I'm getting an exception in the following piece of code. Can someone please tell me what I'm doing wrong, and how I can prevent it?
def self.find_by_data(data = {})
where(name_canonical: data['name'].downcase.gsub(/\s+/, ''),
fuel: data['fuel'],
trim_canonical: data['trim'].downcase.gsub(/\s+/, ''),
year: data['year']).first
end
Exception:
/Users/charlie/Documents/WIP/projectx/ar_models.rb:35:in `find_by_data': undefined method `downcase' for nil:NilClass (NoMethodError)ooooooooooooooooooooooooo| ETA: 0:00:00
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-4.0.0/lib/active_record/relation/delegation.rb:36:in `block in find_by_data'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-4.0.0/lib/active_record/associations/collection_proxy.rb:845:in `block in scoping'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-4.0.0/lib/active_record/relation.rb:270:in `scoping'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-4.0.0/lib/active_record/associations/collection_proxy.rb:845:in `scoping'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-4.0.0/lib/active_record/relation/delegation.rb:36:in `find_by_data'
from /Users/charlie/Documents/WIP/projectx/ar_models.rb:132:in `create_or_assign_existing'
from /Users/charlie/Documents/WIP/projectx/app.rb:230:in `block (2 levels) in work'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-4.0.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in `with_connection'
from /Users/charlie/Documents/WIP/projectx/app.rb:80:in `block in work'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:319:in `call'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:319:in `call_with_index'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:179:in `block (3 levels) in work_in_threads'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:326:in `with_instrumentation'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:177:in `block (2 levels) in work_in_threads'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:171:in `loop'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:171:in `block in work_in_threads'
from /Users/charlie/.rvm/gems/ruby-2.0.0-p0/gems/parallel-0.6.3/lib/parallel.rb:62:in `block (2 levels) in in_threads'
When you see "undefined method ... for nil:NilClass" it means you have a nil value you're trying to call the method on.
In this case, something like data['name'] is not defined.
To make this more bullet-proof:
data['name'].to_s.downcase.gsub(/\s+/, '')
This converts everything to string to start with. nil.to_s is an empty string by default, so it's safe.
Use ternary oprators perhaps:
def self.find_by_data(data = {})
where(name_canonical: data['name'] == nil ? '' : data['name'].downcase.gsub(/\s+/, ''),
fuel: data['fuel'],
trim_canonical: data['trim'] == nil ? '' : data['name'].downcase.gsub(/\s+/, ''),
year: data['year']).first
end
Your
data['name']
or
data['trim']
is a nil.
Check your input data.
Related
I try to get some information from the LDAP (internal AD). Everything work as it should, except when I want get the data out of an empty field.
require 'net/ldap'
...
def getDatafromAD(ad_hostname,ad_dn,ad_password,username)
ldap = Net::LDAP.new :host => ad_hostname, :port => 389, :auth => {
:method => :simple,
:username => ad_dn,
:password => ad_password }
filter = Net::LDAP::Filter.eq("cn", username)
treebase = "ou=myOU,dc=example,dc=com"
attrs = ["givenName", "mobile", "mail", "cn", "sn", "person"]
ldap.search( :base => treebase, :filter => filter, :attributes => attrs ) do |entry|
puts "UID: #{entry.dn}"
puts "#{entry.cn.first}: Surename: #{entry.sn.first} Givenname: #{entry.givenName.first} Mail: #{entry.mail.first} Mobile: #{entry.mobile.first}"
end
end
This is running fine until one field is empty (in this case mobile):
Traceback (most recent call last):
16: from query_userdata.rb:79:in `<main>'
15: from query_userdata.rb:79:in `each'
14: from query_userdata.rb:81:in `block in <main>'
13: from query_userdata.rb:58:in `getDatafromAD'
12: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap.rb:782:in `search'
11: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/instrumentation.rb:19:in `instrument'
10: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap.rb:783:in `block in search'
9: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap.rb:1311:in `use_connection'
8: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap.rb:784:in `block (2 levels) in search'
7: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/connection.rb:388:in `search'
6: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/instrumentation.rb:19:in `instrument'
5: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/connection.rb:399:in `block in search'
4: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/connection.rb:399:in `loop'
3: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/connection.rb:445:in `block (2 levels) in search'
2: from /usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap.rb:786:in `block (3 levels) in search'
1: from query_userdata.rb:62:in `block in getDatafromAD'
/usr/share/gems/gems/net-ldap-0.17.0/lib/net/ldap/entry.rb:185:in `method_missing': undefined method `mobile' for #<Net::LDAP::Entry:0x000055c0d912ac60> (NoMethodError)
Can someone please give me a hint how to solve this. My knowledge/XP can not handle this.
