Talkback

Talkback is a standalone HTTP proxy that can record and playback requests.
Although built as a node.js library, it can be used to playback requests from any language as you should run it as a separate process.
Very useful for integration tests environments or mocking HTTP servers.
Heavily inspired by flickr/yakbak.

Installation

npm install talkback

Usage

Talkback is pretty easy to setup.
Define which host it will be proxying, which port it should listen to and where to find and save tapes.

When a request arrives to talkback, it will try to match it against an existing tape and return the tape's response.
If no tape matches the request, it will forward it to the origin host save the tape to disk for future uses and return the response.

const talkback = require("talkback");

const opts = {
  host: "https://api.myapp.com/foo",
  port: 5544,
  path: "./my-tapes"
};
const server = talkback(opts);
server.start(() => console.log("Talkback Started");
server.close();

talback(opts)

Returns an unstarted talkback server instance.

Options:

Name	Type	Description	Default
host	`String`	Where to proxy unknown requests
port	`String`	Talkback port	8080
path	`String`	Path where to load and save tapes	`./tapes/`
ignoreHeaders	`[String]`	List of headers to ignore when matching tapes. Useful when having dynamic headers like cookies or correlation ids.	`[]`
record	`Boolean`	Whether talkback should proxy and record unknown requests or fail fast and return 404	`true`
summary	`Boolean`	Whether to print a summary of new and unused tapes at exit	`true`

start([callback])

Starts the HTTP server and if provided calls callback after the server has successfully started.

close()

Stops the HTTP server.

Tapes

Tapes can be freely edited to match new requests or return a different response than the original. They are loaded from the path directory at startup.
They use the JSON5 format. JSON5 is an extensions to the JSON format that allows for very neat features like comments, trailing commas and keys without quotes.

Format

All tapes have the following 3 properties:

meta: Stores metadata about the tape.
req: Request object. Used to match incoming requests against the tape.
res: Response object. The HTTP response that will be returned in case the tape matches a request.

Both req and res objects can be freely edited. Since tapes are only loaded on startup, any changes to a tape requires a server restart to be applied.

File Name

New tapes will be created under the path directory with the name unnamed-n.json5, where n is the tape number.
Tapes can be renamed at will, for example to give some meaning to the scenario the tape represents.

Request and Response body

If the content type of the request or response is considered human readable and uncompressed, the body will be saved in plain text.
Otherwise, the body will be saved as a Base64 string, allowing to save binary content.

No recording

Talkback proxying and recording can be disabled through the record option.
When recording is disabled and an unknown requests arrives, talkback will just log an error message, and return a 404 response without proxying the request to host.

It is recommended to disable recording when using talkback for test running. This way, there are no side-effects and broken tests fail faster.

Licence

MIT

timhudson/talkback