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Hard Reset / Rebooting a Soekris Net 5501

2008-05-05T00:25:00Z

If you have a Soekris Net5501, sometimes they will not reboot when you tell them to. Hanging just after the memory test. Here is how you force them to reboot.

The only thing you have to have is a serial connection to the console port of the Soekris. Any good network design should give you some sort of console connection as a backup path, if you don’t have access to the console on your box from remote, you might want to work out how you can do this.

Having a modem with dial back is one way, but I usually cross connect boxes together so that if one fails, I can get to the console via the serial port of another. This way, I can always get to the console of any unit that dies.

So, the reset command is quite easy. Connect to the console and type “+” then wait about 2 seconds and type “POWER”

This will turn the Soekris off, wait about 5 seconds, and then turn it back on again.

This is a life saver when you have a CF card that does not initialize in time for the box to boot.

blogLater

Mikel

Tip #15 - Read Other People's Code

2008-04-26T13:39:00Z

It is a great tip, and one I do fairly often, go download some code and read it until you understand it.

This is a short tip!

Sometimes you just need a different perspective.

Getting and installing say, restful authentication, or downloading the Joyent Connector and reading through some of the code will give you lots of good ideas about where to go and what to do in your own application development.

A great one for the intermediate Railsite is the Caboose sample apps These really give you a new view on how to make an app.

Anyway, happy hunting!

Mikel

Tip #14 - Custom Error Messages in Validations

2008-04-23T11:02:00Z

If you use Rails, you sometimes get a situation where the custom error messages just don’t work, here is how you can fix it…

Say you have a model with a field called ‘country_iso’ which specifies the ISO value of the country the person belongs to.

Database design concerns aside (you should really have it as country_id and a separate country_iso field) you might be stuck with this situation from a legacy database (like I was).

As this is a required field, you set the following in your model:

123	class User < ActiveRecord::Base validates_presence_of :country_isoend

So, you go ahead and make a form which presents the country as just a select box, because you don’t want your users to worry about if Thailand is TH or TL, but then you don’t specify a country and the error message comes back to the user in nice big letters:

Country Iso can’t be blank

Ugh!

Aside from the fact that Iso is capitalized badly, how many of YOUR users know that it stands for “International Standards Organization” and that a Country ISO is usually a two letter representation of the country? I’d wager about 3 of them have some idea :)

So you go in and change the validates line to:

123	class User < ActiveRecord::Base validates_presence_of :country_iso, :message => "Country can't be blank"end

Do your test again, and now you get:

Country Iso Country can’t be blank

Nup.. that’d didn’t really fix it.

Fortunately, the fix is easy:

class User < ActiveRecord::Base
  validate do |user|
    user.errors.add_to_base("Country can't be blank") if user.country_iso.blank?
  end
end

Now, reload your view and you’ll get:

Country can’t be blank

Much better!

blogLater

Mikel

Tip #13 - BangBang Transformations!

2008-04-22T12:51:00Z

Ruby is marvelous, everything evaluates. Which means a lot of the time, you can get away with things like ‘if @user…” and just depend on the existence of the @user var. But what if you just really need a Boolean true or false? Here is a little pattern you can use to do this…

Where two wrongs make a right?

Ruby you have the case that EVERYTHING except nil and false are “truthy” (which means, they evaluate to true in a condition).

So that is why something like this can work in Ruby:

irb(main):001:0> user = "Mikel" 
=> "Mikel" 
irb(main):002:0> if user
irb(main):003:1>   puts "Hello #{user}" 
irb(main):004:1> end 
Hello Mikel

But the “value” of users in that if statement is still ‘Mikel’

What if you had a method in a rails model like this:

123	def logged_in? true if logged_in_date != nilend

That says “Return true if the logged_in_date is not nil, otherwise return nil.

The problem with this, is that if the logged_in_date is already nil, the method will return nil, not false. And nil does not equal false in all cases.

