Ramblings on code, startups, and everything in between

As far as type systems go, PHPs is pretty schizophrenic. You’ve got primitive types, like strings and booleans, the ubiquitous “array” type, and then user defined classes. Most of the time, the type system is invisible since it barely enforces anything. Especially for basic types and the standard library, you can almost always use strings, booleans, and integers interchangeably without much complaining from the interpreter. Where things go sideways is when you start using user defined types, especially with type hinting.

Imagine we’ve got the following setup:

If you run that in a terminal, PHP will throw the following error:

PHP Catchable fatal error: Argument 1 passed to sayHello() must be an instance of Dog, instance of Pet given, called in /home/ashish/Downloads/dog.php on line 19 and defined in /home/ashish/Downloads/dog.php on line 14

Because even though every “Dog” is by definition a superset of the “Pet” class, PHP doesn’t see it that way. And now, our original problem. In most other object oriented languages, you’d be able to simply typecast the instance of Pet to a Dog and then call the function as expected. Unfortunately, PHP doesn’t natively support typecasting so we’re stuck looking for a crazy workaround. Enter Reflection. PHPs reflection library lets you do all sorts of nefarious things, like manipulating private properties and retrieving the source for an arbitrary object.

So how do you use it to do a bootleg typecast? It’s actually pretty straightforward:

The “copyShimmedObject” is the money maker. It basically pulls the private properties out of the “from”, makes the property public, and then sets them on the “to” object. If you run the sample you’ll get the expected output instead of the error above:

Hello: Fluffy of destroyer of worlds

Posted In: PHP, Tips n' Tricks


I was building out an API test console a few days ago and realized I’d never actually looked into how to grab all available routes in Symfony2. The “console” is basically a form with a select box and textarea that lets you “ping” the REST API routes in one of our applications. To make this work, I wanted to traverse all the registered routes, filter for the ones that contained “api_”, and then generate dummy URLs for those routes.

I searched around a bit for how to grab all the registered routes and the only link seems to be Unfortunately, if you try and use the code you’ll discover that “getPattern” no longer exists in the CompiledRoute class. It looks like it’s been replaced by getPathVariables

So, working code to generate a list of route names and “dummy” URLs for you API routes ends up looking like:

Posted In: PHP, Symfony

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I was catching up with a friend of mine recently and she was asking what I “wanted” to build. As we started talking about it, I realized I didn’t really have a “go to” list of what I’d love to try building. At this point, web apps have become a bit boring, I mean how many times can you really write:

Inspired by Y Combinator’s Startup Ideas We’d Like to Fund and more recently Spotify‚Äôs Design Lead on Why Side Projects Should Be Stupid here’s a list of projects we’d love to build.

Bitcoin Hardware Integration

Inspired by Bitcoin: How would you build a parlor game?, I think it would be awesome to build some sort of hardware Bitcoin integration. Any interesting angle would be to take something familiar like a casino game, jukebox, or vending machine and then make it “Bitcoin powered”. Also, with the MIT Bitcoin airdrop in the Fall it seems like Central Square and Kendall Square are the perfect places to roll something like this out.

Real Time Stream Processing

From NodeJS to Websockets, “real time” seems to be all the rage but most applications aren’t really dealing with processing streaming data at scale. Processing data streams, even at moderate scale, seems like it would be a fun challenge and would open up the development of interesting solutions. In the last few years, projects like Apache Storm and Akka have significantly lowered the barriers to development so it seems like the perfect time to jump in. We’d love to leverage these tools to analyze click streams, sensor data, or financial “tick” data.

Badass Visualizations

As the price of storage has decreased, organizations are recording and retaining more data than ever before. Unfortunately, most companies are hesitant to experiment with different visualization options and end up with a handful of charts and tables. I’d love to have the opportunity to really take d3js out for a spin and build some awesome visualizations. From visualizing multi-modal data to helping uncover patterns, I’d love to help organizations get the most out of their data.

Anyway, if anyone wants to build any of these definitely get in touch! Would also love to hear everyone else’s ideas in the comments.

Posted In: General


As has become tradition, Mary Meeker of Kleiner Perkins published her anual “Internet trends” report a couple of days ago. As always, its a great read and you should check it out here. Digging through the slides, a couple of things jumped out to me personally:

Tablets are far from dead

Over the past few months, there’s been a slew of blog posts bemoaning the death of the tablet. Arguments basically ranged from the point that tablet hardware is too immature to the fact that most people don’t have a strong table usecase. Looking at the report though, the # of shipped tablets is clearly exploding and is trending upwards. That said, the report doesn’t break out what kinds of tablets are being shipped – we’ll have to check in with Ben Evans for that.

Print media spend is heavily over indexed

If I worked in print media, slide 15 would be giving me some serious heartburn. Compared to other channels, print is receiving a disproportionate percentage of ad spend compared to how much time consumer spend consuming print media. Obvious outcome here is that advertising dollars are going to continue to shift digital, with mobile picking up the biggest chunk. The buying spree around mobile ad networks is already signalling this shift with the clear example being Twitter buying MoPub.

