squid-js/src/ddo/DDO.ts

import Web3Provider from "../keeper/Web3Provider"
import Logger from "../utils/Logger"
import * as signatureHelpers from "../utils/SignatureHelpers"
import { Authentication } from "./Authentication"
import { Proof } from "./Proof"
import { PublicKey } from "./PublicKey"
import { Service } from "./Service"

/**
 * DID Descriptor Object.
 * Contains all the data related to an asset.
 */
export class DDO {

    /**
     * Serializes the DDO object.
     * @param  {DDO} DDO to be serialized.
     * @return {string} DDO serialized.
     */
    public static serialize(ddo: DDO): string {
        return JSON.stringify(ddo, null, 2)
    }

    /**
     * Deserializes the DDO object.
     * @param  {DDO} DDO to be deserialized.
     * @return {string} DDO deserialized.
     */
    public static deserialize(ddoString: string): DDO {
        const ddo = JSON.parse(ddoString)

        return new DDO(ddo)
    }

    public "@context": string = "https://w3id.org/future-method/v1"

    /**
     * DID, descentralized ID.
     * @type {string}
     */
    public id: string
    public created: string
    public publicKey: PublicKey[]
    public authentication: Authentication[]
    public service: Service[]
    public proof: Proof

    public constructor(ddo?: Partial<DDO>) {
        this.created = (ddo && ddo.created) || new Date(Date.now()).toISOString().replace(/\.[0-9]{3}/, "")
        this.authentication = (ddo && ddo.authentication) || []
        this.id = (ddo && ddo.id) || null
        this.publicKey = (ddo && ddo.publicKey) || []
        this.service = (ddo && ddo.service) || []
    }

    /**
     * Finds a service of a DDO by ID.
     * @param  {string} serviceDefinitionId Service ID.
     * @return {Service} Service.
     */
    public findServiceById(serviceDefinitionId: string): Service {
        if (!serviceDefinitionId) {
            throw new Error("serviceDefinitionId not set")
        }

        const service: Service = this.service.find((s) => s.serviceDefinitionId === serviceDefinitionId)

        return service
    }

    /**
     * Finds a service of a DDO by type.
     * @param  {string} serviceType Service type.
     * @return {Service} Service.
     */
    public findServiceByType(serviceType: string): Service {
        if (!serviceType) {
            throw new Error("serviceType not set")
        }

        const service: Service = this.service.find((s) => s.type === serviceType)

        return service
    }

    /**
     * Generate the checksum using the current content.
     * @return {string[]} DDO checksum.
     */
    public getChecksum(): string {
        const web3 = Web3Provider.getWeb3()
        const {metadata} = this.findServiceByType("Metadata")
        const {files, name, author, license} = metadata.base

        const values = [
            ...(files || [])
                .map(({checksum}) => checksum)
                .filter((_) => !!_),
            name,
            author,
            license,
            this.id,
        ]

        return web3.utils.sha3(values.join("")).replace(/^0x([a-f0-9]{32}).+$/i, "$1")
    }

    /**
     * Generates proof using personal sing.
     * @param  {string}         publicKey Public key to be used on personal sign.
     * @param  {string}         password  Password if it's requirted.
     * @return {Promise<Proof>}           Proof object.
     */
    public async generateProof(publicKey: string, password?: string): Promise<Proof> {
        const checksum = this.getChecksum()

        const signature = await signatureHelpers.signText(checksum, publicKey, password)

        return {
            created: (new Date()).toISOString(),
            creator: publicKey,
            type: "DDOIntegritySignature",
            signatureValue: signature,
        }
    }

    /**
     * Generated and adds the checksum.
     */
    public addChecksum(): void {
        const metadataService = this.findServiceByType("Metadata")
        if (metadataService.metadata.base.checksum) {
            Logger.log("Checksum already exists")
            return
        }
        metadataService.metadata.base.checksum = this.getChecksum()
    }

    /**
     * Generates and adds a proof using personal sing on the DDO.
     * @param  {string}         publicKey Public key to be used on personal sign.
     * @param  {string}         password  Password if it's requirted.
     * @return {Promise<Proof>}           Proof object.
     */
    public async addProof(publicKey: string, password?: string): Promise<void> {
        if (this.proof) {
            throw new Error("Proof already exists")
        }
        this.proof = await this.generateProof(publicKey, password)
    }
}