Add patching support for multiWACZ collections (#131)

* multiwacz: support patching: allow searching in multiple wacz files if resource not found in initial (perhaps make configurable later by comparing page lists)
bump to 2.16.5

* textIndex: catch empty reader and return empty response

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@webrecorder/wabac",
-  "version": "2.16.4",
+  "version": "2.16.5",
   "main": "index.js",
   "type": "module",
   "license": "AGPL-3.0-or-later",

src/wacz/multiwacz.js

@@ -708,6 +708,9 @@ export class MultiWACZ extends OnDemandPayloadArchiveDB// implements WACZLoadSou
       }
 
       const {reader} = result;
+      if (!reader) {
+        return new Response("", {headers});
+      }
 
       const size = this.waczfiles[waczname].getSizeOf(this.textIndex);
 
@@ -756,8 +759,6 @@ export class MultiWACZ extends OnDemandPayloadArchiveDB// implements WACZLoadSou
       }
     }
 
-    const isNavigate = event.request.mode === "navigate";
-
     let hash = pageId;
     let waczname = null;
 
@@ -771,17 +772,18 @@ export class MultiWACZ extends OnDemandPayloadArchiveDB// implements WACZLoadSou
       resp = await super.getResource(request, prefix, event, {waczname});
     }
 
-    if (resp || !isNavigate) {
-      return resp;
-    }
-
     let foundHash = null;
 
     for (const [name, file] of Object.entries(this.waczfiles)) {
       if (file.fileType !== WACZ_LEAF) {
         continue;
       }
 
+      // already checked this file above, don't check again
+      if (file.hash === hash) {
+        continue;
+      }
+
       resp = await super.getResource(request, prefix, event, {waczname: name, noFuzzyCheck: true});
       if (resp) {
         waczname = name;