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Merge pull request #398 from CosmWasm/fallback-on-query

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Fallback on header query if subscription event is the wrong one
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Simon Warta 2020-08-18 14:09:14 +02:00 committed by GitHub
commit 5503484d6b
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1 changed files with 14 additions and 16 deletions
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30
packages/stargate/src/queries/queryclient.ts
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@ -230,7 +230,7 @@ export class QueryClient {
}
const searchHeight = height + 1;
let nextHeader: Header;
let nextHeader: Header | undefined;
let headersSubscription: Stream<NewBlockHeaderEvent> | undefined;
try {
headersSubscription = this.tmClient.subscribeNewBlockHeader();
@ -239,28 +239,26 @@ export class QueryClient {
}
if (headersSubscription) {
// get the header for height+1
nextHeader = await firstEvent(headersSubscription); // TODO: fall back on polling if this returns a too high header
} else {
const firstHeader = await firstEvent(headersSubscription);
// The first header we get might not be n+1 but n+2 or even higher. In such cases we fall back on a query.
if (firstHeader.height === searchHeight) {
nextHeader = firstHeader;
}
}
while (!nextHeader) {
// start from current height to avoid backend error for minHeight in the future
let header = (await this.tmClient.blockchain(height, searchHeight)).blockMetas
const correctHeader = (await this.tmClient.blockchain(height, searchHeight)).blockMetas
.map((meta) => meta.header)
.find((h) => h.height === searchHeight);
while (!header) {
if (correctHeader) {
nextHeader = correctHeader;
} else {
await sleep(1000);
header = (await this.tmClient.blockchain(height, searchHeight)).blockMetas
.map((meta) => meta.header)
.find((h) => h.height === searchHeight);
}
nextHeader = header;
}
if (nextHeader.height !== searchHeight) {
throw new Error(
`Query requires header at height ${searchHeight} for proof verification, but next header was ${nextHeader.height}`,
);
}
assert(nextHeader.height === searchHeight, "Got wrong header. This is a bug in the logic above.");
return nextHeader;
}
}