Music is changing

There was a flurry of attention and armchair quarterbacking around Apple’s acquisition of Beats and slide 50 highlights how music is changing. With consumers favoring streaming over purchasing, the market opportunity for “winning” music is certainly shrinking. Couple that with streaming services being available on multiple devices and the Apple/Beats deal looks even stranger. In any case, the future will definitely be streamed.

The battle for the living room is heating up

Looks like the hotly anticipated “battle for the living room” is heating up. With the proliferation of set top boxes like the Roku and AmazonTV along with release of next gen game consoles, consumers are changing how they consume traditional TV. Coupled with “apps” like HBO Go, there are fewer reasons to avoid “cutting the cord” and abandoning traditional cable TV service. Obviously the content owners still hold the keys but as Netflix proved with House of Cards, making awesome TV as an outsider isn’t impossible.

Anyway, as always would love any thoughts or comments!

Posted In: General


Last weekend, the boys and I were at a bar and we started playing on one of those “parlor game” machines. If you’re unfamiliar, they’re basically a computer with a touch screen in a glorified case. They’re loaded up with dozens of games like “spot the difference”, traditional casino games, and of course X-rated versions of everything. As we were burning cash playing, we started thinking out loud that the game would be “cooler” if you could actually win money back. Games like this do exist in Vegas but they’re consequently heavily regulated by gambling related laws. As we were discussing this, someone mentioned building the game using Bitcoin in hopes of skirting gambling regulations. So, how could you go about building a real world game using Bitcoin for payments?


The natural choice here would be to run with a WiFi enabled RaspberryPi along with a capacitive touchscreen. I’ve never done any work with touchscreens but it looks like TigerDirect has 22″ Planar ones for under $300. Couple that with a WiFi RaspberryPi kit for $50 and we should be in business for <$500. You could obviously grab a smaller screen but go big or go home right?


Now things get interesting. Philosophically, I think you do want to enforce authentication so that users can save scores, carry a BTC balance, and generally make the experience “stickier”. The straightforward approach would be to offer a traditional sign up using an email address and password but that would totally sacrifice leveraging social media. Allowing users to easily “sign in” with Twitter or Facebook would allow you leverage their social graphs to find their friends and drive awareness of the game. An issue I’ve run into in the past is that “kiosks” always ask you to enter you Facebook or Twitter credentials directly on the kiosk – which is a non-starter for most people.

So how can we avoid this? The big idea is that you really just need the user’s OAuth tokens for whatever service they want to use – not their credentials. To do this, you’d need to either distribute an app or have a website where the user could “sign in” while already logged in on Facebook or Twitter on their mobile phone. Then, you’d be able to capture their OAuth tokens and log them in to the kiosk.

Getting the Bitcoin

Ok, so the user is logged in, now we need to get them some Bitcoin to play with. I think what you’d want to do is generate a wallet for each authenticated user and let them transfer in to an address as need be. So since their account is unfunded, they’d be presented with a QR code for an address that they can use to fund it. Another interesting idea would be to let users buy BTC in cash from the bartender which would in turn automatically fund their account. To support this, you’d need an app or website where the bartender could transfer BTC into the user’s wallet after receiving cash on site.

In terms of software to facilitate this, it seems like bitcoinj would be the best option. Written in Java, bitcoinj is a “client node only” implementation of the Bitcoin protocol that allows it to run without a full local copy of the Blockchain. Because of this, bitcoinj will run in resource constrained environments like the RaspberryPi. In addition, bitcoinj supports “simplified payment verification” so you’d be able to clear transactions instantly without waiting for confirmations to settle.

The Games

Graphically and conceptually, the games are all pretty straightforward so your best bet is probably implementing with JavaScript with HTML and CSS. The benefits would be you’re development cycles would be short and you’d be able to develop the games independently of the device itself. With HTML5 hitting it’s stride, you’d also be able to enable “multiplayer” versions using WebSockets.

One interesting consideration is that without being able to definitely vouch for the physical security of the kiosk how can you verify that the running code is authentic?

Sending the Bitcoin

The final step in the dance (and what makes it special) is allowing the user to cash BTC out of their account. I think you’d want to offer the option of allowing the use to generate a “send to” address if they have a mobile wallet and also allow them to cash out in person. If they can generate a “send to” address, they’d have to use the kiosk to scan a QR code where their BTC balance would get sent. To facilitate this, you’d need a webcam attached to the RaspberryPi and then use something like ZXing to decode the data in the QR code.

For the “in-person” option, you’d need to build out functionality to allow the bartender to initiate a transfer from the user’s wallet back to the bar from the web or mobile app. After it settles, they’d simply hand the user back some cash and the account would be settled.

Is this legal?

Therein lays the rub. It probably is but I’m not 100% sure. Eliminating the option to exchange BTC for cash might help the case for legality. Along with that, if you can side step “making odds” as well it might help your case. Would love any thoughts on this!

Posted In: General

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