I am tired of googling the same information over and over, so I am posting it here.
To quickly lock your screen, press Ctrl+Shift+Eject.
Also, you can press Fn+Ctrl+Eject to quickly restart your Mac, shut it down or put to sleep.
Email validation done right
Jan 11
Let’s imagine that you have to check if a string is a valid email. You could come up with something like:
/[a-zA-Z0-9\.]+@[a-z]+\.[a-z]+/
It works, right? WRONG. Sure it’ll handle a couple of your test examples. But it’s not ready for real world usage. Here’s a standards compliant Perl regex.
/(?(DEFINE) (?<address> (?&mailbox) | (?&group)) (?<mailbox> (?&name_addr) | (?&addr_spec)) (?<name_addr> (?&display_name)? (?&angle_addr)) (?<angle_addr> (?&CFWS)? < (?&addr_spec) > (?&CFWS)?) (?<group> (?&display_name) : (?:(?&mailbox_list) | (?&CFWS))? ; (?&CFWS)?) (?<display_name> (?&phrase)) (?<mailbox_list> (?&mailbox) (?: , (?&mailbox))*) (?<addr_spec> (?&local_part) \@ (?&domain)) (?<local_part> (?&dot_atom) | (?"ed_string)) (?<domain> (?&dot_atom) | (?&domain_literal)) (?<domain_literal> (?&CFWS)? \[ (?: (?&FWS)? (?&dcontent))* (?&FWS)? \] (?&CFWS)?) (?<dcontent> (?&dtext) | (?"ed_pair)) (?<dtext> (?&NO_WS_CTL) | [\x21-\x5a\x5e-\x7e]) (?<atext> (?&ALPHA) | (?&DIGIT) | [!#\$%&'*+-/=?^_`{|}~]) (?<atom> (?&CFWS)? (?&atext)+ (?&CFWS)?) (?<dot_atom> (?&CFWS)? (?&dot_atom_text) (?&CFWS)?) (?<dot_atom_text> (?&atext)+ (?: \. (?&atext)+)*) (?<text> [\x01-\x09\x0b\x0c\x0e-\x7f]) (?<quoted_pair> \\ (?&text)) (?<qtext> (?&NO_WS_CTL) | [\x21\x23-\x5b\x5d-\x7e]) (?<qcontent> (?&qtext) | (?"ed_pair)) (?<quoted_string> (?&CFWS)? (?&DQUOTE) (?:(?&FWS)? (?&qcontent))* (?&FWS)? (?&DQUOTE) (?&CFWS)?) (?<word> (?&atom) | (?"ed_string)) (?<phrase> (?&word)+) # Folding white space (?<FWS> (?: (?&WSP)* (?&CRLF))? (?&WSP)+) (?<ctext> (?&NO_WS_CTL) | [\x21-\x27\x2a-\x5b\x5d-\x7e]) (?<ccontent> (?&ctext) | (?"ed_pair) | (?&comment)) (?<comment> \( (?: (?&FWS)? (?&ccontent))* (?&FWS)? \) ) (?<CFWS> (?: (?&FWS)? (?&comment))* (?: (?:(?&FWS)? (?&comment)) | (?&FWS))) # No whitespace control (?<NO_WS_CTL> [\x01-\x08\x0b\x0c\x0e-\x1f\x7f]) (?<ALPHA> [A-Za-z]) (?<DIGIT> [0-9]) (?<CRLF> \x0d \x0a) (?<DQUOTE> ") (?<WSP> [\x20\x09]) ) (?&address)/x
I couldn’t even imagine that the matter is *this* complex.
jQuery chaining
Aug 24
I am beginning to fall in love with jQuery. Screw you, bicycle inventors! :-)
function next_step() { // note how elegant and self-explanatory this code is. var cl = 'step_selected'; $('.' + cl).removeClass(cl).next().addClass(cl); // Also look at previous version of the code, // before I remembered about chaining methods. // var li = $('.step_selected'); // li.removeClass('step_selected'); // li.next().addClass('step_selected'); // Not as sexy, right? :-) }
Funny side benefit :-)
Aug 22
There I was, minding my own business, trying to solve problems in graph theory and I accidentally made a Sudoku puzzle solver! Isn’t it funny how life turns out sometimes? But that’s just how awesome LINQ is.
