Map validation library for Clojure and ClojureScript

Why

Most other validation libraries (such as valip) assume validation is done per key, rather than on a map as a whole. This makes it difficult to write multi-key validations. Validation functions in Verily take an entire map, making multi-key (or single-key) validations easy.

Verily also provides a declarative, data-oriented API in addition to a conventional, function-oriented API. Using data to describe validations has benefits in certain use cases. For instance, you can share validation specifications between Clojure and ClojureScript.

Installation

Leiningen:

[jkkramer/verily "0.6.0"]

Usage

(ns example.core
  (:require [jkkramer.verily :as v]))

There are two ways to validate a map:

With a validation specification - i.e., data, which Verily turns into a validation function for you
With a validation function

To validate using a validation specification:

(def validations
  [[:required [:foo :bar :password]]
   [:equal [:password :confirm-password] "Passwords don't match, dummy"]
   [:min-length 8 :password]])
(v/validate {:foo "foo"
             :password "foobarbaz"
             :password-confirm "foobarba"}
            validations)
;; Returns:
({:keys (:bar), :msg "must not be blank"}
 {:keys [:password :confirm-password], :msg "Passwords don't match, dummy"})

To turn a validation specification into a function yourself:

(def validator (v/validations->fn validations))

You can use validation functions instead of data if you prefer. This makes it easier to write your own:

;; Custom validator
(defn validate-password [m]
  (when (#{"12345" "password" "hunter2"} (:password m))
    {:keys [:password] :msg "You can't use that password"}))
;; Combine several built-in validators and our own custom one
(def validator
  (v/combine
    (v/required [:foo :bar :password])
    (v/equal [:password :password-confirm])
    (v/min-length 8 :password)
    validate-password))
(validator {:foo "foo"
            :password "foobarbaz"
            :password-confirm "foobarba"})
;; Returns:
({:keys (:bar), :msg "must not be blank"}
 {:keys [:password :password-confirm], :msg "must be equal"})

Validation Function Contract

The contract for a validation function is:

Take a map as an argument
If validation succeeded, return nil or an empty collection. If there was a problem, return a problem map or collection of problem maps. Each problem is a map with the following keys:
- :keys (optional) - relevant map keys
- :msg - description of the problem

Built-in Validations

All validation specifications accept a key or sequence of keys. The message is always optional.

Keys can be dotted keywords such as :foo.bar, which will be interpreted as a nested path (if the :foo.bar key does not exist in the top-level map). Strings such as "foo[bar]" are also allowed, and have the same semantics.

Unless :required is used, all validations allow the keys to be absent from the map, or have a nil value (or blank if a string-based type).

:required <keys> [msg] - must not be absent, blank, or nil
:contains <keys> [msg] - must not be absent, but can be blank or nil
:not-blank <keys> [msg] - may be absent but not blank or nil
:exact <value> <keys> [msg] - must be a particular value
:equal <keys> [msg] - all keys must be equal
:email <keys> [msg] - must be a valid email
:url <keys> [msg] - must be a valid URL
:web-url <keys> [msg] - must be a valid website URL (http or https)
:link-url <keys> [msg] - must be a valid link URL (can be relative, http: or https: may be omitted)
:matches <regex> <keys> [msg] - must match a regular expression
:min-length <len> <keys> [msg] - must be a certain length (for strings or collections)
:max-length <len> <keys> [msg] - must not exceed a certain length (for strings or collections)
:complete <keys> [msg] - must be a collection with no blank or nil values
:min-val <min> <keys> [msg] - must be at least a certain value
:max-val <max> <keys> [msg] - must be at most a certain value
:within <min> <max> <keys> [msg] - must be within a certain range (inclusive)
:positive <keys> [msg] - must be a positive number
:negative <keys> [msg] - must be a negative number
:after <date> <keys> [msg] - must be after a certain date
:before <date> <keys> [msg] - must be before a certain date
:in <coll> <keys> [msg] - must be contained within a collection
:every-in <coll> <keys> [msg] - each value must be within a collection (for values that are themselves collections)
:us-zip <keys> [msg] - must be a valid US zip code
:luhn <keys> [msg] - must be pass the Luhn check (e.g., for credit card numbers)
Datatype validations: :string, :boolean, :integer, :float, :decimal, :date (plus aliases)
Datatype collection validations: :strings, :booleans, :integers, :floats, :decimals, :dates (plus aliases)

All validation specifications have corresponding validator functions in the jkkramer.verily namespace, if you prefer to use those directly.

License

Distributed under the Eclipse Public License, the same as Clojure.