feat(helpers): add IPFS helper function

parses v0 ipfs hashes and returns addresses and strings. Will return a
link to the blob if the hash resolves to anything other than a string or
and address

package.json

@@ -45,6 +45,7 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.1.2",
+    "axios": "^0.19.0",
     "bn.js": "^4.11.8",
     "date-fns": "2.0.0-alpha.22",
     "web3-eth": "^1.2.1",

src/helpers/index.js

@@ -6,6 +6,7 @@ import formatPct from './formatPct'
 import tokenAmount from './tokenAmount'
 import transformTime from './transformTime'
 import radspec from './radspec'
+import parseIpfs from './parseIpfs'
 
 const defaultHelpers = {
   formatDate,
@@ -14,7 +15,8 @@ const defaultHelpers = {
   formatPct,
   fromHex,
   radspec,
-  echo
+  echo,
+  parseIpfs
 }
 
 export {
@@ -27,5 +29,6 @@ export {
   fromHex,
   radspec,
   transformTime,
-  tokenAmount
+  tokenAmount,
+  parseIpfs
 }

src/helpers/parseIpfs.js

@@ -0,0 +1,52 @@
+import axios from 'axios'
+import Web3Utils from 'web3-utils'
+
+// default endpoints to be queried
+const ipfsEndpoints = ['https://ipfs.autark.xyz:5001/api/v0']
+
+export default () =>
+  async (cid, node = '', ...keys) => {
+    node && ipfsEndpoints.push(node)
+    let rejectedPromises = 0
+    const results = await Promise.all(
+      ipfsEndpoints.map(async ipfsEndpoint => {
+        const ipfsQuery = `${ipfsEndpoint}/cat?arg=${cid}`
+        try {
+          const { data } = await axios.get(ipfsQuery)
+          return getValue(data, keys, ipfsQuery)
+        } catch (err) {
+          return ++rejectedPromises < ipfsEndpoints.length
+            ? null : {
+              type: 'string',
+              value: `failed getting data from IPFS: ${err}`
+            }
+        }
+      })
+    )
+    return results.reduce((finalResult, candidate) => candidate || finalResult)
+  }
+
+const getValue = (data, keys = [], ipfsQuery) => {
+  const key = keys.shift()
+  if (!key) {
+    switch (typeof data) {
+      case 'string':
+        return Web3Utils.isAddress(data)
+          ? {
+            type: 'address',
+            value: Web3Utils.toChecksumAddress(data)
+          }
+          : {
+            type: 'string',
+            value: data
+          }
+      default:
+        return {
+          type: 'string',
+          value: ipfsQuery
+        }
+    }
+  }
+
+  return data[key] ? getValue(data[key], keys, ipfsQuery) : { value: `failed to find value for key: ${key}`, type: 'string' }
+}

test/examples/examples.js

@@ -359,6 +359,40 @@ const cases = [
     source: "`_bool ? 'h' + _var + 'o' : 'bye'`",
     bindings: { _bool: bool(true), _var: string('ell') }
   }, 'hello'],
+  [{
+    source: 'parse this ipfs hash: `@parseIpfs(test)`',
+    bindings: { test: string('Qmc3zqKcwzbbvw3MQm3hXdg8BQoFjGdZiGdAfXAyAGGdLi') }
+  }, 'parse this ipfs hash: Don\'t we all.'],
+  [{
+    source: 'get registry address: `@parseIpfs(test,"", "env", "registry")`',
+    bindings: { 
+      test: string('QmWP9roMebu5LyV6Q4RNooAw6yj18zKUqXqAc5Lxy1YVFh'),
+    }
+  }, 'get registry address: 0x5f6F7E8cc7346a11ca2dEf8f827b7a0b612c56a1'],
+  [{
+    source: 'works with invalid custom node: `@parseIpfs(test,"http://invalidaddress", "env", "registry")`',
+    bindings: { 
+      test: string('QmWP9roMebu5LyV6Q4RNooAw6yj18zKUqXqAc5Lxy1YVFh'),
+    }
+  }, 'works with invalid custom node: 0x5f6F7E8cc7346a11ca2dEf8f827b7a0b612c56a1'],
+  [{
+    source: 'fails to get networkId: `@parseIpfs(test,"", "env", "networkId")` (undefined key)',
+    bindings: { 
+      test: string('QmWP9roMebu5LyV6Q4RNooAw6yj18zKUqXqAc5Lxy1YVFh'),
+    }
+  }, 'fails to get networkId: failed to find value for key: networkId (undefined key)'],
+  [{
+    source: 'fails to get registry address: `@parseIpfs(test,"", "env", "registry")` (invalid CID)',
+    bindings: { 
+      test: string('Qm'),
+    }
+  }, 'fails to get registry address: failed getting data from IPFS: Error: Request failed with status code 500 (invalid CID)'],
+  [{
+    source: 'returns links for non-string values: `@parseIpfs(test,"", "env")`',
+    bindings: { 
+      test: string('QmWP9roMebu5LyV6Q4RNooAw6yj18zKUqXqAc5Lxy1YVFh'),
+    }
+  }, 'returns links for non-string values: https://ipfs.autark.xyz:5001/api/v0/cat?arg=QmWP9roMebu5LyV6Q4RNooAw6yj18zKUqXqAc5Lxy1YVFh'],
 
   // External calls with multiple return values
   [{