Applied a little DRY to the redirect middleware (#1053)

Author: alexaandru

middleware/redirect.go

@@ -6,29 +6,28 @@ import (
 	"github.com/labstack/echo"
 )
 
-type (
-	// RedirectConfig defines the config for Redirect middleware.
-	RedirectConfig struct {
-		// Skipper defines a function to skip middleware.
-		Skipper Skipper
-
-		// Status code to be used when redirecting the request.
-		// Optional. Default value http.StatusMovedPermanently.
-		Code int `yaml:"code"`
-	}
-)
+// RedirectConfig defines the config for Redirect middleware.
+type RedirectConfig struct {
+	// Skipper defines a function to skip middleware.
+	Skipper
+
+	// Status code to be used when redirecting the request.
+	// Optional. Default value http.StatusMovedPermanently.
+	Code int `yaml:"code"`
+}
 
-const (
-	www = "www"
-)
+// redirectLogic represents a function that given a tls flag, host and uri
+// can both: 1) determine if redirect is needed (will set ok accordingly) and
+// 2) return the appropriate redirect url.
+type redirectLogic func(tls bool, scheme, host, uri string) (ok bool, url string)
 
-var (
-	// DefaultRedirectConfig is the default Redirect middleware config.
-	DefaultRedirectConfig = RedirectConfig{
-		Skipper: DefaultSkipper,
-		Code:    http.StatusMovedPermanently,
-	}
-)
+const www = "www"
+
+// DefaultRedirectConfig is the default Redirect middleware config.
+var DefaultRedirectConfig = RedirectConfig{
+	Skipper: DefaultSkipper,
+	Code:    http.StatusMovedPermanently,
+}
 
 // HTTPSRedirect redirects http requests to https.
 // For example, http://labstack.com will be redirect to https://labstack.com.
@@ -41,29 +40,12 @@ func HTTPSRedirect() echo.MiddlewareFunc {
 // HTTPSRedirectWithConfig returns an HTTPSRedirect middleware with config.
 // See `HTTPSRedirect()`.
 func HTTPSRedirectWithConfig(config RedirectConfig) echo.MiddlewareFunc {
-	// Defaults
-	if config.Skipper == nil {
-		config.Skipper = DefaultTrailingSlashConfig.Skipper
-	}
-	if config.Code == 0 {
-		config.Code = DefaultRedirectConfig.Code
-	}
-
-	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
-			if config.Skipper(c) {
-				return next(c)
-			}
-
-			req := c.Request()
-			host := req.Host
-			uri := req.RequestURI
-			if !c.IsTLS() {
-				return c.Redirect(config.Code, "https://"+host+uri)
-			}
-			return next(c)
+	return redirect(config, func(isTLS bool, _, host, uri string) (ok bool, url string) {
+		if ok = !isTLS; ok {
+			url = "https://" + host + uri
 		}
-	}
+		return
+	})
 }
 
 // HTTPSWWWRedirect redirects http requests to https www.
@@ -77,29 +59,12 @@ func HTTPSWWWRedirect() echo.MiddlewareFunc {
 // HTTPSWWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
 // See `HTTPSWWWRedirect()`.
 func HTTPSWWWRedirectWithConfig(config RedirectConfig) echo.MiddlewareFunc {
-	// Defaults
-	if config.Skipper == nil {
-		config.Skipper = DefaultTrailingSlashConfig.Skipper
-	}
-	if config.Code == 0 {
-		config.Code = DefaultRedirectConfig.Code
-	}
-
-	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
-			if config.Skipper(c) {
-				return next(c)
-			}
-
-			req := c.Request()
-			host := req.Host
-			uri := req.RequestURI
-			if !c.IsTLS() && host[:3] != www {
-				return c.Redirect(config.Code, "https://www."+host+uri)
-			}
-			return next(c)
+	return redirect(config, func(isTLS bool, _, host, uri string) (ok bool, url string) {
+		if ok = !isTLS && host[:3] != www; ok {
+			url = "https://www." + host + uri
 		}
-	}
+		return
+	})
 }
 
