Merge pull request MetaMask#154 from MetaMask/InflightCache

Inflight cache

package.json

@@ -1,6 +1,6 @@
 {
   "name": "web3-provider-engine",
-  "version": "12.1.0",
+  "version": "12.2.0",
   "description": "",
   "repository": "https://github.com/MetaMask/provider-engine",
   "main": "index.js",
@@ -23,6 +23,7 @@
     "ethereumjs-vm": "^2.0.2",
     "fetch-ponyfill": "^4.0.0",
     "json-rpc-error": "^2.0.0",
+    "json-stable-stringify": "^1.0.1",
     "promise-to-callback": "^1.0.0",
     "readable-stream": "^2.2.9",
     "request": "^2.67.0",

subproviders/inflight-cache.js

@@ -0,0 +1,44 @@
+const cacheIdentifierForPayload = require('../util/rpc-cache-utils.js').cacheIdentifierForPayload
+const Subprovider = require('./subprovider.js')
+
+
+class InflightCacheSubprovider extends Subprovider {
+
+  constructor (opts) {
+    super()
+    this.inflightRequests = {}
+  }
+
+  addEngine (engine) {
+    this.engine = engine
+  }
+
+  handleRequest (req, next, end) {
+    const cacheId = cacheIdentifierForPayload(req)
+
+    // if not cacheable, skip
+    if (!cacheId) return next()
+
+    // check for matching requests
+    let activeRequestHandlers = this.inflightRequests[cacheId]
+
+    if (!activeRequestHandlers) {
+      activeRequestHandlers = []
+      this.inflightRequests[cacheId] = activeRequestHandlers
+
+      next((err, result, cb) => {
+        delete this.inflightRequests[cacheId]
+        activeRequestHandlers.forEach((handler) => handler(err, result))
+        cb(err, result)
+      })
+
+    } else {
+      // setup the response lister
+      activeRequestHandlers.push(end)
+    }
+
+  }
+}
+
+module.exports = InflightCacheSubprovider
+

test/filters.js

@@ -19,7 +19,7 @@ filterTest('basic block filter', { method: 'eth_newBlockFilter' },
     cb()
   },
   function filterChangesTwo(t, testMeta, response, cb){
-    var results = response.result        
+    var results = response.result
     t.equal(results.length, 0, 'correct number of results')
     cb()
   }
@@ -49,7 +49,7 @@ filterTest('log filter - basic', {
     cb()
   },
   function filterChangesTwo(t, testMeta, response, cb){
-    var results = response.result        
+    var results = response.result
     t.equal(results.length, 0, 'correct number of results')
     cb()
   }
@@ -88,7 +88,7 @@ filterTest('log filter - and logic', {
     cb()
   },
   function filterChangesTwo(t, testMeta, response, cb){
-    var results = response.result        
+    var results = response.result
     t.equal(results.length, 0, 'correct number of results')
     cb()
   }
@@ -134,7 +134,7 @@ filterTest('log filter - or logic', {
     cb()
   },
   function filterChangesTwo(t, testMeta, response, cb){
-    var results = response.result        
+    var results = response.result
     t.equal(results.length, 0, 'correct number of results')
     cb()
   }
@@ -181,7 +181,7 @@ filterTest('log filter - wildcard logic', {
     cb()
   },
   function filterChangesTwo(t, testMeta, response, cb){
-    var results = response.result        
+    var results = response.result
     t.equal(results.length, 0, 'correct number of results')
     cb()
   }
@@ -211,7 +211,10 @@ function filterTest(label, filterPayload, afterInstall, filterChangesOne, filter
     engine.addProvider(filterProvider)
     engine.addProvider(blockProvider)
     engine.once('block', startTest)
-    engine.start()
+
+    setTimeout(() => {
+      engine.start()
+    }, 1)
 
     function startTest(){
       // install block filter
@@ -228,7 +231,6 @@ function filterTest(label, filterPayload, afterInstall, filterChangesOne, filter
 
         afterInstall(t, testMeta, response, function(err){
           t.ifError(err, 'did not error')
-
           engine.once('block', continueTest)
         })
       })

test/util/block.js

@@ -25,7 +25,6 @@ function TestBlockProvider(methods){
       } else {
         result = self._blockChain[blockRef]
       }
-
       end(null, result)
     },
     eth_getLogs: function(payload, next, end){
@@ -72,7 +71,7 @@ TestBlockProvider.prototype.addTx = function(txParams){
 function createBlock(blockParams, prevBlock, txs) {
   blockParams = blockParams || {}
   txs = txs || []
-  var defaultNumber = prevBlock ? incrementHex(prevBlock.number) : '0x01'
+  var defaultNumber = prevBlock ? incrementHex(prevBlock.number) : '0x1'
   var defaultGasLimit = ethUtil.intToHex(4712388)
   return extend({
     // defaults
@@ -99,9 +98,17 @@ function createBlock(blockParams, prevBlock, txs) {
 }
 
 function incrementHex(hexString){
-  return ethUtil.intToHex(Number(hexString)+1)
+  return stripLeadingZeroes(ethUtil.intToHex(Number(hexString)+1))
 }
 
 function randomHash(){
   return ethUtil.intToHex(Math.floor(Math.random()*Number.MAX_SAFE_INTEGER))
 }
+
+function stripLeadingZeroes (hexString) {
+  let strippedHex = ethUtil.stripHexPrefix(hexString)
+  while (strippedHex[0] === '0') {
+    strippedHex = strippedHex.substr(1)
+  }
+  return ethUtil.addHexPrefix(strippedHex)
+}

util/rpc-cache-utils.js

@@ -1,3 +1,5 @@
+const stringify = require('json-stable-stringify')
+
 module.exports = {
   cacheIdentifierForPayload: cacheIdentifierForPayload,
   canCache: canCache,
@@ -10,7 +12,7 @@ module.exports = {
 function cacheIdentifierForPayload(payload){
   var simpleParams = paramsWithoutBlockTag(payload)
   if (canCache(payload)) {
-    return payload.method+':'+JSON.stringify(simpleParams)
+    return payload.method+':'+ stringify(simpleParams)
   } else {
     return null
   }

zero.js

@@ -3,6 +3,7 @@ const DefaultFixture = require('./subproviders/default-fixture.js')
 const NonceTrackerSubprovider = require('./subproviders/nonce-tracker.js')
 const CacheSubprovider = require('./subproviders/cache.js')
 const FilterSubprovider = require('./subproviders/filters.js')
+const InflightCacheSubprovider = require('./subproviders/inflight-cache')
 const HookedWalletSubprovider = require('./subproviders/hooked-wallet.js')
 const SanitizingSubprovider = require('./subproviders/sanitizer.js')
 const RpcSubprovider = require('./subproviders/rpc.js')
@@ -36,6 +37,10 @@ function ZeroClientProvider(opts){
   const filterSubprovider = new FilterSubprovider()
   engine.addProvider(filterSubprovider)
 
+  // inflight cache
+  const inflightCache = new InflightCacheSubprovider()
+  engine.addProvider(inflightCache)
+
   // id mgmt
   const idmgmtSubprovider = new HookedWalletSubprovider({
     // accounts