Forum: Ruby super simple serving of ruby pages

Hi. I apologize in advance if this is a dumb question, but though I've
searched online I haven't found an answer.

I'm starting to teach my 8yr daughter Ruby. We've covered HTML and CSS
already and she handcoded her own static website. I'd like to
incorporate her Ruby learning experience into her website, which is
much more interesting for her than using Ruby to write scripts or
desktop apps. She's just starting out, so Rails is much too complicated
for her. She's not ready for the whole MVC concept yet. What I'd like
to do is to run very simple Ruby scripts from the site and incorporate
Ruby code into rhtml files, but without Rails. I don't really want a
"framework", just the ability to run a ruby file that will serve up an
rhtml file. In other words, something very simple like PHP (I don't
want to teach her PHP). [I'll get into Rails later once she's more
advanced.]

ERb looks like the ticket, but there's a missing link (for me). I can
write a ruby script that generates an rhtml file, but then how do I
serve that rhtml file without a framework like
Rails/Nitro/Camping/etc.? Probably the answer is with Webrick somehow,
but I'm missing the connection. I can't find a simple tutorial anywhere
online, and I'm no expert on web applications.

Thanks for the help.

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> Ruby code into rhtml files, but without Rails. I don't really want a
> online, and I'm no expert on web applications.
>
> Thanks for the help.
>
>
>

Webrick has WEBrick::HTTPServlet::ERBHandler, which (I believe) serves
ERb pages. Mongrel probably has something similar.

zerohalo wrote:

/ ...

> ERb looks like the ticket, but there's a missing link (for me). I can
> write a ruby script that generates an rhtml file, but then how do I
> serve that rhtml file without a framework like
> Rails/Nitro/Camping/etc.? Probably the answer is with Webrick somehow,
> but I'm missing the connection. I can't find a simple tutorial anywhere
> online, and I'm no expert on web applications.

Just one question. Do you want the existing Web server to serve your 
Ruby
code, or do you require the server to be Ruby-based also?

If the former, you can tell Apache to serve Ruby scripts that contain 
the
usual CGI conventions. That seems simple enough. And it might not be 
what
you are asking for.

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> Ruby code into rhtml files, but without Rails. I don't really want a
> online, and I'm no expert on web applications.
>
> Thanks for the help.

Webrick seems to have support for ERB - see httpservlet/erbhandler.rb,
that is used for .rhtml files by FileHandler. Just find in the
tutorials how to start webrick for a given document root
(Webrick::HttpServer.new({:DocumentRoot = '/var/www/'}) and
something?)

You can use meta_vars and query variables in your rhtml files.

Paul Lutus wrote:
> Just one question. Do you want the existing Web server to serve your Ruby
> code, or do you require the server to be Ruby-based also?
>

No, the server doesn't need to be Ruby-based. I could use lighttpd or
apache to serve the code.

> If the former, you can tell Apache to serve Ruby scripts that contain the
> usual CGI conventions. That seems simple enough. And it might not be what
> you are asking for.

That's the part I'm missing. I find Apache extremely difficult to
configure (beyond the basics). How would I tell Apache to serve Ruby
scripts?

Thanks.

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> > usual CGI conventions. That seems simple enough. And it might not be what
> > you are asking for.
>
> That's the part I'm missing. I find Apache extremely difficult to
> configure (beyond the basics). How would I tell Apache to serve Ruby
> scripts?

In a recent thread (eruby?) someone mentioned adding
> AddType application/x-httpd-eruby .rhtml
> Action application/x-httpd-eruby /cgi-bin/eruby
to httpd.conf

In my win installation there is c:/ruby/bin/erb.bat so I suppose there
is something similar in unix. Now either add #!/usr/bin/erb to the top
of any .cgi file or, preferably, do something similar to the above,
somehow telling apache to run erb.

(I'm not an apache guru, so these are just hints to get you started...)

Jan Svitok wrote:

> Webrick seems to have support for ERB - see httpservlet/erbhandler.rb,
> that is used for .rhtml files by FileHandler. Just find in the
> tutorials how to start webrick for a given document root
> (Webrick::HttpServer.new({:DocumentRoot = '/var/www/'}) and
> something?)

