Files
lighthouse/beacon_node/rest_api/src/helpers.rs
2019-09-12 15:12:54 +10:00

314 lines
11 KiB
Rust

use crate::response_builder::ResponseBuilder;
use crate::{ApiError, ApiResult, BoxFut};
use beacon_chain::{BeaconChain, BeaconChainTypes};
use bls::PublicKey;
use eth2_libp2p::{PubsubMessage, Topic};
use eth2_libp2p::{BEACON_BLOCK_TOPIC, TOPIC_ENCODING_POSTFIX, TOPIC_PREFIX};
use hex;
use http::header;
use hyper::{Body, Request, Response, StatusCode};
use network::NetworkMessage;
use parking_lot::RwLock;
use serde::Serialize;
use ssz::Encode;
use std::sync::Arc;
use store::{iter::AncestorIter, Store};
use tokio::sync::mpsc;
use types::{BeaconBlock, BeaconState, EthSpec, Hash256, RelativeEpoch, Slot};
pub fn success_response<T: Serialize + Encode>(req: Request<Body>, item: &T) -> BoxFut {
Box::new(match ResponseBuilder::new(&req).body(item) {
Ok(resp) => futures::future::ok(resp),
Err(e) => futures::future::err(e),
})
}
pub fn success_response_2<T: Serialize + Encode>(req: Request<Body>, item: &T) -> ApiResult {
ResponseBuilder::new(&req).body(item)
}
pub fn success_response_2_json<T: Serialize>(req: Request<Body>, item: &T) -> ApiResult {
ResponseBuilder::new(&req).body_json(item)
}
pub fn success_response_json<T: Serialize>(req: Request<Body>, item: &T) -> BoxFut {
if let Err(e) = check_content_type_for_json(&req) {
return Box::new(futures::future::err(e));
}
Box::new(match ResponseBuilder::new(&req).body_json(item) {
Ok(resp) => futures::future::ok(resp),
Err(e) => futures::future::err(e),
})
}
pub fn success_response_old(body: Body) -> Response<Body> {
Response::builder()
.status(StatusCode::OK)
.header("content-type", "application/json")
.body(body)
.expect("We should always be able to make response from the success body.")
}
/// Parse a slot from a `0x` preixed string.
///
/// E.g., `"1234"`
pub fn parse_slot(string: &str) -> Result<Slot, ApiError> {
string
.parse::<u64>()
.map(Slot::from)
.map_err(|e| ApiError::InvalidQueryParams(format!("Unable to parse slot: {:?}", e)))
}
/// Checks the provided request to ensure that the `content-type` header.
///
/// The content-type header should either be omitted, in which case JSON is assumed, or it should
/// explicity specify `application/json`. If anything else is provided, an error is returned.
pub fn check_content_type_for_json(req: &Request<Body>) -> Result<(), ApiError> {
match req.headers().get(header::CONTENT_TYPE) {
Some(h) if h == "application/json" => Ok(()),
Some(h) => Err(ApiError::InvalidQueryParams(format!(
"The provided content-type {:?} is not available, this endpoint only supports json.",
h
))),
_ => Ok(()),
}
}
/// Parse a root from a `0x` preixed string.
///
/// E.g., `"0x0000000000000000000000000000000000000000000000000000000000000000"`
pub fn parse_root(string: &str) -> Result<Hash256, ApiError> {
const PREFIX: &str = "0x";
if string.starts_with(PREFIX) {
let trimmed = string.trim_start_matches(PREFIX);
trimmed
.parse()
.map_err(|e| ApiError::InvalidQueryParams(format!("Unable to parse root: {:?}", e)))
} else {
Err(ApiError::InvalidQueryParams(
"Root must have a '0x' prefix".to_string(),
))
}
}
/// Parse a PublicKey from a `0x` prefixed hex string
pub fn parse_pubkey(string: &str) -> Result<PublicKey, ApiError> {
const PREFIX: &str = "0x";
if string.starts_with(PREFIX) {
let pubkey_bytes = hex::decode(string.trim_start_matches(PREFIX))
.map_err(|e| ApiError::InvalidQueryParams(format!("Invalid hex string: {:?}", e)))?;
let pubkey = PublicKey::from_bytes(pubkey_bytes.as_slice()).map_err(|e| {
ApiError::InvalidQueryParams(format!("Unable to deserialize public key: {:?}.", e))
})?;
return Ok(pubkey);
} else {
return Err(ApiError::InvalidQueryParams(
"Public key must have a '0x' prefix".to_string(),
));
}
}
/// Returns the root of the `BeaconBlock` in the canonical chain of `beacon_chain` at the given
/// `slot`, if possible.