Atomic updates, part 2
Jun 2
Let’s review another common scenario: posts and votes. Mongo’s approach would be to store vote count in the post itself (caching) and keep voters also in the post, in an array field. Let’s assume we want to register a new vote on post. This operation consists of three steps:
1. ensure that the voter hasn’t voted yet, and, if not,
2. increment the number of votes and
3. add the new voter to the array.MongoDB’s query and update features allows us to perform all three actions in a single operation. Here’s what that would look like from the shell:
// Assume that story_id and user_id represent real story and user ids. db.stories.update({_id: story_id, voters: {'$ne': user_id}}, {'$inc': {votes: 1}, '$push': {voters: user_id}});What this says is “get me a story with the given id whose voters array does not contain the given user id and, if you find such a story, perform two atomic updates: first, increment votes by 1 and then push the user id onto the voters array.”
This operation highly efficient; it’s also reliable. The one caveat is that, because update operations are “fire and forget,” you won’t get a response from the server. But in most cases, this should be a non-issue.
quote from MongoDB site.
How would you implement this in your regular SQL database?
I am starting to learn this new piece of technology, the MongoDB. It has many sweet features. However, using Ruby driver directly is not too comfortable. Plus we’re all hooked to ORM sweeteners. So people started developing ORM libraries for MongoDB and Ruby (MongoId, MongoMapper to name a few).
I have decided to try MongoId first. It seems to be a quite good library. However, it still has gaps in documentation. Today I was finding out how to perform an atomic increment of a field. In SQL world this would look like:
UPDATE users SET spam_count = spam_count + 1;
Mongo Ruby driver supports this kind of operation, but MongoId doesn’t. So I was trying to get down to the driver. And this is what I couldn’t easily find in the docs. If you’re like me, I’ll save you a couple of hours. Here it is:
# assume we know object id already User.collection.update({'_id' => '4c05848e45760182b5000001'}, {'$inc' => {'spam_count' => 1}})
Intuitive behaviour
May 18
Today I was looking at exception stack trace. One of suspicious places was ‘…\reports_controller.rb:129″. Okay, navigating to this location using RubyMine is a piece of cake. Ctrl+Shift+N to get to reports_controller.rb, then Ctrl+G to position caret at specified line. But hey, that’s two actions. I hit Ctrl+Shift+N, put ‘reports_controller.rb:129′ in and voila! It worked just as I expected!
RubyMine: +1 to intuitivity, +1 to overall impression.
Today I was quite amazed by one of Ruby features. It is about default values of method parameters. For example you can do something like this:
def get_current_actions(project_id, status_id = params[:status_id] || DEFAULT_STATUS_ID) # implementation goes here end
The code is saying basically this: “if status_id is not passed explicitly, try to take its value from params array. If it doesn’t contain specified key, then fall back to a constant”. This feature (as almost all the rest of Ruby magic) made avaiable by Ruby’s nature: it is interpreted language. This type of code is totally unusual to guys like me, who come from the world of static typing and compiled languages. But I think I’m gonna get used to it :-)
Iterations are good
Mar 4
Iterations in software development. Tried to implement proper solution on the first try? I bet you failed. It’s like in Google Earth zooming in your house from the planet view. To achieve your goal, you’ve got to advance a little bit, adjust your position, advance further… Iterate until done.
Making more mockups
Mar 3
Today Elen, my manager, approached me and asked to make a prototype of a new functionality in our project management system. This is a reimbursement management module: employees spend some money (taxi from airport, for example), then they create requests for reimbursements and if they are lucky and management approves the requests, they get the money back :-)
So, prototype it is. Read the rest of this entry »