I tried with .empty?() to check in advance, but it looks like in the moment of accessing the empty field the exception is here.
If a field is empty I would like to put a custom string ("data not there") in the output. Probably it is just a little switch and I can not find it...
Many thanks!
I've faced the same issue 2 days ago ! I can recommend 2 things:
Access entry attributes through hash keys. Calling missing methods will rise an error, but trying to access a missing key's value will return an empty array
entry[:missing_key]
# => []
entry[:missing_key][0]
# => nil
entry.missing_key.first
# => *** NoMethodError Exception: undefined method `missing_key' for #<Net::LDAP::Entry:0x00005605a06bbf88>
Use a || operator when concatenating potential nil values with a String.
puts "SN: #{(entry[:sn][0] || 'data not there')}" +
"Mobile: #{(entry[:mobile][0] || 'data not there')}" +
"Foo: #{(entry[:foo][0] || 'data not there')}"
I have 3 error messages which I believe all relate to one thing - me calling a method on an object that has not been defined properly.
I've checked over for typos, white spacing, syntax, naming. I'm following the same process as other methods in this program which all tested OK.
I've narrowed the loop down and believe the issue is here:
def add(param)
#param << param
Heres the code in full context:
class Todo
def initialize(param)
#param = param
end
def text
return #param
end
end
class TodoList
def initialize
#item_list = []
end
def add(param)
#param << param
end
def print
#item_list.each do |param|
puts "* #{param.text}" #=> .text?
end
end
end
Error Messages:
Here are the error messages I'm trying to resolve. As I mentioned earlier they all look to be pointing to a method I've not defined properly but I've not yet been able to work out why that may be.
1) Q1. Todo list TodoList adding todos adds a todo without raising an error
Failure/Error: expect { todo_list.add(todo) }.to_not raise_error
expected no Exception, got #<NoMethodError: undefined method `<<' for nil:NilClass> with backtrace:
# ./questions/question_1.rb:43:in `add'
# ./spec/question_1_spec.rb:31:in `block (5 levels) in <top (required)>'
# ./spec/question_1_spec.rb:31:in `block (4 levels) in <top (required)>'
# ./spec/question_1_spec.rb:31:in `block (4 levels) in <top (required)>'
2) Q1. Todo list TodoList printing todos one todo prints a single todo with a bullet point
Failure/Error: todo_list.add(todo)
NoMethodError:
undefined method `<<' for nil:NilClass
# ./questions/question_1.rb:43:in `add'
# ./spec/question_1_spec.rb:41:in `block (5 levels) in <top (required)>'
3) Q1. Todo list TodoList printing todos many todos prints the todos, separated by newlines
Failure/Error: todo_list.add(todo_1)
NoMethodError:
undefined method `<<' for nil:NilClass
# ./questions/question_1.rb:43:in `add'
# ./spec/question_1_spec.rb:59:in `block (5 levels) in <top (required)>'
Thanks!
