Add openexchangerates api

cmd/server/convert.go

@@ -79,6 +79,9 @@ var Convert = func(w http.ResponseWriter, r *http.Request) {
 			case `themoneyconverter`:
 				e = ex.NewTheMoneyConverterApi(opt)
 				break
+			case `openexchangerates`:
+				e = ex.NewOpenExchangeRatesApi(opt)
+				break
 			}
 			Swap.AddExchanger(e)
 		}

pkg/exchanger/openexchangerates.go

@@ -1,3 +1,128 @@
 package exchanger
 
-//todo
+import (
+	"fmt"
+	"github.com/bitly/go-simplejson"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"time"
+)
+
+type openExchangeRatesApi struct {
+	attributes
+}
+
+var (
+	openExchangeRatesApiUrl     = `https://openexchangerates.org/api/convert/1/%s/%s?app_id=%s`
+	openExchangeRatesApiHeaders = map[string][]string{
+		`Accept`:          {`text/html,application/xhtml+xml,application/xml,application/json`},
+		`Accept-Encoding`: {`text`},
+	}
+)
+
+func (c *openExchangeRatesApi) requestRate(from string, to string, opt ...interface{}) (*openExchangeRatesApi, error) {
+
+	// todo add option opt to add more headers or client configurations
+	// free mem-leak
+	// optimize for memory leak
+	// todo optimize curl connection
+
+	url := fmt.Sprintf(openExchangeRatesApiUrl, c.apiKey, from, to)
+	req, _ := http.NewRequest("GET", url, nil)
+
+	openExchangeRatesApiHeaders[`User-Agent`] = []string{c.userAgent}
+	req.Header = openExchangeRatesApiHeaders
+
+	res, err := c.Client.Do(req)
+
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	body, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	// free mem-leak
+	// todo discard data
+	c.responseBody = string(body)
+	return c, nil
+}
+
+func (c *openExchangeRatesApi) GetValue() float64 {
+	return c.rateValue
+}
+
+func (c *openExchangeRatesApi) GetDateTime() string {
+	return c.rateDate.Format(time.RFC3339)
+}
+
+func (c *openExchangeRatesApi) GetExchangerName() string {
+	return c.name
+}
+
+func (c *openExchangeRatesApi) Latest(from string, to string, opt ...interface{}) error {
+
+	_, err := c.requestRate(from, to, opt)
+	if err != nil {
+		log.Print(err)
+		return err
+	}
+
+	// if from currency is same as converted currency return value of 1
+	if from == to {
+		c.rateValue = 1
+		return nil
+	}
+
+	json, err := simplejson.NewJson([]byte(c.responseBody))
+
+	if err != nil {
+		log.Print(err)
+		return err
+	}
+
+	// opening price
+	value := json.GetPath(`response`).
+		MustFloat64()
+	// todo handle error
+	c.rateValue = value
+	c.rateDate = time.Now()
+	return nil
+}
+
+func NewOpenExchangeRatesApi(opt map[string]string) *openExchangeRatesApi {
+	keepAliveTimeout := 600 * time.Second
+	timeout := 5 * time.Second
+	defaultTransport := &http.Transport{
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: keepAliveTimeout,
+			DualStack: true,
+		}).DialContext,
+		MaxIdleConns:        100,
+		MaxIdleConnsPerHost: 100,
+	}
+
+	client := &http.Client{
+		Transport: defaultTransport,
+		Timeout:   timeout,
+	}
+
+	attr := attributes{
+		name:      `openexchangerates`,
+		Client:    client,
+		apiKey:    opt[`apiKey`],
+		userAgent: `Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:21.0) Gecko/20100101 Firefox/21.0`,
+	}
+	if opt[`userAgent`] != "" {
+		attr.userAgent = opt[`userAgent`]
+	}
+
+	r := &openExchangeRatesApi{attr}
+	return r
+}

pkg/exchanger/openexchangerates_test.go

@@ -1,3 +1,20 @@
 package exchanger
 
-//todo
+import (
+	"github.com/me-io/go-swap/test/staticMock"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestOpenExchangeRatesApi_Latest(t *testing.T) {
+	rate := NewOpenExchangeRatesApi(nil)
+	assert.Equal(t, rate.name, `openexchangerates`)
+
+	rate.Client.Transport = staticMock.NewTestMT()
+
+	rate.Latest(`EUR`, `EUR`)
+	assert.Equal(t, float64(1), rate.GetValue())
+
+	rate.Latest(`USD`, `AED`)
+	assert.Equal(t, float64(3.6571), rate.GetValue())
+}

test/staticMock/openexchangerates_json_aed_usd.json

@@ -0,0 +1,15 @@
+{
+  "disclaimer": "https://openexchangerates.org/terms/",
+  "license": "https://openexchangerates.org/license/",
+  "request": {
+    "query": "/convert/1/USD/AED",
+    "amount": 1,
+    "from": "USD",
+    "to": "AED"
+  },
+  "meta": {
+    "timestamp": 1449885661,
+    "rate": 3.6571
+  },
+  "response": 3.6571
+}

test/staticMock/transport.go

@@ -63,6 +63,11 @@ func (t *mT) RoundTrip(req *http.Request) (*http.Response, error) {
 		fc, _ := ioutil.ReadFile(fp)
 		responseBody = string(fc)
 		break
+	case host == `openexchangerates.org`:
+		fp, _ := filepath.Abs(tPath + `/openexchangerates_json_aed_usd.json`)
+		fc, _ := ioutil.ReadFile(fp)
+		responseBody = string(fc)
+		break
 	default:
 
 	}