I have an error object e, with the following structure:
e.error_code
e.message
It, however, may have additional symbols, such as:
e.error_details
How do I iterate through the e object?
I tried
e.each do |error|
...
end
But I get an error message:
NoMethodError (undefined method `each' for #<Smartsheet::ApiError: Too many sheets to copy.>)
This is a Smartsheet API error object. The code below works:
begin
#smartsheet.workspaces.copy(workspace_id: workspace_id, body: {new_name: new_name}))
rescue Smartsheet::ApiError => e
puts "Error Code: #{e.error_code}"
puts "Message: #{e.message}"
end
end
try this
e.instance_variables.each do |error|
...
end
This will give you the attributes, if you want the value you could use
e.instance_variable_get(error)
inside the do clause
Related
While debugging a really strange issue with ActionMailer, I came to realize I didn't know how to access an object that was creating the exception. Not the exception, but the object itself.
begin
AppMailer.send_invoice(hostel_resident).deliver_later
flash[:success] = "Your invoice was sent successfully!"
rescue => msg
# display the system generated error message
flash[:error] = "#{msg}"
end
NoMethodError: undefined method `disposition_type' for #<Mail::UnstructuredField:0x009g71c2a68258>
This code works great to catch any exceptions and print the message.
However, how do I get ahold of the <Mail::UnstructuredField:0x009g71c2a68258> object? I'd like to be able to play around with this guy, read messages inside it, and just generally have access to it.
This has to be possible, but inspect doesn't help, cause is no use and backtrace just shows you where it happened. I need that object though, the receiver of the nonexistent method.
Thanks!
actionmailer (4.2.4)
mail (2.6.3)
Seems like you're using mail gem. This is a known issue which is already reported in the GitHub. See #851.
Try using different version of the gem, something in 2.6 series.
This seems to work, using receiver on NameError (which NoMethodError is a child of)
obj = Object.new
puts obj.to_s
begin
obj.do_something
rescue NoMethodError => e
puts e.message
puts e.receiver
end
# #<Object:0x007fa5ac84da88>
# undefined method `do_something' for #<Object:0x007fa5ac84da88>
# #<Object:0x007fa5ac84da88>
This seems to require ruby >= 2.3, to do this for < 2.3, AFAIK you have to do something like this (not tested in older rubies, but should work):
class MyNoMethodError < NoMethodError
attr_accessor :my_receiver
end
obj = Object.new
puts obj.to_s
begin
begin
obj.do_something
rescue NoMethodError => e
# rescue the exception and wrap it in the method that caused it, using `self` instead of `obj`
error = MyNoMethodError.new(e)
error.my_receiver = obj
raise error
end
rescue MyNoMethodError => c
puts c.inspect # custom exception stuff
puts c.cause.inspect # original exception stuff
puts c.my_receiver
end
# #<Object:0x007f884e846d58>
# #<MyNoMethodError: undefined method `do_something' for #<Object:0x007f884e846d58>>
# #<NoMethodError: undefined method `do_something' for #<Object:0x007f884e846d58>>
# #<Object:0x007f884e846d58>
Is there a way, within a rescue clause, to put all the errors into an array and call them from there, if the error is in the array?
For example:
FATAL_ERRORS = %w(Mechanize::ResponseCodeError RestClient::ServiceUnavailable OpenSSL::SSL::SSLError RestClient::BadGateway)
begin
# Do some cool stuff
rescue FATAL_ERRORS => e
puts "Exiting #{e}"
What I've tried:
I've tried grabbing the error from the current thread:
FATAL_ERRORS = Thread.current[:errors] ||= %w(Mechanize::ResponseCodeError RestClient::ServiceUnavailable OpenSSL::SSL::SSLError RestClient::BadGateway)
begin
# Do some cool stuff
rescue FATAL_ERRORS => e
puts "Exiting #{e}"
Also I've tried the splat operator:
FATAL_ERRORS = %w(Mechanize::ResponseCodeError RestClient::ServiceUnavailable OpenSSL::SSL::SSLError RestClient::BadGateway)
begin
# Do some cool stuff
rescue *FATAL_ERRORS => e
puts "Exiting #{e}"
Both the splat and the thread produce the following exception:
rescue in <main>': class or module required for rescue clause (TypeError)
How can I successfully rescue multiple errors without putting them all on the rescue line and making it look bad?
splat does work. Problem is in the way you are making FATAL_ERRORS constant. With %w notation, it converts value as string:
%w(Mechanize::ResponseCodeError)
=> ["Mechanize::ResponseCodeError"] # Note the string value instead of class constant.
