initialize support for versioning as requested, per route -- not finished yet

Former-commit-id: ade66610125f06a0b5ce3e90bcafe349f216a616

versioning/deprecation.go

@@ -0,0 +1,36 @@
+package versioning
+
+import (
+	"time"
+
+	"github.com/kataras/iris/context"
+)
+
+type DeprecationOptions struct {
+	WarnMessage     string
+	DeprecationDate time.Time
+	DeprecationInfo string
+}
+
+var DefaultDeprecationOptions = DeprecationOptions{
+	WarnMessage: "WARNING! You are using a deprecated version of this API.",
+}
+
+func Deprecated(handler context.Handler, options DeprecationOptions) context.Handler {
+	if options.WarnMessage == "" {
+		options.WarnMessage = DefaultDeprecationOptions.WarnMessage
+	}
+
+	return func(ctx context.Context) {
+		handler(ctx)
+		ctx.Header("X-API-Warn", options.WarnMessage)
+
+		if !options.DeprecationDate.IsZero() {
+			ctx.Header("X-API-Deprecation-Date", context.FormatTime(ctx, options.DeprecationDate))
+		}
+
+		if options.DeprecationInfo != "" {
+			ctx.Header("X-API-Deprecation-Info", options.DeprecationInfo)
+		}
+	}
+}