nimbus-eth2/beacon_chain/rpc/rest_utils.nim
Zahary Karadjov 922a0d264c Add CORS support for the REST services
The added options work in opt-in fashion. If they are not specified,
the server will respond to all requests as if the CORS specification
doesn't exist. This will result in errors in CORS-enabled clients.

Please note that future versions may support more than one allowed
origin. The option names will stay the same, but the user will be
able to repeat them on the command line (similar to other options
such as --web3-url).

To be documented in the guide in a separate PR.
2022-02-14 18:52:17 +02:00

281 lines
9.6 KiB
Nim

import std/[options, macros],
stew/byteutils, presto,
../spec/[forks],
../spec/eth2_apis/[rest_types, eth2_rest_serialization],
../beacon_node,
../consensus_object_pools/blockchain_dag,
"."/[rest_constants, state_ttl_cache]
export
options, eth2_rest_serialization, blockchain_dag, presto, rest_types,
rest_constants
type
ValidatorIndexError* {.pure.} = enum
UnsupportedValue, TooHighValue
func match(data: openarray[char], charset: set[char]): int =
for ch in data:
if ch notin charset:
return 1
0
proc validate(key: string, value: string): int =
## This is rough validation procedure which should be simple and fast,
## because it will be used for query routing.
case key
of "{epoch}":
0
of "{slot}":
0
of "{peer_id}":
0
of "{state_id}":
0
of "{block_id}":
0
of "{validator_id}":
0
else:
1
func getCurrentSlot*(node: BeaconNode, slot: Slot):
Result[Slot, cstring] =
if slot <= (node.dag.head.slot + (SLOTS_PER_EPOCH * 2)):
ok(slot)
else:
err("Requesting slot too far ahead of the current head")
func getCurrentBlock*(node: BeaconNode, slot: Slot):
Result[BlockRef, cstring] =
let bs = node.dag.getBlockAtSlot(? node.getCurrentSlot(slot))
if bs.isProposed():
ok(bs.blck)
else:
err("Block not found")
proc getCurrentHead*(node: BeaconNode, slot: Slot): Result[BlockRef, cstring] =
let res = node.dag.head
# if not(node.isSynced(res)):
# return err("Cannot fulfill request until node is synced")
if res.slot + uint64(2 * SLOTS_PER_EPOCH) < slot:
return err("Requesting way ahead of the current head")
ok(res)
proc getCurrentHead*(node: BeaconNode,
epoch: Epoch): Result[BlockRef, cstring] =
if epoch > MaxEpoch:
return err("Requesting epoch for which slot would overflow")
node.getCurrentHead(epoch.start_slot())
proc getBlockSlot*(node: BeaconNode,
stateIdent: StateIdent): Result[BlockSlot, cstring] =
case stateIdent.kind
of StateQueryKind.Slot:
let bs = node.dag.getBlockAtSlot(? node.getCurrentSlot(stateIdent.slot))
if not isNil(bs.blck):
ok(bs)
else:
err("State for given slot not found, history not available?")
of StateQueryKind.Root:
if stateIdent.root == getStateRoot(node.dag.headState.data):
ok(node.dag.headState.blck.atSlot())
else:
# We don't have a state root -> BlockSlot mapping
err("State for given root not found")
of StateQueryKind.Named:
case stateIdent.value
of StateIdentType.Head:
ok(node.dag.head.atSlot())
of StateIdentType.Genesis:
ok(node.dag.genesis.atSlot())
of StateIdentType.Finalized:
ok(node.dag.finalizedHead)
of StateIdentType.Justified:
ok(node.dag.head.atEpochStart(getStateField(
node.dag.headState.data, current_justified_checkpoint).epoch))
proc getBlockId*(node: BeaconNode, id: BlockIdent): Result[BlockId, cstring] =
case id.kind
of BlockQueryKind.Named:
case id.value
of BlockIdentType.Head:
ok(node.dag.head.bid)
of BlockIdentType.Genesis:
ok(node.dag.genesis.bid)
of BlockIdentType.Finalized:
ok(node.dag.finalizedHead.blck.bid)
of BlockQueryKind.Root:
node.dag.getBlockId(id.root).orErr(cstring("Block not found"))
of BlockQueryKind.Slot:
let bsid = node.dag.getBlockIdAtSlot(id.slot)
if bsid.isProposed():
ok bsid.bid
else:
err("Block not found")
proc getForkedBlock*(node: BeaconNode, id: BlockIdent):
Result[ForkedTrustedSignedBeaconBlock, cstring] =
case id.kind
of BlockQueryKind.Named:
case id.value
of BlockIdentType.Head:
ok(node.dag.getForkedBlock(node.dag.head))
of BlockIdentType.Genesis:
ok(node.dag.getForkedBlock(node.dag.genesis))
of BlockIdentType.Finalized:
ok(node.dag.getForkedBlock(node.dag.finalizedHead.blck))
of BlockQueryKind.Root:
node.dag.getForkedBlock(id.root).orErr(cstring("Block not found"))
of BlockQueryKind.Slot:
let bsid = node.dag.getBlockIdAtSlot(id.slot)
if bsid.isProposed():
node.dag.getForkedBlock(bsid.bid).orErr(cstring("Block not found"))
else:
err("Block not found")
proc disallowInterruptionsAux(body: NimNode) =
for n in body:
const because =
"because the `state` variable may be mutated (and thus invalidated) " &
