From e209f97fba89bd2bba348c866d55897df4c72e0d Mon Sep 17 00:00:00 2001
From: Adriel Diaz <adriexnet@gmail.com>
Date: Thu, 10 Sep 2020 09:06:38 -0600
Subject: [PATCH] feat: implement api failover endpoint, resolve #124

---
 .env.example                |  1 +
 src/config/evodex.config.js |  1 +
 src/utils/axios.util.js     | 32 ++++++++++++++++++++++++++++++++
 src/utils/evolutiondex.js   |  9 +++++----
 4 files changed, 39 insertions(+), 4 deletions(-)
 create mode 100644 src/utils/axios.util.js

diff --git a/.env.example b/.env.example
index b55ca88..78834f2 100644
--- a/.env.example
+++ b/.env.example
@@ -8,4 +8,5 @@ REACT_APP_EOS_BLOCK_EXPLORER_URL=https://jungle3.bloks.io
 REACT_APP_VOTE_CONTRACT=wevotethefee
 REACT_APP_EVODEX_CONTRACT=evolutiondex
 REACT_APP_EVODEX_API_URL=https://jungle.api.evolutiondex.io
+REACT_APP_EVODEX_API_URL_FAILOVER=https://jungle.api-2.evolutiondex.io
 REACT_APP_PROJECT_VERSION=v0.1.0-beta
diff --git a/src/config/evodex.config.js b/src/config/evodex.config.js
index 18032bc..2fb8962 100644
--- a/src/config/evodex.config.js
+++ b/src/config/evodex.config.js
@@ -1,5 +1,6 @@
 export const evodexConfig = {
   api: process.env.REACT_APP_EVODEX_API_URL,
+  apiFailover: process.env.REACT_APP_EVODEX_API_URL_FAILOVER,
   contract: process.env.REACT_APP_EVODEX_CONTRACT,
   voteContract: process.env.REACT_APP_VOTE_CONTRACT
 }
diff --git a/src/utils/axios.util.js b/src/utils/axios.util.js
new file mode 100644
index 0000000..e198a4f
--- /dev/null
+++ b/src/utils/axios.util.js
@@ -0,0 +1,32 @@
+import axios from 'axios'
+
+export default (url, failover) => {
+  // Create instance
+  const axiosApi = axios.create({
+    baseURL: url,
+    headers: {
+      'Content-Type': 'application/json'
+    }
+  })
+
+  // Response interceptor failover for API calls
+  axiosApi.interceptors.response.use(
+    (response) => {
+      return response
+    },
+    (error) => {
+      const config = error.config
+
+      if (!config.retry) {
+        config.retry = true
+        config.baseURL = failover
+
+        return axiosApi(config)
+      }
+
+      return Promise.reject(error)
+    }
+  )
+
+  return axiosApi
+}
diff --git a/src/utils/evolutiondex.js b/src/utils/evolutiondex.js
index 63ae7a0..acef249 100644
--- a/src/utils/evolutiondex.js
+++ b/src/utils/evolutiondex.js
@@ -1,12 +1,13 @@
-import axios from 'axios'
 import * as eosCommon from 'eos-common'
 
 import { evodexConfig } from '../config'
 
 import { getScatterError } from './getScatterError'
+import axiosUtil from './axios.util'
 
 const { asset, number_to_asset: numberToAsset } = eosCommon
 const defaultState = { pairs: [], tokens: [] }
+const axios = axiosUtil(evodexConfig.api, evodexConfig.apiFailover)
 
 const amountToAsset = (amount = '0', currentAsset) => {
   if (isNaN(amount)) {
@@ -23,7 +24,7 @@ const amountToAsset = (amount = '0', currentAsset) => {
   return asset(`${validAmount} ${currentAsset.symbol.code().toString()}`)
 }
 const getInfo = async (ual) => {
-  const { data } = await axios.get(`${evodexConfig.api}/list`)
+  const { data } = await axios.get('/list')
   let userPools = []
 
   if (ual?.activeUser) {
@@ -43,7 +44,7 @@ const getInfo = async (ual) => {
           Pool2contract: pool2Contract,
           error
         }
-      } = await axios.get(`${evodexConfig.api}/info`, {
+      } = await axios.get('/info', {
         params: {
           pair: tokenPair
         }
@@ -197,7 +198,7 @@ const exchange = async (amount, pair, ual) => {
               quantity: assetToGive.toString(),
               memo: `exchange: ${
                 pair.token
-                },${assetToReceive.toString()},sent using evodex.io`
+              },${assetToReceive.toString()},sent using evodex.io`
             }
           }
         ]