feat: add HTTP migration bridges and extensible API binding

examples/compatibility/main.go

@@ -0,0 +1,75 @@
+// This example only uses local HTTP and bounded streaming; it has no database.
+package main
+
+import (
+	"io"
+	"log"
+	"net/http"
+	"strings"
+
+	omni "git.yuntuo.hk/k2safe/go-omni"
+	"git.yuntuo.hk/k2safe/go-omni/contract"
+	"git.yuntuo.hk/k2safe/go-omni/examples/compatibility/ids"
+	"git.yuntuo.hk/k2safe/go-omni/httpx"
+)
+
+type echoRequest struct {
+	ID   ids.ID `json:"id"`
+	Data any    `json:"data"`
+}
+
+func main() {
+	app := omni.New(omni.WithLogger(true))
+	defer app.Close()
+	app.Use(httpx.WrapMiddleware(func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("X-Example", "compatibility")
+			next.ServeHTTP(w, r)
+		})
+	}))
+	app.GET("/legacy", httpx.WrapHandler(http.HandlerFunc(http.NotFound)))
+	binder := contract.MustNew[echoRequest](contract.ScalarOf[ids.ID]("string|int64", "string", true))
+	app.POST("/echo", func(c *httpx.Context) error {
+		var req echoRequest
+		if err := binder.Bind(c.Request(), nil, &req); err != nil {
+			return err
+		}
+		return c.OK(req)
+	})
+	app.HandleWithBodyLimit("POST", "/upload", 10<<20, nil, func(c *httpx.Context) error {
+		reader, err := c.Request().MultipartReader()
+		if err != nil {
+			return omni.BadRequest("INVALID_MULTIPART", "multipart body required")
+		}
+		var total int64
+		for {
+			part, err := reader.NextPart()
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				return err
+			}
+			// Replace io.Discard with a streaming storage writer. Do not trust file names
+			// as filesystem paths. io.Copy never buffers the complete uploaded file.
+			n, copyErr := io.Copy(io.Discard, part)
+			closeErr := part.Close()
+			if copyErr != nil {
+				return copyErr
+			}
+			if closeErr != nil {
+				return closeErr
+			}
+			total += n
+		}
+		return c.OK(map[string]int64{"bytes": total})
+	})
+	app.GET("/download", httpx.WrapHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/octet-stream")
+		w.Header().Set("Content-Disposition", `attachment; filename="example.txt"`)
+		_, _ = io.Copy(w, strings.NewReader("A standard Handler keeps its original download response.\n"))
+	})))
+	if err := app.Run("127.0.0.1:8080"); err != nil {
+		log.Fatal(err)
+	}
+}