Switch to http.Handler

The used `func(http.ResponseWriter, *http.Request)` return values made
the HTTP handler factory functions quite unreadable. Thus it is switched
to the http.Handler type.

8 files changed, 185 insertions, 158 deletions

diff --git a/controller/recipe.go b/controller/recipe.go
index 33d4063..5e5fc3d 100644
--- a/controller/recipe.go
+++ b/controller/recipe.go
@@ -10,80 +10,86 @@ import (
 	"xengineering.eu/ceres/model"
 )
 
-func RecipeCreate(db *model.DB) func(http.ResponseWriter, *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		buf, err := io.ReadAll(r.Body)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		recipe := model.Recipe{}
-		err = json.Unmarshal(buf, &recipe)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusBadRequest)
-			return
-		}
-
-		recipe.LastChanged = fmt.Sprint(time.Now().Unix())
-		recipe.Created = recipe.LastChanged
-
-		var obj model.Object = &recipe
-		err = db.Transaction(obj.Create)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		http.Redirect(w, r, "/recipe/"+recipe.Id, http.StatusSeeOther)
-	}
+func RecipeCreate(db *model.DB) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			buf, err := io.ReadAll(r.Body)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			recipe := model.Recipe{}
+			err = json.Unmarshal(buf, &recipe)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusBadRequest)
+				return
+			}
+
+			recipe.LastChanged = fmt.Sprint(time.Now().Unix())
+			recipe.Created = recipe.LastChanged
+
+			var obj model.Object = &recipe
+			err = db.Transaction(obj.Create)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			http.Redirect(w, r, "/recipe/"+recipe.Id, http.StatusSeeOther)
+		},
+	)
 }
 
-func RecipeUpdate(db *model.DB) func(http.ResponseWriter, *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		buf, err := io.ReadAll(r.Body)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		recipe := model.Recipe{}
-		err = json.Unmarshal(buf, &recipe)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusBadRequest)
-			return
-		}
-
-		if recipe.Id != r.PathValue("id") {
-			http.Error(w, "IDs in URL and JSON do not match", http.StatusBadRequest)
-			return
-		}
-
-		recipe.LastChanged = fmt.Sprint(time.Now().Unix())
-
-		var obj model.Object = &recipe
-		err = db.Transaction(obj.Update)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		http.Redirect(w, r, "/recipe/"+recipe.Id, http.StatusSeeOther)
-	}
+func RecipeUpdate(db *model.DB) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			buf, err := io.ReadAll(r.Body)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			recipe := model.Recipe{}
+			err = json.Unmarshal(buf, &recipe)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusBadRequest)
+				return
+			}
+
+			if recipe.Id != r.PathValue("id") {
+				http.Error(w, "IDs in URL and JSON do not match", http.StatusBadRequest)
+				return
+			}
+
+			recipe.LastChanged = fmt.Sprint(time.Now().Unix())
+
+			var obj model.Object = &recipe
+			err = db.Transaction(obj.Update)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			http.Redirect(w, r, "/recipe/"+recipe.Id, http.StatusSeeOther)
+		},
+	)
 }
 
-func RecipeDelete(db *model.DB) func(http.ResponseWriter, *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		recipe := model.Recipe{}
-		recipe.Id = r.PathValue("id")
-
-		var obj model.Object = &recipe
-		err := db.Transaction(obj.Delete)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		http.Redirect(w, r, "/recipes", http.StatusSeeOther)
-	}
+func RecipeDelete(db *model.DB) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			recipe := model.Recipe{}
+			recipe.Id = r.PathValue("id")
+
+			var obj model.Object = &recipe
+			err := db.Transaction(obj.Delete)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			http.Redirect(w, r, "/recipes", http.StatusSeeOther)
+		},
+	)
 }
diff --git a/server.go b/server.go
index 35cd44d..3b17227 100644
--- a/server.go
+++ b/server.go
@@ -19,21 +19,24 @@ var static embed.FS
 func NewServer(addr string, db *model.DB) *Server {
 	mux := http.NewServeMux()
 
-	mux.Handle("GET /static/", http.StripPrefix("/static/", http.FileServer(http.FS(static))))
+	mux.Handle(
+		"GET /static/",
+		http.StripPrefix("/static/", http.FileServer(http.FS(static))),
+	)
 
-	mux.HandleFunc("GET /version", view.VersionRead(version))
+	mux.Handle("GET /version", view.VersionRead(version))
 
-	mux.HandleFunc("GET /recipes", view.RecipesRead(db))
+	mux.Handle("GET /recipes", view.RecipesRead(db))
 
-	mux.HandleFunc("GET /recipe/create", view.RecipeCreate)
-	mux.HandleFunc("POST /recipe", controller.RecipeCreate(db))
-	mux.HandleFunc("GET /recipe/{id}", view.RecipeRead(db))
-	mux.HandleFunc("POST /recipe/{id}", controller.RecipeUpdate(db))
-	mux.HandleFunc("DELETE /recipe/{id}", controller.RecipeDelete(db))
+	mux.Handle("GET /recipe/create", view.RecipeCreate())
+	mux.Handle("POST /recipe", controller.RecipeCreate(db))
+	mux.Handle("GET /recipe/{id}", view.RecipeRead(db))
+	mux.Handle("POST /recipe/{id}", controller.RecipeUpdate(db))
+	mux.Handle("DELETE /recipe/{id}", controller.RecipeDelete(db))
 
-	mux.HandleFunc("GET /favicon.ico", view.FaviconRead)
+	mux.Handle("GET /favicon.ico", view.FaviconRead())
 
