Series URL repair: owner-typed, gated by the poller's own fetch gate (#151)

backend/internal/web/admin_series.go

@@ -225,6 +225,60 @@ func (h *Handler) adminSeriesCorrectLatest(w http.ResponseWriter, r *http.Reques
 	h.render(w, http.StatusOK, "series-detail-meta", h.seriesDetailView(a))
 }
 
+// adminSeriesSetURL is the series URL repair: the owner types one address
+// and the Series' Poll fetches it from then on, verified by the same gate
+// the poller uses before it fetches anything — a URL failing
+// latest.FetchableSeriesURL answers 400 and never reaches the store. The
+// repair is a store, not a verification: it performs no outbound fetch, and
+// the owner presses Check now afterwards. This lifts the write-once rule of
+// Series.SeriesURL for the owner only — a Reader's PUT is still ignored. The
+// owner gate is the route's, not this handler's; the body is capped like the
+// API path caps its bodies; the key is validated here — a malformed key is a
+// 400 and an unknown one a 404.
+func (h *Handler) adminSeriesSetURL(w http.ResponseWriter, r *http.Request) {
+	site, seriesID, ok := strings.Cut(r.PathValue("key"), ":")
+	if !ok || site == "" || seriesID == "" {
+		http.Error(w, "bad series key", http.StatusBadRequest)
+		return
+	}
+	r.Body = http.MaxBytesReader(w, r.Body, 1<<16)
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "invalid form", http.StatusBadRequest)
+		return
+	}
+	seriesURL := r.PostFormValue("series_url")
+	if !latest.FetchableSeriesURL(site, seriesURL) {
+		http.Error(w, "series URL must be an https address on this site's host", http.StatusBadRequest)
+		return
+	}
+	if _, found, err := h.adminSeriesByKey(site, seriesID); err != nil {
+		log.Printf("series url %s: %v", site+":"+seriesID, err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	} else if !found {
+		http.NotFound(w, r)
+		return
+	}
+	if err := h.store.SetSeriesURL(site, seriesID, seriesURL); err != nil {
+		log.Printf("series url %s: %v", site+":"+seriesID, err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	// Re-read after the write: the answer must describe the state after the
+	// press, like the correction's answer does.
+	a, found, err := h.adminSeriesByKey(site, seriesID)
+	if err != nil {
+		log.Printf("series url %s: %v", site+":"+seriesID, err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	if !found {
+		http.NotFound(w, r)
+		return
+	}
+	h.render(w, http.StatusOK, "series-detail-meta", h.seriesDetailView(a))
+}
+
 // seriesListView assembles one Series list view from the request's query
 // string. An unknown filter value is the absent All case, never an error: the
 // select's options are not the only way this URL can be reached.