public ApiModule()
{
// CORS
After.AddItemToEndOfPipeline((ctx) => ctx.Response
.WithHeader("Access-Control-Allow-Origin", "*")
.WithHeader("Access-Control-Allow-Methods", "POST,GET")
.WithHeader("Access-Control-Allow-Headers", "Accept, Origin, Content-type"));
Get("/classify", ctx =>
{
var req = this.Bind <ClassifyRequest>();
if (req.Month == null || req.Day == null || req.DayOfWeek == null ||
req.Airline == null || req.Airport == null)
{
return("{\"error\": \"must provide all parameters\"}");
}
// build example based on params
var example = new Example("");
example.AddAttribute(Attrs.Month, int.Parse(req.Month));
example.AddAttribute(Attrs.Day, int.Parse(req.Day));
example.AddAttribute(Attrs.DayOfWeek, int.Parse(req.DayOfWeek));
example.AddAttribute(Attrs.Airline, req.Airline);
example.AddAttribute(Attrs.Airport, req.Airport);
var result = WebServer.Tree.Classify(example);
var value = result.classification.ToLower();
var ratio = result.randomnessRatio;
return("{\"classification\": " + value + ", \"randomnessRatio\": " + ratio + "}");
});
}
private static DecisionTree.DecisionTree CreateTree(string connStr, int limit)
{
MySqlConnection connection;
try
{
connection = new MySqlConnection(connStr);
connection.Open();
MySqlCommand cmd;
MySqlDataReader reader;
String listStr = null;
int maxId = -1;
{
cmd = new MySqlCommand();
cmd.Connection = connection;
cmd.CommandText = "SELECT MAX(id) FROM flights";
cmd.CommandTimeout = int.MaxValue;
cmd.Prepare();
reader = cmd.ExecuteReader();
while (reader.Read())
{
maxId = reader.GetInt32(0);
}
reader.Close();
}
if (limit > -1)
{
Random rand = new Random();
var listStrBuilder = new StringBuilder("(");
Console.WriteLine("Creating list string...");
for (int i = 0; i < limit; i++)
{
int id = rand.Next(maxId) + 1;
listStrBuilder.Append(id);
if (i != limit - 1)
{
listStrBuilder.Append(",");
}
}
listStrBuilder.Append(")");
listStr = listStrBuilder.ToString();
}
Console.WriteLine("Querying flights...");
cmd = new MySqlCommand();
cmd.Connection = connection;
cmd.CommandText = "SELECT * FROM flights";
if (listStr != null)
{
cmd.CommandText += " WHERE ID in " + listStr;
}
cmd.CommandTimeout = int.MaxValue;
cmd.Prepare();
Stopwatch watch = new Stopwatch();
watch.Start();
List <Example> trainingSet = new List <Example>();
Console.WriteLine("Retrieving data set...");
reader = cmd.ExecuteReader();
while (reader.Read())
{
var delay = reader.GetInt32("DEPARTURE_DELAY");
// it is considered delayed if it leaves more than 5 mins
// after scheduled departure time
var isDelayed = delay > 5;
// construct the example with the classification as
// "true" or "false" depending on if it was delayed
var example = new Example(isDelayed + "");
// fetch attributes
var month = reader.GetInt32("MONTH");
var day = reader.GetInt32("DAY");
var dayOfWeek = reader.GetInt32("DAY_OF_WEEK");
var airline = reader.GetString("AIRLINE");
var airport = reader.GetString("ORIGIN_AIRPORT");
// add attributes
example.AddAttribute(Attrs.Month, month);
example.AddAttribute(Attrs.Day, day);
example.AddAttribute(Attrs.DayOfWeek, dayOfWeek);
example.AddAttribute(Attrs.Airline, airline);
example.AddAttribute(Attrs.Airport, airport);
trainingSet.Add(example);
}
//
// Console.WriteLine("Selecting " + limit + " random entries from data set...");
// Random rand = new Random();
//
// var filteredSet = new List<Example>();
//
// while (filteredSet.Count < limit)
// {
// int index = rand.Next(trainingSet.Count);
// filteredSet.Add(trainingSet[index]);
// trainingSet.RemoveAt(index);
// }
//
// // discard the data
// trainingSet.Clear();
Console.WriteLine("Building decision tree...");
var tree = new DecisionTree.DecisionTree();
tree.BuildTree(trainingSet);
Console.WriteLine("Done.");
Console.Write("Elapsed Time (ms): ");
Console.WriteLine(watch.ElapsedMilliseconds);
return(tree);
}
catch (MySqlException ex)
{
Console.WriteLine(ex.ToString());
return(null);
}
}
