Challenge #2b: Dynamic Configuration

In this challenge, you’ll modify the code you created in the previous challenge. Rather than hard-coding the ROT-13 service port and correlation ID, you’ll use values stored in WwwConfig.

Instructions

1. Revise the "POST asks ROT-13 service to transform text" test:

  1. Configure WwwConfig to use the port 999.
  2. Configure WwwConfig to use the correlation ID "my-correlation-id".
  3. Change the test’s assertion to use the new port and correlation ID.

2. Revise HomePageController.postAsync():

  1. Get the port and correlation ID out of the config parameter.

Remember to commit your changes when you’re done.

API Documentation

const config = WwwConfig.createTestInstance({ rot13ServicePort: 999, correlationId: "my-correlation-id" });

Create a WwwConfig instance with the provided ROT-13 service port and correlation ID. Note that the parameter is an object—don’t forget the curly braces!

  • rot13ServicePort (number) - the port of the ROT-13 service
  • correlationId (string) - a unique ID representing the user’s request
  • returns config (WwwConfig) - the configured instance
const port = config.rot13ServicePort;

Get the configured ROT-13 service port.

  • returns port (number) - the port
const id = config.correlationId;

Get the configured correlation ID.

  • returns id (string) - the ID

JavaScript Primers

No new concepts.

Hints

1
You need to configure the ROT-13 service port and correlation ID.
Change the call to WwwConfig.createTestInstance(). 
it("POST asks ROT-13 service to transform text", async () => {
  // Arrange
	const rot13Client = Rot13Client.createNull();
	const rot13Requests = rot13Client.trackRequests();

	const clock = Clock.createNull();
  const controller = new HomePageController(rot13Client, clock);

	const request = HttpServerRequest.createNull();
	const config = WwwConfig.createTestInstance({
		rot13ServicePort: 999,
		correlationId: "my-correlation-id",
	});

  // Act
	await controller.postAsync(request, config);

  // Assert
	assert.deepEqual(rot13Requests.data, [{
		port: 123,
		text: "some text",
		correlationId: "0000-0000",
	}]);
});
2
Don’t forget to update your assertion. 
it("POST asks ROT-13 service to transform text", async () => {
  // Arrange
	const rot13Client = Rot13Client.createNull();
	const rot13Requests = rot13Client.trackRequests();

	const clock = Clock.createNull();
  const controller = new HomePageController(rot13Client, clock);

	const request = HttpServerRequest.createNull();
	const config = WwwConfig.createTestInstance({
		rot13ServicePort: 999,
		correlationId: "my-correlation-id",
	});

  // Act
	await controller.postAsync(request, config);

  // Assert
	assert.deepEqual(rot13Requests.data, [{
		port: 999,
		text: "some text",
		correlationId: "my-correlation-id",
	}]);
});
3
You’re ready to run the test.
It should fail, saying the port and correlationId are different than expected.

This means your production code isn’t using the values defined in the config.

4
Change your production code to get the port and correlation ID out of the config object.
Use config.rot13ServicePort and config.correlationId. 
async postAsync(request, config) {
	await this._rot13Client.transformAsync(
		config.rot13ServicePort,
		"some text",
		config.correlationId,
	);
}

TypeScript needs a placeholder return:

// TypeScript
async postAsync(request: HttpServerRequest, config: WwwConfig): Promise<HttpServerResponse> {
	await this._rot13Client.transformAsync(
		config.rot13ServicePort,
		"some text",
		config.correlationId,
	);

	// DELETE ME: placeholder to satisfy compiler
	return await HttpServerResponse.createPlainTextResponse({ status: 501, body: "not implemented" });
}

Complete Solution

Test code: 
it("POST asks ROT-13 service to transform text", async () => {
  // Arrange
	const rot13Client = Rot13Client.createNull();
	const rot13Requests = rot13Client.trackRequests();

	const clock = Clock.createNull();
  const controller = new HomePageController(rot13Client, clock);

	const request = HttpServerRequest.createNull();
	const config = WwwConfig.createTestInstance({
		rot13ServicePort: 999,
		correlationId: "my-correlation-id",
	});

  // Act
	await controller.postAsync(request, config);

  // Assert
	assert.deepEqual(rot13Requests.data, [{
		port: 999,
		text: "some text",
		correlationId: "my-correlation-id",
	}]);
});
Production code (JavaScript): 
async postAsync(request, config) {
	await this._rot13Client.transformAsync(
		config.rot13ServicePort,
		"some text",
		config.correlationId,
	);
}
Production code (TypeScript): 
async postAsync(request: HttpServerRequest, config: WwwConfig): Promise<typescript> {
	await this._rot13Client.transformAsync(
		config.rot13ServicePort,
		"some text",
		config.correlationId,
	);

	// DELETE ME: placeholder to satisfy compiler
	return await HttpServerResponse.createPlainTextResponse({ status: 501, body: "not implemented" });
}

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