Rails - Jul 2005 - rescue?

Hey there list-
     i am trying to get my head around some exception handling. Could  
some kind soul please point me in the right direction?

Heres the code in my model:
    def self.fetch (page)
       Net::HTTP.start("192.168.0.2") do |http|
         data = http.get("/#{page}")
         data.body.gsub!(/\/temporaryimages/, "192.168.0.2 
temporaryimages")
         data.body.gsub!(/\/wrappers\/(\d+)\.news/i,
''/page/display/\1'')
       end
    end

What would be the proper way to wrap this in a  
begin..rescue...retry....end block so if the connection is reset or  
some othere http error occurs, the code will retry the fetch until it  
succeeds?

Thanks in advanced-
-Ezra Zygmuntowicz
Yakima Herald-Republic
WebMaster
509-577-7732
ezra-gdxLOakOTQ9oetBuM9ipNAC/G2K4zDHf@public.gmane.org

On 7/8/05, Ezra Zygmuntowicz
<ezra-gdxLOakOTQ9oetBuM9ipNAC/G2K4zDHf@public.gmane.org>
wrote:
> Hey there list-
>      i am trying to get my head around some exception handling. Could
> some kind soul please point me in the right direction?
> 
> Heres the code in my model:
>     def self.fetch (page)
>        Net::HTTP.start("192.168.0.2") do |http|
>          data = http.get("/#{page}")
>          data.body.gsub!(/\/temporaryimages/, "192.168.0.2
> temporaryimages")
>          data.body.gsub!(/\/wrappers\/(\d+)\.news/i,
''/page/display/\1'')
>        end
>     end
> 
> What would be the proper way to wrap this in a
> begin..rescue...retry....end block so if the connection is reset or
> some othere http error occurs, the code will retry the fetch until it
> succeeds?
Ezra-

There is a pretty good example of this in the Net::HTTP documentation,
which can be viewed at:

ruby-doc.org/stdlib/libdoc/net/http/rdoc/index.html

Basically you probably want to just do a recursive call to some method
on the model. Something like this (borrowed straight from the docs)
should help you out.

    def fetch( uri_str, limit = 10 )
      # You should choose better exception.
      raise ArgumentError, ''HTTP redirect too deep'' if limit
== 0

      response = Net::HTTP.get_response(URI.parse(uri_str))
      case response
      when Net::HTTPSuccess     then response
      when Net::HTTPRedirection then
fetch(response[''location''], limit - 1)
      else
        response.error!
      end
    end

Cheers,

Ben

On 7/8/05, Ben Schumacher
<benschumacher-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
>     def fetch( uri_str, limit = 10 )
>       # You should choose better exception.
>       raise ArgumentError, ''HTTP redirect too deep'' if
limit == 0
> 
>       response = Net::HTTP.get_response(URI.parse(uri_str))
>       case response
>       when Net::HTTPSuccess     then response
>       when Net::HTTPRedirection then
fetch(response[''location''], limit - 1)
>       else
>         response.error!
>       end
>     end
...

I suppose I should note that this uses get_response, so it doesn''t
expose the exceptions and therefore saves you from have to rescue --
you just have to deal with the response object.

Cheers,

bs.