Added request headers

Request.go

@@ -4,6 +4,7 @@ import "git.akyoto.dev/go/router"
 
 // Request is an interface for HTTP requests.
 type Request interface {
+	Header(string) string
 	Host() string
 	Method() string
 	Path() string
@@ -13,12 +14,25 @@ type Request interface {
 
 // request represents the HTTP request used in the given context.
 type request struct {
-	scheme string
-	host   string
-	method string
-	path   string
-	query  string
-	params []router.Parameter
+	scheme  string
+	host    string
+	method  string
+	path    string
+	query   string
+	headers []header
+	body    []byte
+	params  []router.Parameter
+}
+
+// Header returns the header value for the given key.
+func (req *request) Header(key string) string {
+	for _, header := range req.headers {
+		if header.Key == key {
+			return header.Value
+		}
+	}
+
+	return ""
 }
 
 // Host returns the requested host.