A better way to write this would be to use the logical NOT operator, you might know that a ! in front of any variable is a logical NOT operator. This means, it takes whatever the value is and returns the opposite as a true or false. So we get stuff like this:

irb(main):001:0> true
=> true
irb(main):002:0> !true
=> false
irb(main):003:0> 1 == 1
=> true
irb(main):004:0> !(1 == 1)
=> false

Easy enough.

So NOT true equals false. But NOT NOT true equals true. And NOT NOT (anything except nil and false) equals true. And NOT NOT anything that is nil or false equals false. Confused? Let me show you the same “logged_in?” method with some ruby goodness:

123	def logged_in? !!logged_in_dateend

What this now says is that if the logged_in_date is nil, then apply NOT to that (which gives you true) and apply NOT to that (which will give you false) so in that case it will return false, which is what you want!

On the other hand, if logged_in_date is ANY value (string, date, anything) then you apply NOT to that and you get false, apply NOT again and you get true. Which is also what you want.

So instead of returning true or nil, that method will now return true or false, just as we expect.

Not bad for two exclamation marks!

blogLater

Mikel

Tip #12 - HTML and HTTP are Your Friends

2008-04-21T00:30:00Z

What is an <em> tag? How do you manually make a select box? What about a multi value select box? Do you know the difference between a <submit> tag and a <button> tag? Can you hand code a form to make a restful post to one of your Rails controllers? If you can’t do all the above with plain HTML and no rails helpers or don’t know the difference between a GET and POST request and when you use either, then you need to read on. If you can, feel free to skip to the next section.

This is part of my 8-Part tip-a-thon on the Must Know Facets of Ruby on Rails. If you haven’t already, please read the first part and then come forward (there is a link at the bottom of each article that links to the next)

Learn All About HTML

You would think it would go without saying, but to do Ruby on Rails, you are GOING to need to know what the old workhorse, HTML, is and how to use it.

HTML is what we use for everything on the web. Unless you are not coding for the web and making an entirely resourceful application that only talks via XML or some other protocol, you will need to understand HTML. After all, it is the presentation layer and with a bad, unusable, unintuitive design, it doesn’t matter how good your application is, your users won’t use it.

Lets give some examples.

You all know Rails has a form helper. This thing is a god-send. It turns making an entire, fully functioning post request into:

<%- form_for @user -%>

But unless you know what that tag is actually generating, you will always go over that and look at it and glibly say “Oh, yeah, that makes the user form” and then when something about it doesn’t work, you are in trouble.

What about the select tag? Rails again to the rescue:

<%= collection_select @person, :job, @jobs, :id, :name -%>

And TADA, you suddenly have a complete select box with all the jobs a person can have with their existing job already selected.

This is all good until you need to go outside the square, then your underlying knowledge of how all the HTML works (or lack of it) will come up and bite you from behind.

So how do you get around this?

Well, believe it or not, your web browser ‘show source’ function is a VERY good start. Make a form and then open up the browser and have a look at the generated code. Then even go as far as not using the helpers and manually type the HTML code into the view and observe that it gasp still looks and works the same as using the helper?????

Too many times in forums and online, I have seen people (and myself too) try to shoe horn a helper into doing exactly what they want, instead of just coding it in HTML and being done with it (or making their own helper).

There are many advantages with the Rails helpers, especially with regards to code maintainability, and that is, if you use helpers you are agreeing to code in a certain manner that will allow yourself and others to read your code much more easily in the future. But at the end of the day, the most important thing is providing a robust and sound product to exchange with your users. If you can’t do this, then why bother?

A great website on all the HTML tags is the w3 schools forums. I highly recommend going through this site and reading up on every tag. For example, did you know that all your efforts to try and style that submit button would be handled by using a button tag, or that select boxes are not that hard to do by hand when you have to?

Also, you need to get a grip about how HTTP works. Understanding what the differences between a GET and POST request, and why would you use each in what scenario is critical to understanding how your rails app works and really throws you if you try to learn anything about RESTful interfaces.

