alumbra.pipeline

This library provides a pipeline implementation for GraphQL query execution, as well as a Ring-compatible handler encapsulating this task. It uses pluggable components that consume/produce data structures as described in alumbra.spec.

Usage

Ring Handler

To create a GraphQL-capable Ring endpoint, you need to supply a series of alumbra.spec-compatible components:

(require '[alumbra.pipeline :as pipeline])

(pipeline/handler
  {:parser-fn       ...
   :validator-fn    ...
   :canonicalize-fn ...
   :context-fn       (fn [request] (read-auth request))
   :executor-fn      (fn [context canonical-operation] ...)})

Note that:

• :parser-fn should consume an InputStream and return a value conforming to either :alumbra/document or :alumbra/parser-errors,
• :validator-fn should consume an :alumbra/document and return either nil or a value conforming to :alumbra/validation-errors,
• :canonicalize-fn should consume a validated :alumbra/document and return a value conforming to :alumbra/canonical-document,
• :context-fn should consume a Ring request map and produce any value representing the context of the GraphQL query,
• :executor-fn should consume the value produced by :context, as well as an :alumbra/canonical-operation, and produce the resolved value as a map.

A variant of this handler that uses pre-defined components can be found in the main alumbra repository.

Raw Executor

A low-level query executor can be constructed using alumbra.pipeline/executor. See its docstring for more information.

License

MIT License

Copyright (c) 2016 Yannick Scherer

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