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Class CloudEvent<T>

A CloudEvent describes event data in common formats to provide interoperability across services, platforms and systems.

see

https://github.com/cloudevents/spec/blob/v1.0/spec.md

Type Parameters

  • T = undefined

Hierarchy

  • CloudEvent

Implements

Indexable

[key: string]: unknown

Index

Constructors

  • Creates a new CloudEvent object with the provided properties. If there is a chance that the event properties will not conform to the CloudEvent specification, you may pass a boolean false as a second parameter to bypass event validation.

    Type Parameters

    • T = undefined

    Parameters

    • event: Partial<CloudEventV1<T>>

      the event properties

    • strict: boolean = true

      whether to perform event validation when creating the object - default: true

    Returns CloudEvent<T>

Properties

data?: T

[OPTIONAL] The event payload. This specification does not place any restriction on the type of this information. It is encoded into a media format which is specified by the datacontenttype attribute (e.g. application/json), and adheres to the dataschema format when those respective attributes are present.

data_base64?: string

[OPTIONAL] The event payload encoded as base64 data. This is used when the data is in binary form.

datacontenttype?: string

[OPTIONAL] Content type of data value. This attribute enables data to carry any type of content, whereby format and encoding might differ from that of the chosen event format. For example, an event rendered using the JSON envelope format might carry an XML payload in data, and the consumer is informed by this attribute being set to "application/xml". The rules for how data content is rendered for different datacontenttype values are defined in the event format specifications; for example, the JSON event format defines the relationship in section 3.1.

dataschema?: string

[OPTIONAL] Identifies the schema that data adheres to. Incompatible changes to the schema SHOULD be reflected by a different URI. See Versioning of Attributes in the Primer for more information. If present, MUST be a non-empty URI.

id: string

[REQUIRED] Identifies the event. Producers MUST ensure that source + id is unique for each distinct event. If a duplicate event is re-sent (e.g. due to a network error) it MAY have the same id. Consumers MAY assume that Events with identical source and id are duplicates.

source: string

[REQUIRED] Identifies the context in which an event happened. Often this will include information such as the type of the event source, the organization publishing the event or the process that produced the event. The exact syntax and semantics behind the data encoded in the URI is defined by the event producer. Producers MUST ensure that source + id is unique for each distinct event. An application MAY assign a unique source to each distinct producer, which makes it easy to produce unique IDs since no other producer will have the same source. The application MAY use UUIDs, URNs, DNS authorities or an application-specific scheme to create unique source identifiers. A source MAY include more than one producer. In that case the producers MUST collaborate to ensure that source + id is unique for each distinct event.

specversion: string

[REQUIRED] The version of the CloudEvents specification which the event uses. This enables the interpretation of the context. Compliant event producers MUST use a value of 1.0 when referring to this version of the specification.

subject?: string

[OPTIONAL] This describes the subject of the event in the context of the event producer (identified by source). In publish-subscribe scenarios, a subscriber will typically subscribe to events emitted by a source, but the source identifier alone might not be sufficient as a qualifier for any specific event if the source context has internal sub-structure.

Identifying the subject of the event in context metadata (opposed to only in the data payload) is particularly helpful in generic subscription filtering scenarios where middleware is unable to interpret the data content. In the above example, the subscriber might only be interested in blobs with names ending with '.jpg' or '.jpeg' and the subject attribute allows for constructing a simple and efficient string-suffix filter for that subset of events.

If present, MUST be a non-empty string.

time?: string

[OPTIONAL] Timestamp of when the occurrence happened. If the time of the occurrence cannot be determined then this attribute MAY be set to some other time (such as the current time) by the CloudEvents producer, however all producers for the same source MUST be consistent in this respect. In other words, either they all use the actual time of the occurrence or they all use the same algorithm to determine the value used.

type: string

[REQUIRED] This attribute contains a value describing the type of event related to the originating occurrence. Often this attribute is used for routing, observability, policy enforcement, etc. The format of this is producer defined and might include information such as the version of the type - see Versioning of Attributes in the Primer for more information.

Methods

  • Clone a CloudEvent with new/updated attributes

    throws

    if the CloudEvent does not conform to the schema

    Parameters

    • options: Partial<CloudEventV1<never>>

      attributes to augment the CloudEvent without a data property

    • Optional strict: boolean

      whether or not to use strict validation when cloning (default: true)

    Returns CloudEvent<T>

    returns a new CloudEvent

  • Clone a CloudEvent with new/updated attributes and new data

    throws

    if the CloudEvent does not conform to the schema

    Type Parameters

    • D

    Parameters

    • options: Partial<CloudEventV1<D>>

      attributes to augment the CloudEvent with a data property and type

    • Optional strict: boolean

      whether or not to use strict validation when cloning (default: true)

    Returns CloudEvent<D>

    returns a new CloudEvent

  • emit(ensureDelivery?: boolean): Promise<CloudEvent<T>>
  • Emit this CloudEvent through the application

    Parameters

    • ensureDelivery: boolean = true

      fail the promise if one listener fail

    Returns Promise<CloudEvent<T>>

    this

  • toJSON(): Record<string, unknown>
  • toString(): string
  • validate(): boolean
  • Validates this CloudEvent against the schema

    throws

    if the CloudEvent does not conform to the schema

    Returns boolean

    true if this event is valid

  • Clone a CloudEvent with new or updated attributes.

    throws

    {ValidationError} if strict is true and the resulting event is invalid

    Parameters

    • event: CloudEventV1<any>

      an object that implements the CloudEventV1 interface

    • options: Partial<CloudEventV1<any>>

      an object with new or updated attributes

    • strict: boolean = true

      true if the resulting event should be valid per the CloudEvent specification

    Returns CloudEvent<any>

    a CloudEvent cloned from event with options applied.

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