Catching timeout errors with ruby mechanize

Question

I have a mechanize function to log me out of a site but on very rare occasions it times me out. The function involves going to a specific page, and then clicking on a logout

Answer 1

Instead of retrying some timeouts on some mechanize requests I think you'd better set Mechanize::HTTP::Agent::read_timeout attribute to a reasonable amount of seconds like 2 or 5, anyway one that prevent timeouts errors for this request.

Then, it seem's that your log out procedure only required access to a simple HTTP GET request. I mean there is no form to fill in so no HTTP POST request. So if I were you, I would prefere inspected the page source code (Ctrl+U with Firefox or Chrome) in order to identify the link which is reached by your agent.click(page.link_with(:text => /Log Out/i)) It should be faster because these type of pages are usually blank and Mechanize will not have to load a full html web page in memory.

Here is the code I would prefer use :

def logmeout(agent)
  begin
  agent.read_timeout=2  #set the agent time out
  page = agent.get('http://www.example.com/logout_url.php')
  agent.history.pop()   #delete this request in the history
  rescue Timeout::Error 
    puts "Timeout!"
    puts "read_timeout attribute is set to #{agent.read_timeout}s" if !agent.read_timeout.nil?
    #retry      #retry is no more needed
  end
end

but you can use your retry function too :

def trythreetimes
  tries = 0
  begin
  yield
  rescue Exception => e  
  tries += 1
  puts "Error: #{e.message}"
  puts "Trying again!" if tries <= 3
  retry if tries <= 3
  puts "No more attempt!"
  end
end

def logmeout(agent)
  trythreetimes do
  agent.read_timeout=2  #set the agent time out
  page = agent.get('http://www.example.com/logout_url.php')
  agent.history.pop()       #delete this request in the history
  end
end

hope it helps ! ;-)

Answer 2

Using mechanize 1.0.0 I got this problem from a different source of error.

In my case I was blocked by proxy and then SSL. This worked for me:

ag = Mechanize.new
ag.set_proxy('yourproxy', yourport)
ag.agent.http.verify_mode = OpenSSL::SSL::VERIFY_NONE
ag.get( url )