feat: publish the Sandwich Hime tutorial starter

This commit is contained in:
2026-08-11 23:59:44 -04:00
commit ddd91c7e7c
20 changed files with 790 additions and 0 deletions
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// SPDX-License-Identifier: 0BSD
// Package server owns the example application's HTTP policy and request data.
package server
import (
"bytes"
"fmt"
"net/http"
"strconv"
"strings"
"sync/atomic"
"time"
"unicode/utf8"
"gamertan.com/sandwich-hime/sando"
"gitea.speelman.ca/gamertan/sandwich-hime-tutorial/internal/views"
)
const maxVisitorRunes = 80
// New returns the complete example application using the system clock.
func New() http.Handler {
return NewWithClock(time.Now)
}
// NewWithClock returns the application with an injectable request clock.
// It is exported from this internal package so tests can make time exact.
func NewWithClock(now func() time.Time) http.Handler {
if now == nil {
now = time.Now
}
application := &application{now: now}
mux := http.NewServeMux()
mux.HandleFunc("GET /{$}", application.home)
return mux
}
type application struct {
now func() time.Time
requests atomic.Uint64
}
func (a *application) home(w http.ResponseWriter, r *http.Request) {
renderedAt := a.now().UTC()
requestNumber := a.requests.Add(1)
body := views.Home(views.HomeView{
Visitor: normalizeVisitor(r.URL.Query().Get("name")),
Trails: trailsForRequest(),
})
page := views.Layout(views.LayoutView{
Title: "A small Sandwich Hime site",
Body: body,
RenderedAtUTC: renderedAt.Format(time.RFC3339Nano),
RequestNumber: requestNumber,
})
var output bytes.Buffer
renderStarted := time.Now()
if err := sando.Render(r.Context(), &output, page); err != nil {
w.Header().Set("Cache-Control", "no-store")
http.Error(w, "could not render page", http.StatusInternalServerError)
return
}
renderDuration := time.Since(renderStarted)
w.Header().Set("Content-Type", "text/html; charset=utf-8")
w.Header().Set("Cache-Control", "no-store")
w.Header().Set("Content-Length", strconv.Itoa(output.Len()))
w.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; base-uri 'none'; form-action 'self'; frame-ancestors 'none'")
w.Header().Set("Referrer-Policy", "no-referrer")
w.Header().Set("X-Content-Type-Options", "nosniff")
w.Header().Set("Server-Timing", fmt.Sprintf(`sando;dur=%.3f;desc="buffered component render"`, float64(renderDuration)/float64(time.Millisecond)))
w.WriteHeader(http.StatusOK)
if r.Method == http.MethodHead {
return
}
_, _ = w.Write(output.Bytes())
}
func trailsForRequest() []views.Trail {
return []views.Trail{
{
Label: "Read the official tutorial",
Description: "Walk through the source one typed component at a time.",
URL: "https://sandwichhime.com/docs/tutorial/",
},
{
Label: "Study the language and safety boundary",
Description: "See where contextual escaping succeeds and where compilation deliberately stops.",
URL: "https://sandwichhime.com/docs/",
},
{
Label: "Render another visitor",
Description: "This local link sends different untrusted request data through the same compiled templates.",
URL: "/?name=friend",
},
}
}
func normalizeVisitor(value string) string {
value = strings.TrimSpace(value)
if value == "" {
return "traveler"
}
if utf8.RuneCountInString(value) <= maxVisitorRunes {
return value
}
runes := []rune(value)
return string(runes[:maxVisitorRunes])
}
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// SPDX-License-Identifier: 0BSD
package server
import (
"io"
"net/http"
"net/http/httptest"
"strconv"
"strings"
"testing"
"time"
)
func TestHomeIsDynamicEscapedAndNotCached(t *testing.T) {
base := time.Date(2026, time.August, 11, 14, 30, 0, 0, time.UTC)
clockCalls := 0
handler := NewWithClock(func() time.Time {
result := base.Add(time.Duration(clockCalls) * time.Second)
clockCalls++
return result
})
first := request(t, handler, http.MethodGet, `/?name=%3Cscript%3Ealert%281%29%3C%2Fscript%3E`)
second := request(t, handler, http.MethodGet, "/?name=friend")
if first.Code != http.StatusOK || second.Code != http.StatusOK {
t.Fatalf("unexpected statuses: first=%d second=%d", first.Code, second.Code)
}
if first.Header().Get("Cache-Control") != "no-store" {
t.Fatalf("Cache-Control = %q", first.Header().Get("Cache-Control"))
}
if timing := first.Header().Get("Server-Timing"); !strings.HasPrefix(timing, "sando;dur=") || !strings.Contains(timing, "buffered component render") {
t.Fatalf("Server-Timing = %q", timing)
}
if strings.Contains(first.Body.String(), "<script>") || !strings.Contains(first.Body.String(), "&lt;script&gt;") {
t.Fatalf("visitor was not safely escaped: %s", first.Body.String())
}
if !strings.Contains(first.Body.String(), "2026-08-11T14:30:00Z") || !strings.Contains(first.Body.String(), "#1") {
t.Fatalf("first response is missing its dynamic proof: %s", first.Body.String())
}
if !strings.Contains(second.Body.String(), "2026-08-11T14:30:01Z") || !strings.Contains(second.Body.String(), "#2") {
t.Fatalf("second response is missing fresh dynamic proof: %s", second.Body.String())
}
if first.Body.String() == second.Body.String() {
t.Fatal("separate requests produced identical bodies")
}
}
func TestHeadHasGetHeadersAndNoBody(t *testing.T) {
handler := NewWithClock(func() time.Time {
return time.Date(2026, time.August, 11, 14, 30, 0, 0, time.UTC)
})
response := request(t, handler, http.MethodHead, "/")
if response.Code != http.StatusOK {
t.Fatalf("status = %d", response.Code)
}
if response.Body.Len() != 0 {
t.Fatalf("HEAD wrote %d body bytes", response.Body.Len())
}
length, err := strconv.Atoi(response.Header().Get("Content-Length"))
if err != nil || length <= 0 {
t.Fatalf("Content-Length = %q, err = %v", response.Header().Get("Content-Length"), err)
}
if response.Header().Get("Cache-Control") != "no-store" || response.Header().Get("Server-Timing") == "" {
t.Fatalf("HEAD omitted dynamic response headers: %v", response.Header())
}
}
func TestRouterOwnsMethodAndPathPolicy(t *testing.T) {
handler := New()
if response := request(t, handler, http.MethodPost, "/"); response.Code != http.StatusMethodNotAllowed {
t.Fatalf("POST / status = %d", response.Code)
}
if response := request(t, handler, http.MethodGet, "/missing"); response.Code != http.StatusNotFound {
t.Fatalf("GET /missing status = %d", response.Code)
}
}
func request(t *testing.T, handler http.Handler, method, target string) *httptest.ResponseRecorder {
t.Helper()
recorder := httptest.NewRecorder()
handler.ServeHTTP(recorder, httptest.NewRequest(method, target, nil))
return recorder
}
func TestGetContentLengthMatchesBufferedBody(t *testing.T) {
handler := New()
response := request(t, handler, http.MethodGet, "/")
want, err := strconv.Atoi(response.Header().Get("Content-Length"))
if err != nil {
t.Fatal(err)
}
body, err := io.ReadAll(response.Result().Body)
if err != nil {
t.Fatal(err)
}
if len(body) != want {
t.Fatalf("body length = %d, Content-Length = %d", len(body), want)
}
}