README.md

Hyperledger Fabric Gateway Client API for Java

The Fabric Gateway client API allows applications to interact with a Hyperledger Fabric blockchain network. It implements the Fabric programming model, providing a simple API to submit transactions to a ledger or query the contents of a ledger with minimal code.

How to use

Samples showing how to create client applications that connect to and interact with a Hyperledger Fabric network, are available in the fabric-samples repository:

• asset-transfer-basic for examples of transaction submit and evaluate.
• asset-transfer-events for examples of chaincode eventing.
• off_chain_data for examples of block eventing.

API documentation

The Gateway client API documentation for Java is available here:

• https://hyperledger.github.io/fabric-gateway/main/api/java/

Installation

The Fabric Gateway client API package is published to Maven Central.

Maven

Add the following dependency to your project's pom.xml file:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.google.protobuf</groupId>
            <artifactId>protobuf-bom</artifactId>
            <version>4.29.2</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.hyperledger.fabric</groupId>
        <artifactId>fabric-gateway</artifactId>
        <version>1.7.0</version>
    </dependency>
</dependencies>

Note the pom import in the dependencyManagement section, which ensures that v4 of the Java protocol buffers package is resolved by your project.

A suitable gRPC channel service provider must also be specified (as described in the gRPC security documentation), such as:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-bom</artifactId>
            <version>1.69.0</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>io.grpc</groupId>
        <artifactId>grpc-api</artifactId>
    </dependency>
    <dependency>
        <groupId>io.grpc</groupId>
        <artifactId>grpc-netty-shaded</artifactId>
        <scope>runtime</scope>
    </dependency>
</dependencies>

Gradle

Add the following dependency to your project's build.gradle file:

implementation 'org.hyperledger.fabric:fabric-gateway:1.7.0'
implementation platform('com.google.protobuf:protobuf-bom:4.29.2')

Note the platform import, which ensures that v4 of the Java protocol buffers package is resolved by your project.

A suitable gRPC channel service provider must also be specified (as described in the gRPC security documentation), such as:

implementation platform('io.grpc:grpc-bom:1.69.0')
compileOnly 'io.grpc:grpc-api'
runtimeOnly 'io.grpc:grpc-netty-shaded'

Compatibility

This API requires Fabric v2.4 (or later) with a Gateway enabled Peer. Additional compatibility information is available in the documentation:

• https://hyperledger.github.io/fabric-gateway/