Try
FATAL_ERRORS = [Mechanize::ResponseCodeError, RestClient::ServiceUnavailable, OpenSSL::SSL::SSLError, RestClient::BadGateway]
In my gem I have the following module:
module EmeraldComponent
def self.create(full_name)
raise StandardError('Base directory for components is missing.') if base_directory_missing?
raise StandardError('An Emerald Component must have a name.') if full_name.empty?
raise StandardError('An Emerald Component must have a namespace.') if simple_name?(full_name)
write_component(full_name)
true
end
def self.write_component(full_name)
## To be implemented
end
def self.simple_name?(full_name)
vet = full_name.split('.')
vet.length == 1
end
def self.base_directory_missing?
not (File.exist?(EmeraldComponent::BASE_DIRECTORY) && File.directory?(EmeraldComponent::BASE_DIRECTORY))
end
end
And among my Rspec tests for this module I have these:
context 'create' do
it 'raises an error if the base directory for components is missing' do
expect {
EmeraldComponent.create('test.component.Name')
}.to raise_error(StandardError)
end
it 'raises an error if it receives an empty string as component name' do
expect {
EmeraldComponent.create('')
}.to raise_error(StandardError)
end
it 'raises an error if it receives a non-namespaced component name' do
expect {
EmeraldComponent.create('test')
}.to raise_error(StandardError)
end
it 'returns true if it receives a non-empty and namespaced component name' do
expect(EmeraldComponent.create('test.component.Name')).to be true
end
It happens that when I run the test all of them are passing, except for the first. This gives me the following error.
1) EmeraldComponent Methods create returns true if it receives a non-empty and namespaced component name
Failure/Error: raise StandardError('Base directory for components is missing.') if base_directory_missing?
NoMethodError:
undefined method `StandardError' for EmeraldComponent:Module
# ./lib/EmeraldComponent.rb:10:in `create'
# ./spec/EmeraldComponent_spec.rb:48:in `block (4 levels) in <top (required)>'
As you may see, it is saying that StandardError is undefined for EmeraldComponent:Module.
But StandardError does not belong to EmeraldComponent:Module!
And besides, this same StandardError is working fine for the other tests!.
I've been fighting this error for a while and then decided to post here. Any suggestions?
You should be doing StandardError.new in place or StandardError in your create method
def self.create(full_name)
raise StandardError.new('Base directory for components is missing.') if base_directory_missing?
raise StandardError.new('An Emerald Component must have a name.') if full_name.empty?
raise StandardError.new('An Emerald Component must have a namespace.') if simple_name?(full_name)
write_component(full_name)
true
end
#victorCui is correct.
Instead of raising StandardError.new(), the recommended approach is to write:
raise StandardError, "message"
See https://github.com/rubocop-hq/ruby-style-guide#exception-class-messages
I have the following code:
rescue Timeout::Error, StandardError => e
puts "Caught exception: #{e.message}".red
log.puts("#{e.backtrace}")
email_ids_all.each do |email_delete|
call= "/api/v2/emails/#{email_delete}/"
......
Before this rescue piece I have defined log and email_ids_all. However, neither of these are recognized within the ruby script. If i do this:
rescue Timeout::Error, StandardError => e
File.open(rescuelogfile, 'w') do |log| #setup log to write response codes.
puts "Caught exception: #{e.message}".red
log.puts("#{e.backtrace}")
email_ids_all.each do |email_delete|
call= "/api/v2/emails/#{email_delete}/"
....
log works fine, which makes sense. It would take a lot of writing to redefine the email_ids_all array and other variables contained inside my rescue block.
Is there anyway to allow variables to be recognized inside the rescue? Basically my code is laid out like this:
begin
#some code
rescue
#above code
end
I am using ruby 1.9.3.
EDIT----
log starts right after my begin statement :
begin
File.open(logfile, 'w') do |log| #setup log to write response codes.
log.puts works throughout the entire code except when an error is thrown, and then it runs the rescue script where log is not available.
The same goes for email_ids_all. There is an API call that generates about 10,000 emails and each of them is added to the array email_ids_all. The script is receiving an error about halfway through generating these emails, and so I need the rescue script to delete all email ids in the email_ids_all array. But for whatever reason, I get the following error:
FS_Test_Env.rb:762:in `block in <main>': undefined local variable or method `email_ids_all' for main:Object (NameError)
from FS_Test_Env.rb:759:in `open'
from FS_Test_Env.rb:759:in `rescue in <main>'
from FS_Test_Env.rb:7:in `<main>'
Any thoughts?
The way you put it, it should work, for example:
irb(main):001:0> begin
irb(main):002:1* x = 1
irb(main):003:1> x / 0
irb(main):004:1> rescue Exception => e
irb(main):005:1> p x
irb(main):006:1> end
1
=> 1
So it looks like the exception is thrown before your variables are defined.
The scope of the block parameter log is limited to that block. This is the whole point of the open with block.
Maybe you want to do:
begin
log = File.open('logfile', 'w')
...
rescue
...
ensure
log.close
end
Note that this does not cover errors when opening the logfile.
