Accessing node services

You can access a node’s ServiceHub within FlowLogic.call. This gives you access to all the node’s services:

• ServiceHub.networkMapCache provides information on other nodes on the network (for example, notaries).
• ServiceHub.identityService lets you resolve anonymous identities into well-known identities if you have the required certificates.
• ServiceHub.attachments gives you access to the node’s attachments.
• ServiceHub.validatedTransactions gives you access to the transactions stored in the node.
• ServiceHub.vaultService stores the node’s current and historic states.
• ServiceHub.keyManagementService manages transaction signing and the generation of fresh public keys.
• ServiceHub.myInfo includes additional information about the node.
• ServiceHub.clock provides access to the node’s internal time and date.
• ServiceHub.diagnosticsService provides diagnostic information about the node, including the node version and currently running apps. This data should only be used for diagnostic purposes.
• ServiceHub.contractUpgradeService provides functionality for secure contract upgrades.

ServiceHub also exposes these properties:

• ServiceHub.loadState and ServiceHub.toStateAndRef to resolve a StateRef into a TransactionState or a StateAndRef.
• ServiceHub.signInitialTransaction to sign a TransactionBuilder and convert it into a SignedTransaction.
• ServiceHub.createSignature and ServiceHub.addSignature to create and add signatures to a SignedTransaction.