How we used Node.js to build real-time award flight search

http://blog.milewise.com/post/8792373531/how-we-used-node

by nmeyer • 15 years ago

85 38 15 years ago

blog.milewise.com

dcaylor2• 15 years ago

Great use case for Node.js.

sausagefeet6• 15 years ago

Great use case for Twisted, Erlang, Ocaml/Lwt, Lua, Python/Gevent too.

IsaacSchlueter4• 15 years ago

Great point! I bet that now thanks to your razor wit, dcaylor will think twice before saying something nice about node without also saying something nice about every other programming platform.

retube• 15 years ago

I have to sign up to search? Is this in production yet?

ftartaggia• 15 years ago

Could you describe the difficulties you encountered with Tornado and asynchronous Python code?

vinayp2• 15 years ago

Don't want to turn this into a Node.js/Python flame war (we love Python as well here at MileWise), but regarding asynchronous Python code:

It's more just an annoyance of the language. Specifically, anonymous functions are must easier in JavaScript, so it was just easier to write read and write maintainable code.

In Python, you are limited to only passing in simple lambda functions (although deferreds do get around this issue somewhat). It's not a show stopper but when combined with all the other advantages of Node.js, it just made the decision to switch a lot easier.

We also ran into a lot of issues related to poor garbage collection in Python and were using up a lot of memory. This was not related to dangling references but rather Python's permanent allocation of Integer and Float objects.

Finally, we just saw better performance out of V8 than Python (although we never tried anything else besides vanilla Python 2.6).

For our specific problem, Node.js worked well. It's not always the right solution. We will write a more detailed blog post soon with specifics of how we used Node.

ljlolel• 15 years ago

>> It's more just an annoyance of the language. Specifically, anonymous functions are must easier in JavaScript, so it was just easier to write read and write maintainable code.

That's pretty specious. You can easily write a function defined inside a function that you can pass by just naming it. "Anonymous" functions are just syntactic sugar. Furthermore, writing a new python named function is easier (fewer chars) to write than a javascript anonymous function, so the "sugar" gained is moot.

Finally, as you build more and bigger systems, you realize that those multi-line anonymous functions you had you actually want to be named (for documentation) and tested. So you'll end up de-anonymizing the complex (multi-line) ones anyway.

As for speed, why not compare a jit (v8) to a jit (pypy) ?

sausagefeet6• 15 years ago

While it doesn't help you for the other issues you mentioned, I have found defer.namedCallbacks to make Twisted code much simpler to read.

danecjensen• 15 years ago

hey nmeyer im interested in building some similar stuff could you email me at danecjensen@gmail.com so we can talk more. Thanks.

nmeyer5• 15 years ago

Awesome. Emailed!

unshift• 15 years ago

they'd do much better with twisted (python) than tornado. using Deferreds is nothing like opening keys with a beer bottle -- it makes a lot of sense.

and as a former ITA Software employee, i can scoff and say they aren't actually doing anything resembling flight search. they're just scraping websites and APIs. node.js might be fine for that, but so is anything else. at that level it's more a matter of preference than capability.

IsaacSchlueter4• 15 years ago

There are deferreds in node as well.

sausagefeet6• 15 years ago

They aren't part of the core API like they are in Twisted, is this correct?

fnl• 15 years ago

Nicely done! Just, the "How" in the title is misleading... ;)

justinsb2• 15 years ago

So does milewise scrape the airline sites for award travel? Does it also integrate with ITA or similar?

I ask because (1) the airline websites tend to be _really_ slow and (2) they tend not to find the cheapest/best flights - an ITA search can often beat them.

nmeyer5• 15 years ago

We actually do both, and then spent a few cycles de-duping etc.

1) Part of our reason for using Node+Socket.IO is to deal with the problem of having a bunch of different sources returning data over a wide spread of time.

2) You'd be surprised about the airline sites. While they don't necessarily have the widest variety of good fares, airline will often reserve their cheapest fares for their own sites (called Last Seat Availability).

justinsb2• 15 years ago

Thanks ... looks like it's time to sign up for MileWise!

blakeperdue• 15 years ago

Not related to Node, but your homepage is really well designed. Attractive, simple and clean. Nice.

nmeyer5• 15 years ago

Sacha Greif did our homepage. (http://www.sachagreif.com/)

He's awesome, super talented and incredibly fun to work with.

sgdesign• 15 years ago

Thanks Nick! You guys are great to work to as well, glad you appreciate the result :)

sgrove• 15 years ago

I've had the pleasure to work with him as well - I'd definitely second all of those points!

apaprocki3• 15 years ago

One comment: I typed in an email/password and right away it is asking me for my airline credentials but it isn't explaining what it is that the site wants to do with them or if it will store my info and collect information from now on. I'm curious about the site, but I thought twice about entering my info and skipped it. Just saying you might want to explain what it is you are doing to make people more comfortable.

EDIT: This information does seem to be covered in the FAQ, but you don't see the link to the FAQ anywhere when you are trying to capture user accounts on initial signup: https://secured.milewise.com/faq

nmeyer5• 15 years ago

Great feedback - we weren't sure whether at this point people would have a clear idea from the homepage of what we were doing w/ the info and they'd just want to get on with things, or if they'd want more contextual explanation.

This is definitely an area for metrics and user testing, but probably better for us to err on the side of caution =)

apaprocki3• 15 years ago

I mean, I'd like to think you were going to provide me some great service.. but then that means I could register a domain name and put up a slick looking homepage and start collecting passwords :)

Just a side note, but do you use some other collection API such as Yodlee or are you maintaining your own data scrapers for all the airline sites?

jscheel• 15 years ago

Gah, right after I finish a site requiring me to write my own node soap interface, you guys come and release yours ;) Thanks for contributing back!

vinayp2• 15 years ago

:) Would still love to see your implementation though. Ours only covers a subset of the spec so lots of room for improvement...

chefsurfing• 15 years ago

This is a killer product and very useful for people who travel often. Way to go! Also, thanks for sharing your code. You all seem like a class act.

sausagefeet6• 15 years ago

Can you go into more detail about how js on front and back helped? What percent of your codebase is actually shared? What type of functions are they? Many people claim that it's a big win while others call shenanigans but I haven't heard empirical data from anyone.

How we used Node.js to build real-time award flight search

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