express-api-base v1.0.5
Express API Base
This project is a simple utility around a lot of Express functionality.
It allows fine-grain control over IO, configuration, CORS, documentation generation, payload standardization, internal event pipeline, user-safe errors, base pathing, and more.
Basic Use
1.) Create a config.js
in the root of your project. See the example config.js for starting base.
2.) Create a config
folder in the root of your project. See example config folder for complementary base configs.
3.) Create an index.js
with the following (customize to your liking):
const createApp = require("express-api-base/app");
const startApp = require("express-api-base");
const config = require("./config");
const app = createApp({
config,
routes: require("./routes")
});
startApp(app, config);
Feature - JSONPayload
This module allows you to standardize route responses, including response codes. Adds the following new properties to the response object:
res.payload // payload object
res.setPayload(payload); // set internal object
res.setError(error); // set internal error
res.noContent(); // set 204 status, remove body
res.sendNoContent();
res.sendPayload(payload, status = 200, metadata = {});
res.sendError(type, details, status = 500, metadata = {});
res.handleError(exception, type = "generic", status = 500);
This module standardizes the output to the following (if not noContent):
{
"error": "Error type, default is 'generic'",
"details": "Actual error here",
"payload": "Actual payload"
}
If an error has occurred, payload
is null. The opposite is the case if there was no error, just a payload. metadata
in the send*()
functions will be spread into the response object.
This allows consuming clients to easily check for problems.
handleError()
is a convenient way to handle exceptions in a route. It will automatically console.error()
the exception and call res.sendError()
with the type, exception and status code.
Feature - Health Check
ECS is a common companion to applications these days. This endpoint simply gives back a 200 with body "Health OK"
Feature - Validation and Documentation
Joi is a popular and powerful validation library. The optional middleware provided allows you to not only validate header, query parameters, path variables or request bodies with joi, but will also populate that in the included OpenAPI endpoint.
OpenAPI is not used, only generated for documentation. Additionally, setting the NODE_ENV to "build" will allow you to save the OpenAPI file to the project root. If you want, you can set your app config's outputType
property to openapi
or postman
to generate either an OpenAPI yaml file or a Postman collection JSON.
Any route registered with validation middleware in express can output its joi description by adding the x-validation-schema
query parameter. This request will be intercepted by the validation middleware. Alternatively, you can retrieve the serialized joi schema with the x-joi-schema
query parameter.
In addition to validation, additional metadata middleware can be used to decorate the virtual OpenAPI definition further. A route description can be set with the metadata
middleware, but in the future more functionality will be added.
Finally, you can view the auto-generated documentation with the /docs
endpoint. This can be disabled when calling createApp()
by setting disableSwagger
to truthy. This endpoint uses swagger-ui-express
to render the constructed OpenAPI definition.
Feature - Error Handling
When combined with the payload standardization technique above, this package will automatically handle route errors and return a 500 with the standard error payload format.
Feature - Event Pipeline
PubSub is a common architecture, even when used internally within an application. Using the EventPipeline utility, which is simply an EventEmitter with a few extra functions, you can publish and subscribe to events within your application, decoupling app features when desired.
Other Utilities
Included in this repo is an example package.json scripts
and nodemon config, example .eslintrc
, example .gitignore
, example jsconfig.json
. Everything you need to get started quickly.