In a nutshell (ignorning anything about REST for now that just builds on top of this), there are two ways most browsers will accept a form sent to them from a web browser. They are called GET and POST. You use GET when you are retrieving something from a application and are not trying to make any changes. You use POST when you are submitting some data to make changes. So a query form (asking the application about something) would usually be a GET request and creating a new user (sending data to the application) would be a POST request.

If you don’t get this, then trying to understand why a CREATE action uses a POST and a SHOW action uses GET would be unintuitive. But with the above single paragraph it becomes quite clear. (I’ll go into RESTful methods in a later post). Here is a good write up about GET and POST. Just one point, it clears up the word ‘idempotent’ about 8 paragraphs in (it basically means, “doesn’t make any change on the server”).

As for HTTP, that is what your Apache Web Server, Mongrel server or mod-rails application are handling. This is the give and take between browsers and their servers. It would do you well to understand how this works.

The bottom line is the HTTP and the HTML you and I use ALL DAY to get our Rails sites up and running is important and a foundation to understanding everything else in Ruby on Rails. Honestly, if you don’t get HTML, you will NOT get Rails, you might be able to punch out a website only using helpers, and if you can, good on you, but if something breaks at 2am and you have to fix it, I am sure you will wish you spent a few hours looking over how that form tag really works.

blogLater

Mikel

Bloggers Unite

2008-04-19T23:57:00Z

This year on May 15th there is going to be a world wide bloggers unite on the subject of Human Rights.

This is a great opportunity to raise public awareness on the subject of Human Rights. We all have them, but in the modern world of pending global governments (which I think are just another way to remove power from the people) It is time for all of us to become away of what it means to be living on this planet, what it means to be a member of this society, what it means to have a family and what it means to just be you.

If you are not sure what human rights actually are, you can view a bunch of short videos at the Youth for Human Rights and then go over to Amnesty International and check out their site to find out what all the fuss is about.

You can, of course, also join in and put up the bloggers unite human rights badge on your site and blog about it on May 15th.

You may or may not know that there are 30 basic human rights which are laid out in the Universal Declaration of Human Rights. There is also a plain english (simplified) version

Have a read, they are quite surprising!

blogLater

Mikel

Tip #11 - Transact Your Migrations!

2008-04-19T03:22:00Z

If you are using Rails, you are most likely using migrations. Have you ever had a migration fail half way through? Have you ever then had to figure out how to find each change and revert it in the database? Would you like to never have to do that again? Here is how…

USE TRANSACTIONS

I sometimes wonder why this just isn’t the default. When I am doing a migration, I either want the thing to work completely all the way through, or I want nothing done to the database.

Luckily, you can do this with transactions.

A transaction (for those non SQL people out there) is an idea of a series of events being atomic. That is, either, they all are executed without error, or if any one of them fails or faults, then no change is made to the database at all.

Luckily, adding transactions to a migration is very easy.

class ComplexMigrationThatCanNotFail < ActiveRecord::Migration

  def self.up
    transaction do
      add_column :table, :name, :type
      add_column :table, :name, :type
      # Complex task #1
      remove_column :table, :name, :type
      remove_column :table, :name, :type
      # Complex task #2
    end
  end

  def self.down
    # ... Down script
  end

end

Now, say your migration fails at the second remove column, no fear, everything is rolled back to the start point, you can read the rake error messages, fix the problem, and try again.

Of course, you are testing this on the development server, so no major harm done if it blows up a couple of times, but I don’t know about you, but I have lots more things to do than try to restore two gigabytes of staging or development database :)

blogLater

Mikel

Tip #10 - The Ruby Language

2008-04-18T00:42:00Z

Learning Rails is hard enough without also facing the task of learning Ruby at the same time. Here I go over some of the must knows in Ruby so that you get some basic understanding of how to do Rails.

Learning Ruby

Ruby is fun.

You have probably heard that, you have also probably heard that Rails is fun. Both are true.

But there is nothing fun about tearing your hair out online trying to figure out why a piece of code doesn’t work, especially if you can’t even read the code!

