Class: SenorArmando::Rack::ExceptionHandler

Inherits:
Object
  • Object
show all
Includes:
Goliath::Rack::Validator
Defined in:
lib/senor_armando/rack/exception_handler.rb

Overview

Middleware to rescue validation errors and send them up the chain as normal non-200 responses

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ ExceptionHandler

Returns a new instance of ExceptionHandler.



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# File 'lib/senor_armando/rack/exception_handler.rb', line 8

def initialize(app)
  @app = app
end

Class Method Details

.error_response(err, headers = {}) ⇒ Object

Parameters:

  • err (Goliath::Validation::Error) —

    error to describe in response

  • headers (Hash) (defaults to: {}) —

    Response headers to preserve in an error response; (the Content-Length header, if any, is removed)



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# File 'lib/senor_armando/rack/exception_handler.rb', line 21

def self.error_response err, headers={}
  headers.merge!({
      'Content-Type'     => "application/json",
      'X-Error-Message' => err.message,
      'X-Error-Detail'  => err.description,
    })
  headers.delete('Content-Length')
  body    = {
    "error"   => err.class.to_s.gsub(/.*::/,""),
    "message" => [err.message, err.description].compact.join(": "),
    "status"  => err.status_code
  }
  [err.status_code, headers, body.to_json]
end

.safely(env, headers = {}) ⇒ Object

Execute a block of code safely.

If the block raises any exception that derives from Goliath::Validation::Error (see specifically those in goliath/validation/standard_http_errors.rb), it will be turned into the corresponding 4xx response with a corresponding message.

If the block raises any other kind of error, we log it and return a less-communicative 500 response.

Examples:

# will convert the ForbiddenError exception into a 403 response
# and an uncaught error in do_something_risky! into a 500 response
safely(env, headers) do
  raise ForbiddenError unless ['valid'] == true
  do_something_risky!
  [status, headers, body]
end

Parameters:

  • env (Goliath::Env) —

    The current request env

  • headers (Hash) (defaults to: {}) —

    Response headers to preserve in an error response



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# File 'lib/senor_armando/rack/exception_handler.rb', line 59

def self.safely(env, headers={})
  begin
    yield
  rescue Goliath::Validation::Error => err
    error_response(err, headers)
  rescue Exception => err
    env.logger.error(err.message)
    env.logger.error(err.backtrace.join("\n"))
    puts(err.message)
    puts(err.backtrace.join("\n"))
    error_response(Goliath::Validation::InternalServerError.new('Internal Server Error'), headers)
  end
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/senor_armando/rack/exception_handler.rb', line 12

def call(env)
  self.class.safely(env) do
    @app.call(env)
  end
end