Generating Events

async setEvent(eventName: string, payload: Buffer): Promise<void>

In this example, eventName is the name to assign to the event, and payload is data associated with the event. The payload can contain any information that you want to send with the event, typically serialized in JSON format.

Chaincode Events for Batch Methods

The enhanced ERC-1155 standard supports batch methods. Batch methods operate on multiple tokens that are passed as parameters. For batch methods, chaincode events are emitted for only the tokens where the events parameter is set to true in the specification file.

For each transaction completed in the batch method, a corresponding chaincode event is generated. The payload of each chaincode event contains the transaction details. For example, if you use the BatchTransfer method to transfer quantities of five different tokens, five corresponding chaincode events are emitted. The payload of each event contains the token details and the quantity transferred, along with common parameters that are applicable to all batch transfers.

@Validator(yup.string(), yup.string(), yup.string(), yup.string(), yup.array().of(yup.string()), yup.array().of(yup.number()))
  public async batchTransferFrom(
    fromOrgId: string,
    fromUserId: string,
    toOrgId: string,
    toUserId: string,
    tokenIds: string[],
    quantity: number[]
  ) {
    const fromAccountId = this.Ctx.ERC1155Account.generateAccountId(fromOrgId, fromUserId, ACCOUNT_TYPE.USER_ACCOUNT);
    const toAccountId = this.Ctx.ERC1155Account.generateAccountId(toOrgId, toUserId, ACCOUNT_TYPE.USER_ACCOUNT);
    let tokenAssets = [];
    for (let i = 0; i < tokenIds.length; i++) {
      const tokenAsset = await this.Ctx.ERC1155Token.get(tokenIds[i]);
      tokenAssets.push(tokenAsset);
    }
    await this.Ctx.Model.createEventForBatch(EVENT_NAME.BATCH_TRANSFER_FROM, { fromOrgId, fromUserId, toOrgId, toUserId }, quantity, tokenAssets);
    return await this.Ctx.ERC1155Token.batchTransferFrom(fromAccountId, toAccountId, tokenIds, quantity);
  }

Chaincode Events for Multiple Assets

The enhanced Token Taxonomy Framework and ERC-1155 standards support defining more than one token asset in a specification file. The chaincode event behavior is different depending on whether a method is token-specific (such as creating or updating a token) or common (such as minting or burning).

For token-specific methods, chaincode events are generated for only the tokens where the events parameter is set to true in the specification file.

For common methods, chaincode events are generated in the scaffolded project if any token has the events parameter set to true in the specification file. The actual chaincode event behavior is based on the number of token ID parameters passed to the method.

• If a single token ID is passed as a parameter, chaincode events are generated only if the events parameter in the corresponding token details is set to true.
• If multiple token IDs are passed as parameters, chaincode events are generated only if the events parameter in any one of the token details is set to true.
• If no token ID is passed as a parameter, chaincode events are always generated.

• addConversionRate(from_token_id: string, to_token_id: string, token_conversion_rate: number)
• updateConversionRate(from_token_id: string, to_token_id: string, token_conversion_rate: number)
• tokenConversion(from_token_id: string, to_token_id: string, to_org_id: string, to_user_id: string,token_quantity: number)
• exchangeToken(fromTokenId: string, fromOrgId: string, fromUserId: string, fromTokenQuantity: number, toTokenId: string, toOrgId: string,toUserId: string,toTokenQuantity: number)

• addTokenAdmin(org_id: string, user_id: string)
• removeTokenAdmin(org_id: string, user_id: string)
• addOrgAdmin(org_id: string, user_id: string)
• removeOrgAdmin(org_id: string, user_id: string)
• createAccount(org_id: string, user_id: string, token_type: string)
• deleteHistoricalTransactions(time_to_expiration: Date)
• initializeExchangePoolUser(org_id: string, user_id: string)

• addTokenAdmin(orgId: string, userId: string)
• removeTokenAdmin(orgId: string, userId: string)
• createAccount(orgId: string, userId: string, ftAccount: boolean, nftAccount: boolean)
• createUserAccount(orgId: string, userId: string)
• createTokenAccount(orgId: string, userId: string, tokenType: TokenType)
• addTokenSysRole(orgId: string, userId: string, role: string)
• removeTokenSysRole(orgId: string, userId: string, role: string)
• transferTokenSysRole(fromOrgId: string, fromUserId: string, toOrgId: string, toUserId: string, role: string)
• deleteHistoricalTransactions(time_to_expiration: Date)

TypeScript SDK Methods for Chaincode Events

createEvent

This method generates events based on a specified event name and payload.

public async createEvent(eventName: any, eventPayload: any, assets?: any)

Parameters:

• eventName: string – The event name to use when generating events.
• eventPayload: map[string]interface{} – The event payload to use when generating events.
• assets – Optionally, the token asset can be passed as a parameter to the method.

createEventForBatch

This method generates events for batch operations such as the mintBatch or burnBatch methods.

public async createEventForBatch(eventName: any, eventPayload: any, quantities: number[], assets: any)

Parameters:

• eventName: string – The event name to use when generating events.
• eventPayload: map[string]interface{} – The event payload to use when generating events.
• quantities: number[] – A list of amounts, corresponding to each token ID, that represent the number of tokens to use in the batch method transactions.
• assets – Optionally, the token asset can be passed as a parameter to the method.

Go SDK Methods for Chaincode Events

CreateEvent

This method generates events based on a specified event name and payload.

func (m *Model) CreateEvent(eventName string, eventPayload map[string]interface{}, assets ...interface{})

Parameters:

• eventName: string – The event name to use when generating events.
• eventPayload: map[string]interface{} – The event payload to use when generating events.
• assets – Optionally, the token asset can be passed as a parameter to the method.

CreateEventForBatch

This method generates events for batch operations such as the mintBatch or burnBatch methods.

func (m *Model) CreateEventForBatch(eventName string, eventPayload map[string]interface{}, quantities []float64, assets []interface{})

Parameters:

• eventName: string – The event name to use when generating events.
• eventPayload: map[string]interface{} – The event payload to use when generating events.
• quantities: []float64 – A list of amounts, corresponding to each token ID, that represent the number of tokens to use in the batch method transactions.
• assets – Optionally, the token asset can be passed as a parameter to the method.

Event Generation in Blockchain App Builder Chaincode

@Validator(yup.string(), yup.string(), yup.string())
public async createAccount(org_id: string, user_id: string, token_type: string) {
  await this.Ctx.Auth.checkAuthorization("ACCOUNT.createAccount", "TOKEN", { org_id });
  await this.Ctx.Model.createEvent(EVENT_NAME.CREATE_ACCOUNT, { org_id, user_id, token_type });
  return await this.Ctx.Account.createAccount(org_id, user_id, token_type);
}

func (t *Controller) CreateAccount(org_id string, user_id string, token_type string, daily_limits ...account.AccountDailyLimits) (interface{}, error) {
    auth, err := t.Ctx.Auth.CheckAuthorization("Account.CreateAccount", "TOKEN", map[string]string{"org_id": org_id})
    if err != nil && !auth {
        return nil, fmt.Errorf("error in authorizing the caller  %s", err.Error())
    }
    err = t.Ctx.Model.CreateEvent(constants.CreateAccountEventName, map[string]interface{}{"org_id": org_id, "user_id": user_id, "token_type": token_type})
    if err != nil {
        return nil, err
    }
    return t.Ctx.Account.CreateAccount(org_id, user_id, token_type, daily_limits...)
}

• EventName: The name of the controller function.
• Payload: A JSON object that contains all of the input parameters of the controller function.