yada

yada is a web library for Clojure, designed to support the creation of production services via HTTP.

It has the following features:

Standards-based, comprehensive HTTP coverage (content negotiation, conditional requests, etc.)
Parameter validation and coercion, automatic Swagger support
Rich extensibility (methods, mime-types, security and more)
Asynchronous, efficient interceptor-chain design built on manifold
Excellent performance, suitable for heavy production workloads

yada is a sibling library to bidi - whereas bidi is based on routes as data, yada is based on resources as data.

The user-manual for the latest (1.1.x) release is available at https://juxt.pro/yada and offline (see below).

The user-manual is also available as an e-book or PDF, at Leanpub.

Installation

Add the following dependency to your project.clj file

Create a yada handler

Typically, yada handlers are created from a configuation expressed in data.

(require '[yada.yada :as yada])

(yada/handler
  {:methods
    {:get
      {:produces "text/html"
       :response "<h1>Hello World!</h1>"}}})

This is a simple example, there are a lot more options in yada than can be expressed here, but the approach is the same. The data configuration can be hand-authored, or generated programmatically leading enabling creation of consisntent APIs at an industrial scale.

Dependencies

yada requires the following :-

a Java JDK/JRE installation, version 8 or above
Clojure 1.8.0
Aleph 0.4.1 (provided via a dependency)
bidi 2.0.9 or above

A project using yada will need to bring in aleph, and optionally bidi.

[aleph "0.4.1"]
[bidi "2.0.9"]

Support for other web-severs, such as undertow, are on the road-map.

Future compatibility

If you want to ensure that your code will not break with future releases of yada, you should only use functions from the yada.yada namespaces.

You are free to use other public functions in yada, but please be warned that these can and do change between releases.

Lean yada

By default, yada is batteries-included, bringing in a large number of dependencies.

However, a leaner version of yada is available which cuts out Swagger, swagger-ui, JSON (cheshire), Transit, buddy, core.async, SSE and other fat.

Instead of requiring yada.yada, require yada.yada.lean but otherwise use yada in the same way.

The following differences apply:

yada doesn't automatically encode/decode JSON bodies, or render JSON as HTML
no parameter validation or coercion
no Swagger
no SSE (currently)
no JWT
no Transit

Running documentation and examples offline

Although yada is a library, if you clone this repo you can run the documentation and examples from the REPL.

cd yada
lein repl

Once the REPL starts, type in and run the following :-

user> (dev)
dev> (go)

Now browse to http://localhost:8090.

Troubleshooting FAQ

Q. I'm migrating from a version before yada 1.1 and my async multipart and other uploads are not working, sometimes throwing NullPointerExceptions or other errors.

A. Either use yada's built-in yada.server function or make sure you have started aleph's server with the option raw-stream? :true. Previous versions of yada left these settings up to the user but it's very important in yada 1.1 that raw-stream? is set.

Support

yadarians mostly chat in the Slack channel plus there is also a dedicated Gitter channel channel

Also, there is a discussion group yada-discuss to discuss ideas.

Contributing

Feel free to raise GitHub issues on this repository.

Pull requests are welcome. Please run the test suite and check that all tests pass prior to submission.

$ lein test

Acknowledgments

Thanks to the following people for inspiration, contributions, feedback and suggestions.

Malcolm Sparks
Martin Trojer
Philipp Meier
David Thomas Hume
Zach Tellman
Stijn Opheide
Frankie Sardo
Jon Pither
Håkan Råberg
Ernestas Lisauskas
Thomas van der Veen
Leandro Demartini
Craig McCraig of the clan McCraig
Imre Kószó
Luo Tian
Joshua Griffith
Joseph Fahey
David Smith
Mike Fikes
Brian Olsen
Stanislas Nanchen
Nicolas Ha
Eric Fode
Leon Mergen
Greg Look
Tom Coupland
Mikkel Gravgaard
Lucas Lago
Johannes Staffans

Also, see the dependency list. In particular, yada would certainly not exist without the considerable efforts of those behind the following libraries.

Manifold & Aleph - Zach Tellman
Prismatic Schema - Jason Wolfe (and others)
Ring-swagger - Tommi Riemann (and others)

Copyright & License

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

naartjie/yada