Yes, I tried that. Unfortunately there is no documentation on the
webrick site on how to use ERBHandler. I have this in a ruby script
which does start up the Webrick server. However, while it serves HTML
files fine, it treats RHTML files as binaries and RB files as just
plain text. Here's my code:

<pre><code>
require 'webrick'
include WEBrick

def start_webrick(config = {})
  config.update(:Port => 8080)
  server = HTTPServer.new(config)
  yield server if block_given?
  ['INT', 'TERM'].each {|signal|
    trap(signal) {server.shutdown}
  }
  ruby_dir = File.expand_path('/data/sandbox/ruby')
  server.mount("/data/sandbox/ruby", HTTPServlet::ERBHandler, ruby_dir)
  server.start
end

start_webrick(:DocumentRoot => '/data/sandbox/ruby')
</code></pre>

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> Yes, I tried that. Unfortunately there is no documentation on the
> webrick site on how to use ERBHandler. I have this in a ruby script
> which does start up the Webrick server. However, while it serves HTML
> files fine, it treats RHTML files as binaries and RB files as just
> plain text. Here's my code:

require 'webrick'
include WEBrick

def start_webrick(config = {})
  config.update(:Port => 8080)
+  config.update(:MimeTypes => {'rhtml' => 'text/html'})
  server = HTTPServer.new(config)
  yield server if block_given?
  ['INT', 'TERM'].each {|signal|
    trap(signal) {server.shutdown}
  }
-  ruby_dir = File.expand_path('/data/sandbox/ruby')
-  server.mount("/data/sandbox/ruby", HTTPServlet::ERBHandler, ruby_dir)
  server.start
end

start_webrick(:DocumentRoot => '/data/sandbox/ruby')

Thanks, Jan. That was easy. Now .rhtml files render correctly.

Is there a way to tell it to execute .rb files rather than treat them
as simple text files?

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> [snip]
>
> > If the former, you can tell Apache to serve Ruby scripts that contain the
> > usual CGI conventions. That seems simple enough. And it might not be what
> > you are asking for.
>
> That's the part I'm missing. I find Apache extremely difficult to
> configure (beyond the basics). How would I tell Apache to serve Ruby
> scripts?

On Debian and Ubuntu, it just works. After you apt-get install
apache2, you just copy some foo.rb file (maybe like the one shown
below) to /usr/lib/cgi-bin/ and then point your browser at
http://localhost/cgi-bin/foo.rb and boom. :)

==== snip /usr/lib/cgi-bin/foo.rb ====
#!/opt/ruby/bin/ruby -w

puts "Content-type: text/html"
puts

puts "<html><body>
<p>The time is now #{Time.now}, so you'd
better get crackin'!
</p>
</body>
</html>"
==== /snip ====

---John

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> > > files fine, it treats RHTML files as binaries and RB files as just
> > > plain text. Here's my code:
> >
> > require 'webrick'
> > include WEBrick
+ module WEBrick
+   module HTTPServlet
+     FileHandler.add_handler("rb", CGIHandler)
+   end
+ end
> > -  server.mount("/data/sandbox/ruby", HTTPServlet::ERBHandler, ruby_dir)
> >   server.start
> > end
> >
> > start_webrick(:DocumentRoot => '/data/sandbox/ruby')

Now it starts .rb for me, although I'm not able to write any good cgi
right now ;-) maybe it's because I'm on windows...

On 9/20/06, zerohalo <zerohalo@gmail.com> wrote:
> I don't really want a
> "framework", just the ability to run a ruby file that will serve up an
> rhtml file. In other words, something very simple like PHP (I don't
> want to teach her PHP). [I'll get into Rails later once she's more
> advanced.]

Does this help?
http://cyll.org/blog/tech/2006-08-26-makingrubyintophp.html

Jan Svitok wrote:

> Now it starts .rb for me, although I'm not able to write any good cgi
> right now ;-) maybe it's because I'm on windows...

Doesn't work for me. With even the simplest .rb file it gives me the
following error:

ERROR Premature end of script headers:

but maybe I need to put a particular include in particular at the top
of each .rb file? Not used to working with .rb files outside Rails.

Wilson Bilkovich wrote:

> Does this help?
> http://cyll.org/blog/tech/2006-08-26-makingrubyintophp.html

Indeed it did. Thanks. That works nicely.

zerohalo wrote:

> 
> Jan Svitok wrote:
> 
>> Now it starts .rb for me, although I'm not able to write any good cgi
>> right now ;-) maybe it's because I'm on windows...
> 
> Doesn't work for me. With even the simplest .rb file it gives me the
> following error:
> 
> ERROR Premature end of script headers:

This is a classic CGI header error, caused by the absence of a 
recognizable
emitted header like:

print "Content-type: text/html\r\n\r\n"

As the first text emitted by the script.

Remember, if you can get the server to read the filetype and treat it as 
a
well-behaved source, and if you can get the Ruby scripts to emit the
expected header information, your server requirements become much 
simpler
to meet.

zerohalo wrote:

>> usual CGI conventions. That seems simple enough. And it might not be what
>> you are asking for.
> 
> That's the part I'm missing. I find Apache extremely difficult to
> configure (beyond the basics). How would I tell Apache to serve Ruby
> scripts?

