initiall commit

apps/backend/internal/middleware/compression.go

@@ -0,0 +1,51 @@
+package middleware
+
+import (
+	"compress/gzip"
+	"io"
+	"strings"
+	"sync"
+
+	"github.com/gin-gonic/gin"
+)
+
+var gzipPool = sync.Pool{
+	New: func() any {
+		w, _ := gzip.NewWriterLevel(io.Discard, gzip.DefaultCompression)
+		return w
+	},
+}
+
+type gzipWriter struct {
+	gin.ResponseWriter
+	writer *gzip.Writer
+}
+
+func (g *gzipWriter) Write(data []byte) (int, error) {
+	return g.writer.Write(data)
+}
+
+func Compression() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if !strings.Contains(c.Request.Header.Get("Accept-Encoding"), "gzip") {
+			c.Next()
+			return
+		}
+
+		// Skip compression for small responses or streaming
+		if c.Request.Method == "HEAD" || c.Request.URL.Path == "/api/v1/health/liveness" {
+			c.Next()
+			return
+		}
+
+		gz := gzipPool.Get().(*gzip.Writer)
+		defer gzipPool.Put(gz)
+		gz.Reset(c.Writer)
+		defer gz.Close()
+
+		c.Header("Content-Encoding", "gzip")
+		c.Header("Vary", "Accept-Encoding")
+		c.Writer = &gzipWriter{ResponseWriter: c.Writer, writer: gz}
+		c.Next()
+	}
+}