So Learning Ruby is probably the most important step to becomming a Ruby on Rails developer.

But how do you do that?

Well, this is how I did it.

Read… — LOTS

If you don’t already own the Pickaxe, then you should go and get it. If you are just looking to see if Ruby is for you, then maybe you could read the online edition of Version 1 of the Pickaxe. It is older, but contains enough information and is current enough to be worthwhile. Ruby hasn’t changed that much since the version 1 and all the basic concepts are the same.

You can read through _why’s (who is basically Ruby’s mad scientist) Poignant Guide to Ruby on learning Ruby. I must admit, I tried, I did… but it lost me about the time the Fox/Dog/Crazy thin dude lost is truck and someone had stolen it… you’ll need to have a look and read to see what I mean :)

There are many other fine Ruby books out there as well. I can also recommend the O’Rielly book, mainly because it has a different approach to the Pickaxe and gives you a different view of the same problem.

If you read through these books, and do the examples (the Pickaxe is good for this as you build a Jukebox as you go!) you will get some good basic understandings about how Ruby ticks.

Use Ruby Everywhere you Can

This is a key one. When you are first learning Ruby, and you need to do something outside of Rails that could use a bit of shell scripting or some basic programming, use Ruby!

There is pretty much no task that Ruby can’t handle. I have used it to parse incomming emails, used it to merge CSV files together and also used it to clean up bad code points in a supposed unicode file.

I have even used it to help handle someone attacking one of our servers.

Once you decide you can use Ruby, go for it and learn all the little tricks inside of that big box called the standard library. There is so much in there that you can use and you will be surprised at how many tools you have at your disposal.

Practice with a different paradigm

Ruby on Rails is one use for Ruby and a very exact use. But following on from the previous point, try Ruby in different paradigms.

What do I mean? Well, make a server in Ruby that serves messages of any type over a network stack. Make a program that searches your hard drive for files, make something that plays some music. Really, anything.

When I did this I found that my understand of how Ruby on Rails works expanded a huge amount. Rails is just one medium sized Ruby program that handles routing, talks to your database and allows you to serve up web pages. Once you know how all the Ruby stuff fits together, you will understand Rails a lot more.

Next Up

Next in the series is the HTML and HTTP are Your Friends

blogLater

Mikel

Apple Release the APPLE-1 - Upgradable to 32k (When Available)

2008-04-17T13:17:00Z

I know it is a bit late, and all the other cooler technology blogs have already covered this…

But I just couldn’t resist. It is such a great computer, and only $666.66 it is a true BARGIN!

Check it out!

blogLater

Mikel

Tip #9 - Learn Programming Theory

2008-04-17T12:11:00Z

Being a Rails developer means that, yes, you too need to learn how to (gasp) program! No, seriously! Here are my tips on that subject.

This is part of my 8-Part tip-a-thon on the Must Know Facets of Ruby on Rails. If you haven’t already, please read the first part and then come forward (there is a link at the bottom of the previous link to this article)

Learning how to Program is an interesting one. Where on Earth do you find a definitive guide on how to program?

I can tell you what not to do here, don’t go out and buy the latest “Learn Ruby on Rails in 24 Hours” book, or “Ruby on Rails for Dummies”, if and when such a beast surfaces. No. Actually, I am not even talking about Ruby, Java, C or any other language, what I am talking about is Learning to Program a computer.

A computer teacher of mine once said “A computer will ALWAYS do what you tell it to do. Not only what you WANT it to do.”. I have kept this as a stable learning datum ever since. When I find a program is not working the way I would expect, I will go through the code, line by line inspecting it until I find where I TOLD it to do something I didn’t WANT it to do.

If you don’t find the idea of pouring through code for hours to find that one bug interesting or exciting, then programming may not be your thing and you might find more fun somewhere else.

But for the rest of us, this is where we want to be.

You know, probably the best write up of this I have found is called Teach Yourself Programming in 10 Years and it is a great read with a lot of good advice. I recommend you go and read this now and see what areas you can clean up and improve on.

