module ActionController #:nodoc:
# Actions that fail to perform as expected throw exceptions. These exceptions can either be rescued for the public view
# (with a nice user-friendly explanation) or for the developers view (with tons of debugging information). The developers view
# is already implemented by the Action Controller, but the public view should be tailored to your specific application. So too
# could the decision on whether something is a public or a developer request.
#
# You can tailor the rescuing behavior and appearance by overwriting the following two stub methods.
module Rescue
def self.included(base) #:nodoc:
base.extend(ClassMethods)
base.class_eval do
alias_method_chain :perform_action, :rescue
end
end
module ClassMethods #:nodoc:
def process_with_exception(request, response, exception)
new.process(request, response, :rescue_action, exception)
end
end
protected
# Exception handler called when the performance of an action raises an exception.
def rescue_action(exception)
log_error(exception) if logger
erase_results if performed?
if consider_all_requests_local || local_request?
rescue_action_locally(exception)
else
rescue_action_in_public(exception)
end
end
# Overwrite to implement custom logging of errors. By default logs as fatal.
def log_error(exception) #:doc:
if ActionView::TemplateError === exception
logger.fatal(exception.to_s)
else
logger.fatal(
"\n\n#{exception.class} (#{exception.message}):\n " +
clean_backtrace(exception).join("\n ") +
"\n\n"
)
end
end
# Overwrite to implement public exception handling (for requests answering false to local_request?).
def rescue_action_in_public(exception) #:doc:
case exception
when RoutingError, UnknownAction then
render_text(IO.read(File.join(RAILS_ROOT, 'public', '404.html')), "404 Not Found")
else render_text "Application error (Rails)
"
end
end
# Overwrite to expand the meaning of a local request in order to show local rescues on other occurrences than
# the remote IP being 127.0.0.1. For example, this could include the IP of the developer machine when debugging
# remotely.
def local_request? #:doc:
[@request.remote_addr, @request.remote_ip] == ["127.0.0.1"] * 2
end
# Renders a detailed diagnostics screen on action exceptions.
def rescue_action_locally(exception)
add_variables_to_assigns
@template.instance_variable_set("@exception", exception)
@template.instance_variable_set("@rescues_path", File.dirname(__FILE__) + "/templates/rescues/")
@template.send(:assign_variables_from_controller)
@template.instance_variable_set("@contents", @template.render_file(template_path_for_local_rescue(exception), false))
@headers["Content-Type"] = "text/html"
render_file(rescues_path("layout"), response_code_for_rescue(exception))
end
private
def perform_action_with_rescue #:nodoc:
begin
perform_action_without_rescue
rescue Object => exception
if defined?(Breakpoint) && params["BP-RETRY"]
msg = exception.backtrace.first
if md = /^(.+?):(\d+)(?::in `(.+)')?$/.match(msg) then
origin_file, origin_line = md[1], md[2].to_i
set_trace_func(lambda do |type, file, line, method, context, klass|
if file == origin_file and line == origin_line then
set_trace_func(nil)
params["BP-RETRY"] = false
callstack = caller
callstack.slice!(0) if callstack.first["rescue.rb"]
file, line, method = *callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/).captures
message = "Exception at #{file}:#{line}#{" in `#{method}'" if method}." # `´ ( for ruby-mode)
Breakpoint.handle_breakpoint(context, message, file, line)
end
end)
retry
end
end
rescue_action(exception)
end
end
def rescues_path(template_name)
File.dirname(__FILE__) + "/templates/rescues/#{template_name}.rhtml"
end
def template_path_for_local_rescue(exception)
rescues_path(
case exception
when MissingTemplate then "missing_template"
when RoutingError then "routing_error"
when UnknownAction then "unknown_action"
when ActionView::TemplateError then "template_error"
else "diagnostics"
end
)
end
def response_code_for_rescue(exception)
case exception
when UnknownAction, RoutingError then "404 Page Not Found"
else "500 Internal Error"
end
end
def clean_backtrace(exception)
exception.backtrace.collect { |line| Object.const_defined?(:RAILS_ROOT) ? line.gsub(RAILS_ROOT, "") : line }
end
end
end