add cryptocompare API bindings

Signed-off-by: Xe Iaso <me@xeiaso.net>

1 files changed, 44 insertions, 0 deletions

diff --git a/web/cryptocompare/cryptocompare.go b/web/cryptocompare/cryptocompare.go
new file mode 100644
index 0000000..6886f77
--- /dev/null
+++ b/web/cryptocompare/cryptocompare.go
@@ -0,0 +1,44 @@
+// Package cryptocompare fetches the latest USD price of a given crpytocurrency from CryptoCompare
+package cryptocompare
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"within.website/x/web"
+	_ "within.website/x/web/useragent"
+)
+
+func Get(symbol string, currencies []string) (map[string]float64, error) {
+	u, err := url.Parse("https://min-api.cryptocompare.com/data/price")
+	if err != nil {
+		return nil, err
+	}
+
+	q := u.Query()
+	q.Set("fsym", symbol)
+	q.Set("tsyms", strings.Join(currencies, ","))
+
+	u.RawQuery = q.Encode()
+
+	resp, err := http.Get(u.String())
+	if err != nil {
+		return nil, fmt.Errorf("cryptocompare: can't fetch result: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, web.NewError(http.StatusOK, resp)
+	}
+
+	defer resp.Body.Close()
+
+	result := make(map[string]float64)
+	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		return nil, fmt.Errorf("cryptocompare: can't decode result: %w")
+	}
+
+	return result, nil
+}