Need help understanding button_to_function (I think)

Rails
#1

This one’s really got me scratching my head.

I’ve got a button_to_function (in application.rhtml) that opens a new
window containing a file from the public directory. Or at least that’s
what it’s supposed to do. It always launches a new window. Sometimes
the file loads as expected. Sometimes the window launches that then I
get an ActionController error (in the newly launched window) saying ‘no
action responded’ to the file name.

I can reproduce the behavior, but have no idea why it’s behaving the way
it is and would really appreciate it if someone could help me understand
it.

I’ll post the code below. It’s not very interesting. What is
interesting is this.

If the URL just calls the controller with no ‘/’ at the end, the new
window is launched and the file opened in it. With the code below, if
my URL is ‘http://localhost:3000/admin’ everything works.

OTOH, if my URL is ‘http://localhost:3000/admin/’ or
‘http://localhost:3000/index’ the new window is launched but I get the
ActionController error saying ‘no action responded’ to the file name.

I can’t figure out why including the action in the URL, or even just
having the ‘/’ at the end of the controller name in the URL, is causing
the window.open javascript call to trigger a call to a Rails
controller/action.

Anybody? I sure would appreciate any help / explanation.

Thanks!
Bill

--------- controller ------------
class AdminController < ApplicationController

def index
end

end

-------------- index.rhtml ---------------

PDF Created!

<%= button_to_function "View/Print PDF", "viewPDF()", :class => 'submit-btn' %>

--------- application.rhtml -------------

YourTimeMatters.com <%= javascript_include_tag :defaults %> <%= stylesheet_link_tag 'scaffold' %>

<%= flash[:notice] %>

<%= @content_for_layout %>

#2

just calls the controller with no ‘/’ at the end, the new window is
launched and the file opened in it. With the code below, if my URL is
‘http://localhost:3000/admin’ everything works. OTOH, if my URL is
‘http://localhost:3000/admin/’ or ‘http://localhost:3000/index’ the new
window is launched but I get the ActionController error saying ‘no
action responded’ to the file name. I can’t figure out why including the
action in the URL, or even just having the ‘/’ at the end of the
controller name in the URL, is causing the window.open javascript call
to trigger a call to a Rails controller/action. Anybody? I sure would
appreciate any help / explanation.

You’re javascript is opening “testfile.pdf”. What you are seeing is
what
I’d expect and has to do with how the browser is going to munge the
current url with what you are opening up since it treats “testfile.pdf”
as
relative to the current url…

http://localhost:3000/admin – this one works because the browser
thinks
‘admin’ is a file since there is no trailing slash. So it drops that
and
substitues ‘testfile.pdf’ resulting in:
http://localhost:3000/testfile.pdf

http://localhost:3000/admin/ – doesn’t work because the browser thinks
you are in a directory presumably viewing the index.html (for example)
in
that directory so it doesn’t remove it and simply appends testfile.pdf
so you end up with: http://localhost:3000/admin/testfile.pdf

http://localhost:3000/index – this one now that I look at it should
work. Be curious to see what your error log says it’s trying to load up
when you hit this.

To fix this, change your viewPDF() function to this (with a leading
slash):

 newWindow=window.open("/testfile.pdf","","width=450");

-philip

#3

Hi Philip,

Philip H. wrote:

What you are seeing is what I’d expect and has
to do with how the browser is going to munge the
current url with what you are opening up since it
treats “testfile.pdf” as relative to the current url…

Thank you for the explanation. I appreciate it very much. I still
don’t
have my arms completely around it, but it sounds like I need to
understand
more about how requests are passed by the browser. Is that right? Any
reading suggestions?

http://localhost:3000/index – this one now that
I look at it should work. Be curious to see what
your error log says it’s trying to load up when you
hit this.

I’d like to figure that out too. What log would I find that in? I’m
developing on InstantRails (WinXP)using Mongrel. I couldn’t find any
log
references and so had pretty much no way to debug this.

To fix this, change your viewPDF() function to
this (with a leading slash):

That did it. Thank you again.

Best regards,
Bill