Halcyon

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Exceptions

The most up-to-date list of HTTP status codes that Halcyon supports can be seen
at the GitHub source page
which is transformed into actual exception classes from the error message.

Here is a list of the actual Exception classes as created by this list and a
brief overview of when to use these exceptions:

• 100 Continue
• 101 SwitchingProtocols
• 102 Processing
• 200 OK — this is the standard response, alias method ok
• 201 Created — can be used to indicated success for create action
• 202 Accepted
• 203 NonAuthoritativeInformation
• 204 NoContent
• 205 ResetContent
• 206 PartialContent
• 207 MultiStatus
• 300 MultipleChoices
• 301 MovedPermanently
• 302 MovedTemporarily
• 303 SeeOther
• 304 NotModified
• 305 UseProxy
• 307 TemporaryRedirect
• 400 BadRequest — can be used to indicate insufficient params, etc
• 401 Unauthorized — can indicate authorization necessary
• 402 PaymentRequired
• 403 Forbidden
• 404 NotFound — can indicate resources not found
• 405 MethodNotAllowed
• 406 NotAcceptable — can be used to indicate method is restricted to certain clients et al
• 407 ProxyAuthenticationRequired
• 408 RequestTimeout
• 409 Conflict
• 410 Gone
• 411 LengthRequired
• 412 PreconditionFailed
• 413 RequestEntityTooLarge
• 414 RequestURITooLarge
• 415 UnsupportedMediaType
• 416 RequestedRangeNotSatisfiable
• 417 ExpectationFailed
• 422 UnprocessableEntity — can be used to indicate models fail validations
• 423 Locked
• 424 FailedDependency
• 425 NoCode
• 426 UpgradeRequired — can be used to indicate change of API versions, etc
• 500 InternalServerError — indicates uncaught error
• 501 NotImplemented — can indicate non-functionality or partial implementation
• 502 BadGateway
• 503 ServiceUnavailable — can indicate the service is temporarily unavailable for maintenance
• 504 GatewayTimeout
• 505 HTTPVersionnotsupported
• 506 VariantAlsoNegotiates
• 507 InsufficientStorage
• 510 NotExtended

Making Your Own

Although the standard exceptions available should be sufficient (they are
the HTTP response codes), you could certainly make up your own HTTP response
codes. Putting this inside of an init file or in the lib directory should
be fine:

 1 ## lib/custom_exception.rb
 2 ## or config/init/custom_exception.rb
 3 class CustomException < Halcyon::Exceptions::Base
 4   
 5   def initialize(body = 'Custom Exception')
 6     super(460, body)
 7   end
 8   
 9 end

As you can see, the status code is the first argument to the base initialize
method and the body variable is set to the default error text. Obviously, the
exception name, file name, and error status should be more descriptive.
Pick a sane error code as well, something that hasn’t been used officially.

If at all possible, use the default response codes/exceptions.