new file tuple API

internal/api/files_tuples.go

@@ -0,0 +1,74 @@
+package api
+
+import "net/http"
+
+// fileTupleJSON is one file-backed root on the wire.
+type fileTupleJSON struct {
+	HashID    string `json:"hashId"`
+	FilePath  string `json:"filePath"`
+	SizeByte  int64  `json:"sizeByte"`
+	MtimeNano int64  `json:"mtimeNano"`
+}
+
+// FileTuplesResponse is the body of GET /api/files/tuples.
+//
+// Files is a pointer so the summary form can omit it while the full form
+// always carries it — an empty library is `"files": []`, never an absent key,
+// which a client could mistake for a meta-core that lacks the rows.
+type FileTuplesResponse struct {
+	Files     *[]fileTupleJSON `json:"files,omitempty"`
+	Count     int              `json:"count"`
+	TotalSize int64            `json:"totalSize"`
+}
+
+// handleGetFileTuples handles GET /api/files/tuples.
+//
+// Lists the FILE-BACKED roots — records carrying filePath, sizeByte and
+// mtimeNano, i.e. what the watcher or /api/files/register minted — with their
+// sizes, plus the count and total. Gateway / cid-rooted records carry no file
+// and are not included; neither is a locator record that only merged a cache
+// file's metadata (it has no mtimeNano).
+//
+// It exists so a client never walks every hashId to answer "how many files,
+// how big": GetTuplesForAllFiles reads the three fields for every root in
+// chunked MGETs server-side (~250 round-trips for 82k roots, no SCAN), where
+// the client-side equivalent was one HTTP request per record.
+//
+// ?summary=1 omits the rows and returns only {count, totalSize}.
+func (s *Server) handleGetFileTuples(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	tuples, err := s.storage.GetTuplesForAllFiles()
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	summary := r.URL.Query().Get("summary")
+	withRows := summary == "" || summary == "0" || summary == "false"
+
+	resp := FileTuplesResponse{Count: len(tuples)}
+	var rows []fileTupleJSON
+	if withRows {
+		rows = make([]fileTupleJSON, 0, len(tuples))
+	}
+	for _, t := range tuples {
+		resp.TotalSize += t.Size
+		if withRows {
+			rows = append(rows, fileTupleJSON{
+				HashID:    t.HashID,
+				FilePath:  t.FilePath,
+				SizeByte:  t.Size,
+				MtimeNano: t.MtimeNano,
+			})
+		}
+	}
+	if withRows {
+		resp.Files = &rows
+	}
+
+	writeJSON(w, http.StatusOK, resp)
+}