# Multiple Threads?

**URL:** <https://www.ruby-forum.com/t/multiple-threads/97085>\
**Category:** Ruby\
**Created:** [July 4, 2006, 8:50pm UTC](https://www.ruby-forum.com/t/multiple-threads/97085 "2006-07-04T20:50:41Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 4, 2006, 8:50pm UTC](https://www.ruby-forum.com/t/multiple-threads/97085/1 "2006-07-04T20:50:41Z")

</div>

I need to create a little client for a third party web service. The  
client should poll the service constantly. I need to monitor for new  
events (they don’t have callbacks apparently…) so they keep the  
connection open for 15 seconds and returns nothing if nothing has  
happened. If an event happens then it returns when it actually happens.  
After returning I should immediately request again.

This is fine as long as I only need to poll for one customer (since one  
request only can check for one customer). The problem is that we need to  
poll this service for multiple customers at the same time and then I of  
course need threads.

I was thinking along the following lines (something is wrong with the  
threading parts, when I run it without threads it works so it is not the  
soap stuff that is wrong)

require ‘soap/rpc/driver’

CreateSessionResponse = Struct.new(:response\_code, :session\_id, :host)

proxy = SOAP::RPC::Driver.new('url\_to\_service, ‘urn:webservice’)  
[  
%w(createSession password name type tenant domain application),  
%w(getEvents sessionId)  
].each do |signature|  
proxy.add\_method(\*signature)  
end

class Client

def initialize(name = “”, password = “”, type = “”, tenant = “”,  
domain = “”, application = “”)  
@name, @password, @type, @tenant, @domain, @application = name,  
password, type, tenant, domain, application  
end

def run(proxy)  
thread = Thread.new {  
while true  
# log in to server and get a session id  
session =  
CreateSessionResponse.new(\*proxy.createSession(@password, @name, @type,  
@tenant, @domain, @application))  
# fetch events. returns after 15 seconds if no new events  
events = proxy.getEvents(session.session\_id)  
if events  
notify\_stb(events)  
else  
puts “no new events” # never see’s this  
end  
end  
}  
thread.join # without joining the program exits immediately  
end

def notify\_stb(events)  
puts “Notifying client with data #{events}” # never see’s this  
end

end

puts “Starting…”

# when testing I only have data for one client, will be more later

clients = [[“name”, “pwd”,"","",“domain”,“application”]].inject([]) {  
|result, client\_data| result \<\< Client.new(\*client\_data)}  
clients.each { |client| client.run(proxy) }

It might be that I actually do requests. The service is remote and I  
don’t have a chance to check if the requests are actually getting there  
(and there is also this 4:th of July in the States apparently…).

Can anyone see anything obviously wrong? I haven’t really done anything  
with threads in Ruby before so…

Regards,

Marcus

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 4, 2006, 10:15pm UTC](https://www.ruby-forum.com/t/multiple-threads/97085/2 "2006-07-04T22:15:20Z")

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Francis C. skrev:

> Look at EventMachine in Rubyforge.

On Windows XP:

C:\Downloads\>gem install eventmachine-0.5.3-mswin32.gem  
Attempting local installation of ‘eventmachine-0.5.3-mswin32.gem’  
ERROR: Error installing gem eventmachine-0.5.3-mswin32.gem[.gem]:  
buffer error

I looked in the readme. There is an example there on how to create a  
server. How would I use EventMachine to work as a client app?

Regards,

/Marcus

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 4, 2006, 10:06pm UTC](https://www.ruby-forum.com/t/multiple-threads/97085/3 "2006-07-04T22:06:03Z")

</div>

Look at EventMachine in Rubyforge.

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 4, 2006, 10:24pm UTC](https://www.ruby-forum.com/t/multiple-threads/97085/4 "2006-07-04T22:24:55Z")

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Marcus A. skrev:

> Francis C. skrev:
> 
> > Look at EventMachine in Rubyforge.
> 
> On Windows XP:
> 
> C:\Downloads\>gem install eventmachine-0.5.3-mswin32.gem  
> Attempting local installation of ‘eventmachine-0.5.3-mswin32.gem’  
> ERROR: Error installing gem eventmachine-0.5.3-mswin32.gem[.gem]:  
> buffer error

Also tried to do

gem install eventmachine

But then it tried to build native extensions and I don’t have a build  
environment for C on my WinXP setup.

/Marcus

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 5, 2006, 12:07am UTC](https://www.ruby-forum.com/t/multiple-threads/97085/5 "2006-07-05T00:07:56Z")

</div>

On Jul 4, 2006, at 1:27 PM, Francis C. wrote:

> EventMachine). I can also write you a sample app based on my  
> understanding  
> of what you’re trying to do. If it works and you like it, we can  
> post it  
> back to this list for the benefit of others.

Francis-

```
I am interested in EventMachine as well so I would love to follow

```

your process of building something simple like this with  
EventMachine. So I vote to keep it on the list or please cc me in the  
process.

Thanks  
-Ezra

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 5, 2006, 12:48am UTC](https://www.ruby-forum.com/t/multiple-threads/97085/6 "2006-07-05T00:48:15Z")

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Ezra: I sent Marcus the following description of an approach to his  
application, and will post more to this list if the approach turns out  
to be  
worth something.

(snipped from a private email:)  
Ok, here’s what I would do:  
I assume you have a global hash that maps the description of each  
“customer”  
with a status indicating whether or not it currently has an active  
client.  
(You can use the same data structure to store and report status results  
received from the connections.)  
Have the EventMachine fire a timer every five seconds that examines each  
of  
the customers and starts up a new client connection for every one that  
is  
inactive. Once a connection is open for each customer, your  
connection-handling code can start up a new connection whenever they  
close  
(which is an event passed by EM to your code). The five-second timer is  
only  
there for a heartbeat, to bootstrap the system, and in case an  
unexpected  
exception occurs. Because there are no threads, there are no race  
conditions. Very simple.

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 4, 2006, 10:28pm UTC](https://www.ruby-forum.com/t/multiple-threads/97085/7 "2006-07-04T22:28:15Z")

</div>

Your application sounds in many ways like a “server” in the sense that  
it  
needs to maintain a lot of open connections (the fact that a threaded  
implementation seems natural to you is a strong clue). The only real  
difference here is that you originate the connections instead of  
accepting  
them. Feel free to write me a private email and I can support you  
through  
the Windows install problem you’re having (you need a compiler to  
install  
EventMachine). I can also write you a sample app based on my  
understanding  
of what you’re trying to do. If it works and you like it, we can post it  
back to this list for the benefit of others.

---

<div class="post-metadata">

**Author:** ![marcan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/6bbea6/32.png) [@marcan](https://www.ruby-forum.com/u/marcan)\
**Post date:** [July 5, 2006, 1:27am UTC](https://www.ruby-forum.com/t/multiple-threads/97085/8 "2006-07-05T01:27:44Z")

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Quoting Ezra Z. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> > of what you’re trying to do. If it works and you like it, we can post it  
> > back to this list for the benefit of others.
> 
> Francis-
> 
> I am interested in EventMachine as well so I would love to follow your  
> process of building something simple like this with EventMachine. So I  
> vote to keep it on the list or please cc me in the process.
> 
> Thanks  
> -Ezra

Me too, please.