Others have offered good advice. The simplest way is to give the server 
what
it expects to see:

---------------------------------------

#!/usr/bin/ruby -w

print "Content-type: text/html\r\n\r\n"

print "<html><body><center><h1>Hello world!</h1></center></body></html>"

---------------------------------------

Put this file in a directory where executable content is expected to be,
like /serverpath/cgi-bin, and chances are Apache will treat it as you 
would
expect, without any special configuration.

Paul Lutus wrote:
> This is a classic CGI header error, caused by the absence of a recognizable
> emitted header like:
>
> print "Content-type: text/html\r\n\r\n"
>
> As the first text emitted by the script.

Got it. That works, thanks, Paul, and Jan, for your patience with my
ignorance.

zerohalo wrote:
> Hi.

Hi.

> She's just starting out, so Rails is much too complicated
> for her. She's not ready for the whole MVC concept yet.

FWIW, I have the brain of an 8yr old in when it comes
to web-aps, and I managed to write a /couple/ Camping aps
the other evening.

Regards,

François Montel wrote:

> Got it. That works, thanks, Paul, and Jan, for your patience with my
> ignorance.

It seems like I am at the same level as your daughter [although a whole 
9 years older] and am trying to do the same thing you are. I could not 
get anything working from what I gathered in this thread, but it seems 
you have. Can you tell me what you ended up doing so I can do that too?

thanks

Bil Kleb wrote:
> 
> FWIW, I have the brain of an 8yr old in when it comes
> to web-aps, and I managed to write a /couple/ Camping aps
> the other evening.
> 

Fascinating. I've looked at Camping but haven't really
grasped it yet.

I'm not a web guy. I do it slowly and painfully.

I also have the brain of an eight year old. I keep it
in a jar on my desk.


Hal

Jonathan Denni wrote:

> François Montel wrote:
> 
>> Got it. That works, thanks, Paul, and Jan, for your patience with my
>> ignorance.
> 
> It seems like I am at the same level as your daughter [although a whole
> 9 years older] and am trying to do the same thing you are. I could not
> get anything working from what I gathered in this thread, but it seems
> you have. Can you tell me what you ended up doing so I can do that too?

It's very simple, really. Apache requires that executable pages (pages 
that
have to be processed by an interpreter like Ruby) by placed in a special
directory. The default for this is usually /sitedirectry/cgi-bin.

Write an ordinary Ruby script, but make sure the first thing it prints 
is a
CGI header, like this:

print "Content-type: text/html\r\n\r\n"

After this first line, just output HTML, as in my prior example, and the
page will appear to all intents and purposes as though it contains the 
text
it is printing. Therefore your Ruby code decides what the page content 
is,
and it is obviously dynamic.

A Ruby interpreter must be installed on the server machine. Apart from 
that,
it should work without any fuss.

zerohalo wrote:
> Ruby code into rhtml files, but without Rails. I don't really want a
> online, and I'm no expert on web applications.
I've an example of this that's ~100 lines of code, if you're interested.

Maps URLs to classes and templates and renders them, using erb and
Webrick.



--
James Britt

"A principle or axiom is of no value without the rules for applying it."
   - Len Bullard

On Sep 20, 2006, at 8:05 PM, James Britt wrote:

>> complicated
>> write a ruby script that generates an rhtml file, but then how do I
> Maps URLs to classes and templates and renders them, using erb and  
> Webrick.
>
>
>
> -- 
> James Britt

I'd be interested in seeing that James.

Thanks
-Ezra

Paul Lutus wrote:

> A Ruby interpreter must be installed on the server machine. Apart from 
> that,
> it should work without any fuss.

ahh, well, thats probably my problem. i'm using the cheapest server i 
could find (canaca.com), which obviousely has no support for ruby. i was 
hoping there was some shortcut way i could use ruby on my website 
without having to change servers. is there some way to do that, or is it 
totally hopeless?

Jonathan Denni wrote:

> totally hopeless?
I didn't realize this was an offsite, commercial server. Many 
traditional
servers stay away from anything relatively new, to avoid instabilities.

Some commercial webservers allow you to install your own binaries. All 
you
have to do is find out what kind of processor and OS are in use, just as
you would for your home computer in choosing a binary. Then drop the
appropriate binary into /usr/bin or another suitable location, and you 
are
good to go.

But without this option or one like it, your instinct is correct -- you
wouldn't be able to run Ruby.

This works fine:

eRuby: The Erb Alternative to Embedded Ruby in HTML
http://www.hiveminds.co.uk/node/3105

It is extremly easy to setup, I have tried this solution in 2 shared
hosting services without a problem.

--
Aníbal Rojas
http://www.rubycorner.com

Thanks a lot. I didn't get it working. I put erb.cgi and a .htaccess in 
/var/www/cgi-bin/ as directed in http://www.hiveminds.co.uk/node/3105 
but I can't find out what kind of OS the server is using, and i cannot 
create/edit files or directories in /bin or /usr/bin

at this point, it looks to me like i should give up trying to use ruby 
on that server.

