1 files changed, 73 insertions, 0 deletions
diff --git a/vendor/github.com/gorilla/handlers/canonical.go b/vendor/github.com/gorilla/handlers/canonical.go
new file mode 100644
index 0000000..7121f53
--- /dev/null
+++ b/vendor/github.com/gorilla/handlers/canonical.go
@@ -0,0 +1,73 @@
+package handlers
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+type canonical struct {
+	h      http.Handler
+	domain string
+	code   int
+}
+
+// CanonicalHost is HTTP middleware that re-directs requests to the canonical
+// domain. It accepts a domain and a status code (e.g. 301 or 302) and
+// re-directs clients to this domain. The existing request path is maintained.
+//
+// Note: If the provided domain is considered invalid by url.Parse or otherwise
+// returns an empty scheme or host, clients are not re-directed.
+//
+// Example:
+//
+//	r := mux.NewRouter()
+//	canonical := handlers.CanonicalHost("http://www.gorillatoolkit.org", 302)
+//	r.HandleFunc("/route", YourHandler)
+//
+//	log.Fatal(http.ListenAndServe(":7000", canonical(r)))
+func CanonicalHost(domain string, code int) func(h http.Handler) http.Handler {
+	fn := func(h http.Handler) http.Handler {
+		return canonical{h, domain, code}
+	}
+
+	return fn
+}
+
+func (c canonical) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	dest, err := url.Parse(c.domain)
+	if err != nil {
+		// Call the next handler if the provided domain fails to parse.
+		c.h.ServeHTTP(w, r)
+		return
+	}
+
+	if dest.Scheme == "" || dest.Host == "" {
+		// Call the next handler if the scheme or host are empty.
+		// Note that url.Parse won't fail on in this case.
+		c.h.ServeHTTP(w, r)
+		return
+	}
+
+	if !strings.EqualFold(cleanHost(r.Host), dest.Host) {
+		// Re-build the destination URL
+		dest := dest.Scheme + "://" + dest.Host + r.URL.Path
+		if r.URL.RawQuery != "" {
+			dest += "?" + r.URL.RawQuery
+		}
+		http.Redirect(w, r, dest, c.code)
+		return
+	}
+
+	c.h.ServeHTTP(w, r)
+}
+
+// cleanHost cleans invalid Host headers by stripping anything after '/' or ' '.
+// This is backported from Go 1.5 (in response to issue #11206) and attempts to
+// mitigate malformed Host headers that do not match the format in RFC7230.
+func cleanHost(in string) string {
+	if i := strings.IndexAny(in, " /"); i != -1 {
+		return in[:i]
+	}
+	return in
+}