chore(ods): rewrite the core http server handling

index.html

@@ -14,13 +14,13 @@
         <input class="fullwidth" type="text" placeholder="Entrez un mot" id="query" name="query" value="{{ .Query }}" minlength="2" maxlength="32" onfocus="this.select()" required autofocus/>
 		<div class=".btn-group">
 		  <input type="submit" value="Valider"/>
-		  {{ if .HasQuery }}
+		  {{ if ne .Query "" }}
 		  <input type="submit" formmethod="GET" value="Effacer"/>
 		  {{ end }}
 		</div>
 	  </form>
 	  <p>
-        {{ if .HasQuery }}
+        {{ if ne .Query "" }}
         <a href="https://dictionnaire.lerobert.com/definition/{{ .Query }}">{{ .Query }}</a> est un mot <span class="{{ if .Invalid }}invalid">IN{{ else }}valid">{{ end }}VALIDE</span> au scrabble.
         {{ end }}
 	  </p>

main.go

@@ -1,20 +1,23 @@
 package main
 
 import (
+	"context"
 	"embed"
+	"fmt"
+	"html/template"
+	"log/slog"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+	"time"
+	"unicode"
+
 	"golang.org/x/text/runes"
 	"golang.org/x/text/transform"
 	"golang.org/x/text/unicode/norm"
-	"html/template"
-	"log/slog"
-	"net/http"
-	"strings"
-	"unicode"
-)
-
-// Variables to customise the search
-const (
-	listenStr = "0.0.0.0:8090"
 )
 
 //go:embed ods.txt
@@ -30,16 +33,14 @@ var static embed.FS
 var indexTemplate = template.Must(template.New("index").ParseFS(templatesFS, "index.html"))
 
 type IndexData struct {
-	HasQuery bool
-	Query    string
-	Invalid  bool
+	Invalid bool
+	Query   string
 }
 
 func getIndex() http.Handler {
 	data := IndexData{
-		HasQuery: false,
-		Query:    "",
-		Invalid:  true,
+		Query:   "",
+		Invalid: true,
 	}
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Cache-Control", "no-store, no-cache")
@@ -52,9 +53,8 @@ func postIndex() http.Handler {
 	words := strings.Split(ods, "\n")
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		data := IndexData{
-			HasQuery: true,
-			Query:    r.FormValue("query"),
-			Invalid:  true,
+			Query:   r.FormValue("query"),
+			Invalid: true,
 		}
 		query, _, _ := transform.String(normalizer, strings.TrimSpace(strings.ToUpper(data.Query)))
 		for _, w := range words {
@@ -68,12 +68,72 @@ func postIndex() http.Handler {
 	})
 }
 
+func run(
+	ctx context.Context,
+	getenv func(string) string,
+) error {
+	ctx, cancel := signal.NotifyContext(ctx, os.Interrupt, syscall.SIGTERM)
+	defer cancel()
+
+	mux := http.NewServeMux()
+	mux.Handle("GET /static/", http.FileServer(http.FS(static)))
+	mux.Handle("GET /", getIndex())
+	mux.Handle("POST /", postIndex())
+
+	host := getenv("ODS_HOST")
+	if host == "" {
+		host = "127.0.0.1"
+	}
+	port := getenv("ODS_PORT")
+	if port == "" {
+		port = "8080"
+	}
+
+	httpServer := &http.Server{
+		Addr:    net.JoinHostPort(host, port),
+		Handler: mux,
+	}
+	errChan := make(chan error, 1)
+	go func() {
+		slog.Info("backend http server listening", "address", httpServer.Addr)
+		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			errChan <- fmt.Errorf("error listening and serving backend http server on %s: %w", httpServer.Addr, err)
+		}
+	}()
+
+	select {
+	case err := <-errChan:
+		return err
+	case <-ctx.Done():
+		slog.Info("backend http server shutting down")
+		shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer shutdownCancel()
+		if err := httpServer.Shutdown(shutdownCtx); err != nil {
+			return fmt.Errorf("error shutting down backend http server: %w", err)
+		}
+	}
+
+	return nil
+}
+
 func main() {
-	http.Handle("GET /static/", http.FileServer(http.FS(static)))
-	http.Handle("GET /", getIndex())
-	http.Handle("POST /", postIndex())
-	slog.Info("listening", "addr", listenStr)
-	if err := http.ListenAndServe(listenStr, nil); err != nil && err != http.ErrServerClosed {
-		slog.Error("error listening and serving", "error", err)
+	ctx := context.Background()
+
+	var opts *slog.HandlerOptions
+	if os.Getenv("ODS_DEBUG") != "" {
+		opts = &slog.HandlerOptions{
+			AddSource: true,
+			Level:     slog.LevelDebug,
+		}
+	}
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, opts))
+	slog.SetDefault(logger)
+
+	if err := run(
+		ctx,
+		os.Getenv,
+	); err != nil {
+		fmt.Fprintf(os.Stderr, "%+v\n", err)
+		os.Exit(1)
 	}
 }