diff --git a/internal/server/pages.go b/internal/server/pages.go
index b7e3289..8acfb5b 100644
--- a/internal/server/pages.go
+++ b/internal/server/pages.go
@@ -22,11 +22,6 @@ func writeJSON(w http.ResponseWriter, status int, v any) {
w.Write(append(b, '\n'))
}
-// absBase is the absolute URL of this service, for links and examples.
-//
-// It prefers --public-url. Falling back to the request's Host is display-only:
-// the header is caller-controlled, so it is never used for anything a third
-// party would see.
func (s *Server) absBase(r *http.Request) string {
if s.cfg.PublicURL != "" {
return s.cfg.PublicURL + s.cfg.BasePath
@@ -38,11 +33,14 @@ func (s *Server) absBase(r *http.Request) string {
return scheme + "://" + r.Host + s.cfg.BasePath
}
-// objectURL builds the download link handed back to an uploader.
func (s *Server) objectURL(r *http.Request, id string) string {
return s.absBase(r) + "d/" + id
}
+func (s *Server) infoURL(r *http.Request, id string) string {
+ return s.absBase(r) + "i/" + id
+}
+
type indexPage struct {
page
MaxSize string
@@ -60,8 +58,6 @@ type indexPage struct {
}
func (s *Server) handleIndex(w http.ResponseWriter, r *http.Request) {
- // A remembered token is resolved server-side, so the page can show the real
- // limits without the cookie ever being readable by a script.
lim, err := s.limitsFor(r, s.cookieCredential(r))
stale := false
switch {
@@ -124,12 +120,19 @@ func (s *Server) handleInfo(w http.ResponseWriter, r *http.Request) {
// delete attempt, so a mistyped token lands back on the form rather than on a
// dead end.
func (s *Server) renderInfo(w http.ResponseWriter, r *http.Request, m *store.Meta, status int, errMsg string) {
+ infoURL := s.infoURL(r, m.ID)
+ head := s.page(r, m.Filename, true)
+ // This is the page people paste at each other, so it is the one that has
+ // to unfurl into something readable.
+ head.Preview = objectPreview(m, infoURL)
+
s.render(w, status, "info.html", objectPage{
- page: s.page(r, m.Filename, true),
+ page: head,
Meta: m,
Size: config.FormatSize(m.Size),
Expires: describeExpiry(m.Expires, s.now()),
URL: s.objectURL(r, m.ID),
+ InfoURL: infoURL,
CanDelete: s.mayDelete(r, m, s.credential(r)),
Error: errMsg,
})
diff --git a/internal/server/preview.go b/internal/server/preview.go
new file mode 100644
index 0000000..a2bf29b
--- /dev/null
+++ b/internal/server/preview.go
@@ -0,0 +1,29 @@
+package server
+
+import (
+ "strings"
+
+ "uncensored-send/internal/config"
+ "uncensored-send/internal/store"
+)
+
+type preview struct {
+ Description string
+ Author string
+ URL string
+}
+
+func objectPreview(m *store.Meta, url string) *preview {
+ facts := []string{config.FormatBytes(m.Size)}
+ if m.Owner != "" {
+ facts = append(facts, "uploaded by "+m.Owner)
+ }
+ if m.Expires != nil {
+ facts = append(facts, "expires "+absolute(m.Expires))
+ }
+ return &preview{
+ Description: strings.Join(facts, ", ") + ". Open the page to download it.",
+ Author: m.Owner,
+ URL: url,
+ }
+}
diff --git a/internal/server/server.go b/internal/server/server.go
index 8aa228c..62d36d5 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -245,6 +245,10 @@ type page struct {
// The reading measure that suits the upload page is far too narrow for a
// listing, which otherwise ends up behind a horizontal scrollbar.
Wide bool
+
+ // Preview is the link card for this page, nil when there is nothing
+ // sensible to tell somebody who has only been handed the URL.
+ Preview *preview
}
// page builds the common fields, resolving the session so the header can show
diff --git a/internal/server/server_test.go b/internal/server/server_test.go
index a69bd6b..e2dedad 100644
--- a/internal/server/server_test.go
+++ b/internal/server/server_test.go
@@ -2346,3 +2346,130 @@ func TestFilesPageIsLaidOutForATable(t *testing.T) {
t.Error("the listing still relies on a horizontal scroll container")
}
}
+
+// --- link previews -------------------------------------------------------
+
+// metaContent pulls a meta tag's content out of a rendered page, keyed by
+// either the property or the name attribute, so a test reads what an unfurler
+// would rather than matching a whole tag it does not care about.
+func metaContent(page, key string) string {
+ for _, attr := range []string{"property", "name"} {
+ marker := fmt.Sprintf("= 0 {
+ return rest[1 : 1+end]
+ }
+ }
+ return ""
+}
+
+// A /i/ link is the thing people paste at each other, so it has to unfurl into
+// something that says what is on the other end of it.
