1 files changed, 33 insertions, 0 deletions
diff --git a/app/scripts/controllers/network/createLocalhostClient.js b/app/scripts/controllers/network/createLocalhostClient.js
new file mode 100644
index 000000000..404415532
--- /dev/null
+++ b/app/scripts/controllers/network/createLocalhostClient.js
@@ -0,0 +1,33 @@
+const mergeMiddleware = require('json-rpc-engine/src/mergeMiddleware')
+const createAsyncMiddleware = require('json-rpc-engine/src/createAsyncMiddleware')
+const createFetchMiddleware = require('eth-json-rpc-middleware/fetch')
+const createBlockRefMiddleware = require('eth-json-rpc-middleware/block-ref')
+const createBlockRefMiddleware = require('eth-json-rpc-middleware/block-cache')
+const BlockTracker = require('eth-block-tracker')
+
+module.exports = createLocalhostClient
+
+function createLocalhostClient() {
+  const fetchMiddleware = createFetchMiddleware({ rpcUrl: 'http://localhost:8545/' })
+  const blockProvider = providerFromMiddleware(fetchMiddleware)
+  const blockTracker = new BlockTracker({ provider: blockProvider, pollingInterval: 1000 })
+
+  const networkMiddleware = mergeMiddleware([
+    createBlockRefMiddleware({ blockTracker }),
+    createBlockTrackerInspectorMiddleware({ blockTracker }),
+    fetchMiddleware,
+  ])
+  return { networkMiddleware, blockTracker }
+}
+
+// inspect if response contains a block ref higher than our latest block
+const futureBlockRefRequests = ['eth_getTransactionByHash', 'eth_getTransactionReceipt']
+function createBlockTrackerInspectorMiddleware ({ blockTracker }) {
+  return createAsyncMiddleware(async (req, res, next) => {
+    if (!futureBlockRefRequests.includes(req.method)) return next()
+    await next()
+    const blockNumber = Number.parseInt(res.result.blockNumber, 16)
+    const currentBlockNumber = Number.parseInt(blockTracker.getCurrentBlock(), 16)
+    if (blockNumber > currentBlockNumber) await blockTracker.checkForLatestBlock()
+  })
+}