(style) does this make sense?

rubyonrails-talk
1

... or is this overly gratuitous use of the bang (!)... the documentation says "potentially dangerous"... is raising an exception potentially dangerous? or should i get rid of the bang?

def is_admin!(groupname=nil)   unless logged_in?     raise AdminAuthenticationError.new, "not logged in"   end

  [...] end

def is_admin?(groupname=nil)   begin     return is_admin!(groupname)   rescue AdminAuthenticationError => detail     logger.error "is_admin? failed: #{detail}"     return false   end end

Thanks,   Tyler

2

... or is this overly gratuitous use of the bang (!)... the documentation says "potentially dangerous"... is raising an exception potentially dangerous? or should i get rid of the bang?

def is_admin!(groupname=nil) unless logged_in?    raise AdminAuthenticationError.new, "not logged in" end

[...] end

def is_admin?(groupname=nil) begin    return is_admin!(groupname) rescue AdminAuthenticationError => detail    logger.error "is_admin? failed: #{detail}"    return false end end

I've always thought of methods that end with ! as altering the object that calls them directly instead of returning a new value. So in the above case, I'd say the is_admin! is uncalled for.

But that's just me.

3

def is_admin!(groupname=nil) unless logged_in? raise AdminAuthenticationError.new , “not logged in” end I’ve always thought of methods that end with ! as altering the object that calls them directly instead of returning a new value. So in the above case, I’d say the is_admin! is uncalled for.

But that’s just me.

I agree… I think, in this particular case, what would make sense for a bang would be something like def is_admin!

self.admin == true end Not that I’m sure that makes sense in your particular case, but I think it demonstrates the point.

4

def is_admin!(groupname=nil) unless logged_in?    raise AdminAuthenticationError.new, "not logged in" end

I've always thought of methods that end with ! as altering the object that calls them directly instead of returning a new value. So in the above case, I'd say the is_admin! is uncalled for.

But that's just me.

I agree... I think, in this particular case, what would make sense for a bang would be something like

def is_admin! self.admin == true end

Really? I would have thought this would make more sense...

def is_admin?    self.admin == true end

def is_admin!    self.admin = true end

The former is a question, the later is modifying self... although maybe that's what you mean and just added an extra equal in there...

5

Yep.

6

Hi --

... or is this overly gratuitous use of the bang (!)... the documentation says "potentially dangerous"... is raising an exception potentially dangerous? or should i get rid of the bang?

def is_admin!(groupname=nil) unless logged_in?    raise AdminAuthenticationError.new, "not logged in" end

You're right that the ! means "potentially dangerous", and does not specifically mean "changes the receiver" (though that's often potentially dangerous, so a lot of methods that do it have the !).

But it's normally used as one of a pair of methods, where one is "dangerous" and one isn't (map/map!, exit/exit!, etc.). Raising an exception is not, per se, "dangerous", in this sense.

David

7

HI --

8

in ruby, we usually get rid of the is_ prefix.

is_admin? *appears* redundant, why not just admin?

9

But in Rails, don’t we usually use the is_ prefix to denote a boolean attribute?

RSL

10

Hey guys...

I just subscribed today and have read through the first couple dozen posts. I'm VERY excited to jump into Rails development... but until I have a working development environment, it won't happen.

I think I've gotten it installed and running on my Linux Fedora Core 6 machine, and I can go to localhost:3000 with Mongrel running and get the "welcome" page. But when I go to anywhere else, such as localhost:3000/category, to see the tutorial work I've done by reading the article at ONLamp.com, I get this in the browser:

Routing Error no route found to match '/category' with {:method=>"get}

In the development log, I see: /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:270:in `each' /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:270:in `run'      /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:127:in `run' /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/command.rb:211:in `run'      /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:243      /usr/bin/mongrel_rails:16:in `load'      /usr/bin/mongrel_rails:16

Rendering /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.2/lib/action_controller/templates/rescues/layout.rhtml (404 Page Not Found)

11

Hey Rob,

From what I gather here, there’s something wrong with your Mongrel setup.

Remember that the web root has to be set to the public folder within your application, from there it gets the routes and everything to work properly.

Why not try just running script/server from the rails app directory… should get you up and running easily.

12

Hey Juan...

That is how I'm running Mongrel... from script/server. And I still get those errors.

This is the tutorial I've been trying to make work:

Unfortunately, I know almost nothing about Rails, and little about Ruby.   I've played with Ruby and Watir a bit on Windows, but I want to get Rails running on a Linux machine if at all possible...

Rob

Juan Roberto Morales wrote: