Groovy HTTP Builder- fetching JSON data over post and supply parameters

Right now I'm playing around with the MtGox api to issue online transactions to buy and sell bitcoins. Yes I'm still obsessed with these and don't think this is going to change anytime soon, since It's starting to actually generate money.

But the big pain right now is that you have togo to so many different websites todo a simple transaction and I really want to have this all combined in one single tool.

So the api exspects from you to be queried over post arguments and the first thing which came to my mind was to use the fantastic HttpBuilder in groovy.

so let's define a simple method to simplify life a bit for us


private executeQuery(Map parameter, String path) {

def http = new HTTPBuilder("https://mtgox.com/")

def result = ""
http.post(body: parameter, path: path, requestContentType: URLENC) { resp, json ->

if (resp.statusLine.statusCode == 200) {
result = json
}
else {
result = false
}

}

return result


and a second method to actually call this


def getCurrentBalance() {

if (MtGoxAccessHandler.isConfigured()) {
def values = executeQuery([

name: MtGoxAccessHandler.getUserName(),
pass: MtGoxAccessHandler.getPassword()],
"/code/getFunds.php")

return [usd: values.usds, coins: values.btcs]
}
else {
return false
}
}



The class MtGoxAccessHandler is just a little helper, which stores the username and password and allows me to simplify the code a bit and easy testing.

This post is also related to the google code project DeepBitView

JSON and SSL in groovy, how to ignore certificates

In the last couple of days I became more and more interested in bitmining and the first thing I noticed was the utter lack of integrated tools and hence statistics I would like to associated with my miners.

This resulted in me creating a tiny grails application to synchronzie my deepbit statistics with the current market data from mtgox to calculate at which point it becomes pointless to mine these thing. I basically hope that this pays for the 700$ for my 2x6950 radeons and associated cooling the 100+F heat we have here in California.

Now originally you could assume that this is rather straightforward. After all you got json data, which just need to be parsed.


Map jsonArray = JSON.parse(new InputStreamReader(new URL("https://mtgox.com/code/data/ticker.php").openStream()))

println jsonArray



but sadly the java ssl security manager does not agree here with us and tosses a fit..



javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:174)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1649)



Now java is kinda smart, if want's to force you install a security certificate from the server you access and authorize yourself. But sometimes you don't want this. In this case it's overkill, since we are having a readonly transaction.

So what has to be done?

you need to create your own security manager implementation. Which basically is a 3 step procedure

1. implement an interface
   

class TrustManager implements X509TrustManager {

public java.security.cert.X509Certificate[] getAcceptedIssuers() {
return null;
}

public void checkClientTrusted(
java.security.cert.X509Certificate[] certs, String authType) {
}

public void checkServerTrusted(
java.security.cert.X509Certificate[] certs, String authType) {
}

}


   
   
   
2. register the interface and update the context configuration
   
TrustManager[] trustAllCerts = new TrustManager[1]

trustAllCerts[0] = new TrustManager()
try {
SSLContext sc = SSLContext.getInstance("SSL");
sc.init(null, trustAllCerts, new java.security.SecureRandom());
HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
} catch (Exception e) {
}

   
3. and continue like always with your json script
   
Map jsonArray = JSON.parse(new InputStreamReader(new URL("https://mtgox.com/code/data/ticker.php").openStream()))




and the result should be now the current ticker for the USD to BitCoin exchange rate.


{"ticker":{"high":15.4989,"low":13.31415,"avg":14.726503862,"vol":42862,"last":13.31415,"buy":13.331,"sell":13.35999}}