How has soundcloud hidden the URL of streaming audio

Question

I am trying to hide the URL of my audio streams for my HTML5 player and was really struggling to think of a way to do so and then I realised, soundcloud must hide the URL\'s

Answer 1

Soundcloud is pretty much a pure JS site.

As you said, there is no ID of the song loaded with the HTML. The way songs are recognized is by the page URL. The is done via. this url (example):

https://api.sndcdn.com/resolve?url=https%3A//soundcloud.com/hoodinternet/joywave-tongues-hood-internet-remix&_status_code_map%5B302%5D=200&_status_format=json&client_id=YOUR_CLIENT_ID

This returns something like this:

{"status":"302 - Found","location":"https://api.soundcloud.com/tracks/100270342?client_id=YOUR_CLIENT_ID"}

Next up it loads the location URL, from the JSON above. This returns a bunch of information about the track, including:

stream_url: "https://api.soundcloud.com/tracks/100270342/stream"

Then it loads this URL:

https://api.sndcdn.com/i1/tracks/100270342/streams?client_id=YOUR_CLIENT_IT

Which returns a response like this:

{"http_mp3_128_url":"https://ec-media.soundcloud.com/2gNVBYiZ06bU.128.mp3?ff61182e3c2ecefa438cd021sdf02d0e385713f0c1faf3b0339595664fe070de810d30a8e3a1186eda958909e9ed97799adfeceabc135efac83aee4271217a108450591db3b88\u0026AWSAccessKeyId=AKIAsdfJ4IAZE5EOIdsf7PA7VQ\u0026Expires=1374883403\u0026Signature=%2B1%2B7dfdfLN4NWP3C3bNF3gizSEVIU%3D"}

So that's how they hide their stream URL's. The only non obvious part is that they find the song ID, by hitting an API with the URL as a parameter. Same can be done with download URL's on tracks that support it.