-	mux.HandleFunc("GET /", view.IndexRead)
+	mux.Handle("GET /", view.IndexRead())
 
 	var srv http.Server
 	srv.Addr = addr
diff --git a/view/favicon.go b/view/favicon.go
index 8e3ea79..67d7051 100644
--- a/view/favicon.go
+++ b/view/favicon.go
@@ -4,6 +4,10 @@ import (
 	"net/http"
 )
 
-func FaviconRead(w http.ResponseWriter, r *http.Request) {
-	w.WriteHeader(http.StatusNoContent)
+func FaviconRead() http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusNoContent)
+		},
+	)
 }
diff --git a/view/index.go b/view/index.go
index 7d12783..46389d5 100644
--- a/view/index.go
+++ b/view/index.go
@@ -4,6 +4,10 @@ import (
 	"net/http"
 )
 
-func IndexRead(w http.ResponseWriter, r *http.Request) {
-	http.Redirect(w, r, "/recipes", http.StatusSeeOther)
+func IndexRead() http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			http.Redirect(w, r, "/recipes", http.StatusSeeOther)
+		},
+	)
 }
diff --git a/view/index_test.go b/view/index_test.go
index 3ab35d5..68167f6 100644
--- a/view/index_test.go
+++ b/view/index_test.go
@@ -14,7 +14,7 @@ func TestIndexRead(t *testing.T) {
 
 	rec := httptest.NewRecorder()
 
-	handler := http.HandlerFunc(IndexRead)
+	handler := IndexRead()
 	handler.ServeHTTP(rec, req)
 
 	if rec.Code != http.StatusSeeOther {
diff --git a/view/recipe.go b/view/recipe.go
index c18c078..889f6ec 100644
--- a/view/recipe.go
+++ b/view/recipe.go
@@ -6,58 +6,64 @@ import (
 	"xengineering.eu/ceres/model"
 )
 
-func RecipeRead(db *model.DB) func(http.ResponseWriter, *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		recipe := model.Recipe{}
-		recipe.Id = r.PathValue("id")
-
-		var obj model.Object = &recipe
-		err := db.Transaction(obj.Read)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		template := "recipe"
-		view, ok := r.URL.Query()["view"]
-		if ok {
-			if len(view) > 1 {
-				http.Error(w, "More than one 'view' parameter given in URL", http.StatusBadRequest)
+func RecipeRead(db *model.DB) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			recipe := model.Recipe{}
+			recipe.Id = r.PathValue("id")
+
+			var obj model.Object = &recipe
+			err := db.Transaction(obj.Read)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			template := "recipe"
+			view, ok := r.URL.Query()["view"]
+			if ok {
+				if len(view) > 1 {
+					http.Error(w, "More than one 'view' parameter given in URL", http.StatusBadRequest)
+					return
+				}
+				template = view[0]
+			}
+
+			is_valid := false
+			valid_templates := []string{
+				"recipe",
+				"recipe-edit",
+				"recipe-confirm-deletion",
+			}
+			for _, v := range valid_templates {
+				if template == v {
+					is_valid = true
+				}
+			}
+			if !is_valid {
+				http.Error(w, "Unsupported view: "+template, http.StatusBadRequest)
 				return
 			}
-			template = view[0]
-		}
-
-		is_valid := false
-		valid_templates := []string{
-			"recipe",
-			"recipe-edit",
-			"recipe-confirm-deletion",
-		}
-		for _, v := range valid_templates {
-			if template == v {
-				is_valid = true
+
+			err = html.ExecuteTemplate(w, template, recipe)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
 			}
-		}
-		if !is_valid {
-			http.Error(w, "Unsupported view: "+template, http.StatusBadRequest)
-			return
-		}
-
-		err = html.ExecuteTemplate(w, template, recipe)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-	}
+		},
+	)
 }
 
-func RecipeCreate(w http.ResponseWriter, r *http.Request) {
-	recipe := model.Recipe{}
+func RecipeCreate() http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			recipe := model.Recipe{}
 
-	err := html.ExecuteTemplate(w, "recipe-edit", recipe)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
+			err := html.ExecuteTemplate(w, "recipe-edit", recipe)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+		},
+	)
 }
diff --git a/view/recipes.go b/view/recipes.go
index e7153cd..8cd107e 100644
--- a/view/recipes.go
+++ b/view/recipes.go
@@ -6,21 +6,23 @@ import (
 	"xengineering.eu/ceres/model"
 )
 
-func RecipesRead(db *model.DB) func(http.ResponseWriter, *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		recipes := make(model.Recipes, 0)
+func RecipesRead(db *model.DB) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			recipes := make(model.Recipes, 0)
 
-		var obj model.Object = &recipes
-		err := db.Transaction(obj.Read)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
+			var obj model.Object = &recipes
+			err := db.Transaction(obj.Read)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
 
-		err = html.ExecuteTemplate(w, "recipes", recipes)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-	}
+			err = html.ExecuteTemplate(w, "recipes", recipes)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+		},
+	)
 }
diff --git a/view/version.go b/view/version.go
index faf91b1..337200e 100644
--- a/view/version.go
+++ b/view/version.go
@@ -5,13 +5,15 @@ import (
 	"net/http"
 )
 
-func VersionRead(version string) func(http.ResponseWriter, *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		if version == "" {
-			http.Error(w, "This build has no version information", http.StatusNotFound)
-			return
-		}
+func VersionRead(version string) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			if version == "" {
+				http.Error(w, "This build has no version information", http.StatusNotFound)
+				return
+			}
 
-		fmt.Fprintln(w, version)
-	}
+			fmt.Fprintln(w, version)
+		},
+	)
 }