Node.js SDK Demo

Preparations

Creating a BCS Instance

1. Log in to the BCS console.
2. Click Create BCS Instance in the upper right corner.
3. Configure basic information about the BCS instance by referring to Table 1.
   

   To ensure that the demo runs properly, set the parameters as described in the following table.

   Table 1 Basic settings

   Parameter	Setting
   Region	Retain the default value.
   Enterprise project	Select default.
   Instance Name	Enter node-sdk-demo.
   Edition	Professional
   Blockchain Type	Select Private.
   Enhanced Hyperledger Fabric Version	v2.2
   Consensus Mechanism	Select SOLO.
   Resource Access Initial Password	Enter a password.
   Confirm Password	Confirm the password.

4. Click Next: Configure Resources. Table 2 describes the resource parameters.

   Table 2 Resource configurations

   Parameter	Example
   Environment Resources	Select Custom.
   Cluster	Select Create a new CCE cluster.
   AZ	Select an AZ.
   ECS Specifications	Select the flavor for 4 vCPUs | 8 GB.
   ECS Quantity	Enter 1.
   High Availability	Select No.
   VPC	Select Automatically create VPC.
   Subnet	Select Automatically create subnet.
   ECS Login Method	Select Password.
   Password of Root User	If you do not enter a password here, the previously specified resource access initial password will be used.
   Confirm Password	-
   Use EIP of a CCE Node	Select Yes.
   EIP Billed By	Retain the default value.
   EIP Bandwidth	Set it to 5 Mbit/s.

5. Click Next: Configure Blockchain. Table 3 describes the blockchain parameters.

   Table 3 Blockchain configurations

   Parameter	Example
   Blockchain Configuration	Select Custom.
   Blockchain Mgmt. Initial Password	If you do not enter a password here, the previously specified resource access initial password will be used.
   Confirm Password	-
   Volume Type	Select SFS Turbo.
   Storage Capacity of Peer Organization (GB)	Retain the default value.
   Ledger Storage	Select File database (GoLevelDB).
   Peer Organization	A peer organization named organization has been automatically created. Change the peer quantity to 1.
   Channel Configuration	The organization organization has been added to the channel automatically. Retain this default setting.
   Orderer Quantity	Retain the default value.
   Security Mechanism	Select ECDSA. NOTICE: Only ECDSA can be selected.
   Configure Block Generation	Select No.
   Enable Support for RESTful API	Select No.

6. Click Next: Confirm.
7. Confirm the configurations and finish the creation process.

   Wait for several minutes. After a message is displayed indicating successful installation, check the status of the instance. If it is Normal, the deployment is completed.

Installing and Instantiating a Chaincode

1. Log in to the BCS console.
2. In the navigation pane on the left, click Instance Management.
3. Find the instance you just created and click Manage Blockchain to go to the Blockchain Management console.
4. On the login page, enter the username and password, and click Log In.
   

   The username is admin, and the password is the Blockchain Mgmt. Initial Password set when you created the BCS instance. If you have not set this password, use the resource access initial password.

5. Click in the upper left corner of the page.
   The parameters for chaincode installation are as follows.

   Parameter	Setting
   Chaincode Name	Enter bcsysq.
   Chaincode Version	Enter 1.0
   Ledger Storage	File database (goleveldb)
   Select All Peers	Check the box.
   Organization & Peer	Select peer-0.
   Language	Select Node.js.
   Chaincode File	Add the downloaded chaincode file nodejs-chaincode.zip.
   Chaincode Description	Enter a description of the chaincode.

6. Click Install.
7. After installing the chaincode, click Instantiate in the Operation column of the chaincode list.
   The parameters for chaincode instantiation are as follows.

   Parameter	Setting
   Chaincode Name	Enter bcsysq.
   Channel	Select channel.
   Chaincode Version	Enter 1.0
   Initialization Function	Enter init.
   Chaincode Parameters	Enter a,200,b,250.
   Endorsement Policy	Select Endorsement from any of the following organizations.
   Endorsing Organizations	Select organization.
   Privacy Protection Configuration	Select No.

Deploying the Application

1. Download and decompress the demo project code package nodejs-demo.zip to the local PC, and use an IDE to open it.

   This demo is compiled using Node.js. It contains the fabric-client library to enable money transfer from user A to user B by running the chaincode. Use the IDE that you prefer to open the script. The following table lists the files included in the project.

   Table 4 Project content

   Fie	Description
   invoke.js	Invoking the chaincode to transfer money from user A to user B.
   query.js	Querying the chaincode to determine the account balance of user A.
   sdk-config.js	Parsing the blockchain network configuration file sdk-config.json downloaded from the BCS console.
   sdk-config.json	Containing the blockchain network configuration data.

2. Download SDK configurations and certificates.
   1. On the Instance Management page, click Download Client Configuration on an instance card.
   2. Select SDK Configuration File and set the parameters as described in the following table.

      Parameter	Description
      Chaincode Name	Enter bcsysq. NOTICE: The chaincode name must be the same as the name specified during chaincode installation and instantiation.
      Certificate Root Path	Specify a path for storing certificates. In this example, the path is E:\code\temp.
      Channel	Select channel.
      Organization & Peer	Retain the default value.

      Select Orderer Certificate.

      Select Peer Certificates, select organization for Peer Organization, and select Administrator certificate.

   3. Click Download to download the SDK configuration file and the administrator certificates for the node-sdk-demo-orderer and organization organizations.

3. Copy and decompress the package.
   1. Download the project source code javasdkdemo_src.zip and decompress it.
   2. Decompress the .zip package obtained in 2 and copy the content in the orderer and peer folders to the certificate storage path. Copy the sdk-config.json file to the directory where the certificate is stored and name the file node-sdk-demo-sdk-config.json.

Debugging the Application

1. Open the sdk-config.js file, and change the path of the SDK configuration file to the path of node-sdk-demo-sdk-config.json.

   

2. Run the node query.js command in the path where the project is located to query the account balance of user A. (As shown in the following figure, user A's balance is 10,000 in this example.)

   

3. Run the node invoke.js command in the path where the project is located to execute the chaincode to transfer money from user A to user B. As shown in the following figure, the chaincode is successfully executed.

   

4. Query the account balance of user A again. The result shows that the money has been successfully transferred. (As shown in the following figure, user A's balance is 9990 in this example.)

   

Description

• This demo uses demos in the Fabric community as references. For more demos, visit https://github.com/hyperledger/fabric-samples.
• Method of customizing an npm repository in the chaincode
  • Create a personal configuration file named .npmrc in the path of the chaincode package. The content of the file is as follows: Registry=https://registry.npm.taobao.org/
  • In this way, when the chaincode container is instantiated, the class library is extracted from the specified repository.
  • Run the npm config get registry command to check whether the address of the customized npm repository has been correctly configured.