API’s (application programming interfaces) provide methods for programs (other than web browsers) to access Internet data. Any app that access data from the web uses an API.
For example, if you copy this URL into a web browser address bar, it will return a block of data in JSON format about the most popular videos on Vine: https://api.vineapp.com/timelines/popular
HTTP requests
An HTTP request transfers data to or from a server. A web browser handles HTTP requests in the background. You can also write programs that make HTTP requests. A program called “curl” runs http requests from the terminal command line. Here are examples: https://reactivemusic.net/?p=5916
Response data
Data is usually returned in one of 3 formats:
JSON
XML
HTML
JSON is the preferred method because its easy to access the data structure.
Max HTTP requests
There are several ways to make HTTP requests in Max, but the best method is the js object: Here is the code that runs the GET request for the Vine API:
function get(url)
{
var ajaxreq = new XMLHttpRequest();
ajaxreq.open("GET", url);
ajaxreq.onreadystatechange = readystatechange;
ajaxreq.send();
}
function readystatechange()
{
var rawtext = this._getResponseKey("body");
var body = JSON.parse(rawtext);
outlet(0, body.data.records[0].videoUrl);
}
The function: get() formats and sends an HTTP request using the URL passed in with the get message from Max. When the data is returned to Max, the readystatechange() function parses it and sends the URL of the most popular Vine video out the left outlet of the js object.
Playing Internet audio/video files in Max
The qt.movie object will play videos, with the URL passed in by the read message.
Unfortunately, qt.movie sends its audio to the system, not to Max. You can use Soundflower, or a virtual audio routing app, to get the audio back into Max.
Replace the potentiometer in the “Arduino Serial Read” project with a photocell (LDR: Light dependent resistor) and a 10K pulldown resistor, wired as shown in the image above and explained here: https://learn.adafruit.com/photocells/using-a-photocell (from Adadfruit)
The “Analog” lead represents the center terminal of a potentiometer and connects to A0.
The Arduino sketch is the example sketch: Analog | analogInOutSerial
First, think of a way to get the same results without writing an external. For example, borrow other code, use javascript, gen, Processing, or MSPaint.
Apparently that didn’t work out. Well I can only get you so far.
The .mxo file will be under the Products folder. <Ctrl> click to show in finder
Copy the .mxo file into the same folder as your Max patch
What Max patch? This one:
The window on the left is inverted because its getting that way in the object we just hacked.
That’s all
I didn’t really explain anything. Sometimes going through the motions is a start. If I had to do this for a living I would find the example that is most like a desired result and hack away.