///
/// May return a root for a previous slot, in the case of skip slots.
pub fn block_root_at_slot<T: BeaconChainTypes>(
beacon_chain: &BeaconChain<T>,
target: Slot,
) -> Option<Hash256> {
beacon_chain
.rev_iter_block_roots()
.take_while(|(_root, slot)| *slot >= target)
.find(|(_root, slot)| *slot == target)
.map(|(root, _slot)| root)
}
/// Returns a `BeaconState` and it's root in the canonical chain of `beacon_chain` at the given
/// `slot`, if possible.
///
/// Will not return a state if the request slot is in the future. Will return states higher than
/// the current head by skipping slots.
pub fn state_at_slot<T: BeaconChainTypes>(
beacon_chain: &BeaconChain<T>,
slot: Slot,
) -> Result<(Hash256, BeaconState<T::EthSpec>), ApiError> {
let head_state = &beacon_chain.head().beacon_state;
if head_state.slot == slot {
// The request slot is the same as the best block (head) slot.
// I'm not sure if this `.clone()` will be optimized out. If not, it seems unnecessary.
Ok((
beacon_chain.head().beacon_state_root,
beacon_chain.head().beacon_state.clone(),
))
} else {
let root = state_root_at_slot(beacon_chain, slot)?;
let state: BeaconState<T::EthSpec> = beacon_chain
.store
.get(&root)?
.ok_or_else(|| ApiError::NotFound(format!("Unable to find state at root {}", root)))?;
Ok((root, state))
}
}
/// Returns the root of the `BeaconState` in the canonical chain of `beacon_chain` at the given
/// `slot`, if possible.
///
/// Will not return a state root if the request slot is in the future. Will return state roots
/// higher than the current head by skipping slots.
pub fn state_root_at_slot<T: BeaconChainTypes>(
beacon_chain: &BeaconChain<T>,
slot: Slot,
) -> Result<Hash256, ApiError> {
let head_state = &beacon_chain.head().beacon_state;
let current_slot = beacon_chain
.slot()
.map_err(|_| ApiError::ServerError("Unable to read slot clock".to_string()))?;
// There are four scenarios when obtaining a state for a given slot:
//
// 1. The request slot is in the future.
// 2. The request slot is the same as the best block (head) slot.
// 3. The request slot is prior to the head slot.
// 4. The request slot is later than the head slot.
if current_slot < slot {
// 1. The request slot is in the future. Reject the request.
//
// We could actually speculate about future state roots by skipping slots, however that's
// likely to cause confusion for API users.
Err(ApiError::InvalidQueryParams(format!(
"Requested slot {} is past the current slot {}",
slot, current_slot
)))
} else if head_state.slot == slot {
// 2. The request slot is the same as the best block (head) slot.
//
// The head state root is stored in memory, return a reference.
Ok(beacon_chain.head().beacon_state_root)
} else if head_state.slot > slot {
// 3. The request slot is prior to the head slot.
//
// Iterate through the state roots on the head state to find the root for that
// slot. Once the root is found, load it from the database.
Ok(head_state
.try_iter_ancestor_roots(beacon_chain.store.clone())
.ok_or_else(|| ApiError::ServerError("Failed to create roots iterator".to_string()))?