If you are a complete beginner to programming, don’t fear, the way to mastery is by taking small and deliberate steps.

I would recommend you go and read Chris Pine’s fantastic “Learn to Program:http://pine.fm/LearnToProgram/ book. The first edition is on the website for free and is very good. You can get later editions from the store from his site.

Where to go from there? Well, for starters, you should subscribe to the Ruby Talk mailing list at least, maybe even Ruby Core. You should read through some of the posts from the more experienced Ruby Programmers as they come up and watch with interest when someone says “How do I solve XYZ?” and see the answers, test the answers and see if you could do better (you might surprise yourself).

Also, if you do see an answer from one of the Ruby Gurus, don’t be afraid to ask how it works if you don’t understand it. The Ruby Community is one of the friendliest communities I have met, and they are always willing to explain their methodologies or ways of answering a problem.

Finally, go look at the Ruby Quiz Series done and hosted by James Edward Gray II. It is a good exercise to sit down and actually try to do these quizzes in any order. It teaches you a LOT about programming. Just like an elite Athlete needs to train in all sorts of exercises to be competent at their core devotion, so to do you need to exercise your programming mental powers to think about problems differently or to expand your ideas and ability to think.

Next step, The Ruby Language

blogLater

Mikel

Tip #8 - Must Know Facets of Ruby on Rails

2008-04-17T12:10:00Z

Sometimes it is easy to forget that when you take the plunge to learn something as encompassing as ruby on Rails, you forget just how MUCH you need to learn, and it can all seem a bit overwhelming at first. Here is a good way to go about learning it.

This might seem obvious, but one of the hardest things to get is that you are not just learning a programming Language with Ruby on Rails, you are learning (or trying to learn) a full stack web development Framework.

Now, just have a think about what that means. Ok. What does Full Stack imply here? Well, for starters, it means that you need to know something about all of the following to get anything meaningful done in Ruby on Rails:

Must Know

Programming Theory
The Ruby Language
HTTP and HTML Tags & Design
Cascading Style Sheets
Database Theory & Design
Javascript & AJAX
At least one of the three database server implementations
BDD or TDD

Will Need To Know

Version Control
Representative State Transfer (REST)
Unix (or another Server Technology)
Web Serving
EMail and EMail servers
Domain Name Systems (sometimes)

Now, if you don’t have a basic understand of the first 8 layers above, honestly, you will have a HARD time getting your head around Ruby on Rails. Seriously, it will make you feel spinny and frustrated that you can’t get the darn thing to work.

The 6 that follow are optional, depending on what type of application you are developing. Some will argue that BDD and TDD are an absolute requirement, and to be fair, to make a real application, they are. But they also are not part of what you MUST know to get something working and they fall under the programming theory and design as a methodology.

There are of course many other technologies that you CAN use in a Rails app, but the above are, I think, the core minimum to get started.

Now, what do I mean by “Make sure you understand what you are doing” ? Well, what I mean is that if you have decided to learn Rails, sure, go ahead and make the 10 minute blog or todo list, or even go get the Peepcode on starting Rails from Scratch (very good by the way), but once you have whetted your appetite, come back to that list of the Must Know 8 and start at the top.

The other trick here is, if you find something in a tutorial that you don’t understand, spend the time to go and find out about it and why it works and how it works. Getting these underlying understandings will build a strong foundation for you to expand your knowledge overall.

I am going to do a series of posts that walk through the top 8 layers above. The first one I have already posted and it is called Learn Programming Theory

blogLater

Mikel

Tip #7 - Shell Shortcuts You Should Know and Love

2008-04-16T22:12:00Z

Face it, you use Ruby, you use Rails, you are going to use the shell, either in the console or directly, here are some shortcuts I can’t live without.

