Doing a Pixel Ping without a server

17 December 2010

Content is slippery stuff now days, everyone, and your grandma wants to know how to track it. Even more so now that content can meander all over the internet.

There are some technical hurdles to this problem. First, a classic way of keeping abreast of your stats is to use a javascript method. This works well on the source so, or on sites that you control the domain, but as content makes it’s way into the community. You can’t bring JS with you.

For this reason some people have turned to using small unobtrusive images, that allow them some insight into where there content is going. A while ago a nice piece of content tracking was released, by a fledgling news org.

There solution is great, but you need to own a server, but there is another way, and you don’t need a server. Mixpanel is a new player, there whole company is about tracking data. If you dig through there docs you can find that they offer this “pixel ping”, as apart of there API.

If I wanted to do this for say, this article I would start by signing up, and getting an account. Then you get a token. Mine is, 15de388dc6d39118b914db428a8975de, you will see what sharing this with you isn’t a bad thing in a moment. Our goal is to create a JSON string, and the base64 encode it. What I want is to track a content-view. This is incredibly inaccurate, but gives you some amount trackiness. Here is my string.

{
    "event": "content-view", 
    "properties": {
        "token": "15de388dc6d39118b914db428a8975de",
        "url": "http://alexkessinger.net/my-story"
    }
}

In python I can create something like the above

import base64
import simplejson

item = {
    'event':'content-view',
    'properties': {
        'token': '15de388dc6d39118b914db428a8975de',
        'url': 'http://alexkessinger.net/my-story'
}

data = base64.b64encode(simplejson.dumps(item))
url = 'http://api.mixpanel.com/track/?data='
url = url + data
url = url + "&img=1"
print url 
>>> http://api.mixpanel.com/track/?data=eyJldmVudCI6ICJjb250ZW50LXZpZXciLCAicHJvcGVydGllcyI6IHsidXJsIjogImh0dHA6Ly9hbGV4a2Vzc2luZ2VyLm5ldC9teS1zdG9yeSIsICJ0b2tlbiI6ICIxNWRlMzg4ZGM2ZDM5MTE4YjkxNGRiNDI4YTg5NzVkZSJ9fQ==&img=1

Now I can take that url and embed it in an image tag

<img src="http://..." width=1 height=1 >

And if I embed that into this article I can know how many times it’s been viewed, although not necessarily read.

The other thing to keep in mind is that just because it looks like gobbeldy gook doesn’t mean it’s secure. People just have to base64 decode to see the string, so it shouldn’t be counted upon. While if Mixpanel did want to get serious they could do some form of encrypting with a private shared secret and make it harder to tell what data was being sent.