Add Crypto prices internal API

[martinberlin]

This weekend adding PhpPlot charts for #crypto prices of

1. BTC
2. ETH
3. Litecoin

No real time, just updated hourly.

Views:
daily, hourly or minutes.

Time span: last week, last N days, last N hours

Candle type: Filled candles or hollow candles

Data source cryptodatadownload from provider Bitstamp:
http://www.cryptodatadownload.com/data/bitstamp/

Example candlesticks generated with PHPPlot from this data:

phpPlot output. Image should be returned using this

EncodeImage — Returns the plot image data

Synopsis

$plot->EncodeImage(‘raw’);

So we can output from a symfony controller . This didn't work fine, but there must be a way to use a Symfony response for this, check:
https://stackoverflow.com/questions/19236592/output-jpgraph-in-symfony-2
(ob_start -> get_contents) Otherwise the image url gives an error when being opened in the browser directly and WKHTMLToimage will not work correctly.

[martinberlin]

Implemented and deployed live. Before closing, would be nice to add:

data/symbols.json

{
  "BTCEUR": "Bitcoin/Euro",
  "ETHEUR": "Ethereum/Euro",
  "LTCEUR": "Litecoin/Euro",
  "BTCUSD": "Bitcoin/Dollar",
  "ETHUSD": "Ethereum/Dollar",
  "LTCUSD": "Litecoin/Dollar"
}

As a feed for the dropdown so more coins can be added without modifying the FormType

[martinberlin]

Live since last week