Have you ever done this?

baci:~/rails_app mikel$ ./script/generate user first_name:string
mid_name:string last_name:string address1:string address2:string
address3:string suburb:string state:string country:string
post_code:string home_phone:string work_phone:string mobile_phone:string
email:string

Couldn't find 'users' generator
baci:~/rails_app mikel$

Grr… of course, you forgot to put the word “model” before the word “user”.

You can hit the up arrow and get all the text back, but if you were like me, you used to hit the left arrow and hold it down for about half an hour to get to the start of the line. Well, no more. Shell Shortcuts are your friend!

Simply type up arrow and then “Ctrl-A” and you are at the start of the line.

Hit “Ctrl-E” and you will be at the end of the line.

Or, if you want a clean screen, “Ctrl-L” will do it for you.

If you make a mistake, “Ctrl-_” will undo it.

And you also have cut and paste on the command line.

“Ctrl-U” cuts the beginning of the line to the cursor

“Ctrl-K” cuts from the cursor to the end of the line

and “Ctrl-Y” pastes whatever you have cut out back into the screen at the cursor.

The cool thing is, all of these work within the Rails console as well!.

So, you are in the console and type:

12	>> User.find(:all, :conditions => ["user_name = ? AND first_name = ?", "mikel", "Mikel"])

And forget that you want to assign it to the “user” variable? Well, type “Ctrl-A” and then “*user = *” and hit return and you are done.

Nice, handy time saving short cuts.

You can also find out other ones by Googling Bash shell short cuts

Of course, the above assumes you are using Bash, Ksh or other SH like shells on Mac or *nix

blogLater

Mikel

PostgreSQL on Windows - Startup Errors

2008-04-16T03:16:00Z

If you are using PostgreSQL on Windows and you get: FATAL: pre-existing shared memory block is still in use Or you get: HINT: Check if there are any old server processes still running, and terminate them. errors, here is how you fix it.

What has happened is your postgres server has crashed some how, or failed to start, and now it can’t start again at all.

But you look through your task manager, and nothing is there that looks like postgres.

Well, look again, you will probably find a “drwatson” process running, owned by the postgres service account user.

Kill this task, and all will be good again.

blogLater

Mikel

Tip #6 - Validating the Domain of an Email Address with Ruby on Rails

2008-04-15T23:02:00Z

So, in the last two tips, I have shown how to check the format of the email and save the actual address only in the database. But how to check that the email domain name is valid? Easy!

When you are getting an email address from a user, sometimes it might not matter that it is not a real address (like on this blog, I don’t check).

But if you are creating an account, yeah, it matters, you want to know that the address is for the right person.

Now, the only way you can really do this is by sending them a confirmation email that they have to reply to. But, when the user is filling out the form, we should do everything we can, then and there to make sure that the address is correct, especially since we don’t want them sitting, waiting at their inbox for the email that will never come!

Luckily again, using TMail and a bit of built in ruby goodness, we can do something about it.

What we need to do in a nutshell, is take the email address, split off the domain, look up the domain, find any mail exchanger records for that domain and then if all of that passes, accept the email address as probably valid.

If any of those steps fail though, we know that the domain name is either an incorrect one, or misspelt somehow.

Anyway, enough talk, lets see the code.

First we need to set up the validation, so I am going to assume you are using the email validation from Tip #4 and so I am just going to add to it:

class User < ActiveRecord::Base

  validate :valid_email?

  def valid_email?
    begin
      domain_name = TMail::Address.parse(email).domain
      domain_valid?(domain_name)
    rescue
      errors.add(:email, "has an invalid format.")
    end
  end

end

Now, what I have added is the “addr = TMail::Address.parse(email).domain”, what does this do? Well, lets ask the console:

1234	TMail::Address.parse('Mikel A. <spam@lindsaar.net>').domain#=> "lindsaar.net"TMail::Address.parse('spam@ruby-lang.org').domain#=> "ruby-lang.org"

As you can see, it parses the email, then finds the domain name and gives it back to you as a string, very handy!

