case...when statement bug when using openid_authentication?

rubyonrails-talk
#1

Hello people!
I'm asking for help to solve a little problem concerning the usage of
the openid_authentication plugin. I'm following the README file included
by DHH, so I wrote this method in my SessionsController:

    def open_id_authentication(identity_url)
      # Pass optional :required and :optional keys to specify what sreg
fields you want.
      # Be sure to yield registration, a third argument in the
#authenticate_with_open_id block.
      authenticate_with_open_id(identity_url,
          :required => [ :nickname, :email ],
          :optional => :fullname) do |status, identity_url,
registration>
            logger.debug "Received status #{status.inspect}"
        if (status === :successful)
          logger.debug "We got a successful answer"
        end
        case status
        when :missing
          logger.debug "Missing!"
          failed_login "Sorry, the OpenID server couldn't be found"
        when :canceled
          logger.debug "Canceled!"
          failed_login "OpenID verification was canceled"
        when :failed
          logger.debug "Failed!"
          failed_login "Sorry, the OpenID verification failed"
        when :successful
          logger.debug "Correct!"
          if @current_user =
@account.users.find_by_identity_url(identity_url)
            assign_registration_attributes!(registration)

            if current_user.save
              successful_login
            else
              failed_login "Your OpenID profile registration failed: " +
                @current_user.errors.full_messages.to_sentence
            end
          else
            failed_login "Sorry, no user by that identity URL exists"
          end
        else
          logger.debug "Something other ..."
        end
      end
    end

If you look at the logger.debug calls, you'll see that when we get a
successful response, the logger "should" print "We got a successful
answer" and then "Correct!". But, in fact, it prints "We got a
successful answer" and then "Something other ...". So, apparently, the
status === :successful comparison is true, but the case ... when
:successful test is false, even if this statement uses the === operator.

What's wrong in this code? I really can't figure out ... and I really
need some "expert" help.

Thank you!

-daniele-

#2

Damn it! I'm going mad ... this "bug" is really impossible to
understand, and no one here seems to help me ...
Maybe I'll ask DHH directly :smiley:

#3

If you look at the logger.debug calls, you'll see that when we get a
successful response, the logger "should" print "We got a successful
answer" and then "Correct!". But, in fact, it prints "We got a
successful answer" and then "Something other ...". So, apparently, the
status === :successful comparison is true, but the case ... when
:successful test is false, even if this statement uses the ===
operator.

What's wrong in this code? I really can't figure out ... and I really
need some "expert" help.

Well it's worth remembering that === is not reflexive:
1 === Numeric => false
Numeric === 1 => true

And that a case statement will do label === value (but in your if
you've got value === label)

But the real question is what exactly is the value of status ? is it
actually a symbol or something else (hint: look at the code. it's not
a symbol)

Fred

#4

Frederick Cheung wrote:

What's wrong in this code? I really can't figure out ... and I really
need some "expert" help.

Well it's worth remembering that === is not reflexive:
1 === Numeric => false
Numeric === 1 => true

And that a case statement will do label === value (but in your if
you've got value === label)

Thanks, didn't know that.

But the real question is what exactly is the value of status ? is it
actually a symbol or something else (hint: look at the code. it's not
a symbol)

Already looked at it. In fact, status it's not a simbol, it's an
instance of the class Result, defined within the openid_authentication
plugin:

  class Result
    ERROR_MESSAGES = {
      :missing => "Sorry, the OpenID server couldn't be found",
      :canceled => "OpenID verification was canceled",
      :failed => "OpenID verification failed",
      :setup_needed => "OpenID verification needs setup"
    }

    def self.[](code)
      new(code)
    end

    def initialize(code)
      @code = code
    end

    def ===(code)
      if code == :unsuccessful && unsuccessful?
        true
      else
        @code == code
      end
    end

    ERROR_MESSAGES.keys.each { |state| define_method("#{state}?") {
@code == state } }

    def successful?
      @code == :successful
    end

    def unsuccessful?
      ERROR_MESSAGES.keys.include?(@code)
    end

    def message
      ERROR_MESSAGES[@code]
    end
  end

in which we find the definition of ===.
From the logs, I get something like this, from status.inspect:

#<OpenIdAuthentication::Result:0x481ce38 @code=:successful>

The code in my controller is taken from the README file, written by DHH.
Strange, really strange ...

#5

Frederick Cheung wrote:

Thanks, didn't know that.

> But the real question is what exactly is the value of status ? is it
> actually a symbol or something else (hint: look at the code. it's not
> a symbol)

Already looked at it. In fact, status it's not a simbol, it's an
instance of the class Result, defined within the openid_authentication
plugin:

in which we find the definition of ===.

which makes it obvious why status === :success works, but :success ===
status doesn't (since at that point Symbol's implementatio will be
called.

From the logs, I get something like this, from status.inspect:

#<OpenIdAuthentication::Result:0x481ce38 @code=:successful>

The code in my controller is taken from the README file, written by DHH.
Strange, really strange ...

The code was changed (rev 6318) but the documentation wasn't. the
readme's just wrong.

Fred

#6

Daniele Di Bernardo wrote:

The code was changed (rev 6318) but the documentation wasn't. the
readme's just wrong.

I didn't of a desync

didn't think of ...