseOcelotWhenRouteMatch(this IApplicationBuilder app,
            Action<OcelotPipelineConfiguration> pipelineConfigurationAction)
        {
            var pipelineConfiguration = new OcelotPipelineConfiguration();
            pipelineConfigurationAction?.Invoke(pipelineConfiguration);
            return UseOcelotWhenRouteMatch(app, pipelineConfiguration);
        }

        public static IApplicationBuilder UseOcelotWhenRouteMatch(this IApplicationBuilder app, OcelotPipelineConfiguration configuration)
        {
            app.MapWhen(context =>
            {
                // 獲取 OcelotConfiguration
                var internalConfigurationResponse =
                    context.RequestServices.GetRequiredService<IInternalConfigurationRepository>().Get();
                if (internalConfigurationResponse.IsError || internalConfigurationResponse.Data.Routes.Count == 0)
                {
                    // 如果沒有配置路由信息，不符合分支路由的條件，直接退出
                    return false;
                }

                var internalConfiguration = internalConfigurationResponse.Data;
                var downstreamRouteFinder = context.RequestServices
                    .GetRequiredService<IDownstreamRouteProviderFactory>()
                    .Get(internalConfiguration);

                // 根據請求以及上面獲取的Ocelot配置獲取下游路由
                var response = downstreamRouteFinder.Get(context.Request.Path, context.Request.QueryString.ToString(),
                    context.Request.Method, internalConfiguration, context.Request.Host.ToString());

                // 如果有匹配路由則滿足該分支路由的條件，交給 Ocelot 處理
                return !response.IsError
                       && !string.IsNullOrEmpty(response.Data?.Route?.DownstreamRoute?.FirstOrDefault()
                           ?.DownstreamScheme);
            }, appBuilder => appBuilder.UseOcelot(configuration).Wait());
            return app;
        }
    }
}

2.在Program.cs調用

app.UseOcelotWhenRouteMatch(); // 此處調用
app.UseRouting();
app.UseHttpsRedirection();
app.UseAuthentication();
app.UseAuthorization();