fix: block filters can be also recreated (#85)

* fix: block filters can be also recreated

* refactor: rename filter to logFilter

Author: AuHau

ethers/providers/jsonrpc/subscriptions.nim

@@ -140,7 +140,7 @@ type
     # We need to keep around the filters that are used to create log filters on the RPC node
     # as there might be a time when they need to be recreated as RPC node might prune/forget
     # about them
-    filters: Table[JsonNode, EventFilter]
+    logFilters: Table[JsonNode, EventFilter]
 
     # Used when filters are recreated to translate from the id that user
     # originally got returned to new filter id
@@ -167,8 +167,15 @@ proc new*(_: type JsonRpcSubscriptions,
       raise e
     except CatchableError as e:
       if "filter not found" in e.msg:
-        let filter = subscriptions.filters[originalId]
-        let newId = await subscriptions.client.eth_newFilter(filter)
+        var newId: JsonNode
+        # Log filters are stored in logFilters, block filters are not persisted
+        # there is they do not need any specific data for their recreation.
+        # We use this to determine if the filter was log or block filter here.
+        if subscriptions.logFilters.hasKey(originalId):
+          let filter = subscriptions.logFilters[originalId]
+          newId = await subscriptions.client.eth_newFilter(filter)
+        else:
+          newId = await subscriptions.client.eth_newBlockFilter()
         subscriptions.subscriptionMapping[originalId] = newId
         return await getChanges(originalId)
       else:
@@ -225,14 +232,14 @@ method subscribeLogs(subscriptions: PollingSubscriptions,
 
   let id = await subscriptions.client.eth_newFilter(filter)
   subscriptions.callbacks[id] = callback
-  subscriptions.filters[id] = filter
+  subscriptions.logFilters[id] = filter
   subscriptions.subscriptionMapping[id] = id
   return id
 
 method unsubscribe*(subscriptions: PollingSubscriptions,
                    id: JsonNode)
                   {.async.} =
-  subscriptions.filters.del(id)
+  subscriptions.logFilters.del(id)
   subscriptions.callbacks.del(id)
   let sub = subscriptions.subscriptionMapping[id]
   subscriptions.subscriptionMapping.del(id)

testmodule/providers/jsonrpc/rpc_mock.nim

@@ -25,6 +25,11 @@ proc start*(server: MockRpcHttpServer) =
     server.filters.add filterId
     return filterId
 
+  server.srv.router.rpc("eth_newBlockFilter") do() -> string:
+    let filterId = "0x" & (array[16, byte].example).toHex
+    server.filters.add filterId
+    return filterId
+
   server.srv.router.rpc("eth_getFilterChanges") do(id: string) -> seq[string]:
     if id notin server.filters:
       raise (ref ApplicationError)(code: -32000, msg: "filter not found")

testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim

@@ -124,25 +124,25 @@ suite "HTTP polling subscriptions - filter not found":
     await client.close()
     await mockServer.stop()
 
-  test "filter not found error recreates filter":
+  test "filter not found error recreates log filter":
     let filter = EventFilter(address: Address.example, topics: @[array[32, byte].example])
     let emptyHandler = proc(log: Log) = discard
 
-    check subscriptions.filters.len == 0
+    check subscriptions.logFilters.len == 0
     check subscriptions.subscriptionMapping.len == 0
 
     let id = await subscriptions.subscribeLogs(filter, emptyHandler)
 
-    check subscriptions.filters[id] == filter
+    check subscriptions.logFilters[id] == filter
     check subscriptions.subscriptionMapping[id] == id
-    check subscriptions.filters.len == 1
+    check subscriptions.logFilters.len == 1
     check subscriptions.subscriptionMapping.len == 1
 
     mockServer.invalidateFilter(id)
 
     check eventually subscriptions.subscriptionMapping[id] != id
 
-  test "recreated filter can be still unsubscribed using the original id":
+  test "recreated log filter can be still unsubscribed using the original id":
     let filter = EventFilter(address: Address.example, topics: @[array[32, byte].example])
     let emptyHandler = proc(log: Log) = discard
     let id = await subscriptions.subscribeLogs(filter, emptyHandler)
@@ -151,5 +151,26 @@ suite "HTTP polling subscriptions - filter not found":
 
     await subscriptions.unsubscribe(id)
 
-    check not subscriptions.filters.hasKey id
+    check not subscriptions.logFilters.hasKey id
+    check not subscriptions.subscriptionMapping.hasKey id
+
+  test "filter not found error recreates block filter":
+    let emptyHandler = proc(blck: Block) = discard
+
+    check subscriptions.subscriptionMapping.len == 0
+    let id = await subscriptions.subscribeBlocks(emptyHandler)
+    check subscriptions.subscriptionMapping[id] == id
+
+    mockServer.invalidateFilter(id)
+
+    check eventually subscriptions.subscriptionMapping[id] != id
+
+  test "recreated block filter can be still unsubscribed using the original id":
+    let emptyHandler = proc(blck: Block) = discard
+    let id = await subscriptions.subscribeBlocks(emptyHandler)
+    mockServer.invalidateFilter(id)
+    check eventually subscriptions.subscriptionMapping[id] != id
+
+    await subscriptions.unsubscribe(id)
+
     check not subscriptions.subscriptionMapping.hasKey id