tacitus/http/trade_handler.go

package http

import (
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"github.com/kcotugno/tacitus"
)

type TradeHandler struct {
	TradeService tacitus.TradeService

	logger tacitus.Logger
}

type tradesResponse struct {
	Trades []tacitus.Trade `json:"trades,omitempty"`
	Error  string          `json:"error,omitempty"`
}

func (t *TradeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	paths := strings.Split(r.URL.Path, "/")

	if len(paths) < 3 || !tacitus.ValidProduct(paths[3]) {
		errorResp(w, tacitus.Error("Invalid product"))
		return
	}

	params := r.URL.Query()
	params.Set("product", paths[3])

	switch r.Method {
	case "GET":
		t.getTrades(w, params)
	default:
		errorResp(w, tacitus.Error("Invalid request"))
	}
}

func (t *TradeHandler) getTrades(w http.ResponseWriter, params url.Values) {
	var trades []tacitus.Trade
	var err error
	limit := parseLimit(params.Get("limit"))
	prod := params.Get("product")
	after, _ := strconv.ParseInt(params.Get("after"), 10, 0)
	before, _ := strconv.ParseInt(params.Get("before"), 10, 0)

	if params.Get("after") != "" {
		trades, err = t.TradeService.TradesAfter(prod, int(after), limit)
	} else if params.Get("before") != "" {
		trades, err = t.TradeService.TradesBefore(prod, int(before), limit)
	} else {
		trades, err = t.TradeService.LastTrades(prod, limit)
	}

	if err == nil {
		encodeJson(w, &tradesResponse{Trades: trades})
	} else {
		errorResp(w, tacitus.Error("Invalid request"))
	}
}

func parseLimit(limit string) int {
	l, err := strconv.ParseInt(limit, 10, 0)
	if err != nil {
		l = 1000
	}

	if l > 1000 {
		l = 1000
	}

	return int(l)
}