YoYoYo I'm Awesome YoYoYo I'm Awesome - 2 months ago 18
Ruby Question

Using a splat to catch errors is not working

I have a lot of errors that I need to catch, so I put them all into two arrays and made a constant to hold them, however, when I run the program I receive the exception:

C:/Users/thomas_j_perkins/bin/ruby/tool/sql_tool/whitewidow/lib/imports/constants_and_requires.rb:62:in `<top (required)>': uninitialized constant RestClient::MaxRedirectsReached (NameError)
from whitewidow.rb:6:in `require_relative'
from whitewidow.rb:6:in `<main>'


Here's how the constants look:

LOADING_ERRORS = [RestClient::ResourceNotFound, RestClient::InternalServerError, RestClient::RequestTimeout,
RestClient::Gone, RestClient::SSLCertificateNotVerified, RestClient::Forbidden,
OpenSSL::SSL::SSLError, Errno::ECONNREFUSED, URI::InvalidURIError, Errno::ECONNRESET,
Timeout::Error, OpenSSL::SSL::SSLError, Zlib::GzipFile::Error, RestClient::MultipleChoices,
RestClient::Unauthorized, SocketError, RestClient::BadRequest, RestClient::ServerBrokeConnection,
RestClient::MaxRedirectsReached]
FATAL_ERRORS = [Mechanize::ResponseCodeError, RestClient::ServiceUnavailable, OpenSSL::SSL::SSLError,
RestClient::BadGateway]


Here's how I'm using them:

begin
# Do some cool stuff
rescue *FATAL_ERRORS => e
puts e
end


--

begin
# Do some more cool stuff
rescue *LOADING_ERRORS => e
puts e
end


Am I doing something wrong to where I will receive a top required error? Just in case you need it here's the entire requiring file that the error is specifying:

# Built in libraries
require 'rubygems'
require 'bundler/setup'
require 'mechanize'
require 'nokogiri'
require 'rest-client'
require 'timeout'
require 'uri'
require 'fileutils'
require 'yaml'
require 'date'
require 'optparse'
require 'tempfile'
require 'socket'
require 'net/http'

# Created libraries
require_relative '../../lib/modules/format'
require_relative '../../lib/misc/credits'
require_relative '../../lib/misc/legal'
require_relative '../../lib/misc/spider'
require_relative '../../lib/modules/copy'
require_relative '../../lib/modules/site_info'
require_relative '../../lib/modules/expansion/string_expan'

# Modules that need to be included
include Format
include Credits
include Legal
include Whitewidow
include Copy
include SiteInfo

# Constants used throughout the program
=begin
USER_AGENTS = { # Temporary fix for user agents until I can refactor the YAML file
1 => 'Mozilla/5.0 (compatible; 008/0.83; http://www.80legs.com/webcrawler.html) Gecko/2008032620',
2 => 'Mozilla/5.0 (compatible; U; ABrowse 0.6; Syllable) AppleWebKit/420+ (KHTML, like Gecko)',
3 => 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3pre) Gecko/20100403 Lorentz/3.6.3plugin2pre (.NET CLR 4.0.20506)',
4 => 'Mozilla/5.0 (compatible; Yahoo! Slurp; http://help.yahoo.com/help/us/ysearch/slurp)',
5 => 'igdeSpyder (compatible; igde.ru; +http://igde.ru/doc/tech.html)',
6 => 'larbin_2.6.3 (ltaa_web_crawler@groupes.epfl.ch)',
7 => 'Mozilla/5.0 (Linux; Android 5.0.2; SAMSUNG SM-T550 Build/LRX22G) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/3.3 Chrome/38.0.2125.102 Safari/537.36',
8 => 'Dalvik/2.1.0 (Linux; U; Android 6.0.1; Nexus Player Build/MMB29T)',
9 => 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:15.0) Gecko/20100101 Firefox/15.0.1',
10 => 'Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)',
}
=end
FORMAT = Format::StringFormat.new
PATH = Dir.pwd
VERSION = Whitewidow.version
SEARCH = File.readlines("#{PATH}/lib/lists/search_query.txt").sample
USER_AGENTS = YAML.load_file("#{PATH}/lib/lists/rand-age.yml")
OPTIONS = {}
USER_AGENT = USER_AGENTS[rand(1..10)]
SKIP = %w(/webcache.googleusercontent.com stackoverflow.com github.com)
LOADING_ERRORS = [RestClient::ResourceNotFound, RestClient::InternalServerError, RestClient::RequestTimeout,
RestClient::Gone, RestClient::SSLCertificateNotVerified, RestClient::Forbidden,
OpenSSL::SSL::SSLError, Errno::ECONNREFUSED, URI::InvalidURIError, Errno::ECONNRESET,
Timeout::Error, OpenSSL::SSL::SSLError, Zlib::GzipFile::Error, RestClient::MultipleChoices,
RestClient::Unauthorized, SocketError, RestClient::BadRequest, RestClient::ServerBrokeConnection,
RestClient::MaxRedirectsReached]
FATAL_ERRORS = [Mechanize::ResponseCodeError, RestClient::ServiceUnavailable, OpenSSL::SSL::SSLError,
RestClient::BadGateway]

Answer

I installed mechanize and rest_client

gem install mechanize gem install rest_client

then I opened an IRB session

require mechanize require rest_client

then tested you FATAL_ERROR array and was able to raise the error and handle it with your code.

I thought maybe require rest_client isn't the same as require rest-client (as in your example), but it turns out, both functioned.

So there is no problem with the way you are using the * splat operator.

The problem is in your LOADING_ERRORS array.

When I tried doing the same thing with your LOADING_ERRORS array, I got the same error message as you.

I cloned the rest_client git repository and searched in the lib/restclient/exceptions.rb file and it seems like there is no RestClient::MaxRedirectsReached defined..

If you remove that exception from your array, the code works..

After further research in the repository, there is a history.md file and it states:

  • Changes to redirection behavior: (#381, #484)
    • Remove RestClient::MaxRedirectsReached in favor of the normal ExceptionWithResponse subclasses. This makes the response accessible on the exception object as .response, making it possible for callers to tell what has actually happened when the redirect limit is reached.
    • When following HTTP redirection, store a list of each previous response on the response object as .history. This makes it possible to access the original response headers and body before the redirection was followed.
    • Follow redirection consistently, regardless of whether the HTTP method was passed as a symbol or string. Under the hood rest-client now normalizes the HTTP request method to a lowercase string.

So it seems like that exception has been removed from the rest_client library.

You may want to replace it with RestClient::ExceptionWithResponse

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