ruby do not know what #param is in your TodoList class, you have to initialize it in your constructor like this #param = [] that fix your issue
By default instance variables are initialized to nil, hence the error. So in your TodoList class, you need to initialize #param to an object that can respond to <<, which in your own case, is an array []
class TodoList
def initialize
#param = []
end
end
class MainTabsWidget < PageObject::Elements::UnorderedList
include PageObject
include PageObject::PageFactory
link(:first_link, :text => 'First')
link(:second_link, :text => 'Second')
link(:third_link, :text => 'Third')
link(:category_link, :text => 'Category')
link(:subcat1_link, :text => 'Subcat1')
link(:subcat2_link, :text => 'Subcat2')
def goto_tab_item(tab_item)
items = tab_item.split /\//
items.each do |item|
case item
when 'First'
first_link
when 'Second'
second_link
when 'Third'
third_link
when 'Category'
category_link
when 'Subcat1'
subcat1_link
when 'Subcat2'
subcat2_link
end
end
end
end
PageObject.register_widget :main_menu, MainTabsWidget , :ul
I have a page called landing page that uses the widget in the following manner....
class LandingPage
include PageObject
include PageObject::PageFactory
main_menu(:menu_tabs, :id => 'mainMenu')
def select_menu_item(item)
menu_tabs_element.go_to_tab_item item
end
end
This actually did work at one point. If you pass 'First' for select_menu_item, it will click to the page specified by first_link. If you specify 'Category/Subcat1' it will click on the category link and then subcat1.
Howerver, something changed. We are transition from watir-webdriver gem to watir (6.10) gem, and now the code gets the argument exeption
'ArgumentError: wrong number of arguments (0 for 1..2)'
This occurs when menu_tabs_element gets referenced in any way. I've run out of ideas to remedy this.
Stack Trace:
ArgumentError: wrong number of arguments (0 for 1..2)
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object/element_locators.rb:10:in `element'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object/elements/element.rb:191:in `respond_to_missing?'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object.rb:53:in `respond_to_missing?'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object.rb:70:in `respond_to?'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object.rb:70:in `initialize'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object/platforms/watir/page_object.rb:1047:in `new'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object/platforms/watir/page_object.rb:1047:in `find_watir_element'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object/platforms/watir/page_object.rb:1118:in `block in define_widget_singular_accessor'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page-object-2.2.4/lib/page-object/widgets.rb:38:in `block (3 levels) in define_accessors'
./lib/pages/menu.rb:13:in `select_menu_item'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page_navigation-0.10/lib/page_navigation.rb:134:in `block in navigate_through_pages'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page_navigation-0.10/lib/page_navigation.rb:129:in `each'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page_navigation-0.10/lib/page_navigation.rb:129:in `navigate_through_pages'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/page_navigation-0.10/lib/page_navigation.rb:67:in `navigate_to'
./spec/refactor/test_spec.rb:6:in `block (2 levels) in <top (required)>'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/hooks.rb:350:in `instance_exec'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/hooks.rb:350:in `run'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/hooks.rb:509:in `block in run_owned_hooks_for'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/hooks.rb:508:in `each'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/hooks.rb:508:in `run_owned_hooks_for'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/hooks.rb:460:in `run'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/example_group.rb:537:in `block in run_before_context_hooks'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/memoized_helpers.rb:186:in `block in isolate_for_context_hook'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/memoized_helpers.rb:182:in `instance_exec'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/memoized_helpers.rb:182:in `isolate_for_context_hook'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/example_group.rb:536:in `run_before_context_hooks'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/example_group.rb:589:in `run'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:118:in `block (3 levels) in run_specs'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:118:in `map'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:118:in `block (2 levels) in run_specs'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/configuration.rb:1896:in `with_suite_hooks'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:113:in `block in run_specs'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/reporter.rb:79:in `report'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:112:in `run_specs'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:87:in `run'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:71:in `run'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/lib/rspec/core/runner.rb:45:in `invoke'
C:/Ruby22/lib/ruby/gems/2.2.0/gems/rspec-core-3.7.0/exe/rspec:4:in `<top (required)>'
C:/Ruby22/bin/rspec:23:in `load'
C:/Ruby22/bin/rspec:23:in `<top (required)>'
-e:1:in `load'
-e:1:in `<main>'
1 example, 1 failure, 0 passed
Finished in 6.087 seconds
Process finished with exit code 1
It is not clear to me which change in Watir would cause this issue. It seems more likely a change in Page-Object. At any rate, here are 2 solutions. Note that this was tested with Page-Object v 2.2.4.