"before the function resumes execution."
if n.kind == nnkYieldStmt:
macros.error "You cannot use yield in this block " & because, n
if (n.kind in {nnkCall, nnkCommand} and
n[0].kind in {nnkIdent, nnkSym} and
$n[0] == "await"):
macros.error "You cannot use await in this block " & because, n
disallowInterruptionsAux(n)
macro disallowInterruptions(body: untyped) =
disallowInterruptionsAux(body)
template withStateForBlockSlot*(nodeParam: BeaconNode,
blockSlotParam: BlockSlot,
body: untyped): untyped =
block:
let
node = nodeParam
blockSlot = blockSlotParam
template isState(state: StateData): bool =
state.blck.atSlot(getStateField(state.data, slot)) == blockSlot
var cache {.inject, used.}: StateCache
# If we have a cache hit, there is a concern that the REST request
# handler may continue executing asynchronously while we hit the same
# advanced state is another request. We don't want the two requests
# to work over the same state object because mutations to it will be
# visible in both, so we must outlaw yielding within the `body` block.
# Please note that the problem is not limited to the situations where
# we have a cache hit. Working with the `headState` will result in the
# same problem as it may change while the request is executing.
#
# TODO
# The solution below is only partion, because it theory yields or awaits
# can still be hidden in the body through the use of helper templates
disallowInterruptions(body)
# TODO view-types
# Avoid the code bloat produced by the double `body` reference through a lent var
if isState(node.dag.headState):
withStateVars(node.dag.headState):
body
else:
let cachedState = if node.stateTtlCache != nil:
node.stateTtlCache.getClosestState(blockSlot)
else:
nil
let stateToAdvance = if cachedState != nil:
cachedState
else:
assignClone(node.dag.headState)
if node.dag.updateStateData(stateToAdvance[], blockSlot, false, cache):
if cachedState == nil and node.stateTtlCache != nil:
# This was not a cached state, we can cache it now
node.stateTtlCache.add(stateToAdvance)
withStateVars(stateToAdvance[]):
body
template strData*(body: ContentBody): string =
bind fromBytes
string.fromBytes(body.data)
proc toValidatorIndex*(value: RestValidatorIndex): Result[ValidatorIndex,
ValidatorIndexError] =
when sizeof(ValidatorIndex) == 4:
if uint64(value) < VALIDATOR_REGISTRY_LIMIT:
# On x86 platform Nim allows only `int32` indexes, so all the indexes in
# range `2^31 <= x < 2^32` are not supported.
if uint64(value) <= uint64(high(int32)):
ok(ValidatorIndex(value))
else:
err(ValidatorIndexError.UnsupportedValue)
else:
err(ValidatorIndexError.TooHighValue)
elif sizeof(ValidatorIndex) == 8:
if uint64(value) < VALIDATOR_REGISTRY_LIMIT:
ok(ValidatorIndex(value))
else:
err(ValidatorIndexError.TooHighValue)
else:
doAssert(false, "ValidatorIndex type size is incorrect")
func syncCommitteeParticipants*(forkedState: ForkedHashedBeaconState,
epoch: Epoch
): Result[seq[ValidatorPubKey], cstring] =
withState(forkedState):
when stateFork >= BeaconStateFork.Altair:
let
epochPeriod = sync_committee_period(epoch)
curPeriod = sync_committee_period(state.data.slot)
if epochPeriod == curPeriod:
ok(@(state.data.current_sync_committee.pubkeys.data))
elif epochPeriod == curPeriod + 1:
ok(@(state.data.next_sync_committee.pubkeys.data))
else:
err("Epoch is outside the sync committee period of the state")
else:
err("State's fork do not support sync committees")
func keysToIndices*(cacheTable: var Table[ValidatorPubKey, ValidatorIndex],
forkedState: ForkedHashedBeaconState,
keys: openArray[ValidatorPubKey]
): seq[Option[ValidatorIndex]] =
var indices = newSeq[Option[ValidatorIndex]](len(keys))
var keyset =
block:
var res: Table[ValidatorPubKey, int]
for inputIndex, pubkey in keys.pairs():
# Try to search in cache first.
cacheTable.withValue(pubkey, vindex):
indices[inputIndex] = some(vindex[])
do:
res[pubkey] = inputIndex
res
if len(keyset) > 0:
for validatorIndex, validator in getStateField(forkedState,
validators).pairs():
keyset.withValue(validator.pubkey, listIndex):
# Store pair (pubkey, index) into cache table.
cacheTable[validator.pubkey] = ValidatorIndex(validatorIndex)
# Fill result sequence.
indices[listIndex[]] = some(ValidatorIndex(validatorIndex))
indices
proc getRouter*(allowedOrigin: Option[string]): RestRouter =
RestRouter.init(validate, allowedOrigin = allowedOrigin)
const
jsonMediaType* = MediaType.init("application/json")
sszMediaType* = MediaType.init("application/octet-stream")
textEventStreamMediaType* = MediaType.init("text/event-stream")