fix: retry api requests on rate limit or persistent connection errors

Author: leomp12

lib/Api.js

@@ -13,24 +13,24 @@ let baseUri
 let port
 
 function requestEnd (res, rawData, errorCallback, successCallback) {
+  let str, err
   switch (res.statusCode) {
     case 200:
     case 201:
     case 204:
       successCallback()
       break
-
     case 412:
       // no store found with provided ID
       errorCallback(null, 412, 'Invalid store ID')
       break
-
     default:
       // unexpected status code
-      let str = 'Unexpected response status code from Store API' +
+      str = 'Unexpected response status code from Store API' +
         '\nStatus: ' + res.statusCode +
         '\nResponse: ' + rawData
-      let err = new Error(str)
+      err = new Error(str)
+      err.statusCode = res.statusCode
       errorCallback(err)
   }
 }
@@ -48,8 +48,57 @@ require('./../lib/Config.js')((config) => {
   port = config.apiPort
 })
 
-module.exports = (endpoint, method, body, storeId, errorCallback, successCallback, publicApi = false) => {
-  let options = {
+const request = (
+  client,
+  options,
+  body,
+  errorCallback,
+  successCallback
+) => {
+  const req = client.request(options, (res) => {
+    let rawData = ''
+    res.setEncoding('utf8')
+    res.on('data', (chunk) => { rawData += chunk })
+    res.on('end', () => {
+      requestEnd(res, rawData, errorCallback, () => {
+        // OK
+        let parsedData
+        if (rawData) {
+          try {
+            parsedData = JSON.parse(rawData)
+          } catch (e) {
+            // not a valid JSON
+            // callback without response body
+            errorCallback(e)
+            return
+          }
+        }
+        if (typeof successCallback === 'function') {
+          // pass parsed JSON
+          successCallback(parsedData)
+        }
+      })
+    })
+  })
+  req.on('error', errorCallback)
+  if (body) {
+    // write data to request body
+    req.write(JSON.stringify(body))
+  }
+  req.end()
+}
+
+module.exports = (
+  endpoint,
+  method,
+  body,
+  storeId,
+  errorCallback,
+  successCallback,
+  publicApi = false,
+  canRetry = true
+) => {
+  const options = {
     hostname: !publicApi ? host : 'api.e-com.plus',
     path: baseUri + endpoint,
     method: method,
@@ -60,53 +109,35 @@ module.exports = (endpoint, method, body, storeId, errorCallback, successCallbac
   if (!publicApi && port) {
     options.port = port
   }
+  const client = !publicApi ? http : https
 
-  let client = !publicApi ? http : https
-  let req = client.request(options, (res) => {
-    if (typeof errorCallback === 'function') {
-      let rawData = ''
-      res.setEncoding('utf8')
-      res.on('data', (chunk) => { rawData += chunk })
-      res.on('end', () => {
-        requestEnd(res, rawData, errorCallback, () => {
-          // OK
-          let parsedData
-          if (rawData) {
-            try {
-              parsedData = JSON.parse(rawData)
-            } catch (e) {
-              // not a valid JSON
-              // callback without response body
-              errorCallback(e)
-              return
-            }
-          }
-
-          if (typeof successCallback === 'function') {
-            // pass parsed JSON
-            successCallback(parsedData)
-          }
-        })
-      })
-    } else {
-      // consume response data to free up memory
-      res.resume()
-    }
-  })
-
-  req.on('error', (e) => {
-    if (typeof errorCallback === 'function') {
-      errorCallback(e)
-    } else {
-      // no callback
-      // just log the unexpected error
-      logger.error(e)
-    }
-  })
-
-  if (body) {
-    // write data to request body
-    req.write(JSON.stringify(body))
+  let retries = 0
+  const maxRetries = canRetry
+    ? endpoint.startsWith('orders') ? 2 : 1
+    : 0
+  const requestWithRetry = () => {
+    request(
+      client,
+      options,
+      body,
+      (err) => {
+        if (err instanceof Error && !(err.statusCode < 500) && retries < maxRetries) {
+          retries++
+          setTimeout(() => {
+            requestWithRetry()
+          }, retries * (publicApi ? 600 : 1000))
+          return
+        }
+        if (typeof errorCallback === 'function') {
+          errorCallback(err)
+        } else {
+          // no callback
+          // just log the unexpected error
+          logger.error(err)
+        }
+      },
+      successCallback
+    )
   }
-  req.end()
+  requestWithRetry()
 }