feat: add a constructor parameter for loose validation

This commit adds a second, optional boolean parameter to the `CloudEvent`
constructor. When `false` is provided, the event constructor will not
perform validation of the event properties, values and extension names.

Fixes: #325

Signed-off-by: Lance Ball <lball@redhat.com>

Author: lance

src/event/cloudevent.ts

@@ -46,7 +46,15 @@ export class CloudEvent implements CloudEventV1, CloudEventV03 {
   schemaurl?: string;
   datacontentencoding?: string;
 
-  constructor(event: CloudEventV1 | CloudEventV1Attributes | CloudEventV03 | CloudEventV03Attributes) {
+  /**
+   * 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.
+   *
+   * @param {object} event the event properties
+   * @param {boolean?} strict whether to perform event validation when creating the object - default: true
+   */
+  constructor(event: CloudEventV1 | CloudEventV1Attributes | CloudEventV03 | CloudEventV03Attributes, strict = true) {
     // copy the incoming event so that we can delete properties as we go
     // everything left after we have deleted know properties becomes an extension
     const properties = { ...event };
@@ -105,20 +113,20 @@ export class CloudEvent implements CloudEventV1, CloudEventV03 {
     for (const [key, value] of Object.entries(properties)) {
       // Extension names should only allow lowercase a-z and 0-9 in the name
       // names should not exceed 20 characters in length
-      if (!key.match(/^[a-z0-9]{1,20}$/)) {
+      if (!key.match(/^[a-z0-9]{1,20}$/) && strict) {
         throw new ValidationError("invalid extension name");
       }
 
       // Value should be spec compliant
       // https://github.com/cloudevents/spec/blob/master/spec.md#type-system
-      if (!isValidType(value)) {
+      if (!isValidType(value) && strict) {
         throw new ValidationError("invalid extension value");
       }
 
       this[key] = value;
     }
 
-    this.validate();
+    strict ? this.validate() : undefined;
 
     Object.freeze(this);
   }
@@ -187,6 +195,7 @@ export class CloudEvent implements CloudEventV1, CloudEventV03 {
   /**
    * Clone a CloudEvent with new/update attributes
    * @param {object} options attributes to augment the CloudEvent with
+   * @param {boolean} strict whether or not to use strict validation when cloning (default: true)
    * @throws if the CloudEvent does not conform to the schema
    * @return {CloudEvent} returns a new CloudEvent
    */
@@ -198,7 +207,8 @@ export class CloudEvent implements CloudEventV1, CloudEventV03 {
       | CloudEventV03
       | CloudEventV03Attributes
       | CloudEventV03OptionalAttributes,
+    strict = true,
   ): CloudEvent {
-    return new CloudEvent(Object.assign({}, this.toJSON(), options) as CloudEvent);
+    return new CloudEvent(Object.assign({}, this.toJSON(), options) as CloudEvent, strict);
   }
 }

test/integration/cloud_event_test.ts

@@ -1,3 +1,4 @@
+import { ValidationError } from "ajv";
 import { expect } from "chai";
 import { CloudEvent, Version } from "../../src";
 import { CloudEventV03, CloudEventV1 } from "../../src/event/interfaces";
@@ -20,6 +21,22 @@ describe("A CloudEvent", () => {
     expect(ce.source).to.equal(source);
   });
 
+  it("Can be constructed with loose validation", () => {
+    const ce = new CloudEvent({} as CloudEventV1, false);
+    expect(ce).to.be.instanceOf(CloudEvent);
+  });
+
+  it("Loosely validated events can be cloned", () => {
+    const ce = new CloudEvent({} as CloudEventV1, false);
+    expect(ce.cloneWith({}, false)).to.be.instanceOf(CloudEvent);
+    console.error(ce);
+  });
+
+  it("Loosely validated events throw when validated", () => {
+    const ce = new CloudEvent({} as CloudEventV1, false);
+    expect(ce.validate).to.throw(TypeError, "invalid payload");
+  });
+
   it("serializes as JSON with toString()", () => {
     const ce = new CloudEvent(fixture);
     expect(ce.toString()).to.deep.equal(JSON.stringify(ce));