Regarding email_ids_all, I guess (!) you have the exception in a statement like:
email_ids_all = ... a long and complex calculation which raises an exception
If yes, the problem is that the assignment happens only after the whole right-hand side is calculated. The var email_ids_all is not yet created when the exception happens.
In order to access the elements created before the exception, you have to keep track of them, e.g.
begin
email_ids = []
10000.times do
email_ids << ... # create element eventually raising an exception
end
rescue
... # treat the already created elements
end
I know how to catch the exceptions but what we do is to put "rescue" after a suspicious section of a code. what if you had a lot functions sending a query to mysql through mysql2 gem and you want to catch their exceptions. One thing you can do is to put a "rescue" statement in each of them. but i want to do that just by one rescue statement. So I put a "rescue" in end of code and put all of code in a "begin" and "end" but it didn't work.
Here is my code and as you see there is a problem in mysql query and just because of "rescue" being end of file, it doesn't catch the exception but when I put it after that query it works.
require 'mysql2'
require 'colored'
begin
def log(string)
p "["+string.cyan+"]"
end
def err
p "["+"FAIL".red+"]"
end
def done
p "["+"DONE".red+"]"
end
class SqlClient
def initialize()
log "SqlClient/initialize"
puts "Host: \n"
#host = gets.strip
puts "User: \n"
#user = gets.strip
puts "Pass: \n"
#pass = gets.strip
#client = Mysql2::Client.new(host: #host , username: #user , password: #pass)
end
def list_databases()
puts "We are listing your databases(not just projects) \n \n \n "
#client.query("ELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA").each do |row|
p row["SCHEMA_NAME"]
end
puts "\n \n \n"
end
end
rescue Mysql2::Error
err
abort
end
`query': You have an error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near 'ELECT SCHEMA_NAME FROM
INFORMATION_SCHEMA.SCHEMATA' at line 1 (Mysql2::Error)
I'm not looking for something like:
begin
# my code
rescue # this line is right after the code which is going to have problem and we catch it.
end
I'm looking for something like this:
begin
# first method
# second method
# thrid method
# rest of code and etc ...
# now this is end of file:
rescue
end
but as you saw in my code, it didn't work.
UPDATE: I found a similar question here and it seems there will be no answer :| maybe this is a sort of ruby Weakness.
if you want to see ANY error just use e for example
begin
# your call to a method of Mysql2 gem. for example:
client = Mysql2::Client.new(:host => "localhost", :username => "root", etc...)
rescue => e
puts e.message
puts e.backtrace.inspect
end
In order to catch every exception you'd need to wrap each method call with a begin rescue end. When an exception is raised it bails out of the execution so it wouldn't hit the next methods.
To catch all errors I guess I'd do something like this. Keep in mind, this is ugly and I'd recommend for you NOT to do this, but... if you want to try, maybe try something like this:
all_errors = []
# first method you call
begin
# some error might happen here
first_response = Mysql2::Client.new(:host => "localhost", :username => "root", etc...)
rescue => e
all_errors << e
end
# second method you call
begin
# some error might happen here
second_response = Mysql2::Client.new(:host => "localhost", :username => "root", etc...)
rescue => e
all_errors << e
end
puts all_errors.inspect
After a quick search I've found: (http://coderrr.wordpress.com/2008/11/07/the-simple-way-to-print-exceptions-in-ruby/)
# catch all exceptions (anything that derives from Exception)
begin
...
rescue Exception
puts $!, $#
end
You could use an at_exit handler, which has access to the last exception in $!
like
at_exit {
puts "the exception that killed us is", $!
}
If you want to catch Exceptions "as soon as they occur" (not after they're caught) you could use ruby's "debug mode" (which outputs messages when they occur to the console) or ruby-debug see Is there any way to start the Ruby debugger on exception?
Just wrap all your code in:
begin
#yourcode
#as much as you want
rescue
end
Nobody seemed to notice it but using rescue without a class will catch all StandardError and there are so much more.
If you want to catch ALL exceptions you need to do
begin
# your code where you call SqlClient.new etc
rescue Exception => e
puts "error raised"
puts [e, e.backtrace].flatten.join("\n")
end
List of all error classes:
Exception
NoMemoryError
ScriptError
LoadError
NotImplementedError
SyntaxError
SignalException
Interrupt
StandardError
ArgumentError
IOError
EOFError
IndexError
LocalJumpError
NameError
NoMethodError
RangeError
FloatDomainError
RegexpError
RuntimeError
SecurityError
SystemCallError
SystemStackError
ThreadError
TypeError
ZeroDivisionError
SystemExit
fatal
have you tried adding an at_exit method in your class? This would allow you to do something when ruby is exiting. like in this article.
Ruby at_exit
or
From Ruby 2.0 API Docs
However beware of cleverly rescuing from an exception!
You'll start pulling your hair out down the road (or another dev will) when you try to figure out why your code isn't failing when it should be failing. I prefer to fail massively with a bright shiny sign saying the code failed here! hehe.
Good luck!