how to add new field to mechanize form (ruby/mechanize) - ruby

Question

there is a public class method to add field to mechanize form
I tried ..
#login_form.field.new('auth_login','Login')
#login_form.field.new('auth_login','Login')
and both gives me an error undefined method "new" for #<WWW::Mechanize::Form::Field:0x3683cbc> (NoMethodError)
I tried login_form.field.new('auth_login','Login') which gives me an error
mechanize-0.9.3/lib/www/mechanize/page.rb:13 n `meta': undefined method `search' for nil:NilClass (NoMethodError)
but at the time I submit the form. The field does not exist in html source. I want to add it so POST query sent by my script will contain auth_username=myusername&auth_password=mypassword&auth_login=Login So far it sends only auth_username=radek&auth_password=mypassword which might be why I cannot get logged in. Just my thought.
The script looks like
require 'rubygems'
require 'mechanize'
require 'logger'
agent = WWW::Mechanize.new {|a| a.log = Logger.new("loginYOTA.log") }
agent.follow_meta_refresh = true #Mechanize does not follow meta refreshes by default, we need to set that option.
page = agent.get("http://www.somedomain.com/login?auth_successurl=http://www.somedomain.com/forum/yota?baz_r=1")
login_form = page.form_with(:method => 'POST')
puts login_form.buttons.inspect
puts page.forms.inspect
#STDIN.gets
login_form.fields.each { |f| puts "#{f.name} : #{f.value}" }
login_form['auth_username'] = 'radeks'
login_form['auth_password'] = 'TestPass01'
#login_form['auth_login'] = 'Login'
#login_form.field.new('auth_login','Login')
#login_form.field.new('auth_login','Login')
#login_form.fields.each { |f| puts "#{f.name} : #{f.value}" }
#STDIN.gets
page = agent.submit login_form
#Display welcome message if logged in
puts page.parser.xpath("/html/body/div/div/div/table/tr/td[2]/div/strong").xpath('text()').to_s.strip
puts
puts page.parser.xpath("/html/body/div/div/div/table/tr/td[2]/div").xpath('text()').to_s.strip
output = File.open("login.html", "w") {|f| f.write(page.parser.to_html) }
The .inspect of the form looks like
[#<WWW::Mechanize::Form
{name nil}
{method "POST"}
{action
"http://www.somedomain.com/login?auth_successurl=http://www.somedomain.com/forum/yota?baz_r=1"}
{fields
#<WWW::Mechanize::Form::Field:0x36946c0 #name="auth_username", #value="">
#<WWW::Mechanize::Form::Field:0x369451c #name="auth_password", #value="">}
{radiobuttons}
{checkboxes}
{file_uploads}
{buttons
#<WWW::Mechanize::Form::Button:0x36943b4
#name="auth_login",
#value="Login">}>
]

Answer 1

I think what you're looking for is
login_form.add_field!(field_name, value = nil)
Here are the docs:
http://rdoc.info/projects/tenderlove/mechanize
The difference between this and the method WWW::Mechanize::Form::Field.new is not much, aside from the fact that there aren't many ways to add fields to a form. Here's how the add_field! method is implemented....you can see that it's exactly what you'd expect. It instantiates a Field object, then adds it to the form's 'fields' array. You wouldn't be able to do this in your code because the method "fields<<" is a private method inside "Form."
# File lib/www/mechanize/form.rb, line 65
def add_field!(field_name, value = nil)
fields << Field.new(field_name, value)
end
On a side note, according to the docs you should be able to do the first variation you proposed:
login_form['field_name']='value'
Hope this helps!

Answer 2

another way how to add new field is to so at the time of posting the form
page = agent.post( url, {'auth_username'=>'myusername', #existing field
'auth_password'=>'mypassword', #existing field
'auth_login'=>'Login'}) #new field