nguyentienlong · December 1, 2020 17:45 · Apr 7, 2019 · Apr 7, 2019
diff --git a/main.go b/main.go
@@ -35,15 +35,8 @@ func timeoutMiddleware(timeout time.Duration) func(c *gin.Context) {
 	}
 }
 
-func main() {
-	// create new gin without any middleware
-	engine := gin.New()
-
-	// add timeout middleware with 2 second duration
-	engine.Use(timeoutMiddleware(time.Second * 2))
-
-	// create a route that will last 5 seconds
-	engine.GET("/long", func(c *gin.Context) {
+func timedHandler(duration time.Duration) func(c *gin.Context) {
+	return func(c *gin.Context) {
 
 		// get the underlying request context
 		ctx := c.Request.Context()
@@ -61,7 +54,7 @@ func main() {
 		// and then send the doneChan with the status and body
 		// to finish the request by writing the response
 		go func() {
-			time.Sleep(time.Second * 5)
+			time.Sleep(duration)
 			doneChan <- responseData{
 				status: 200,
 				body:   gin.H{"hello": "world"},
@@ -82,7 +75,21 @@ func main() {
 		case res := <-doneChan:
 			c.JSON(res.status, res.body)
 		}
-	})
+	}
+}
+
+func main() {
+	// create new gin without any middleware
+	engine := gin.New()
+
+	// add timeout middleware with 2 second duration
+	engine.Use(timeoutMiddleware(time.Second * 2))
+
+	// create a handler that will last 1 seconds
+	engine.GET("/short", timedHandler(time.Second))
+
+	// create a route that will last 5 seconds
+	engine.GET("/long", timedHandler(time.Second*5))
 
 	// run the server
 	log.Fatal(engine.Run(":8080"))

diff --git a/main.go b/main.go
@@ -0,0 +1,89 @@
+package main
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+// timeout middleware wraps the request context with a timeout
+func timeoutMiddleware(timeout time.Duration) func(c *gin.Context) {
+	return func(c *gin.Context) {
+
+		// wrap the request context with a timeout
+		ctx, cancel := context.WithTimeout(c.Request.Context(), timeout)
+
+		defer func() {
+			// check if context timeout was reached
+			if ctx.Err() == context.DeadlineExceeded {
+
+				// write response and abort the request
+				c.Writer.WriteHeader(http.StatusGatewayTimeout)
+				c.Abort()
+			}
+
+			//cancel to clear resources after finished
+			cancel()
+		}()
+
+		// replace request with context wrapped request
+		c.Request = c.Request.WithContext(ctx)
+		c.Next()
+	}
+}
+
+func main() {
+	// create new gin without any middleware
+	engine := gin.New()
+
+	// add timeout middleware with 2 second duration
+	engine.Use(timeoutMiddleware(time.Second * 2))
+
+	// create a route that will last 5 seconds
+	engine.GET("/long", func(c *gin.Context) {
+
+		// get the underlying request context
+		ctx := c.Request.Context()
+
+		// create the response data type to use as a channel type
+		type responseData struct {
+			status int
+			body   map[string]interface{}
+		}
+
+		// create a done channel to tell the request it's done
+		doneChan := make(chan responseData)
+
+		// here you put the actual work needed for the request
+		// and then send the doneChan with the status and body
+		// to finish the request by writing the response
+		go func() {
+			time.Sleep(time.Second * 5)
+			doneChan <- responseData{
+				status: 200,
+				body:   gin.H{"hello": "world"},
+			}
+		}()
+
+		// non-blocking select on two channels see if the request
+		// times out or finishes
+		select {
+
+		// if the context is done it timed out or was cancelled
+		// so don't return anything
+		case <-ctx.Done():
+			return
+
+			// if the request finished then finish the request by
+			// writing the response
+		case res := <-doneChan:
+			c.JSON(res.status, res.body)
+		}
+	})
+
+	// run the server
+	log.Fatal(engine.Run(":8080"))
+}
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