feat: release v0.26 portable i18n and presentation adapters

i18n/httpi18n/http.go

@@ -0,0 +1,131 @@
+// Package httpi18n negotiates an i18n language for standard HTTP requests.
+package httpi18n
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"git.yuntuo.hk/k2safe/go-omni/i18n"
+	"golang.org/x/text/language"
+)
+
+// Resolver supplies ordered language tags, e.g. from an authenticated preference.
+// It must be safe for concurrent requests. It does not receive a mutable Bundle.
+// A panic is treated as no preference, preserving request execution.
+type Resolver func(*http.Request) []string
+type Option func(*Policy) error
+type Policy struct {
+	bundle   *i18n.Bundle
+	resolver Resolver
+	vary     []string
+	private  bool
+}
+
+// WithResolver overrides the default Accept-Language resolver. Cache variation
+// is explicit. With no varying headers, responses are marked private.
+func WithResolver(resolver Resolver, varyHeaders ...string) Option {
+	return func(p *Policy) error {
+		if resolver == nil {
+			return fmt.Errorf("httpi18n: nil resolver")
+		}
+		p.resolver = resolver
+		p.vary = nil
+		p.private = len(varyHeaders) == 0
+		for _, h := range varyHeaders {
+			if !headerName(h) {
+				return fmt.Errorf("httpi18n: invalid Vary header")
+			}
+			p.vary = append(p.vary, http.CanonicalHeaderKey(h))
+		}
+		return nil
+	}
+}
+func headerName(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, c := range s {
+		if c > 127 || !(c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c >= '0' && c <= '9' || strings.ContainsRune("!#$%&'*+-.^_`|~", c)) {
+			return false
+		}
+	}
+	return true
+}
+
+func New(bundle *i18n.Bundle, options ...Option) (*Policy, error) {
+	if bundle == nil {
+		return nil, fmt.Errorf("httpi18n: bundle required")
+	}
+	p := &Policy{bundle: bundle, vary: []string{"Accept-Language"}, resolver: func(r *http.Request) []string {
+		header := r.Header.Get("Accept-Language")
+		if len(header) > 8192 {
+			return nil
+		}
+		tags, _, err := language.ParseAcceptLanguage(header)
+		if err != nil {
+			return nil
+		}
+		out := []string{}
+		for _, tag := range tags {
+			if len(out) == 64 {
+				break
+			}
+			out = append(out, tag.String())
+		}
+		return out
+	}}
+	for _, o := range options {
+		if o == nil {
+			return nil, fmt.Errorf("httpi18n: nil option")
+		}
+		if err := o(p); err != nil {
+			return nil, err
+		}
+	}
+	return p, nil
+}
+
+// Apply installs the negotiated language before application middleware. An
+// explicit context preference takes priority and makes the response private.
+// It does not claim Content-Language: individual messages may use fallbacks.
+func (p *Policy) Apply(w http.ResponseWriter, r *http.Request) *http.Request {
+	if p == nil {
+		return r
+	}
+	preferences := []string{}
+	explicit := i18n.Locale(r.Context())
+	if explicit != "" {
+		preferences = append(preferences, explicit)
+	}
+	preferences = append(preferences, p.resolve(r)...)
+	for _, h := range p.vary {
+		addVary(w.Header(), h)
+	}
+	if p.private || explicit != "" {
+		w.Header().Add("Cache-Control", "private")
+	}
+	return r.WithContext(i18n.WithLocale(r.Context(), p.bundle.Match(preferences...)))
+}
+
+func (p *Policy) resolve(r *http.Request) (preferences []string) {
+	defer func() {
+		if recover() != nil {
+			preferences = nil
+		}
+	}()
+	return p.resolver(r)
+}
+func addVary(h http.Header, value string) {
+	for _, line := range h.Values("Vary") {
+		for _, v := range strings.Split(line, ",") {
+			if strings.EqualFold(strings.TrimSpace(v), value) || strings.TrimSpace(v) == "*" {
+				return
+			}
+		}
+	}
+	h.Add("Vary", value)
+}
+func (p *Policy) Wrap(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { next.ServeHTTP(w, p.Apply(w, r)) })
+}

i18n/httpi18n/http_test.go

@@ -0,0 +1,59 @@
+package httpi18n_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"git.yuntuo.hk/k2safe/go-omni/i18n"
+	"git.yuntuo.hk/k2safe/go-omni/i18n/httpi18n"
+)
+
+func TestNegotiationAndExplicitResolvers(t *testing.T) {
+	b, err := i18n.New(i18n.Config{SourceLocale: "en", DefaultLocale: "en", Locales: []string{"en", "fr", "zh-Hans", "zh-Hant"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	p, err := httpi18n.New(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, test := range []struct{ header, explicit, want string }{{"fr;q=0.8,en;q=0.1", "", "fr"}, {"fr;q=0,en;q=1", "", "en"}, {"zh-TW", "", "zh-Hant"}, {"zh-CN", "", "zh-Hans"}, {"invalid;garbage", "", "en"}, {strings.Repeat("x", 8193), "", "en"}, {"fr", "en", "en"}} {
+		r := httptest.NewRequest("GET", "/", nil)
+		r.Header.Set("Accept-Language", test.header)
+		if test.explicit != "" {
+			r = r.WithContext(i18n.WithLocale(r.Context(), test.explicit))
+		}
+		w := httptest.NewRecorder()
+		w.Header().Set("Vary", "Origin")
+		p.Wrap(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+			if got := i18n.Locale(r.Context()); got != test.want {
+				t.Errorf("got %s want %s", got, test.want)
+			}
+		})).ServeHTTP(w, r)
+		if strings.Join(w.Header().Values("Vary"), ",") != "Origin,Accept-Language" {
+			t.Fatal(w.Header())
+		}
+		if test.explicit != "" && !strings.Contains(w.Header().Get("Cache-Control"), "private") {
+			t.Fatal(w.Header())
+		}
+	}
+	custom, err := httpi18n.New(b, httpi18n.WithResolver(func(*http.Request) []string { return []string{"fr"} }))
+	if err != nil {
+		t.Fatal(err)
+	}
+	w := httptest.NewRecorder()
+	r := custom.Apply(w, httptest.NewRequest("GET", "/", nil))
+	if i18n.Locale(r.Context()) != "fr" || w.Header().Get("Cache-Control") != "private" {
+		t.Fatal(r, w.Header())
+	}
+	broken, err := httpi18n.New(b, httpi18n.WithResolver(func(*http.Request) []string { panic("preference lookup failed") }))
+	if err != nil {
+		t.Fatal(err)
+	}
+	r = broken.Apply(httptest.NewRecorder(), httptest.NewRequest("GET", "/", nil))
+	if i18n.Locale(r.Context()) != "en" {
+		t.Fatal("resolver panic must preserve default selection")
+	}
+}