+func TestInfoPageUnfurls(t *testing.T) {
+ h := newHarness(t, func(c *config.Config) { c.PublicURL = "https://drop.example" })
+ res := decode[uploadResult](t, h.uploadReader(t,
+ strings.NewReader(strings.Repeat("x", 4096)),
+ map[string]string{
+ "Content-Disposition": `attachment; filename="MyGame.zip"`,
+ "Authorization": "Bearer " + h.token,
+ }))
+
+ info := h.get(t, "/i/"+res.ID, "")
+ raw, _ := io.ReadAll(info.Body)
+ info.Body.Close()
+ page := string(raw)
+
+ if got, want := metaContent(page, "og:title"), "MyGame.zip - Uncensored Send"; got != want {
+ t.Errorf("og:title = %q, want %q", got, want)
+ }
+ if got, want := metaContent(page, "og:url"), "https://drop.example/i/"+res.ID; got != want {
+ t.Errorf("og:url = %q, want %q", got, want)
+ }
+ if got, want := metaContent(page, "author"), "friend"; got != want {
+ t.Errorf("author = %q, want %q", got, want)
+ }
+ if metaContent(page, "twitter:card") != "summary" {
+ t.Error("no twitter:card, so clients holding to that vocabulary draw nothing")
+ }
+
+ desc := metaContent(page, "og:description")
+ for _, want := range []string{"4 KiB", "uploaded by friend", "expires 2026-09-15 10:00 UTC"} {
+ if !strings.Contains(desc, want) {
+ t.Errorf("og:description = %q, missing %q", desc, want)
+ }
+ }
+ if !strings.Contains(desc, "Open the page") {
+ t.Errorf("og:description = %q, says nothing about what to do with the link", desc)
+ }
+ // The deadline is cached by the chat platform and read back days later, so
+ // it has to be an absolute time rather than a countdown that goes stale.
+ if strings.Contains(desc, "in 3d") {
+ t.Errorf("og:description = %q, carries a relative deadline", desc)
+ }
+ if metaContent(page, "description") != desc {
+ t.Error("the plain description tag disagrees with the Open Graph one")
+ }
+}
+
+// An anonymous upload has no uploader to name, and the card must not claim one.
+func TestAnonymousUploadHasNoAuthorInItsCard(t *testing.T) {
+ h := newHarness(t, nil)
+ res := decode[uploadResult](t, h.upload(t, []byte("x"), nil))
+
+ info := h.get(t, "/i/"+res.ID, "")
+ raw, _ := io.ReadAll(info.Body)
+ info.Body.Close()
+ page := string(raw)
+
+ if got := metaContent(page, "author"); got != "" {
+ t.Errorf("author = %q, want none", got)
+ }
+ if desc := metaContent(page, "og:description"); strings.Contains(desc, "uploaded by") {
+ t.Errorf("og:description = %q, names an uploader there is none of", desc)
+ }
+ if !strings.Contains(page, "anonymous") {
+ t.Error("the page itself does not say the upload was anonymous")
+ }
+}
+
+// A filename is caller-supplied and ends up inside an attribute; the escaping
+// has to hold there as well as in the body.
+func TestPreviewEscapesTheFilename(t *testing.T) {
+ h := newHarness(t, nil)
+ res := decode[uploadResult](t, h.upload(t, []byte("x"), map[string]string{
+ "Content-Disposition": `attachment; filename="\" onload=\"alert(1)"`}))
+
+ info := h.get(t, "/i/"+res.ID, "")
+ raw, _ := io.ReadAll(info.Body)
+ info.Body.Close()
+ page := string(raw)
+
+ if strings.Contains(page, `onload="alert(1)"`) {
+ t.Fatalf("a filename broke out of the meta attribute:\n%s", page)
+ }
+ if got, want := metaContent(page, "og:title"), res.Filename; !strings.Contains(got, "onload") && got != want {
+ // The value is escaped, so this only checks the tag is there at all.
+ t.Errorf("og:title = %q", got)
+ }
+}
+
+// Pages whose content depends on who is asking say nothing to an unfurler,
+// which presents no token and would otherwise be shown a stranger's view.
+func TestOnlyTheInfoPageCarriesACard(t *testing.T) {
+ h := newHarness(t, nil)
+ for _, path := range []string{"/", "/login", "/files"} {
+ resp := h.get(t, path, "")
+ raw, _ := io.ReadAll(resp.Body)
+ resp.Body.Close()
+ if got := metaContent(string(raw), "og:title"); got != "" {
+ t.Errorf("%s carries og:title = %q", path, got)
+ }
+ }
+}
diff --git a/internal/server/upload.go b/internal/server/upload.go
index b9956fc..da8d433 100644
--- a/internal/server/upload.go
+++ b/internal/server/upload.go
@@ -403,7 +403,7 @@ func (s *Server) respondUploaded(w http.ResponseWriter, r *http.Request, m *stor
ID: m.ID, Filename: m.Filename, Size: m.Size, SHA256: m.SHA256,
Expires: expires,
URL: url,
- InfoURL: s.absBase(r) + "i/" + m.ID,
+ InfoURL: s.infoURL(r, m.ID),
DeleteToken: secret,
DeleteURL: s.absBase(r) + "d/" + m.ID + "/delete",
})
@@ -419,7 +419,7 @@ func (s *Server) respondUploaded(w http.ResponseWriter, r *http.Request, m *stor
Size: config.FormatSize(m.Size),
Expires: describeExpiry(m.Expires, s.now()),
URL: url,
- InfoURL: s.absBase(r) + "i/" + m.ID,
+ InfoURL: s.infoURL(r, m.ID),
DeleteToken: secret,
})
}
diff --git a/web/templates/info.html b/web/templates/info.html
index 0c0d8e8..41e1e6d 100644
--- a/web/templates/info.html
+++ b/web/templates/info.html
@@ -3,6 +3,7 @@