Merge pull request #74 from cmditch/event-sentry-fix

All kinds of tricky considerations arose as the re-implementation moved along.

Basically we mark all requests as pending until a block number is returned from the EventSentry.init RPC call. Once we get a blockNumber, the whole machinery starts.

This accounts for the edge case "What if two or more blocks are mined between the 2-second polling period?".

This also implements the EventySentry.watch API a bit more honestly, as the old one ignored the LogFilter's fromBlock and toBlock fields, and mutated them to watch the latest block off the bat. This implementation will allow you to grab arbitrary block ranges, as well as continuously poll the latest blocks.

Author: cmditch

elm.json

@@ -3,7 +3,7 @@
     "name": "cmditch/elm-ethereum",
     "summary": "feed the tree some ether.",
     "license": "MIT",
-    "version": "3.0.0",
+    "version": "3.0.1",
     "exposed-modules": [
         "Eth",
         "Eth.Decode",

integration-tests/src/Main.elm

@@ -95,8 +95,9 @@ view model =
 
 type Msg
     = InitTest
-    | WatchOnce
-    | ContinousWatching
+    | WatchLatest
+    | WatchRanged
+    | WatchOnceRangeToLatest
     | NewResponse String
     | EventSentryMsg EventSentry.Msg
 
@@ -112,26 +113,36 @@ update msg model =
                 , transactionCmd
                 , blockCmd
                 , contractCmds
-                , watchOnceEvent
-                , continuousWatchingEvent
+                , watchLatest
+                , watchRanged
+                , watchOnceRangeToLatest
                 ]
             )
 
-        WatchOnce ->
+        WatchLatest ->
             let
-                ( subModel, subCmd ) =
-                    EventSentry.watchOnce (logToString >> (++) "WatchOnce Cmd: " >> NewResponse)
+                ( subModel, subCmd, _ ) =
+                    EventSentry.watch watchLatestHelper
                         model.eventSentry
-                        daiTransferFilter
+                        filterLatest
             in
             ( { model | eventSentry = subModel }, subCmd )
 
-        ContinousWatching ->
+        WatchRanged ->
             let
                 ( subModel, subCmd, _ ) =
-                    EventSentry.watch (logToString >> (++) "ContinousWatching Cmd: " >> NewResponse)
+                    EventSentry.watch watchRangedHelper
+                        model.eventSentry
+                        filterRanged
+            in
+            ( { model | eventSentry = subModel }, subCmd )
+
+        WatchOnceRangeToLatest ->
+            let
+                ( subModel, subCmd ) =
+                    EventSentry.watchOnce watchOnceRangeToLatestHelper
                         model.eventSentry
-                        daiTransferFilter
+                        filterRangeToLatest
             in
             ( { model | eventSentry = subModel }, subCmd )
 
@@ -150,16 +161,6 @@ update msg model =
 -- Test Cmds
 
 
-watchOnceEvent : Cmd Msg
-watchOnceEvent =
-    Task.perform (\_ -> WatchOnce) (Task.succeed ())
-
-
-continuousWatchingEvent : Cmd Msg
-continuousWatchingEvent =
-    Task.perform (\_ -> ContinousWatching) (Task.succeed ())
-
-
 logCmd : Cmd Msg
 logCmd =
     Eth.getLogs ethNode erc20TransferFilter
@@ -268,15 +269,6 @@ erc20TransferFilter =
     }
 
 
-daiTransferFilter : LogFilter
-daiTransferFilter =
-    { fromBlock = LatestBlock
-    , toBlock = LatestBlock
-    , address = Utils.unsafeToAddress "0x89d24A6b4CcB1B6fAA2625fE562bDD9a23260359"
-    , topics = [ Just <| Utils.unsafeToHex "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef" ]
-    }
-
-
 erc20Contract : Address
 erc20Contract =
     Utils.unsafeToAddress "0x9f8f72aa9304c8b593d555f12ef6589cc3a579a2"
@@ -310,3 +302,68 @@ responseToString okToString result =
 
         Err err ->
             String.Conversions.fromHttpError err
+
+
+
+-- EventSentry Helpers
+-- ( Using DAI transfer event )
+
+
+watchLatest : Cmd Msg
+watchLatest =
+    Task.perform (\_ -> WatchLatest) (Task.succeed ())
+
+
+watchLatestHelper =
+    logToString >> (++) "WatchLatest Cmd: " >> NewResponse
+
+
+filterLatest : LogFilter
+filterLatest =
+    { fromBlock = LatestBlock
+    , toBlock = LatestBlock
+    , address = Utils.unsafeToAddress "0x89d24A6b4CcB1B6fAA2625fE562bDD9a23260359"
+    , topics = [ Just <| Utils.unsafeToHex "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef" ]
+    }
+
+
+
+--
+
+
+watchRanged : Cmd Msg
+watchRanged =
+    Task.perform (\_ -> WatchRanged) (Task.succeed ())
+
+
+watchRangedHelper =
+    logToString >> (++) "WatchRanged Cmd: " >> NewResponse
+
+
+filterRanged : LogFilter
+filterRanged =
+    { filterLatest
+        | fromBlock = BlockNum 7396400
+        , toBlock = BlockNum 7396404
+    }
+
+
+
+--
+
+
+watchOnceRangeToLatest : Cmd Msg
+watchOnceRangeToLatest =
+    Task.perform (\_ -> WatchOnceRangeToLatest) (Task.succeed ())
+
+
+watchOnceRangeToLatestHelper =
+    logToString >> (++) "WatchOnceRangeToLatest Cmd: " >> NewResponse
+
+
+filterRangeToLatest : LogFilter
+filterRangeToLatest =
+    { filterLatest
+        | fromBlock = BlockNum 7396400
+        , toBlock = LatestBlock
+    }