nimbus-eth1/nimbus/rpc/hexstrings.nim

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# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
# * MIT license ([LICENSE-MIT](LICENSE-MIT))
# at your option.
# This file may not be copied, modified, or distributed except according to
# those terms.
## This module implements the Ethereum hexadecimal string formats for JSON
## See: https://github.com/ethereum/wiki/wiki/JSON-RPC#hex-value-encoding
#[
Note:
The following types are converted to hex strings when marshalled to JSON:
* EthAddress
* ref EthAddress
* Hash256
* UInt256
* seq[byte]
* openArray[seq]
* ref BloomFilter
]#
import eth_common/eth_types, stint, byteutils, nimcrypto
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type
HexQuantityStr* = distinct string
HexDataStr* = distinct string
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EthAddressStr* = distinct string # Same as HexDataStr but must be less <= 20 bytes
EthHashStr* = distinct string # Same as HexDataStr but must be exactly 32 bytes
WhisperIdentityStr* = distinct string # 60 bytes
HexStrings = HexQuantityStr | HexDataStr | EthAddressStr | EthHashStr | WhisperIdentityStr
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template len*(value: HexStrings): int = value.string.len
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# Hex validation
template stripLeadingZeros(value: string): string =
var cidx = 0
# ignore the last character so we retain '0' on zero value
while cidx < value.len - 1 and value[cidx] == '0':
cidx.inc
value[cidx .. ^1]
func encodeQuantity*(value: SomeUnsignedInt): string {.inline.} =
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var hValue = value.toHex.stripLeadingZeros
result = "0x" & hValue
template hasHexHeader(value: string): bool =
if value.len >= 2 and value[0] == '0' and value[1] in {'x', 'X'}: true
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else: false
template isHexChar(c: char): bool =
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if c notin {'0'..'9'} and
c notin {'a'..'f'} and
c notin {'A'..'F'}: false
else: true
func isValidHexQuantity*(value: string): bool =
if not value.hasHexHeader:
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return false
# No leading zeros (but allow 0x0)
if value.len < 3 or (value.len > 3 and value[2] == '0'): return false
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for i in 2 ..< value.len:
let c = value[i]
if not c.isHexChar:
return false
return true
func isValidHexData*(value: string): bool =
if not value.hasHexHeader:
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return false
# Must be even number of digits
if value.len mod 2 != 0: return false
# Leading zeros are allowed
for i in 2 ..< value.len:
let c = value[i]
if not c.isHexChar:
return false
return true
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func isValidEthAddress*(value: string): bool =
# 20 bytes for EthAddress plus "0x"
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# Addresses are allowed to be shorter than 20 bytes for convenience
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result = value.len <= 42 and value.isValidHexData
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func isValidEthHash*(value: string): bool =
# 32 bytes for EthAddress plus "0x"
# Currently hashes are required to be exact lengths
# TODO: Allow shorter hashes (pad with zeros) for convenience?
result = value.len == 66 and value.isValidHexData
func isValidWhisperIdentity*(value: string): bool =
# 60 bytes for WhisperIdentity plus "0x"
# TODO: Are the HexData constratins applicable to Whisper identities?
result = value.len == 122 and value.isValidHexData
const
SInvalidQuantity = "Invalid hex quantity format for Ethereum"
SInvalidData = "Invalid hex data format for Ethereum"
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SInvalidAddress = "Invalid address format for Ethereum"
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SInvalidHash = "Invalid hash format for Ethereum"
SInvalidWhisperIdentity = "Invalid format for whisper identity"
proc validateHexQuantity*(value: string) {.inline.} =
if unlikely(not value.isValidHexQuantity):
raise newException(ValueError, SInvalidQuantity & ": " & value)
proc validateHexData*(value: string) {.inline.} =
if unlikely(not value.isValidHexData):
raise newException(ValueError, SInvalidData & ": " & value)
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proc validateHexAddressStr*(value: string) {.inline.} =
if unlikely(not value.isValidEthAddress):
raise newException(ValueError, SInvalidAddress & ": " & value)
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proc validateHashStr*(value: string) {.inline.} =
if unlikely(not value.isValidEthHash):
raise newException(ValueError, SInvalidHash & ": " & value)
proc validateWhisperIdentity*(value: string) {.inline.} =
if unlikely(not value.isValidWhisperIdentity):
raise newException(ValueError, SInvalidWhisperIdentity & ": " & value)
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# Initialisation
proc hexQuantityStr*(value: string): HexQuantityStr {.inline.} =
value.validateHexQuantity
result = value.HexQuantityStr
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proc hexDataStr*(value: string): HexDataStr {.inline.} =
value.validateHexData
result = value.HexDataStr
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proc ethAddressStr*(value: string): EthAddressStr {.inline.} =
value.validateHexAddressStr
result = value.EthAddressStr
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proc ethHashStr*(value: string): EthHashStr {.inline.} =
value.validateHashStr
result = value.EthHashStr
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proc whisperIdentity*(value: string): WhisperIdentityStr {.inline.} =
value.validateWhisperIdentity
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result = value.WhisperIdentityStr
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# Converters for use in RPC
import json
from json_rpc/rpcserver import expect
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proc `%`*(value: HexStrings): JsonNode =
result = %(value.string)
# Overloads to support expected representation of hex data
proc `%`*(value: EthAddress): JsonNode =
result = %("0x" & value.toHex)
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proc `%`*(value: ref EthAddress): JsonNode =
result = %("0x" & value[].toHex)
proc `%`*(value: Hash256): JsonNode =
result = %("0x" & $value)
proc `%`*(value: UInt256): JsonNode =
result = %("0x" & value.toString)
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proc `%`*(value: WhisperIdentity): JsonNode =
result = %("0x" & byteutils.toHex(value))
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proc `%`*(value: ref BloomFilter): JsonNode =
result = %("0x" & toHex[256](value[]))
# Marshalling from JSON to Nim types that includes format checking
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proc fromJson*(n: JsonNode, argName: string, result: var HexQuantityStr) =
n.kind.expect(JString, argName)
let hexStr = n.getStr()
if not hexStr.isValidHexQuantity:
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raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as an Ethereum hex quantity \"" & hexStr & "\"")
result = hexStr.hexQuantityStr
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proc fromJson*(n: JsonNode, argName: string, result: var HexDataStr) =
n.kind.expect(JString, argName)
let hexStr = n.getStr()
if not hexStr.isValidHexData:
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raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as Ethereum data \"" & hexStr & "\"")
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result = hexStr.hexDataStr
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proc fromJson*(n: JsonNode, argName: string, result: var EthAddressStr) =
n.kind.expect(JString, argName)
let hexStr = n.getStr()
if not hexStr.isValidEthAddress:
raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as an Ethereum address \"" & hexStr & "\"")
result = hexStr.EthAddressStr
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proc fromJson*(n: JsonNode, argName: string, result: var EthHashStr) =
n.kind.expect(JString, argName)
let hexStr = n.getStr()
if not hexStr.isValidEthHash:
raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as an Ethereum hash \"" & hexStr & "\"")
result = hexStr.EthHashStr
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proc fromJson*(n: JsonNode, argName: string, result: var WhisperIdentityStr) =
n.kind.expect(JString, argName)
let hexStr = n.getStr()
if not hexStr.isValidWhisperIdentity:
raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as a Whisper identity \"" & hexStr & "\"")
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result = hexStr.WhisperIdentityStr