fup: create serve subcommand and fuphttp package

This is the skeleton of the application. Let's goooo!

web/fup/cmd/serve.go

@@ -0,0 +1,41 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+
+	"github.com/spf13/cobra"
+	"hg.lukegb.com/lukegb/depot/web/fup/fuphttp"
+	"hg.lukegb.com/lukegb/depot/web/fup/fupstatic"
+)
+
+func init() {
+	rootCmd.AddCommand(serveCmd)
+
+	serveCmd.Flags().StringVarP(&serveBind, "listen", "l", ":8191", "Bind address for HTTP server.")
+}
+
+var (
+	serveBind string
+
+	serveCmd = &cobra.Command{
+		Use:   "serve",
+		Short: "Serve HTTP",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			ctx := context.Background()
+			cfg := &fuphttp.Config{
+				Templates:  fupstatic.Templates,
+				Static:     fupstatic.Static,
+				StaticRoot: "/static/",
+			}
+			a, err := fuphttp.New(ctx, cfg)
+			if err != nil {
+				return fmt.Errorf("constructing application: %w", err)
+			}
+			http.Handle("/", a.Handler())
+			http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.FS(fupstatic.Static))))
+			return http.ListenAndServe(serveBind, nil)
+		},
+	}
+)

web/fup/fuphttp/fuphttp.go

@@ -0,0 +1,79 @@
+package fuphttp
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"net/http"
+
+	"github.com/google/safehtml/template"
+	"github.com/google/safehtml/template/uncheckedconversions"
+	"github.com/gorilla/mux"
+)
+
+type Config struct {
+	Templates  fs.FS
+	Static     fs.FS
+	StaticRoot string
+}
+
+type Application struct {
+	indexTmpl    *template.Template
+	notFoundTmpl *template.Template
+}
+
+func (a *Application) Handler() http.Handler {
+	r := mux.NewRouter()
+
+	r.NotFoundHandler = http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		rw.WriteHeader(http.StatusNotFound)
+		a.notFoundTmpl.Execute(rw, nil)
+	})
+
+	return r
+}
+
+func parseTemplate(t *template.Template, fsys fs.FS, name string) (*template.Template, error) {
+	bs, err := fs.ReadFile(fsys, name)
+	if err != nil {
+		return nil, fmt.Errorf("reading template %q: %w", name, err)
+	}
+
+	return t.ParseFromTrustedTemplate(
+		uncheckedconversions.TrustedTemplateFromStringKnownToSatisfyTypeContract(string(bs)),
+	)
+}
+
+func loadTemplate(fsys fs.FS, name string) (*template.Template, error) {
+	t := template.New(name)
+	var err error
+	if t, err = parseTemplate(t, fsys, "base.html"); err != nil {
+		return nil, fmt.Errorf("loading base template: %w", err)
+	}
+	if t, err = parseTemplate(t, fsys, fmt.Sprintf("%s.html", name)); err != nil {
+		return nil, fmt.Errorf("loading leaf template: %w", err)
+	}
+	return t, nil
+}
+
+func New(ctx context.Context, cfg *Config) (*Application, error) {
+	a := new(Application)
+
+	tmpls := []struct {
+		t    **template.Template
+		name string
+	}{
+		{&a.indexTmpl, "index"},
+		{&a.notFoundTmpl, "404"},
+	}
+
+	for _, tmpl := range tmpls {
+		t, err := loadTemplate(cfg.Templates, tmpl.name)
+		if err != nil {
+			return nil, fmt.Errorf("loading template %q: %w", tmpl.name, err)
+		}
+		*tmpl.t = t
+	}
+
+	return a, nil
+}

web/fup/fuphttp/fuphttp_test.go

@@ -0,0 +1,35 @@
+package fuphttp_test
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"hg.lukegb.com/lukegb/depot/web/fup/fuphttp"
+	"hg.lukegb.com/lukegb/depot/web/fup/fupstatic"
+)
+
+var cfg = &fuphttp.Config{
+	Templates: fupstatic.Templates,
+}
+
+func TestNotFound(t *testing.T) {
+	ctx := context.Background()
+
+	a, err := fuphttp.New(ctx, cfg)
+	if err != nil {
+		t.Fatalf("fuphttp.New: %v", err)
+	}
+	s := httptest.NewServer(a.Handler())
+	defer s.Close()
+
+	resp, err := s.Client().Get(fmt.Sprintf("%s/not-found", s.URL))
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	if resp.StatusCode != http.StatusNotFound {
+		t.Errorf("response status was %v; want %v", resp.StatusCode, http.StatusNotFound)
+	}
+}