 Thanks again for your help.

Ezra Zygmuntowicz wrote:
> 
> On Sep 20, 2006, at 8:05 PM, James Britt wrote:

> 
> 
> I'd be interested in seeing that James.
> 

Here ya go!

http://jamesbritt.com/code/wb_erb.tgz

Fairly simple, few features, demos a few concepts.


--
James Britt

"Simplicity of the language  is not what matters, but
simplicity of use."
  - Richard A. O'Keefe in squeak-dev mailing list

On Sep 21, 2006, at 10:58 AM, James Britt wrote:

> http://jamesbritt.com/code/wb_erb.tgz
>
> Fairly simple, few features, demos a few concepts.

Interesting.  Thanks for sharing.

I'll try and pay you back at least some of the effort by addressing
one of your TODOs.  From your code:

# Windows only. TODO: figure out
# how to do the same thing on Mac and 'nix boxen.
Thread.new {
   # Wait a bit for the server to start, then launch a Web browser
   # to show the default page
   sleep( 5 )
   warn `start http://127.0.0.1:#{PORT}`
}

On Mac OS X, replace the word "start" with "open" and it will work.

Hope that helps.

James Edward Gray II

On Thu, 21 Sep 2006, James Britt wrote:

>> ERb looks like the ticket, but there's a missing link (for me). I can
>> write a ruby script that generates an rhtml file, but then how do I
>> serve that rhtml file without a framework like
>> Rails/Nitro/Camping/etc.? Probably the answer is with Webrick somehow,
>> but I'm missing the connection. I can't find a simple tutorial anywhere
>> online, and I'm no expert on web applications.
>
> I've an example of this that's ~100 lines of code, if you're interested.
>
> Maps URLs to classes and templates and renders them, using erb and Webrick.

I'd like to see it, just because I might find it educational.

I've also been wondering if framework support for this sort of thing, 
but
very simple to setup, would be useful to people?

Something akin to this:

app.rb
-----
require 'iowa'

Iowa.run
-----


app.cnf
-----
socket:
   hostname: foo.bar.com
   port: 3000
application:
   dispatcher:
     class: StandardDispatcher
     mapfile: mapfile.cnf
-----


mapfile.cnf:
-----
:map:
   /index.html: Index
   /form.html: Myform
   /response.html: Myresponse
-----


If one had an index.rhtml, myform.rhtml, and myresponse.rhtml, they 
would
be mapped to classes Index, Myform, and Myresponse, and requests for the
urls above would go to the class in question and be rendered as an erb
template.

You'd run it with:

ruby app.rb -r webrick
or
ruby app.rb -r mongrel

No other code or config necessary to serve those rhtml files.  Would
anyone use this ability (as I personally would not).  Worth my time to
make the above work?



Kirk haines

Jonathan Denni wrote:

> 
> Thanks a lot. I didn't get it working. I put erb.cgi and a .htaccess in
> /var/www/cgi-bin/ as directed in http://www.hiveminds.co.uk/node/3105
> but I can't find out what kind of OS the server is using, and i cannot
> create/edit files or directories in /bin or /usr/bin

Will any CGI script work in the /var/www/cgi-bin directory, for example 
one
that relies on "sh" or Perl? If so, put your own CGI script
in /var/www/cgi-bin that reveals things about the OS.

-------------------------------------

#!/bin/sh

echo -e "Content-type: text/html\r\n\r\n"

data=`set`

echo "<html><body><pre>$data</pre></body></html>"

-------------------------------------

Don't leave this script in place, just use it temporarily to find out 
what's
going on.

> 
> at this point, it looks to me like i should give up trying to use ruby
> on that server.

Use the above script and change:

data=`whereis ruby`

> 
>  Thanks again for your help.

Just some ideas, and your conclusion may be correct.

Paul Lutus wrote:


> Don't leave this script in place, just use it temporarily to find out 
> what's
> going on.


how do i access the script output?

Jonathan Denni wrote:

> how do i access the script output?

nevermind, I was able to try it but i just got an error message

Jonathan Denni wrote:

> Jonathan Denni wrote:
> 
>> how do i access the script output?
> 
> nevermind, I was able to try it but i just got an error message

What error message? For most typical errors, it's because you put the 
script
in a place where it cannot be executed. Also, in some cases the script 
has
to be given executable permissions.

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Jonathan Denni wrote:
> ahh, well, thats probably my problem. i'm using the cheapest server i 
> could find (canaca.com), which obviousely has no support for ruby. i was 
> hoping there was some shortcut way i could use ruby on my website 
> without having to change servers. is there some way to do that, or is it 
> totally hopeless?
> 

Serve (part) of your website from your PC over which you have control?
If it's a personal website or to display some experiments, this should
be sufficient.

David Vallner
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