Using Widgets
As pointed out by Alexis in Page-Object Issue 263, including page object accessor methods in widgets is not as straight forward as one would expect. In the MainTabsWidget class, instead of include PageObject, you need to do:
extend PageObject::Accessors # to get the accessor methods
attr_reader :platform # the accessor methods don't work without a platform
With this change, your page object should work.
Using Page Section
Page-Object has a page section feature that might better suit your needs. It simplifies some of the code (ie address the above issue).
You define a class to represent your main tabs section. Note that you do not need to register the section or have the multi-line setup as with Widgets.
class MainTabs
include PageObject
include PageObject::PageFactory
link(:first_link, :text => 'First')
link(:second_link, :text => 'Second')
link(:third_link, :text => 'Third')
link(:category_link, :text => 'Category')
link(:subcat1_link, :text => 'Subcat1')
link(:subcat2_link, :text => 'Subcat2')
def select_menu_item(tab_item)
items = tab_item.split /\//
items.each do |item|
case item
when 'First'
first_link
when 'Second'
second_link
when 'Third'
third_link
when 'Category'
category_link
when 'Subcat1'
subcat1_link
when 'Subcat2'
subcat2_link
end
end
end
end
The page object can simply become:
class LandingPage
include PageObject
include PageObject::PageFactory
page_section(:menu_tabs, MainTabs, :id => 'mainMenu')
end
The clicking of the menu would change to:
page.menu_tabs.select_menu_item('First')
(or you could continue to define a #select_menu_item method in LandingPage to avoid downstream changes)
In application.rb I tried to read a YAML file:
config.before_configuration do
env_file = File.join(Rails.root, 'config', 'local_env.yml')
YAML.load(File.open(env_file)).each do |key, value|
ENV[key.to_s] = value
end if File.exists?(env_file)
end
but, I get this error:
/var/www/config/application.rb:26:in `block in <class:Application>': undefined method `each' for #<String:0x00000007afb7f0> (NoMethodError)
from /usr/local/rvm/gems/ruby-2.2.1/gems/activesupport-4.1.6/lib/active_support/lazy_load_hooks.rb:36:in `call'
from /usr/local/rvm/gems/ruby-2.2.1/gems/activesupport-4.1.6/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
from /usr/local/rvm/gems/ruby-2.2.1/gems/activesupport-4.1.6/lib/active_support/lazy_load_hooks.rb:28:in `block in on_load'
from /usr/local/rvm/gems/ruby-2.2.1/gems/activesupport-4.1.6/lib/active_support/lazy_load_hooks.rb:27:in `each'
from /usr/local/rvm/gems/ruby-2.2.1/gems/activesupport-4.1.6/lib/active_support/lazy_load_hooks.rb:27:in `on_load'
from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.1.6/lib/rails/railtie/configuration.rb:53:in `before_configuration'
from /var/www/config/application.rb:24:in `<class:Application>'
Any idea?
EDIT
My yaml file:
LOAD_JS_FROM_AMAZON:no
RACK_ENV:production
S3_BUCKET_NAME:bucket_name
S3_CMS_BUCKET_NAME:cms_bucket_name
YAML.load(File.open(env_file))
Your YAML is returning a String not a Hash
You need spaces between colon and value:
LOAD_JS_FROM_AMAZON: no
RACK_ENV: production
S3_BUCKET_NAME: bucket_name
S3_CMS_BUCKET_NAME: cms_bucket_name
Been at this for a while. If i tell Category to just create, everything works fine. If I tell it to find_or_create I get errors.
