Add pagination to token relayers endpoint (#368)

Author: cbovis

src/app/routes/v1/token.js

@@ -47,9 +47,14 @@ const createRouter = () => {
       ['fillCount', 'fillVolumeUSD', 'tradeCount', 'tradeVolumeUSD'],
       'tradeVolumeUSD',
     ),
-    middleware.limit(50, 10),
-    async ({ params, response }, next) => {
-      const { limit, sortBy, statsPeriod, tokenAddress } = params;
+    middleware.pagination({
+      defaultLimit: 20,
+      maxLimit: 50,
+      maxPage: Infinity,
+    }),
+    async ({ pagination, params, response }, next) => {
+      const { sortBy, statsPeriod, tokenAddress } = params;
+      const { limit, page } = pagination;
 
       const token = await Token.findOne({
         address: tokenAddress,
@@ -61,13 +66,25 @@ const createRouter = () => {
         return;
       }
 
-      const relayers = await getRelayersForTokenInPeriod(
+      const { relayers, resultCount } = await getRelayersForTokenInPeriod(
         tokenAddress,
         statsPeriod,
-        { sortBy, limit },
+        {
+          sortBy,
+          limit,
+          page,
+        },
       );
 
-      response.body = { limit, relayers, sortBy, statsPeriod };
+      response.body = {
+        limit,
+        page,
+        pageCount: Math.ceil(resultCount / limit),
+        relayers,
+        sortBy,
+        statsPeriod,
+        total: resultCount,
+      };
 
       await next();
     },

src/relayers/get-relayers-for-token-in-period.js

@@ -13,9 +13,11 @@ const getOrderByKey = sortBy => {
 };
 
 const getRelayersForTokenInPeriod = async (tokenAddress, period, options) => {
-  const { limit, sortBy } = options;
+  const { limit, page, sortBy } = options;
   const { dateFrom, dateTo } = getDatesForPeriod(period);
 
+  const startIndex = (page - 1) * limit;
+
   const response = await elasticsearch.getClient().search({
     index: 'traded_tokens',
     body: {
@@ -42,7 +44,7 @@ const getRelayersForTokenInPeriod = async (tokenAddress, period, options) => {
         stats_by_relayer: {
           terms: {
             field: 'relayerId',
-            size: limit,
+            size: limit * page,
             missing: -1,
             order: {
               [getOrderByKey(sortBy)]: 'desc',
@@ -74,6 +76,17 @@ const getRelayersForTokenInPeriod = async (tokenAddress, period, options) => {
                 field: 'tradedAmountUSD',
               },
             },
+            bucket_truncate: {
+              bucket_sort: {
+                size: limit,
+                from: startIndex,
+              },
+            },
+          },
+        },
+        relayerCount: {
+          cardinality: {
+            field: 'relayerId',
           },
         },
       },
@@ -86,32 +99,39 @@ const getRelayersForTokenInPeriod = async (tokenAddress, period, options) => {
 
   const relayers = await Relayer.find({ lookupId: { $in: relayerIds } }).lean();
 
-  return response.body.aggregations.stats_by_relayer.buckets.map(bucket => {
-    const relayer =
-      bucket.key === -1
-        ? { id: 'unknown', name: 'Unknown', slug: 'unknown' }
-        : relayers.find(r => r.lookupId === bucket.key);
+  const relayerCount = response.body.aggregations.relayerCount.value;
 
-    return {
-      id: _.get(relayer, 'id', null),
-      imageUrl: _.get(relayer, 'imageUrl', null),
-      name: _.get(relayer, 'name', null),
-      slug: _.get(relayer, 'slug', null),
-      stats: {
-        fillCount: bucket.doc_count,
-        fillVolume: {
-          token: bucket.fillVolume.value,
-          USD: bucket.fillVolumeUSD.value,
-        },
-        tradeCount: bucket.tradeCount.value,
-        tradeVolume: {
-          token: bucket.tradeVolume.value,
-          USD: bucket.tradeVolumeUSD.value,
-        },
+  return {
+    relayers: response.body.aggregations.stats_by_relayer.buckets.map(
+      bucket => {
+        const relayer =
+          bucket.key === -1
+            ? { id: 'unknown', name: 'Unknown', slug: 'unknown' }
+            : relayers.find(r => r.lookupId === bucket.key);
+
+        return {
+          id: _.get(relayer, 'id', null),
+          imageUrl: _.get(relayer, 'imageUrl', null),
+          name: _.get(relayer, 'name', null),
+          slug: _.get(relayer, 'slug', null),
+          stats: {
+            fillCount: bucket.doc_count,
+            fillVolume: {
+              token: bucket.fillVolume.value,
+              USD: bucket.fillVolumeUSD.value,
+            },
+            tradeCount: bucket.tradeCount.value,
+            tradeVolume: {
+              token: bucket.tradeVolume.value,
+              USD: bucket.tradeVolumeUSD.value,
+            },
+          },
+          url: _.get(relayer, 'url', null),
+        };
       },
-      url: _.get(relayer, 'url', null),
-    };
-  });
+    ),
+    resultCount: relayerCount,
+  };
 };
 
 module.exports = getRelayersForTokenInPeriod;