So after I did that, I make a call to “domain_valid?(domain_name)”, now, unfortunately, this isn’t built into Ruby or Rails, but it is pretty simple to set up. To do it, we need the resolv library that ships with Ruby, so, in your User class still, you can add the following method:

class User < ActiveRecord::Base

  require 'resolv'

  def domain_valid?(domain)
    Resolv::DNS.open do |dns|
      @mx = dns.getresources(domain.to_s, Resolv::DNS::Resource::IN::MX)
    end
    if @mx.empty?
      errors_add(:email, 'domain name can not be found.')
    end
  end

end

Now, this method is fairly neat.

What it does is load the resolve library, then it opens up the DNS system, and gets all the MX records for the domain name you give it. If there are MX records (which means there is a way for SMTP servers to route email to the domain name recipient) then the instance variable @mx will be an array containing each MX record object. So all we have to do is check to see if that is empty or not. If it is, we know that there are no MX records and so we add an error to the object on the email attribute that tells the user that the domain name is invalid.

So, there you go. Your user fills out the form, and you do a quick check on the domain name to see if the domain has an MX record as WELL as checking that the address itself is valid.

Now the only way a user can enter a wrong address and you accept it, is if they enter a false address, but this, you will catch with your verification email, and besides, this type of user will not be waiting for their verification email anyway, so who cares?

blogLater

Mikel

Tip #5 - Cleaning Up an Email Address with Ruby on Rails

2008-04-14T20:21:00Z

So you have an email address field on a form in Rails, but how are you going to make sure that all those users enter a sane and well formatted email address? Here is a simple fix to that problem.

If you read the previous tip then you would have setup some basic validation of the format of your email address.

One thing I didn’t tell you here is that it will also clean up any address you give it.

To show you what I mean, lets try some basics in the console:

1234	TMail::Address.parse('spam@lindsaar.net')#=> #<TMail::Address spam@lindsaar.net>TMail::Address.parse('spam@lindsaar.net').to_s#=> "spam@lindsaar.net"

OK, no surprises there, we give tmail ‘spam@lindsaar.net’ and it returns what we gave it.

But the magic comes when we enter some slightly wrong addresses. What happens if the user accidently adds some spaces:

12	TMail::Address.parse('spam @ lindsaar . net').to_s#=> "spam@lindsaar.net"

No problem, TMail sees that it is a basic mistake (though a bit contrived) and handles it.

What else can it handle? Well, lets see:

TMail::Address.parse('"mikel" <spam@lindsaar.net>').to_s
#=> "mikel <spam@lindsaar.net>"
TMail::Address.parse('<spam@lindsaar.net>').to_s
#=> "spam@lindsaar.net"
TMail::Address.parse('Mikel A. <spam@lindsaar.net>').to_s
#=> "\"Mikel A.\" <spam@lindsaar.net>"

OK, the basics are covered.

But, what is nice is that you can choose just to save the email address itself in your database, without the phrase at the front (that is the bit that the owner of the address can put in quotes). You can do this like so:

12	TMail::Address.parse('Mikel A. <spam@lindsaar.net>').spec=> "spam@lindsaar.net"

So in your model, you can make a write attribute filter on the “email” attribute of the class you are working on and do something like this:

class User < ActiveRecord::Base
  def email=(address)
    write_attribute(:email, TMail::Address.parse(address).spec)
  end
end

Which means the only thing saved in your model will be the actual email address in a known and standard format.

Now, the only problem with this is that when you send an email to your user, you want to put the phrase (the bit at the front with the name) back into the email, that way it shows up as more of a personalized email in their inbox. To do this is quite easy, just whack this in your model (assuming you have a first_name and last_name attribute for your user model):

class User < ActiveRecord::Base
  def email
    phrase = %("#{first_name} #{last_name}")
    address = read_attribute(:email)
    "#{phrase} <#{address}>"
  end
end

Now you will always get ‘FirstName LastName <email@domain.com>’ as the address whenever you ask for the email of the person.

Nice hey?

Next tip, validating the email address by domain before saving.

blogLater

Mikel