Add hash support when parsing BlockTag (#242)

* Add hash support when parsing BlockTag

* Fix test

* Fix test

Author: jangko

tests/test_json_marshalling.nim

@@ -1,5 +1,5 @@
 # nim-web3
-# Copyright (c) 2018-2025 Status Research & Development GmbH
+# Copyright (c) 2018-2026 Status Research & Development GmbH
 # Licensed under either of
 #  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
 #  * MIT license ([LICENSE-MIT](LICENSE-MIT))
@@ -249,6 +249,11 @@ suite "JSON-RPC Quantity":
       let d = JrpcConv.decode("10", RtBlockIdentifier)
       discard d
 
+    const w = hash32"0x0012c7b99594801d513ae92396379e5ffcf60e23127cbcabb166db28586f01aa"
+    let e = JrpcConv.decode("\"" & $w & "\"", RtBlockIdentifier)
+    check e.kind == bidHash
+    check e.hash == w
+
   test "check address or list":
     let a = AddressOrList(kind: slkNull)
     let x = JrpcConv.encode(a)
@@ -264,7 +269,7 @@ suite "JSON-RPC Quantity":
         check b == "\"0x16345785d8a0000\""
 
         let x = JrpcConv.decode("\"0xFFFF_FFFF_FFFF_FFFF\"", typeName)
-        check x.uint64 == 0xFFFF_FFFF_FFFF_FFFF_FFFF'u64
+        check x.uint64 == 0xFFFF_FFFF_FFFF_FFFF'u64
         let y = JrpcConv.encode(x)
         check y == "\"0xffffffffffffffff\""
 

web3/conversions.nim

@@ -1,5 +1,5 @@
 # nim-web3
-# Copyright (c) 2019-2025 Status Research & Development GmbH
+# Copyright (c) 2019-2026 Status Research & Development GmbH
 # Licensed under either of
 #  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
 #  * MIT license ([LICENSE-MIT](LICENSE-MIT))
@@ -189,6 +189,13 @@ func valid(hex: string): bool =
     if x notin HexDigits: return false
   true
 
+func validHash(hex: string): bool =
+  # assume `hex` has been checked before by `valid`
+  const hexHashLen = 32*2
+  if hex[0] == '0' and hex[1] in {'x', 'X'}:
+    return hex.len == hexHashLen + 2
+  hex.len == hexHashLen
+
 when not declared(json_serialization.streamElement): # json_serialization < 0.3.0
   template streamElement(w: var JsonWriter, s, body: untyped) =
     template s: untyped = w.stream
@@ -376,8 +383,12 @@ proc readValue*(r: var JsonReader[JrpcConv], val: var RtBlockIdentifier)
   let hexStr = r.parseString()
   wrapValueError:
     if valid(hexStr):
-      val = RtBlockIdentifier(
-        kind: bidNumber, number: Quantity fromHex[uint64](hexStr))
+      if validHash(hexStr):
+        val = RtBlockIdentifier(
+          kind: bidHash, hash: fromHex(Hash32, hexStr))
+      else:
+        val = RtBlockIdentifier(
+          kind: bidNumber, number: Quantity fromHex[uint64](hexStr))
     else:
       val = RtBlockIdentifier(kind: bidAlias, alias: hexStr)
 
@@ -386,6 +397,7 @@ proc writeValue*(w: var JsonWriter[JrpcConv], v: RtBlockIdentifier)
   case v.kind
   of bidNumber: w.writeValue(v.number)
   of bidAlias: w.writeValue(v.alias)
+  of bidHash: w.writeValue(v.hash)
 
 proc readValue*(r: var JsonReader[JrpcConv], val: var TxOrHash)
        {.gcsafe, raises: [IOError, SerializationError].} =

web3/eth_api_types.nim

@@ -244,13 +244,16 @@ type
   BlockIdentifierKind* = enum
     bidNumber
     bidAlias
+    bidHash
 
   RtBlockIdentifier* = object
     case kind*: BlockIdentifierKind
     of bidNumber:
       number*: Quantity
     of bidAlias:
       alias*: string
+    of bidHash:
+      hash*: Hash32
 
   FeeHistoryReward* = seq[UInt256]