Hi, for background interest - could I ask what usecase do you have (or anybody actually) for access the block information. 

 

As to channel info, I believe there are new APIs to get some there, but would need to check.

 

 

Regards, Matthew.

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----- Original message -----
From: "David Faulstich Diniz Reis" <davidfdr@...>
Sent by: fabric@...
To: "fabric" <fabric@...>
Cc:
Subject: [EXTERNAL] [Hyperledger Fabric] Query qscc system chaincodes using NODE.js
Date: Wed, Oct 27, 2021 8:35 PM
 
Hi. I am querying qscc chaincode using Node.js but I am unable to find more information in official documentation. To query the block number and get channel info, I am using the following code (test purposes only): import { Gateway, Wallets ZjQcmQRYFpfptBannerStart

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Hi.

 

I am querying qscc chaincode using Node.js but I am unable to find more information in official documentation.

 

To query the block number and get channel info, I am using the following code (test purposes only):

 

import { Gateway, Wallets } from 'fabric-network';

import * as common from 'fabric-common';

import * as fabproto6 from 'fabric-protos';

import * as path from 'path';

import * as fs from 'fs';

import { createQueryHandler } from './config/queryhandler/QueryHandler';

 

//const BlockDecoder = (common as any).BlockDecoder;

 

async function main() {

  try {

    // Create a new file system based wallet for managing identities.

    const walletPath = path.join(process.cwd(), 'Org1Wallet');

    const wallet = await Wallets.newFileSystemWallet(walletPath);

    console.log(`Wallet path: ${walletPath}`);

    // Create a new gateway for connecting to our peer node.

    const gateway = new Gateway();

    const connectionProfilePath = path.resolve(__dirname, '..', 'connection.json');

    const connectionProfile = JSON.parse(fs.readFileSync(connectionProfilePath, 'utf8'));

    const connectionOptions = {

      wallet,

      identity: 'Org1 Admin',

      discovery: { enabled: true, asLocalhost: true },

      queryHandlerOptions: {

        timeout: 10, // timeout in seconds

        strategy: createQueryHandler,

      },

    };

    await gateway.connect(connectionProfile, connectionOptions);

 

    // Get the network (channel) our contract is deployed to.

    const network = await gateway.getNetwork('mychannel');

 

    // Get the contract from the network.

    const contract = network.getContract('qscc');

 

    // Submit the specified transaction.

    const currentTimeBefore = new Date().getMilliseconds();

 

    const result = await contract.evaluateTransaction('GetChainInfo', 'mychannel');

 

    const blockProto = JSON.stringify(fabproto6.common.BlockchainInfo.decode(result));

 

    console.log(`# GetChainInfo: ${blockProto} \n`);

 

    const resultGetBlockByNumber = await contract.evaluateTransaction('GetBlockByNumber', 'mychannel', '5');

 

    //const resultDecoded = JSON.stringify(BlockDecoder.decode(resultGetBlockByNumber));

 

    const resultDecoded = JSON.stringify(fabproto6.common.Block.decode(resultGetBlockByNumber));

 

    const currentTimeAfter = new Date().getMilliseconds();

 

    console.log(`# GetBlockByNumber: ${resultDecoded} \n`);

 

    const totalRunTime = (currentTimeAfter - currentTimeBefore) / 1000;

 

    console.log(`#==> Totaltime: ${totalRunTime} seconds.`);

 

    // Disconnect from the gateway.

    gateway.disconnect();

  } catch (error) {

    if (error instanceof Error) {

      console.error(error.stack);

    }

    console.error('RED ALERT, SHIELDS UP, PHASER CHARGED:', error);

 

    process.exit(1);

  }

}

 

main();

 

 

I am doing it right?

GetChainInfo decode:

const blockProto = JSON.stringify(fabproto6.common.BlockchainInfo.decode(result));

 

GetBlockByNumber:

const resultDecoded = JSON.stringify(fabproto6.common.Block.decode(resultGetBlockByNumber));

 

I tried to import the BlockDecoder class (https://github.com/hyperledger/fabric-sdk-node/blob/main/fabric-common/lib/BlockDecoder.js) but the type definition is missing, so I used fabric_protos lib directly.

 

Thanks in advance,

 

 

David

 

 

 

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David Reis

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@davidfdr (Github)

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