From 3deb2022b889e950b82f739a52083651b2292e34 Mon Sep 17 00:00:00 2001
From: tamsin johnson <tomjohnson@ucsb.edu>
Date: Thu, 25 Jan 2024 15:06:28 -0800
Subject: [PATCH] lets-go:5.4

---
 snippetbox/cmd/web/handlers.go  | 35 ++------------------------------
 snippetbox/cmd/web/helpers.go   | 23 +++++++++++++++++++++
 snippetbox/cmd/web/main.go      |  9 +++++++++
 snippetbox/cmd/web/templates.go | 36 +++++++++++++++++++++++++++++++++
 4 files changed, 70 insertions(+), 33 deletions(-)

diff --git a/snippetbox/cmd/web/handlers.go b/snippetbox/cmd/web/handlers.go
index 94dcf53..5c77f5e 100644
--- a/snippetbox/cmd/web/handlers.go
+++ b/snippetbox/cmd/web/handlers.go
@@ -3,7 +3,6 @@ package main
 import (
 	"errors"
 	"fmt"
-	"html/template"
 	"net/http"
 	"strconv"
 
@@ -23,26 +22,11 @@ func (app *application) home(w http.ResponseWriter, r *http.Request)  {
 		return
 	}
 
-	files := []string{
-		"./ui/html/base.tmpl",
-		"./ui/html/partials/nav.tmpl",
-		"./ui/html/pages/home.tmpl",
-	}
-
-	ts, err := template.ParseFiles(files...)
-	if err != nil {
-		app.serverError(w, r, err)
-		return
-	}
-
 	data := templateData{
 		Snippets: snippets,
 	}
 
-	err = ts.ExecuteTemplate(w, "base", data)
-	if err != nil {
-		app.serverError(w, r, err)
-	}
+	app.render(w, r, http.StatusOK, "home.tmpl", data)
 }
 
 // snippetView ...
@@ -63,26 +47,11 @@ func (app *application) snippetView(w http.ResponseWriter, r *http.Request)  {
 		return
 	}
 
-	files := []string{
-		"./ui/html/base.tmpl",
-		"./ui/html/partials/nav.tmpl",
-		"./ui/html/pages/view.tmpl",
-	}
-
-	ts, err := template.ParseFiles(files...)
-	if err != nil {
-		app.serverError(w, r, err)
-		return
-	}
-
 	data := templateData{
 		Snippet: snippet,
 	}
 
-	err = ts.ExecuteTemplate(w, "base", data)
-	if err != nil {
-		app.serverError(w, r, err)
-	}
+	app.render(w, r, http.StatusOK, "view.tmpl", data)
 }
 
 // snippetCreate ...
diff --git a/snippetbox/cmd/web/helpers.go b/snippetbox/cmd/web/helpers.go
index d7392c6..6b7e19c 100644
--- a/snippetbox/cmd/web/helpers.go
+++ b/snippetbox/cmd/web/helpers.go
@@ -1,11 +1,34 @@
 package main
 
 import (
+	"bytes"
+	"fmt"
 	"log/slog"
 	"net/http"
 	"runtime/debug"
 )
 
+// render ...
+func (app *application) render(w http.ResponseWriter, r *http.Request, status int, page string, data templateData) {
+	ts, ok := app.templateCache[page]
+	if !ok {
+		err := fmt.Errorf("the template %s does not exist", page)
+		app.serverError(w, r, err)
+		return
+	}
+
+	buf := new(bytes.Buffer)
+
+	err := ts.ExecuteTemplate(buf, "base", data)
+	if err != nil {
+		app.serverError(w, r, err)
+		return
+	}
+
+	w.WriteHeader(status)
+	buf.WriteTo(w)
+}
+
 func (app *application) serverError(w http.ResponseWriter, r *http.Request, err error) {
 	var (
 		method = r.Method
diff --git a/snippetbox/cmd/web/main.go b/snippetbox/cmd/web/main.go
index 7ccebcc..1a09036 100644
--- a/snippetbox/cmd/web/main.go
+++ b/snippetbox/cmd/web/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"database/sql"
 	"flag"
+	"html/template"
 	"log/slog"
 	"net/http"
 	"regexp"
@@ -17,6 +18,7 @@ import (
 type application struct {
 	logger *slog.Logger
 	snippets *models.SnippetModel
+	templateCache map[string]*template.Template
 }
 
 // main it's the snippetbox webapp
@@ -38,10 +40,17 @@ func main() {
 
 	defer db.Close()
 
+	templateCache, err := newTemplateCache()
+	if err != nil {
+		logger.Error(err.Error())
+		os.Exit(1)
+	}
+
 	// setup the application
 	app := &application{
 		logger: logger,
 		snippets: &models.SnippetModel{DB: db},
+		templateCache: templateCache,
 	}
 
 	logger.Info("starting server", slog.String("addr", *addr))
diff --git a/snippetbox/cmd/web/templates.go b/snippetbox/cmd/web/templates.go
index 61e5975..79e5d76 100644
--- a/snippetbox/cmd/web/templates.go
+++ b/snippetbox/cmd/web/templates.go
@@ -1,6 +1,9 @@
 package main
 
 import (
+	"html/template"
+	"path/filepath"
+
 	"snippetbox.chaosfem.tw/internal/models"
 )
 
@@ -8,3 +11,36 @@ type templateData struct {
 	Snippet models.Snippet
 	Snippets []models.Snippet
 }
+
+// newTemplateCache ...
+func newTemplateCache() (map[string]*template.Template, error) {
+	cache := map[string]*template.Template{}
+
+	pages, err := filepath.Glob("./ui/html/pages/*.tmpl")
+	if err != nil {
+		return nil, err
+	}
+
+	for _, page := range pages {
+		name := filepath.Base(page)
+
+		ts, err := template.ParseFiles("./ui/html/base.tmpl")
+		if err != nil {
+			return nil, err
+		}
+
+		ts, err = ts.ParseGlob("./ui/html/partials/*.tmpl")
+		if err != nil {
+			return nil, err
+		}
+
+		ts, err = ts.ParseFiles(page)
+		if err != nil {
+			return nil, err
+		}
+
+		cache[name] = ts
+	}
+
+	return cache, nil
+}