.find(|(_root, s)| *s == slot)
.map(|(root, _slot)| root)
.ok_or_else(|| ApiError::NotFound(format!("Unable to find state at slot {}", slot)))?)
} else {
// 4. The request slot is later than the head slot.
//
// Use `per_slot_processing` to advance the head state to the present slot,
// assuming that all slots do not contain a block (i.e., they are skipped slots).
let mut state = beacon_chain.head().beacon_state.clone();
let spec = &T::EthSpec::default_spec();
for _ in state.slot.as_u64()..slot.as_u64() {
// Ensure the next epoch state caches are built in case of an epoch transition.
state.build_committee_cache(RelativeEpoch::Next, spec)?;
state_processing::per_slot_processing(&mut state, spec)?;
}
// Note: this is an expensive operation. Once the tree hash cache is implement it may be
// used here.
Ok(state.canonical_root())
}
}
pub fn implementation_pending_response(_req: Request<Body>) -> ApiResult {
Err(ApiError::NotImplemented(
"API endpoint has not yet been implemented, but is planned to be soon.".to_owned(),
))
}
pub fn get_beacon_chain_from_request<T: BeaconChainTypes + 'static>(
req: &Request<Body>,
) -> Result<(Arc<BeaconChain<T>>), ApiError> {
// Get beacon state
let beacon_chain = req
.extensions()
.get::<Arc<BeaconChain<T>>>()
.ok_or_else(|| ApiError::ServerError("Beacon chain extension missing".into()))?;
Ok(beacon_chain.clone())
}
pub fn get_head_state<T: BeaconChainTypes + 'static>(
bc: Arc<BeaconChain<T>>,
) -> Result<BeaconState<T::EthSpec>, ApiError> {
let mut head_state = bc.head().beacon_state;
head_state
.build_all_caches(&bc.spec)
.map_err(|e| ApiError::ServerError(format!("Unable to build state cache: {:?}", e)))?;
Ok(head_state)
}
pub fn get_logger_from_request(req: &Request<Body>) -> slog::Logger {
let log = req
.extensions()
.get::<slog::Logger>()
.expect("Should always get the logger from the request, since we put it in there.");
log.to_owned()
}
pub fn publish_beacon_block_to_network<T: BeaconChainTypes + 'static>(
chan: Arc<RwLock<mpsc::UnboundedSender<NetworkMessage>>>,
block: BeaconBlock<T::EthSpec>,
) -> Result<(), ApiError> {
// create the network topic to send on
let topic_string = format!(
"/{}/{}/{}",
TOPIC_PREFIX, BEACON_BLOCK_TOPIC, TOPIC_ENCODING_POSTFIX
);
let topic = Topic::new(topic_string);
let message = PubsubMessage::Block(block.as_ssz_bytes());
// Publish the block to the p2p network via gossipsub.
if let Err(e) = chan.write().try_send(NetworkMessage::Publish {
topics: vec![topic],
message: message,
}) {
return Err(ApiError::ServerError(format!(
"Unable to send new block to network: {:?}",
e
)));
}
Ok(())
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn parse_root_works() {
assert_eq!(
parse_root("0x0000000000000000000000000000000000000000000000000000000000000000"),
Ok(Hash256::zero())
);
assert_eq!(
parse_root("0x000000000000000000000000000000000000000000000000000000000000002a"),
Ok(Hash256::from_low_u64_be(42))
);
assert!(
parse_root("0000000000000000000000000000000000000000000000000000000000000042").is_err()
);
assert!(parse_root("0x").is_err());
assert!(parse_root("0x00").is_err());
}
#[test]
fn parse_slot_works() {
assert_eq!(parse_slot("0"), Ok(Slot::new(0)));
assert_eq!(parse_slot("42"), Ok(Slot::new(42)));
assert_eq!(parse_slot("10000000"), Ok(Slot::new(10_000_000)));
assert!(parse_slot("cats").is_err());
}
}