Route data can be anything, so it's easy to go wrong. Accidentally adding a :role
key instead of :roles
might hinder the whole routing app without any authorization in place.
To fail fast, we could use the custom :coerce
and :compile
hooks to apply data validation and throw exceptions on first sighted problem.
But there is a better way. Router has a :validation
hook to validate the whole route tree after it's successfully compiled. It expects a 2-arity function routes opts => ()
that can side-effect in case of validation errors.
Namespace reitit.spec
contains specs for main parts of reitit.core
and a helper function validate
that runs spec validation for all route data and throws an exception if any errors are found.
A Router with invalid route data:
(require '[reitit.core :as r])
(r/router
["/api" {:handler "identity"}])
; #object[reitit.core$...]
Failing fast with clojure.spec
validation turned on:
(require '[reitit.spec :as rs])
(r/router
["/api" {:handler "identity"}]
{:validate rs/validate})
; CompilerException clojure.lang.ExceptionInfo: Invalid route data:
;
; -- On route -----------------------
;
; "/api"
;
; In: [:handler] val: "identity" fails spec: :reitit.spec/handler at: [:handler] predicate: fn?
;
; {:problems (#reitit.spec.Problem{:path "/api", :scope nil, :data {:handler "identity"}, :spec :reitit.spec/default-data, :problems #:clojure.spec.alpha{:problems ({:path [:handler], :pred clojure.core/fn?, :val "identity", :via [:reitit.spec/default-data :reitit.spec/handler], :in [:handler]}), :spec :reitit.spec/default-data, :value {:handler "identity"}}})}, compiling: ...
Turning on Pretty Errors will give much nicer error messages:
(require '[reitit.dev.pretty :as pretty])
(r/router
["/api" {:handler "identity"}]
{:validate rs/validate
:exception pretty/exception})
rs/validate
reads the following router options:
key | description |
---|---|
:spec | the spec to verify the route data (default ::rs/default-data ) |
:reitit.spec/wrap | function of spec => spec to wrap all route specs |
NOTE: clojure.spec
implicitly validates all values with fully-qualified keys if specs exist with the same name.
Invalid spec value:
(require '[clojure.spec.alpha :as s])
(s/def ::role #{:admin :manager})
(s/def ::roles (s/coll-of ::role :into #{}))
(r/router
["/api" {:handler identity
::roles #{:adminz}}]
{:validate rs/validate
:exception pretty/exception})
To fail-fast on non-defined and misspelled keys on route data, we can close the specs using :reitit.spec/wrap
options with value of spec-tools.spell/closed
that closed the top-level specs.
Requiring a:description
and validating using closed specs:
(require '[spec-tools.spell :as spell])
(s/def ::description string?)
(r/router
["/api" {:summary "kikka"}]
{:validate rs/validate
:spec (s/merge ::rs/default-data
(s/keys :req-un [::description]))
::rs/wrap spell/closed
:exception pretty/exception})
It catches also typing errors:
(r/router
["/api" {:descriptionz "kikka"}]
{:validate rs/validate
:spec (s/merge ::rs/default-data
(s/keys :req-un [::description]))
::rs/wrap spell/closed
:exception pretty/exception})
Can you improve this documentation? These fine people already did:
Tommi Reiman, Marcus Spiegel & Aaron GroomEdit on GitHub
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