From a9c161e94093b73e09b24c874b03435d9bda3957 Mon Sep 17 00:00:00 2001
From: Aaron L <aaron@bettercoder.net>
Date: Mon, 30 Apr 2018 18:21:56 -0700
Subject: [PATCH] Add module list middleware

---
 html_data.go   |  4 ++++
 module.go      | 35 ++++++++++++++++++++++++++++++++++-
 module_test.go | 31 +++++++++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/html_data.go b/html_data.go
index 9dc47c4..7a33f49 100644
--- a/html_data.go
+++ b/html_data.go
@@ -9,6 +9,10 @@ const (
 	DataValidation = "errors"
 	// DataPreserve preserves fields
 	DataPreserve = "preserve"
+	// DataModules contains a map[string]Moduler of which modules are loaded
+	// the Init() method should NEVER be called in a template. This structure
+	// is only returned to avoid allocations.
+	DataModules = "modules"
 )
 
 // HTMLData is used to render templates with.
diff --git a/module.go b/module.go
index b142d2b..ac3980c 100644
--- a/module.go
+++ b/module.go
@@ -1,6 +1,10 @@
 package authboss
 
-import "reflect"
+import (
+	"context"
+	"net/http"
+	"reflect"
+)
 
 var registeredModules = make(map[string]Moduler)
 
@@ -80,3 +84,32 @@ func (a *Authboss) loadModule(name string) error {
 	a.loadedModules[name] = mod
 	return mod.Init(a)
 }
+
+// ModuleListMiddleware puts a map in the data that can be used
+// to provide the renderer with information about which pieces of the
+// views to show.
+// Data looks like:
+// map[modulename] = Moduler
+//
+// The Moduler interface type should be ignored, and the key being present
+// or not is the only important point. Copying this data structure ignores
+// allocations.
+func ModuleListMiddleware(ab *Authboss) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			var data HTMLData
+
+			ctx := r.Context()
+			dataIntf := ctx.Value(CTXKeyData)
+			if dataIntf != nil {
+				data = dataIntf.(HTMLData)
+			} else {
+				data = HTMLData{}
+			}
+
+			data[DataModules] = ab.loadedModules
+			r = r.WithContext(context.WithValue(ctx, CTXKeyData, data))
+			next.ServeHTTP(w, r)
+		})
+	}
+}
diff --git a/module_test.go b/module_test.go
index 430d1c8..a83f0a0 100644
--- a/module_test.go
+++ b/module_test.go
@@ -2,6 +2,7 @@ package authboss
 
 import (
 	"net/http"
+	"net/http/httptest"
 	"testing"
 )
 
@@ -68,3 +69,33 @@ func TestIsLoaded(t *testing.T) {
 		t.Error("Loaded modules wrong:", loaded)
 	}
 }
+
+func TestModuleLoadedMiddleware(t *testing.T) {
+	t.Parallel()
+
+	ab := New()
+
+	ab.loadedModules = map[string]Moduler{
+		"recover": nil,
+		"auth":    nil,
+	}
+
+	var mods map[string]Moduler
+	server := ModuleListMiddleware(ab)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		data := r.Context().Value(CTXKeyData).(HTMLData)
+		mods = data[DataModules].(map[string]Moduler)
+	}))
+
+	server.ServeHTTP(nil, httptest.NewRequest("GET", "/", nil))
+
+	if len(mods) != 2 {
+		t.Error("want two modules, got:", len(mods))
+	}
+
+	if _, ok := mods["auth"]; !ok {
+		t.Error("auth should be loaded")
+	}
+	if _, ok := mods["recover"]; !ok {
+		t.Error("auth should be loaded")
+	}
+}