diff options
Diffstat (limited to 'packages/website/ts/subproviders/redundant_rpc_subprovider.ts')
-rw-r--r-- | packages/website/ts/subproviders/redundant_rpc_subprovider.ts | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/packages/website/ts/subproviders/redundant_rpc_subprovider.ts b/packages/website/ts/subproviders/redundant_rpc_subprovider.ts new file mode 100644 index 000000000..a6c53ebd1 --- /dev/null +++ b/packages/website/ts/subproviders/redundant_rpc_subprovider.ts @@ -0,0 +1,41 @@ +import * as _ from 'lodash'; +import {JSONRPCPayload} from 'ts/types'; +import promisify = require('es6-promisify'); +import Subprovider = require('web3-provider-engine/subproviders/subprovider'); +import RpcSubprovider = require('web3-provider-engine/subproviders/rpc'); + +export class RedundantRPCSubprovider extends Subprovider { + private rpcs: RpcSubprovider[]; + constructor(endpoints: string[]) { + super(); + this.rpcs = _.map(endpoints, endpoint => { + return new RpcSubprovider({ + rpcUrl: endpoint, + }); + }); + } + public async handleRequest(payload: JSONRPCPayload, next: () => void, + end: (err?: Error, data?: any) => void): Promise<void> { + const rpcsCopy = this.rpcs.slice(); + try { + const data = await this.firstSuccessAsync(rpcsCopy, payload, next); + end(null, data); + } catch (err) { + end(err); + } + + } + private async firstSuccessAsync(rpcs: RpcSubprovider[], payload: JSONRPCPayload, next: () => void): Promise<any> { + let lastErr; + for (const rpc of rpcs) { + try { + const data = await promisify(rpc.handleRequest.bind(rpc))(payload, next); + return data; + } catch (err) { + lastErr = err; + continue; + } + } + throw Error(lastErr); + } +} |