Create a Chaincode Project with the Blockchain App Builder CLI

To create a chaincode project when using the Blockchain App Builder CLI, you scaffold a chaincode project from a detailed specification file. The generated project then contains all the files than you need.

Background

Blockchain App Builder's init command initializes and scaffolds a ready-to-use chaincode project. Based on simple input, the init command can generate complex chaincode projects that include the following features:

Multiple assets (models) and their behaviors (controllers)
Auto-generate CRUD (Create/Read/Update/Delete) and non-CRUD methods
Automatic validation of arguments
Marshalling/unmarshalling of arguments
Transparent persistence capability (ORM)
The ability to call rich queries

The generated project follows the model/controller and decorator pattern, which allows an asset's properties that are maintained on the ledger to be specified as typed fields and extended with specific behaviors and validation rules. This pattern reduces the number of lines of code, which helps in readability and scalability.

Prerequisites

Before you scaffold a project, you must create an input specification file. For more information, see Input Specification File.

Scaffolding the Chaincode Project with the init Command

Typing ochain init -h will list the command usage with all its options. The init command has the following options:

--cc/-c:
The name of the chaincode project. The default value is MyChaincode.
--lang/-l
The language of the scaffolded chaincode. Blockchain App Builder supports Typescript (ts) and Go (go). If no option is specified, the language defaults to ts.
--conf/-f or --spec
The path to an input specification file. Blockchain App Builder reads the input specification file and generates the scaffolded project with many helper tools, which help in reducing the overall development effort. Taking full advantage of the input specification file can significantly reduce the development time.

The specification file can be in yaml or json format. If the path is not specified, it defaults to the current directory. See Input Specification File.
--out/-o
The output directory of the scaffolded chaincode project. If not specified, the scaffolded project is generated in the current directory.

The output is a fully contained, lightweight, and scalable Typescript or Go chaincode project.
--root/-r
Valid and required only for Go. The root directory in the GOHOME variable for your Go chaincodes. The default value is example.com.

Example

my-mac:~ name$ ochain init --cc MyNewTsProject --lang ts --conf spec.yml

Defaults

If no options are specified in the ochain init command, the name of the scaffolded project is MyChaincode and the language is TypeScript.

The MyChaincode.model.ts file contains only one asset, called MyAsset, with one property named value. The MyChaincode.controller.ts file contains one controller with the corresponding CRUD methods for the MyAsset model.

Output

When the process is complete, you'll have a fully-functional chaincode project that you can deploy either locally or to a remote Oracle Blockchain Platform instance. For a detailed overview of the files created, see:

For a detailed overview of a token-based project, see also: