method conditional option pattern

rubyonrails-talk
1

When I have this pattern

sign_me(@user, :event => :authentication, :subdomain => subdomain)

how can I write it to avoid sending the :subdomain option if subdomain.nil? ( if possible …)

sign_me(@user, :event => :authentication #?, :subdomain => subdomain unless subdomain.nil? )

2

When I have this pattern

       sign_me(@user, :event => :authentication, :subdomain => subdomain)

how can I write it to avoid sending the :subdomain option if subdomain.nil? ( if possible ..)

       sign_me(@user, :event => :authentication #?, :subdomain => subdomain unless subdomain.nil? )

I'm not sure if it's possible to do it in a single line (as far as you want to have a tidy code)

opts = { event: :authentication } opts[:subdomain] = subdomain if subdomain

sign_me @user, opts

3

thanks

4

When I have this pattern

       sign_me(@user, :event => :authentication, :subdomain => subdomain)

how can I write it to avoid sending the :subdomain option if subdomain.nil? ( if possible ..)

       sign_me(@user, :event => :authentication #?, :subdomain => subdomain unless subdomain.nil? )

You could try         sign_me(@user, :event => :authentication, (:subdomain => subdomain unless subdomain.nil?) ) or         sign_me(@user, :event => :authentication, :subdomain => (subdomain unless subdomain.nil?) )

Colin

5

> When I have this pattern > > sign_me(@user, :event => :authentication, :subdomain => subdomain) > > how can I write it to avoid sending the :subdomain option if subdomain.nil? > ( if possible ..) > > sign_me(@user, :event => :authentication #?, :subdomain => subdomain > unless subdomain.nil? )

You could try         sign_me(@user, :event => :authentication, (:subdomain => subdomain unless subdomain.nil?) )

I was surprised that you answered this Colin so I tried it out but I got a syntax error

app.root_path(foo: 'me', (bar: 'blah' if false))

SyntaxError: (irb):17: syntax error, unexpected tLABEL app.root_path(foo: 'me', (bar: 'blah' if false))                               ^ (irb):17: syntax error, unexpected ')', expecting tASSOC from /home/jim/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.2/lib/rails/commands/console.rb:47:in `start' from /home/jim/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.2/lib/rails/commands/console.rb:8:in `start' from /home/jim/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.2/lib/rails/commands.rb:41:in `<top (required)>' from script/rails:6:in `require' from script/rails:6:in `<main>'

or         sign_me(@user, :event => :authentication, :subdomain => (subdomain unless subdomain.nil?) )

and this still passes subdomain as a key if used in a hash but if used in a routes helper, this will work :smiley:

app.root_path(foo: 'me', bar: ('blah' if false))

=> "/?foo=me"

6

> When I have this pattern > > sign_me(@user, :event => :authentication, :subdomain => > subdomain) > > how can I write it to avoid sending the :subdomain option if > subdomain.nil? > ( if possible ..) > > sign_me(@user, :event => :authentication #?, :subdomain => > subdomain > unless subdomain.nil? )

You could try         sign_me(@user, :event => :authentication, (:subdomain => subdomain unless subdomain.nil?) )

I was surprised that you answered this Colin so I tried it out but I got a syntax error

app.root_path(foo: 'me', (bar: 'blah' if false))

SyntaxError: (irb):17: syntax error, unexpected tLABEL app.root_path(foo: 'me', (bar: 'blah' if false))                               ^ (irb):17: syntax error, unexpected ')', expecting tASSOC from /home/jim/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.2/lib/rails/commands/console.rb:47:in `start' from /home/jim/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.2/lib/rails/commands/console.rb:8:in `start' from /home/jim/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.2/lib/rails/commands.rb:41:in `<top (required)>' from script/rails:6:in `require' from script/rails:6:in `<main>'

I am not surprised that did not work, my answer was not intended to convey any suggestion that it would work, just something that would be interesting to try.

or         sign_me(@user, :event => :authentication, :subdomain => (subdomain unless subdomain.nil?) )

and this still passes subdomain as a key if used in a hash but if used in a routes helper, this will work :smiley:

Yes, it will pass the subdomain as nil, so it depends on the context whether this is satisfactory.

Colin

7

I have a related question. I was suggesting Erwin to use just:

sign_me(@user, :event => :authentication #?, :subdomain => subdomain)

because if subdomain is nil, sign_me should correctly handle it. I mean, in an hypothetical sign_in method I'd write:

def sign_me(user, options)    if options[:subdomain]      # do_something    end end

if subdomain is nil the method handles it correctly. but with this code:

def sign_me(user, options)    if options.has_key? :subdomain      # do_something    end end

this goes wrong ("options.has_key? :subdomain" is true)! So I'd say the first implementation seems more correct, do you agree with me or I' missing something important about checking hash parameters?

8

I have a related question. I was suggesting Erwin to use just:

sign_me(@user, :event => :authentication #?, :subdomain => subdomain)

because if subdomain is nil, sign_me should correctly handle it. I mean, in an hypothetical sign_in method I'd write:

def sign_me(user, options)   if options[:subdomain]     # do_something   end end

if subdomain is nil the method handles it correctly.

That is the way I would do it.

Colin

9

Thanks Colin

I finally decided to keep the :subdomain option and let the method decide about what to do with it ( seems to be the common pattern)