lets-go:3.4 wrapping up chapter 3 with error and config refactors

snippetbox/cmd/web/handlers.go

@@ -3,7 +3,6 @@ package main
 import (
 	"fmt"
 	"html/template"
-	"log/slog"
 	"net/http"
 	"strconv"
 )
@@ -23,16 +22,13 @@ func (app *application) home(w http.ResponseWriter, r *http.Request)  {
 
 	ts, err := template.ParseFiles(files...)
 	if err != nil {
-		app.logger.Error(err.Error(), slog.String("method", r.Method), slog.String("uri", r.URL.RequestURI()))
+		app.serverError(w, r, err)
-		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 		return
 	}
 
 	err = ts.ExecuteTemplate(w, "base", nil)
 	if err != nil {
-		app.logger.Error(err.Error(), slog.String("method", r.Method), slog.String("uri", r.URL.RequestURI()))
+		app.serverError(w, r, err)
-		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
-		return
 	}
 }
 
@@ -40,7 +36,7 @@ func (app *application) home(w http.ResponseWriter, r *http.Request)  {
 func (app *application) snippetView(w http.ResponseWriter, r *http.Request)  {
 	id, err := strconv.Atoi(r.URL.Query().Get("id"))
 	if err != nil || id < 1 {
-		http.NotFound(w, r)
+		app.notFound(w)
 		return
 	}
 
@@ -52,7 +48,7 @@ func (app *application) snippetCreate(w http.ResponseWriter, r *http.Request)  {
 	w.Header().Set("Allow", "POST")
 
 	if r.Method != http.MethodPost {
-		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		app.clientError(w, http.StatusMethodNotAllowed)
 		return
 	}
 

snippetbox/cmd/web/helpers.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"log/slog"
+	"net/http"
+	"runtime/debug"
+)
+
+func (app *application) serverError(w http.ResponseWriter, r *http.Request, err error) {
+	var (
+		method = r.Method
+		trace  = string(debug.Stack())
+		uri    = r.URL.RequestURI()
+	)
+
+	app.logger.Error(err.Error(), slog.String("method", method), slog.String("trace", trace), slog.String("uri", uri))
+	http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+}
+
+func (app *application) clientError(w http.ResponseWriter, status int) {
+	http.Error(w, http.StatusText(status), status)
+}
+
+func (app *application) notFound(w http.ResponseWriter) {
+	app.clientError(w, http.StatusNotFound)
+}

snippetbox/cmd/web/logger.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"log/slog"
+	"os"
+)
+
+// loggerBuilder ...
+func loggerBuilder(logfmt *string, loglevel *string) *slog.Logger {
+	var logger *slog.Logger
+	var handler_options slog.HandlerOptions
+
+	switch *loglevel {
+        case "DEBUG": handler_options = slog.HandlerOptions{Level: slog.LevelDebug}
+	case "INFO": handler_options = slog.HandlerOptions{Level: slog.LevelInfo}
+	case "WARN": handler_options = slog.HandlerOptions{Level: slog.LevelWarn}
+	case "ERROR": handler_options = slog.HandlerOptions{Level: slog.LevelError}
+	}
+
+	switch *logfmt {
+	case "json": logger = slog.New(slog.NewJSONHandler(os.Stdout, &handler_options))
+	default: logger = slog.New(slog.NewTextHandler(os.Stdout, &handler_options))
+	}
+
+	return logger
+}

snippetbox/cmd/web/main.go

@@ -20,37 +20,13 @@ func main() {
 	loglevel := flag.String("loglevel", "INFO", "Log level: DEBUG, INFO, WARN, or ERROR")
 	flag.Parse()
 
-	var logger *slog.Logger
+	// setup the application
-	var handler_options slog.HandlerOptions
-
-	switch *loglevel {
-        case "DEBUG": handler_options = slog.HandlerOptions{Level: slog.LevelDebug}
-	case "INFO": handler_options = slog.HandlerOptions{Level: slog.LevelInfo}
-	case "WARN": handler_options = slog.HandlerOptions{Level: slog.LevelWarn}
-	case "ERROR": handler_options = slog.HandlerOptions{Level: slog.LevelError}
-	}
-
-	switch *logfmt {
-	case "json": logger = slog.New(slog.NewJSONHandler(os.Stdout, &handler_options))
-	default: logger = slog.New(slog.NewTextHandler(os.Stdout, &handler_options))
-	}
-
 	app := &application{
-		logger: logger,
+		logger: loggerBuilder(logfmt, loglevel),
 	}
 
-	mux := http.NewServeMux()
+	app.logger.Info("starting server", slog.String("addr", *addr))
-
+	err := http.ListenAndServe(*addr, app.routes())
-	// setup server for static files
+	app.logger.Error(err.Error())
-	fileServer := http.FileServer(http.Dir("./ui/static"))
-	mux.Handle("/static/", http.StripPrefix("/static", fileServer))
-
-	mux.HandleFunc("/", app.home)
-	mux.HandleFunc("/snippet/view", app.snippetView)
-	mux.HandleFunc("/snippet/create", app.snippetCreate)
-
-	logger.Info("starting server", slog.String("addr", *addr))
-	err := http.ListenAndServe(*addr, mux)
-	logger.Error(err.Error())
 	os.Exit(1)
 }

snippetbox/cmd/web/routes.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"net/http"
+)
+
+// routes ...
+func (app *application) routes() *http.ServeMux {
+	mux := http.NewServeMux()
+
+	// setup server for static files
+	fileServer := http.FileServer(http.Dir("./ui/static"))
+	mux.Handle("/static/", http.StripPrefix("/static", fileServer))
+
+	mux.HandleFunc("/", app.home)
+	mux.HandleFunc("/snippet/view", app.snippetView)
+	mux.HandleFunc("/snippet/create", app.snippetCreate)
+
+	return mux
+}