Web3j Ethereum Blockchain

Since Camel 2.22

The Ethereum blockchain component uses the web3j client API and allows you to interact with Ethereum compatible nodes such as Geth, Parity, Quorum, Infura, etc.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-web3j</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI Format

web3j://<local/remote host:port or local IPC path>[?options]

Web3j Options

The Web3j Ethereum Blockchain component supports 2 options, which are listed below.

Name Description Default Type

configuration (common)

Default configuration

Web3jConfiguration

resolveProperty Placeholders (advanced)

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

boolean

The Web3j Ethereum Blockchain endpoint is configured using URI syntax:

web3j:nodeAddress

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

nodeAddress

Required Sets the node address used to communicate

String

Query Parameters (38 parameters):

Name Description Default Type

addresses (common)

Contract address or a list of addresses.

List

fromAddress (common)

The address the transaction is send from

String

fromBlock (common)

The block number, or the string latest for the last mined block or pending, earliest for not yet mined transactions.

latest

DefaultBlockParameter

fullTransactionObjects (common)

If true it returns the full transaction objects, if false only the hashes of the transactions.

false

boolean

gasLimit (common)

The maximum gas allowed in this block.

BigInteger

privateFor (common)

A transaction privateFor nodes with public keys in a Quorum network

List

quorumAPI (common)

If true, this will support Quorum API.

false

boolean

toAddress (common)

The address the transaction is directed to.

String

toBlock (common)

The block number, or the string latest for the last mined block or pending, earliest for not yet mined transactions.

latest

DefaultBlockParameter

topics (common)

Topics are order-dependent. Each topic can also be a list of topics. Specify multiple topics separated by comma.

String

web3j (common)

The preconfigured Web3j object.

Web3j

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer)

Sets the exchange pattern when the consumer creates an exchange.

ExchangePattern

address (producer)

Contract address.

String

atBlock (producer)

The block number, or the string latest for the last mined block or pending, earliest for not yet mined transactions.

latest

DefaultBlockParameter

blockHash (producer)

Hash of the block where this transaction was in.

String

clientId (producer)

A random hexadecimal(32 bytes) ID identifying the client.

String

data (producer)

The compiled code of a contract OR the hash of the invoked method signature and encoded parameters.

String

databaseName (producer)

The local database name.

String

filterId (producer)

The filter id to use.

BigInteger

gasPrice (producer)

Gas price used for each paid gas.

BigInteger

hashrate (producer)

A hexadecimal string representation (32 bytes) of the hash rate.

String

headerPowHash (producer)

The header’s pow-hash (256 bits) used for submitting a proof-of-work solution.

String

index (producer)

The transactions/uncle index position in the block.

BigInteger

keyName (producer)

The key name in the database.

String

mixDigest (producer)

The mix digest (256 bits) used for submitting a proof-of-work solution.

String

nonce (producer)

The nonce found (64 bits) used for submitting a proof-of-work solution.

String

operation (producer)

Operation to use.

transaction

String

position (producer)

The transaction index position withing a block.

BigInteger

priority (producer)

The priority of a whisper message.

BigInteger

sha3HashOfDataToSign (producer)

Message to sign by calculating an Ethereum specific signature.

String

signedTransactionData (producer)

The signed transaction data for a new message call transaction or a contract creation for signed transactions.

String

sourceCode (producer)

The source code to compile.

String

transactionHash (producer)

The information about a transaction requested by transaction hash.

String

ttl (producer)

The time to live in seconds of a whisper message.

BigInteger

value (producer)

The value sent within a transaction.

BigInteger

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-web3j-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 33 options, which are listed below.

Name Description Default Type

camel.component.web3j.configuration.address

Contract address.

String

camel.component.web3j.configuration.addresses

Contract address or a list of addresses.

List

camel.component.web3j.configuration.block-hash

Hash of the block where this transaction was in.

String

camel.component.web3j.configuration.client-id

A random hexadecimal(32 bytes) ID identifying the client.

String

camel.component.web3j.configuration.data

The compiled code of a contract OR the hash of the invoked method signature and encoded parameters.

String

camel.component.web3j.configuration.database-name

The local database name.

String

camel.component.web3j.configuration.filter-id

The filter id to use.

BigInteger

camel.component.web3j.configuration.from-address

The address the transaction is send from

String

camel.component.web3j.configuration.full-transaction-objects

If true it returns the full transaction objects, if false only the hashes of the transactions.

false

Boolean

camel.component.web3j.configuration.gas-limit

The maximum gas allowed in this block.

BigInteger

camel.component.web3j.configuration.gas-price

Gas price used for each paid gas.

BigInteger

camel.component.web3j.configuration.hashrate

A hexadecimal string representation (32 bytes) of the hash rate.

String

camel.component.web3j.configuration.header-pow-hash

The header’s pow-hash (256 bits) used for submitting a proof-of-work solution.

String

camel.component.web3j.configuration.index

The transactions/uncle index position in the block.

BigInteger

camel.component.web3j.configuration.key-name

The key name in the database.

String

camel.component.web3j.configuration.mix-digest

The mix digest (256 bits) used for submitting a proof-of-work solution.

String

camel.component.web3j.configuration.nonce

The nonce found (64 bits) used for submitting a proof-of-work solution.

String

camel.component.web3j.configuration.operation

Operation to use.

transaction

String

camel.component.web3j.configuration.position

The transaction index position withing a block.

BigInteger

camel.component.web3j.configuration.priority

The priority of a whisper message.

BigInteger

camel.component.web3j.configuration.private-for

A transaction privateFor nodes with public keys in a Quorum network

List

camel.component.web3j.configuration.quorum-a-p-i

If true, this will support Quorum API.

false

Boolean

camel.component.web3j.configuration.sha3-hash-of-data-to-sign

Message to sign by calculating an Ethereum specific signature.

String

camel.component.web3j.configuration.signed-transaction-data

The signed transaction data for a new message call transaction or a contract creation for signed transactions.

String

camel.component.web3j.configuration.source-code

The source code to compile.

String

camel.component.web3j.configuration.to-address

The address the transaction is directed to.

String

camel.component.web3j.configuration.topics

Topics are order-dependent. Each topic can also be a list of topics. Specify multiple topics separated by comma.

List

camel.component.web3j.configuration.transaction-hash

The information about a transaction requested by transaction hash.

String

camel.component.web3j.configuration.ttl

The time to live in seconds of a whisper message.

BigInteger

camel.component.web3j.configuration.value

The value sent within a transaction.

BigInteger

camel.component.web3j.configuration.web3j

The preconfigured Web3j object.

Web3j

camel.component.web3j.enabled

Enable web3j component

true

Boolean

camel.component.web3j.resolve-property-placeholders

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

Boolean

You can append query options to the URI in the following format, ?options=value&option2=value&…​

Message Headers

Header Description

All URI options

All URI options can also be set as exchange headers.

Samples

Listen for new mined blocks and send the block hash to a jms queue:

from("web3j://http://127.0.0.1:7545?operation=ETH_BLOCK_HASH_OBSERVABLE")
    .to("jms:queue:blocks");

Use the block hash code to retrieve the block and full transaction details:

from("jms:queue:blocks")
    .setHeader(BLOCK_HASH, body())
    .to("web3j://http://127.0.0.1:7545?operation=ETH_GET_BLOCK_BY_HASH&fullTransactionObjects=true");

Read the balance of an address at a specific block number:

from("direct:start")
    .to("web3j://http://127.0.0.1:7545?operation=ETH_GET_BALANCE&address=0xc8CDceCE5d006dAB638029EBCf6Dd666efF5A952&atBlock=10");
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