claro

Documentation | Guides

claro is a library that allows you to streamline your data access, providing powerful optimisations and abstractions along the way.

It is inspired by muse and heavily influenced by GraphQL.

claro requires Clojure ≥ 1.7.0.

Features

claro is designed to be flexible and extensible. It'll make your data access more elegant, efficient and testable, providing things like:

• batched resolution of similar entities,
• automatic caching of already known resolution results,
• engine middlewares to hook into the resolution logic, allowing e.g. generic cache or circuit breaker implementations,
• pluggable resolution strategies in the form of Resolvable selectors,
• an exchangeable deferred implementation, defaulting to manifold,
• and pre-built middlewares for data source mocking, introspection and result transformation.

Quickstart

Data access is defined within records implementing the Resolvable interface. Note that they can always produce more resolvables:

(require '[claro.data :as data]
         '[manifold.deferred :as d])

(defrecord Person [id]
  data/Resolvable
  (resolve! [_ env]
    (d/future
      (fetch-person! (:db env) id)))
  data/Transform
  (transform [_ {:keys [friend-ids] :as person}]
    (assoc person :friends (map #(Person. %) friend-ids))))

Blindly resolving an infinite tree like this is usually not a good idea – but claro offers tree projections you can use to describe abstract transformations of infinite structures:

(require '[claro.projection :as projection])

(def person-with-friend-names
  {:id      projection/leaf
   :name    projection/leaf
   :friends [(projection/extract :name)]})

And here we go:

(require '[claro.engine :as engine])

(engine/run!!
  (-> (->Person 1)
      (projection/apply person-with-friend-names)))
;; => {:id 1, :name "Sherlock Holmes", :friends ["Dr. Watson", "Ms. Hudson"]}

Related Projects

Library	Description
alumbra	GraphQL implementation on top of claro
claro.circuit-breaker	Circuit-breaker middleware based on resilience4j

Feel free to open a pull request to add your project to this table.

Documentation

1. Basic Resolution
2. Projections
3. Advanced Projections
4. Engine
5. Testing & Debugging
6. Implementation Notes

All these topics are also available in claro's auto-generated documentation.

Contributing

Contributions are always welcome. Please take a look at the Contribution Guidelines for a quick overview of how your changes can best make it to master.

License

MIT License

Copyright (c) 2015-2017 Yannick Scherer

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.