finish redirect middlewares

example-project/internal/mid/redirect.go

@@ -0,0 +1,198 @@
+package mid
+
+import (
+	"context"
+	"geeks-accelerator/oss/saas-starter-kit/example-project/internal/platform/web"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+	"net/http"
+)
+
+type (
+	// Skipper defines a function to skip middleware. Returning true skips processing
+	// the middleware.
+	Skipper func(ctx context.Context, w http.ResponseWriter, r *http.Request, params map[string]string) bool
+
+	// RedirectConfig defines the config for Redirect middleware.
+	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
+	}
+
+	// DomainNameRedirectConfig defines the details needed to apply redirects based on domain names.
+	DomainNameRedirectConfig struct {
+		RedirectConfig
+		DomainName       	string
+		HTTPSEnabled bool
+	}
+
+	// redirectLogic represents a function that given a scheme, host and uri
+	// can both: 1) determine if redirect is needed (will set ok accordingly) and
+	// 2) return the appropriate redirect url.
+	redirectLogic func(scheme, host, uri string) (ok bool, url string)
+)
+
+const www = "www."
+
+// DefaultRedirectConfig is the default Redirect middleware config.
+var DefaultRedirectConfig = RedirectConfig{
+	Skipper: DefaultSkipper,
+	Code:    http.StatusMovedPermanently,
+}
+
+// DefaultSkipper returns false which processes the middleware.
+func DefaultSkipper(ctx context.Context, w http.ResponseWriter, r *http.Request, params map[string]string) bool {
+	return false
+}
+
+// HTTPSRedirectWithConfig returns an HTTPSRedirect middleware with config.
+// See `HTTPSRedirect()`.
+func DomainNameRedirect(config DomainNameRedirectConfig) web.Middleware  {
+	return redirect(config.RedirectConfig, func(scheme, host, uri string) (ok bool, url string) {
+
+		// Redirects http requests to https.
+		if config.HTTPSEnabled {
+			if ok = scheme != "https"; ok {
+				url = "https://" + host + uri
+
+				scheme = "https"
+			}
+		}
+
+		// Redirects all domain name alternatives to the primary hostname.
+		if host != config.DomainName {
+			host = config.DomainName
+		}
+
+
+		url = scheme + "://" + host + uri
+
+		return
+	})
+}
+
+
+// HTTPSRedirect redirects http requests to https.
+// For example, http://geeksinthewoods.com will be redirect to https://geeksinthewoods.com.
+func HTTPSRedirect() web.Middleware {
+	return HTTPSRedirectWithConfig(DefaultRedirectConfig)
+}
+
+// HTTPSRedirectWithConfig returns an HTTPSRedirect middleware with config.
+// See `HTTPSRedirect()`.
+func HTTPSRedirectWithConfig(config RedirectConfig)web.Middleware  {
+	return redirect(config, func(scheme, host, uri string) (ok bool, url string) {
+		if ok = scheme != "https"; ok {
+			url = "https://" + host + uri
+		}
+		return
+	})
+}
+
+// HTTPSWWWRedirect redirects http requests to https www.
+// For example, http://geeksinthewoods.com will be redirect to https://www.geeksinthewoods.com.
+func HTTPSWWWRedirect() web.Middleware {
+	return HTTPSWWWRedirectWithConfig(DefaultRedirectConfig)
+}
+
+// HTTPSWWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
+// See `HTTPSWWWRedirect()`.
+func HTTPSWWWRedirectWithConfig(config RedirectConfig) web.Middleware  {
+	return redirect(config, func(scheme, host, uri string) (ok bool, url string) {
+		if ok = scheme != "https" && host[:3] != www; ok {
+			url = "https://www." + host + uri
+		}
+		return
+	})
+}
+
+// HTTPSNonWWWRedirect redirects http requests to https non www.
+// For example, http://www.geeksinthewoods.com will be redirect to https://geeksinthewoods.com.
+func HTTPSNonWWWRedirect() web.Middleware {
+	return HTTPSNonWWWRedirectWithConfig(DefaultRedirectConfig)
+}
+
+// HTTPSNonWWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
+// See `HTTPSNonWWWRedirect()`.
+func HTTPSNonWWWRedirectWithConfig(config RedirectConfig) web.Middleware  {
+	return redirect(config, func(scheme, host, uri string) (ok bool, url string) {
+		if ok = scheme != "https"; ok {
+			if host[:3] == www {
+				host = host[4:]
+			}
+			url = "https://" + host + uri
+		}
+		return
+	})
+}
+
+// WWWRedirect redirects non www requests to www.
+// For example, http://geeksinthewoods.com will be redirect to http://www.geeksinthewoods.com.
+func WWWRedirect() web.Middleware {
+	return WWWRedirectWithConfig(DefaultRedirectConfig)
+}
+
+// WWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
+// See `WWWRedirect()`.
+func WWWRedirectWithConfig(config RedirectConfig) web.Middleware {
+	return redirect(config, func(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.
+// For example, http://www.geeksinthewoods.com will be redirect to http://geeksinthewoods.com.
+func NonWWWRedirect() web.Middleware {
+	return NonWWWRedirectWithConfig(DefaultRedirectConfig)
+}
+
+// NonWWWRedirectWithConfig returns an HTTPSRedirect middleware with config.
+// See `NonWWWRedirect()`.
+func NonWWWRedirectWithConfig(config RedirectConfig)  web.Middleware {
+	return redirect(config, func(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) web.Middleware {
+	if config.Skipper == nil {
+		config.Skipper = DefaultSkipper
+	}
+	if config.Code == 0 {
+		config.Code = DefaultRedirectConfig.Code
+	}
+
+	// This is the actual middleware function to be executed.
+	f := func(after web.Handler) web.Handler {
+
+		h := func(ctx context.Context, w http.ResponseWriter, r *http.Request, params map[string]string) error {
+			span, ctx := tracer.StartSpanFromContext(ctx, "internal.mid.redirect")
+			defer span.Finish()
+
+			if config.Skipper(ctx, w, r, params) {
+				return after(ctx, w, r, params)
+			}
+
+			scheme := web.RequestScheme(r)
+			if ok, url := cb(scheme, r.Host, r.RequestURI); ok {
+				http.Redirect(w, r, url, config.Code)
+				return nil
+			}
+
+			return after(ctx, w, r, params)
+		}
+
+		return h
+	}
+
+	return f
+}