 // HTTPSNonWWWRedirect redirects http requests to https non www.
@@ -113,32 +78,15 @@ func HTTPSNonWWWRedirect() echo.MiddlewareFunc {
 // HTTPSNonWWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
 // See `HTTPSNonWWWRedirect()`.
 func HTTPSNonWWWRedirectWithConfig(config RedirectConfig) echo.MiddlewareFunc {
-	// Defaults
-	if config.Skipper == nil {
-		config.Skipper = DefaultTrailingSlashConfig.Skipper
-	}
-	if config.Code == 0 {
-		config.Code = DefaultRedirectConfig.Code
-	}
-
-	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
-			if config.Skipper(c) {
-				return next(c)
-			}
-
-			req := c.Request()
-			host := req.Host
-			uri := req.RequestURI
-			if !c.IsTLS() {
-				if host[:3] == www {
-					return c.Redirect(config.Code, "https://"+host[4:]+uri)
-				}
-				return c.Redirect(config.Code, "https://"+host+uri)
+	return redirect(config, func(isTLS bool, _, host, uri string) (ok bool, url string) {
+		if ok = !isTLS; ok {
+			if host[:3] == www {
+				host = host[4:]
 			}
-			return next(c)
+			url = "https://" + host + uri
 		}
-	}
+		return
+	})
 }
 
 // WWWRedirect redirects non www requests to www.
@@ -152,30 +100,12 @@ func WWWRedirect() echo.MiddlewareFunc {
 // WWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
 // See `WWWRedirect()`.
 func WWWRedirectWithConfig(config RedirectConfig) echo.MiddlewareFunc {
-	// Defaults
-	if config.Skipper == nil {
-		config.Skipper = DefaultTrailingSlashConfig.Skipper
-	}
-	if config.Code == 0 {
-		config.Code = DefaultRedirectConfig.Code
-	}
-
-	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
-			if config.Skipper(c) {
-				return next(c)
-			}
-
-			req := c.Request()
-			scheme := c.Scheme()
-			host := req.Host
-			if host[:3] != www {
-				uri := req.RequestURI
-				return c.Redirect(config.Code, scheme+"://www."+host+uri)
-			}
-			return next(c)
+	return redirect(config, func(_ bool, scheme, host, uri string) (ok bool, url string) {
+		if ok = host[:3] != www; ok {
+			url = scheme + "://www." + host + uri
 		}
-	}
+		return
+	})
 }
 
 // NonWWWRedirect redirects www requests to non www.
@@ -189,6 +119,15 @@ func NonWWWRedirect() echo.MiddlewareFunc {
 // NonWWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
 // See `NonWWWRedirect()`.
 func NonWWWRedirectWithConfig(config RedirectConfig) echo.MiddlewareFunc {
+	return redirect(config, func(isTLS bool, scheme, host, uri string) (ok bool, url string) {
+		if ok = host[:3] == www; ok {
+			url = scheme + "://" + host[4:] + uri
+		}
+		return
+	})
+}
+
+func redirect(config RedirectConfig, cb redirectLogic) echo.MiddlewareFunc {
 	if config.Skipper == nil {
 		config.Skipper = DefaultTrailingSlashConfig.Skipper
 	}
@@ -202,13 +141,12 @@ func NonWWWRedirectWithConfig(config RedirectConfig) echo.MiddlewareFunc {
 				return next(c)
 			}
 
-			req := c.Request()
-			scheme := c.Scheme()
+			req, scheme := c.Request(), c.Scheme()
 			host := req.Host
-			if host[:3] == www {
-				uri := req.RequestURI
-				return c.Redirect(config.Code, scheme+"://"+host[4:]+uri)
+			if ok, url := cb(c.IsTLS(), scheme, host, req.RequestURI); ok {
+				return c.Redirect(config.Code, url)
 			}
+
 			return next(c)
 		}
 	}