nnet/examples/interceptor/server.go

//go:build server || (!server && !client)

package main

import (
	"log"
	"os"
	"os/signal"
	"syscall"

	internalinterceptor "github.com/noahlann/nnet/internal/interceptor"
	"github.com/noahlann/nnet/internal/interceptor/builtin"
	"github.com/noahlann/nnet/pkg/interceptor"
	"github.com/noahlann/nnet/pkg/nnet"
	routerpkg "github.com/noahlann/nnet/pkg/router"
)

// This example demonstrates interceptor chain usage.
// Interceptors can validate, transform, or filter data before it reaches handlers.
func main() {
	cfg := &nnet.Config{
		Addr: "tcp://:8084",
		Codec: &nnet.CodecConfig{
			DefaultCodec:         "json",
			EnableProtocolEncode: false,
		},
	}

	srv, err := nnet.NewServer(cfg)
	if err != nil {
		log.Fatal("create server:", err)
	}

	// 创建拦截器链
	// 拦截器1：最小长度验证（至少5字节）
	minLenInterceptor := builtin.MinLengthInterceptor(5)

	// 拦截器2：最大长度验证（最多100字节）
	maxLenInterceptor := builtin.MaxLengthInterceptor(100)

	// 拦截器3：自定义验证拦截器（验证数据不为空且不为"forbidden"）
	customInterceptor := interceptor.HandlerFunc(func(data []byte, ctx nnet.Context, next interceptor.Chain) ([]byte, bool, error) {
		if len(data) == 0 {
			return nil, false, interceptor.New("data cannot be empty")
		}

		if string(data) == "forbidden" {
			return nil, false, interceptor.New("forbidden data")
		}

		// 记录到上下文
		ctx.Set("intercepted", true)
		ctx.Set("data_length", len(data))

		return next.Next(data, ctx)
	})

	// 使用自定义匹配器，匹配所有请求并在handler中应用拦截器
	// 路由1：验证端点（使用拦截器链）
	srv.Router().RegisterCustom(
		func(input routerpkg.MatchInput, ctx nnet.Context) bool {
			data := input.Raw
			// 匹配以"validate"开头的数据
			return len(data) >= 8 && string(data[:8]) == "validate"
		},
		func(ctx nnet.Context) error {
			rawData := ctx.Request().Raw()
			// 提取实际数据（跳过"validate"命令）
			var actualData []byte
			if len(rawData) > 8 {
				actualData = rawData[8:]
				// 跳过空格或换行
				for len(actualData) > 0 && (actualData[0] == ' ' || actualData[0] == '\n') {
					actualData = actualData[1:]
				}
			}

			// 如果没有数据，使用默认测试数据
			if len(actualData) == 0 {
				actualData = []byte("test data for validation")
			}

			// 执行拦截器链
			interceptors := []interceptor.Interceptor{
				minLenInterceptor,
				maxLenInterceptor,
				customInterceptor,
			}

			data, continueProcessing, err := internalinterceptor.Execute(actualData, ctx, interceptors...)
			if err != nil {
				return ctx.Response().Write(map[string]any{
					"error":   err.Error(),
					"valid":   false,
					"message": "validation failed",
				})
			}

			if !continueProcessing {
				return ctx.Response().Write(map[string]any{
					"error": "processing stopped",
					"valid": false,
				})
			}

			// 获取拦截器设置的值
			intercepted := ctx.GetBool("intercepted")
			dataLength := ctx.GetInt("data_length")

			return ctx.Response().Write(map[string]any{
				"valid":       true,
				"data":        string(data),
				"intercepted": intercepted,
				"data_length": dataLength,
				"message":     "validation passed",
			})
		},
	)

	// 路由2：简单的echo
	srv.Router().RegisterString("echo", func(ctx nnet.Context) error {
		data := ctx.Request().Raw()
		return ctx.Response().Write(map[string]any{
			"echo": string(data),
		})
	})

	// 路由3：测试端点（使用最小长度拦截器）
	srv.Router().RegisterString("test", func(ctx nnet.Context) error {
		rawData := ctx.Request().Raw()

		// 只使用最小长度拦截器
		data, continueProcessing, err := internalinterceptor.Execute(rawData, ctx, minLenInterceptor)
		if err != nil {
			return ctx.Response().Write(map[string]any{
				"error": err.Error(),
				"valid": false,
			})
		}

		if !continueProcessing {
			return ctx.Response().Write(map[string]any{
				"error": "processing stopped",
				"valid": false,
			})
		}

		return ctx.Response().Write(map[string]any{
			"valid": true,
			"data":  string(data),
		})
	})

	log.Println("interceptor_server listening on :8084")
	log.Println("Interceptors:")
	log.Println("  - MinLengthInterceptor (min: 5 bytes)")
	log.Println("  - MaxLengthInterceptor (max: 100 bytes)")
	log.Println("  - CustomInterceptor (rejects 'forbidden')")
	if err := srv.Start(); err != nil {
		log.Fatal("start server:", err)
	}
	defer srv.Stop()

	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit
}