Changed queryToken from once per offer to once per search

src/api/routes/offer.js

@@ -20,20 +20,21 @@ export default (app) => {
     router.use(offerMiddleware.setTargetOwner);
 
     /**
-     * Gets all currently active offers (without filtering, for now)
-     * supports offset and limit as query params
+     * Gets active offers based on passed filters and full-text search.
+     * Returns the offers found and a queryToken used for pagination.
+     * Also takes queryToken and limit as query params.
      */
     router.get("/", validators.get, async (req, res, next) => {
         try {
-            const offers = await (new OfferService()).get(
+            const searchResults = await (new OfferService()).get(
                 {
                     ...req.query,
                     showHidden: req?.query?.showHidden && req.hasAdminPrivileges,
                     showAdminReason: req.hasAdminPrivileges
                 }
             );
 
-            return res.json(offers);
+            return res.json(searchResults);
         } catch (err) {
             console.error(err);
             return next(err);

src/services/offer.js

@@ -212,9 +212,9 @@ class OfferService {
             score: lastOfferScore
         } = queryToken ? this.decodeQueryToken(queryToken) : {};
 
-        let offers;
+        let results;
         if (lastOfferId && value) {
-            offers = Offer.aggregate([
+            results = Offer.aggregate([
                 { $match: { $text: { $search: value } } },
                 { $addFields: {
                     score: { $meta: "textScore" },
@@ -231,32 +231,35 @@ class OfferService {
         } else {
             if (lastOfferId) {
 
-                offers = Offer.find({ "$and": [
+                results = Offer.find({ "$and": [
                     this._buildFilterQuery(filters),
                     { _id: { "$gt": ObjectId(lastOfferId) } }
                 ] });
 
             } else {
 
-                offers = (value ? Offer.find({ "$and": [
+                results = (value ? Offer.find({ "$and": [
                     this._buildFilterQuery(filters),
                     { "$text": { "$search": value } }
                 ] }, { score: { "$meta": "textScore" } }
 
                 ) : Offer.find(this._buildFilterQuery(filters)));
             }
 
-            offers.current();
-            if (!showHidden) offers.withoutHidden();
-            if (!showAdminReason) offers.select("-adminReason");
+            results.current();
+            if (!showHidden) results.withoutHidden();
+            if (!showAdminReason) results.select("-adminReason");
         }
 
-        const results = await offers
+        const offers = await results
             .sort(value ? { score: { "$meta": "textScore" }, _id: 1 } : { _id: 1 })
             .limit(limit)
         ;
 
-        return results.map(this.buildQueryToken);
+        return offers.length > 0 ?
+            { offers, queryToken: this.encodeQueryToken(offers[offers.length - 1]) }
+            :
+            { offers };
     }
 
     _buildFilterQuery(filters) {
@@ -307,17 +310,14 @@ class OfferService {
     }
 
     /**
-     * Builds a query token, by taking the offer's id and FTS score (if present) and decoding in safe base64
+     * Encodes a query token, by taking the offer's id and FTS score (if present) and decoding in safe url base64
      * @param {*} offer
      */
-    buildQueryToken(offer) {
-        return {
-            ...(offer.toJSON ? offer.toJSON() : offer), // Aggregation differs from query
-            queryToken: base64url.encode(JSON.stringify({
-                id: offer._id,
-                score: offer.score || offer._doc?.score
-            })),
-        };
+    encodeQueryToken(offer) {
+        return base64url.encode(JSON.stringify({
+            id: offer._id,
+            score: offer.score || offer._doc?.score
+        }));
     }
 
     /**