From 76b0d216c196d246d776d01fd1e710ddc79e586e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=2E=20Efe=20=C3=87etin?=
 <45270788+efectn@users.noreply.github.com>
Date: Mon, 13 Sep 2021 09:51:44 +0300
Subject: [PATCH] Add next support for Monitor middleware. (#1527)

---
 middleware/monitor/README.md       | 20 +++++++++++++++++++
 middleware/monitor/config.go       | 32 ++++++++++++++++++++++++++++++
 middleware/monitor/monitor.go      | 11 +++++++++-
 middleware/monitor/monitor_test.go | 17 ++++++++++++++++
 4 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 middleware/monitor/config.go

diff --git a/middleware/monitor/README.md b/middleware/monitor/README.md
index 1ac0a33e..cc551aba 100644
--- a/middleware/monitor/README.md
+++ b/middleware/monitor/README.md
@@ -30,3 +30,23 @@ func main() {
 	log.Fatal(app.Listen(":3000"))
 }
 ```
+
+## Config
+
+```go
+// Config defines the config for middleware.
+type Config struct {
+	// Next defines a function to skip this middleware when returned true.
+	//
+	// Optional. Default: nil
+	Next func(c *fiber.Ctx) bool
+}
+```
+
+## Default Config
+
+```go
+var ConfigDefault = Config{
+	Next: nil,
+}
+```
\ No newline at end of file
diff --git a/middleware/monitor/config.go b/middleware/monitor/config.go
new file mode 100644
index 00000000..584284d9
--- /dev/null
+++ b/middleware/monitor/config.go
@@ -0,0 +1,32 @@
+package monitor
+
+import "github.com/gofiber/fiber/v2"
+
+// Config defines the config for middleware.
+type Config struct {
+	// Next defines a function to skip this middleware when returned true.
+	//
+	// Optional. Default: nil
+	Next func(c *fiber.Ctx) bool
+}
+
+var ConfigDefault = Config{
+	Next: nil,
+}
+
+func configDefault(config ...Config) Config {
+	// Return default config if nothing provided
+	if len(config) < 1 {
+		return ConfigDefault
+	}
+
+	// Override default config
+	cfg := config[0]
+
+	// Set default values
+	if cfg.Next == nil {
+		cfg.Next = ConfigDefault.Next
+	}
+
+	return cfg
+}
diff --git a/middleware/monitor/monitor.go b/middleware/monitor/monitor.go
index e62d6748..727ef4e9 100644
--- a/middleware/monitor/monitor.go
+++ b/middleware/monitor/monitor.go
@@ -48,7 +48,10 @@ var (
 )
 
 // New creates a new middleware handler
-func New() fiber.Handler {
+func New(config ...Config) fiber.Handler {
+	// Set default config
+	cfg := configDefault(config...)
+
 	// Start routine to update statistics
 	once.Do(func() {
 		p, _ := process.NewProcess(int32(os.Getpid()))
@@ -66,6 +69,11 @@ func New() fiber.Handler {
 
 	// Return new handler
 	return func(c *fiber.Ctx) error {
+		// Don't execute middleware if Next returns true
+		if cfg.Next != nil && cfg.Next(c) {
+			return c.Next()
+		}
+
 		if c.Method() != fiber.MethodGet {
 			return fiber.ErrMethodNotAllowed
 		}
@@ -87,6 +95,7 @@ func New() fiber.Handler {
 	}
 }
 
+
 func updateStatistics(p *process.Process) {
 	pidCpu, _ := p.CPUPercent()
 	monitPidCpu.Store(pidCpu / 10)
diff --git a/middleware/monitor/monitor_test.go b/middleware/monitor/monitor_test.go
index e50dacdb..a49a7efc 100644
--- a/middleware/monitor/monitor_test.go
+++ b/middleware/monitor/monitor_test.go
@@ -88,3 +88,20 @@ func Benchmark_Monitor(b *testing.B) {
 		fiber.MIMEApplicationJSON,
 		string(fctx.Response.Header.Peek(fiber.HeaderContentType)))
 }
+
+// go test -run Test_Monitor_Next
+func Test_Monitor_Next(t *testing.T) {
+	t.Parallel()
+
+	app := fiber.New()
+
+	app.Use("/", New(Config{
+		Next: func(_ *fiber.Ctx) bool {
+			return true
+		},
+	}))
+
+	resp, err := app.Test(httptest.NewRequest(fiber.MethodPost, "/", nil))
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, 404, resp.StatusCode)
+}