fix(BatchReader): test response object in getDirectoryFileHashes (#697)

fix(BatchReader): eliminate mongodb error for normal behavior

do not attempt to store an empty value to mongodb if the poetAnchorBlock is not yet available.

Fixes: #650 
References: #697

src/BatchReader/IPFS.ts

@@ -1,6 +1,8 @@
 import { inject, injectable } from 'inversify'
 import fetch from 'node-fetch'
 
+import { isNotNil } from 'Helpers/isNotNil'
+
 enum Type {
   File = 'File',
   Directory = 'Directory',
@@ -48,7 +50,11 @@ export class IPFS {
 
   getDirectoryFileHashes: getDirectoryFileHashes = async (hash: string) => {
     const response = await this.ls(hash)
-    return response.Objects[hash].Links.map(x => x.Hash)
+    const validResponse = isNotNil(response) &&
+      isNotNil(response.Objects) &&
+      isNotNil(response.Objects[hash]) &&
+      isNotNil(response.Objects[hash].Links)
+    return validResponse ? response.Objects[hash].Links.map(x => x.Hash) : []
   }
 
   ls: ls = async (hash: string) => {

src/BatchReader/Router.ts

@@ -1,5 +1,6 @@
 import { inject, injectable } from 'inversify'
 import * as Pino from 'pino'
+import { isNil } from 'ramda'
 
 import { childWithFileName } from 'Helpers/Logging'
 import { BlockDownloaded } from 'Messaging/Messages'
@@ -55,6 +56,7 @@ export class Router {
     )
 
     try {
+      if (isNil(poetBlockAnchors) || poetBlockAnchors.length === 0) return
       await this.claimController.addEntries(poetBlockAnchors)
     } catch (error) {
       logger.error({ error, poetBlockAnchors }, 'Failed to store directory hashes to DB collection')

src/Helpers/isNotNil.test.ts

@@ -0,0 +1,51 @@
+import { describe } from 'riteway'
+
+import { isNotNil } from './isNotNil'
+
+describe('isNotNil', async assert => {
+
+  const returnTrue = 'return true'
+  const returnFalse = 'return false'
+
+  assert({
+    given: 'an empty string',
+    should: returnTrue,
+    actual: isNotNil(''),
+    expected: true,
+  })
+
+  assert({
+    given: 'an empty array',
+    should: returnTrue,
+    actual: isNotNil([]),
+    expected: true,
+  })
+
+  assert({
+    given: 'an empty object',
+    should: returnTrue,
+    actual: isNotNil({}),
+    expected: true,
+  })
+
+  assert({
+    given: 'undefined',
+    should: returnFalse,
+    actual: isNotNil(undefined),
+    expected: false,
+  })
+
+  assert({
+    given: 'null',
+    should: returnFalse,
+    actual: isNotNil(null),
+    expected: false,
+  })
+
+  assert({
+    given: 'no value',
+    should: returnFalse,
+    actual: isNotNil(),
+    expected: false,
+  })
+})

src/Helpers/isNotNil.ts

@@ -0,0 +1,6 @@
+import { isNil, not, pipe } from 'ramda'
+
+export const isNotNil = pipe(
+  isNil,
+  not,
+)

tests/unit/index.ts

@@ -17,6 +17,7 @@ import '../../src/Helpers/Logging.test.ts'
 import '../../src/Helpers/Time.test.ts'
 import '../../src/Helpers/asyncPipe.test.ts'
 import '../../src/Helpers/camelCaseToScreamingSnakeCase.test'
+import '../../src/Helpers/isNotNil.test'
 import '../../src/Helpers/isTruthy.test'
 import '../../src/Helpers/to-promise.test.ts'
 import '../../src/Interfaces.test.ts'