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Handlers

For every http status code there is a handler function defined in liberator. All have sensible defaults and will return a simple english error message or an empty response, whatever is appropriate.

Exception Handler since 0.12.0

If an exception is thrown by a decision or action function, it will be caught and the handler handle-exception is called.

List of all handler

Handler key status code redirect?
handle-ok 200  
handle-created 201  
handle-options 201  
handle-accepted 202  
handle-no-content 204  
handle-moved-permanently 301 yes
handle-see-other 303 yes
handle-not-modified 304  
handle-moved-temporarily 307 yes
handle-multiple-representations 310  
handle-malformed 400  
handle-unauthorized 401  
handle-forbidden 403  
handle-not-found 404  
handle-method-not-allowed 405  
handle-not-acceptable 406  
handle-conflict 409  
handle-gone 410  
handle-precondition-failed 412  
handle-request-entity-too-large 413  
handle-uri-too-long 414  
handle-unsupported-media-type 415  
handle-unprocessable-entity since 0.9.0 422  
handle-exception since 0.12.0 500  
handle-not-implemented 501  
handle-unknown-method 501  
handle-service-not-available 503  

Redirecting

The handlers that are marked as redirecting will set a “Location” header that is generated from the following mechanism:

Lookup in context since 0.9.0

Liberator uses the lookup key :location in the context. You can set this key from a decision function that decides on the redirection, e.g. :post-redirect?. The value can either be a constant value or a function that will be called with the current context.

Example:

(defresource postbox
:allowed-methods [:post]
:post-redirect? (fn [ctx] {:location "http://example.com/look-here/"}))

You could also use a constant value for :post-redirect like the execution model for liberator describes.

Lookup in resource

If no location was found in the context, then Liberator will lookup the key :location in the resource definition. Note that this value is used for all redirecting handlers if :location was not set the context.

Example:

(defresource postbox
:allowed-methods [:post]
:post-redirect? true
:location (fn [ctx] "http://example.com/look-here/"))