fabric-samples/fabcar/query.js

'use strict';

/*
 * Hyperledger Fabric Sample Query Program
 */

var hfc = require('fabric-client');
var path = require('path');

var options = {
	  wallet_path : path.join(__dirname, './network/creds'),
	  user_id: 'PeerAdmin',
	  channel_id: 'mychannel',
	  chaincode_id: 'fabcar',
	  network_url: 'grpc://localhost:7051',
	  };

var channel = {};
var client = null;

Promise.resolve().then (() => {
	 console.log("Create a client and set the wallet location");
     client = new hfc();
	 return hfc.newDefaultKeyValueStore({path: options.wallet_path});
}).then((wallet) => {
	 console.log("Set wallet path, and associate user ",options.user_id," with application");
	 client.setStateStore(wallet);
	 return client.getUserContext(options.user_id, true);
}).then ((user) => {
         console.log("Check user is enrolled, and set a query URL in the network");
     	 if (user===undefined || user.isEnrolled()===false) {
	  	console.error("User not defined, or not enrolled - error");
	 }
     	 channel = client.newChannel(options.channel_id);
	 channel.addPeer(client.newPeer(options.network_url));
	 return;
}).then (() => {
	 console.log("Make query");
	 var transaction_id = client.newTransactionID();
	 console.log("Assigning transaction_id: ", transaction_id._transaction_id);

  // queryCar - requires 1 argument, ex: args: ['CAR4'],
  // queryAllCars - requires no arguments , ex: args: [''],
   const request = {
         chaincodeId: options.chaincode_id,
         txId: transaction_id,
         fcn: 'queryAllCars',
         args: ['']
     };
     return channel.queryByChaincode(request);
}).then ((query_responses) => {
     console.log("returned from query");
	 if (!query_responses.length) {
	 	console.log("No payloads were returned from query");
	 } else {
	 	console.log("Query result count = ", query_responses.length)
	 }
	 if (query_responses[0] instanceof Error) {
        	console.error("error from query = ", query_responses[0]);
	 }
	 console.log("Response is ", query_responses[0].toString());
})
.catch ((err) => {
     console.error("Caught Error", err);
});