These work:
puts topic.at_xpath("#topicid")
puts topic.at_xpath("#topicname")
and
Category.create!(:topic_id => topic.at_xpath("#topicid"), :name => topic.at_xpath("#topicname"))
But these don't:
Category.find_by_name(topic.at_xpath("#topicname"))
or
Category.find_or_create_by_topic_id_and_name(topic.at_xpath("#topicid"), topic.at_xpath("#topicname"))
Where am I messing up?
class FeedEntry < ActiveRecord::Base
require 'nokogiri'
require 'open-uri'
has_many :category_feeds
has_many :categories, :through => :category_feeds
accepts_nested_attributes_for :categories, :allow_destroy => true, :reject_if => proc { |obj| obj.blank? }
def self.nokogiri_get_feed
url = "http://some_feed.com/atom_feed"
doc = Nokogiri::HTML(open(url))
doc.remove_namespaces!
doc.search('feed entry').each do |item|
unless exists? :guid => item.css('id').text
create!(:name => item.css('title').text, :summary => item.css('title').text, :url => item.at_css("link")[:href], :published_at => item.css('updated').text, :guid => item.css('id').text)
item.xpath('content').each do |i|
i.css('topic').each do |topic|
id = topic.at_xpath("#topicid")
name = topic.at_xpath("#topicname")
update_attributes!(:categories=>[Category.find_or_create_by_topic_id_and_name(id, name)])
end
end
end
end
end
end
errors are:
ruby-1.9.2-p180 :001 > FeedEntry.nokogiri_get_feed
TypeError: Cannot visit Nokogiri::XML::Attr
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/visitor.rb:21:in `rescue in visit'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/visitor.rb:15:in `visit'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:260:in `visit_Arel_Nodes_Equality'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/visitor.rb:15:in `visit'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:120:in `visit_Arel_Nodes_Grouping'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/visitor.rb:15:in `visit'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:91:in `block in visit_Arel_Nodes_SelectCore'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:91:in `map'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:91:in `visit_Arel_Nodes_SelectCore'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:77:in `block in visit_Arel_Nodes_SelectStatement'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:77:in `map'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:77:in `visit_Arel_Nodes_SelectStatement'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/sqlite.rb:7:in `visit_Arel_Nodes_SelectStatement'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/visitor.rb:15:in `visit'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/visitor.rb:5:in `accept'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/arel-2.0.9/lib/arel/visitors/to_sql.rb:19:in `block in accept' ... 11 levels...
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:238:in `each'
from /Users/pca/projects/cdapp/cdrails/app/models/feed_entry.rb:35:in `block (2 levels) in nokogiri_get_feed'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:239:in `block in each'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:238:in `upto'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:238:in `each'
from /Users/pca/projects/cdapp/cdrails/app/models/feed_entry.rb:33:in `block in nokogiri_get_feed'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:239:in `block in each'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:238:in `upto'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/nokogiri-1.4.4/lib/nokogiri/xml/node_set.rb:238:in `each'
from /Users/pca/projects/cdapp/cdrails/app/models/feed_entry.rb:30:in `nokogiri_get_feed'
from (irb):1
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands/console.rb:44:in `start'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands/console.rb:8:in `start'
from /Users/pca/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands.rb:23:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
Summary
Instead of these lines:
id = topic.at_xpath("#topicid")
name = topic.at_xpath("#topicname")
Use these instead:
id = topic['topicid']
name = topic['topicname']
Explanation
Let's look at a simple test case:
require 'nokogiri'
xml = Nokogiri::XML("<root foo='bar' />")
foo = xml.root.at_xpath('#foo')
puts foo
#=> bar
p foo
#=> #<Nokogiri::XML::Attr:0x15c1d64 name="foo" value="bar">
p foo.text
#=> "bar"
p xml.root['foo']
#=> "bar"
As you can see from the above, selecting an attribute via XPath actually gives you an Attr node, which is not the same as the string value of that attribute. (Using puts causes the to_s method of the Attr to show you only the value, but that doesn't mean that it's actually a string.)
As shown above, you need to use the text method (or value or content) on the Attr nodes to get the string value back that you really wanted:
id = topic.at_xpath("#topicid").text
name = topic.at_xpath("#topicname").text
Alternatively (and more simply) use the Element#[] method to fetch the value of an attribute off of an element directly:
id = topic['topicid']
name = topic['topicname']