Sunday, January 13, 2013

Dreamhost Server Blocking Emails From Getting Sent

For anyone who has a rails project hosted on Dreamhost that sends emails this might affect you. Some time recently Dreamhost updated their security setting for sending mail through their SMTP servers and now require plain authentication to send mail through your localhost.

If your error log looks like this, you definitely need to make sure you are getting authenticated to send email.

Dec 28 17:51:16 servernuts postfix/smtpd[57430]: NOQUEUE: reject: RCPT from localhost[]: 554 5.7.1 : Recipient address rejected: Access denied;
In your rails app environment files you can enable authentication:
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
:address => "localhost",
:port => 587,
:domain => '',
:user_name => '',
:password => '',
:authentication => 'plain',
:enable_starttls_auto => true }

I am not a fan of this update since one would have to put their shell account credentials in a codebase. This is a good reason to check out something like postmarkapp or sendgrid.

Saturday, January 12, 2013

Problem Solving: Thread a 1/2 in. tube

Problem solving is an art. Here's a problem I recently faced outside of the software engineering space, but I felt it was worth posting here.

The problem: Running copper wire through 90 meters of 1/2 tubing

Background: I decided it was time to extend my electricity line to a structure about 60 meters from the source. With 120 meters of copper wire in hand I set off on the challenge. To protect from weather, I wanted to make sure the wire is insulated in a plastic tube. It became apparent rather quickly that the cable wasn't going to walk itself through the tube.

The solution: +1 to my neighbor who happened to be walking by and gave the suggestion that ultimately did the trick.

100 meters of fishing line
Small piece of foam that with a little squeezing will fit in the 1/2 in tube
100 meters of all purpose twine
Water source (hose will work)
Sharp piercing object that will pierce tube

  1. Start off by unraveling the tubing
  2. With your piercing object, make a small hole about 2 inches from the high end of the tube. My hole was small enough to pass the fishing line through, but small enough that a pencil wouldn't enter
  3. Put the tip of the fishing line through this hole and pull it out the closest end of the tube
  4. Tie off the sponge
  5. Push the sponge towards the low and end apply water source
  6. Watch the fishing line get pulled into the tube with the sponge fighting the force of the water
  7. Your sponge will eventually come our of the other end of the tube and you can tie off the fishing line the the all purpose twine and feed the twine through the tube by pulling on the fishing line that the water fed down the line. I had to run the twine because my fishing line was pretty light weight and probably would snap if the copper wires were tied off to the line
  8. With the twine capable of resisting more force, tie it off of the copper cables and pull the suckers through.

A     .                            B

Monday, January 7, 2013

Suppress RestClient gem Exceptions

This is a little rant on how the RestClient gem handles 400 'bad request' responses. I often use RestClient to handle calls to third-party APIs. I recently hit a use case that had me a little stumped.

I was working on a task that required me to hit a few endpoints on the API. No biggie. I set up a RestClient post like normal and expected to get a response back.

ruby-1.9.3-p194 :023 > cp = {"to"=>"121212121212", "from"=>"12121212121212", "answer_url"=>"", "answer_method"=>"GET", "hangup_url"=>"", "time_limit"=>10}
 => {"to"=>"121212121212", "from"=>"12121212121212", "answer_url"=>"", "answer_method"=>"GET", "hangup_url"=>"", "time_limit"=>10} 
ruby-1.9.3-p194 :024 > call ="", "XXXXXXXXX", "XXXXXXXXXXXX")
ruby-1.9.3-p194 :025 > r = call["/Call/"].post cp.to_json, :content_type => 'application/json'

RestClient::BadRequest: 400 Bad Request
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/abstract_response.rb:48:in `return!'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/request.rb:231:in `process_result'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/request.rb:178:in `block in transmit'
        from /Users/user/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/http.rb:745:in `start'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/request.rb:172:in `transmit'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/request.rb:64:in `execute'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/request.rb:33:in `execute'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/rest-client-1.6.7/lib/restclient/resource.rb:67:in `post'
        from (irb):25
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.9/lib/rails/commands/console.rb:47:in `start'
        from /Users/user/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.9/lib/rails/commands/console.rb:8:in `start' 

The problem was that instead of giving me a readable response, it gave me a RestClient exception. Shouldn't a REST-Client return a verbose response regardless of that the http status sent? It should be noted that in the case I was working with, the 400 bad request response also returned a message that would help users get a grasp of the problem, but in this case, RestClient just chokes and never passes the returned response message on. I added a 'puts' on the response instance in the request.rb to check out the body of the response and sure enough I saw the message that I was looking for.

  "api_id": "0f00e214-62d1-11e2-a3f8-22000abc1360",
  "error": "insufficient balance"

From the RestClient request.rb source:

# Return the default behavior corresponding to the response code: 
# the response itself for code in 200..206, redirection for 301, 302 and 307 in get and head cases, redirection for 303 and an exception in other cases

Don't get too hung up on not seeing your 400 responses with RestClient. I did a little digging around and it turns out that you actually can disable the exceptions by passing a block with the request.

call["/Call/"].post(cp.to_json, :content_type => 'application/json'){|response| response }
 => "{\n  \"api_id\": \"7def1e60-62d7-11e2-a3f8-22000abc1360\",\n  \"error\": \"insufficient balance\"\n}" 

This is why we read the code :)

Tuesday, January 1, 2013

Mountable Deals API for Rails 3 Apps

Well written targeted deals online lead to sales. It's that simple.

Now it's really simple to add a powerful deals engine to any Rails 3 site. Check out the "deals" gem that I just authored here.

The deals gem will add an API to your app so you can publish your deals to your partner sites. The deals webservice can also serve as the back end to a rich client app since RESTful requests serve JSON responses.

The deals gem is built with the RailsAdmin UI so you can easily edit the deals and place them in categories and location. This gives you a deep and wide approach to dominate the deals in your niche.

The code for the gem is available on github.