From 454787b52d031523975220ed3f7e3619b3c75164 Mon Sep 17 00:00:00 2001
From: Eduard Urbach <e.urbach@gmail.com>
Date: Thu, 9 Nov 2017 08:45:51 +0100
Subject: [PATCH] Deterministic output

---
 layout/layout.go   | 24 +++++++++++++++++++++++-
 layout/layout.pixy | 16 ++++++++--------
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/layout/layout.go b/layout/layout.go
index 384528a8..2d38d112 100644
--- a/layout/layout.go
+++ b/layout/layout.go
@@ -1,6 +1,8 @@
 package layout
 
 import (
+	"sort"
+
 	"github.com/aerogo/aero"
 	"github.com/animenotifier/arn"
 	"github.com/animenotifier/notify.moe/components"
@@ -11,5 +13,25 @@ import (
 func Render(ctx *aero.Context, content string) string {
 	user := utils.GetUser(ctx)
 	openGraph, _ := ctx.Data.(*arn.OpenGraph)
-	return components.Layout(ctx.App, ctx, user, openGraph, content)
+
+	// Make output order deterministic to profit from Aero caching.
+	// To do this, we need to create slices and sort the tags.
+	var meta []string
+	var tags []string
+
+	if openGraph != nil {
+		for name := range openGraph.Meta {
+			meta = append(meta, name)
+		}
+
+		sort.Strings(meta)
+
+		for name := range openGraph.Tags {
+			tags = append(tags, name)
+		}
+
+		sort.Strings(tags)
+	}
+
+	return components.Layout(ctx.App, ctx, user, openGraph, meta, tags, content)
 }
diff --git a/layout/layout.pixy b/layout/layout.pixy
index d63fa6d9..808a79a8 100644
--- a/layout/layout.pixy
+++ b/layout/layout.pixy
@@ -1,4 +1,4 @@
-component Layout(app *aero.Application, ctx *aero.Context, user *arn.User, openGraph *arn.OpenGraph, content string)
+component Layout(app *aero.Application, ctx *aero.Context, user *arn.User, openGraph *arn.OpenGraph, meta, tags []string, content string)
 	html(lang="en")
 		head
 			if openGraph != nil
@@ -8,14 +8,14 @@ component Layout(app *aero.Application, ctx *aero.Context, user *arn.User, openG
 
 			meta(name="viewport", content="width=device-width, minimum-scale=1.0, initial-scale=1.0, user-scalable=yes")
 			meta(name="theme-color", content=app.Config.Manifest.ThemeColor)
-			
+
 			if openGraph != nil
-				for name, value := range openGraph.Meta
-					meta(name=name, content=value)
-				
-				for property, content := range openGraph.Tags
-					meta(property=property, content=content)
-			
+				for _, name := range meta
+					meta(name=name, content=openGraph.Meta[name])
+
+				for _, name := range tags
+					meta(property=name, content=openGraph.Tags[name])
+
 			link(rel="chrome-webstore-item", href="https://chrome.google.com/webstore/detail/hajchfikckiofgilinkpifobdbiajfch")
 			link(rel="manifest", href="/manifest.json")
 		body