Initial public commit.

coindesk/lib_test.go

@@ -0,0 +1,29 @@
+package coindesk_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"code.humancabbage.net/moonmath/coindesk"
+)
+
+func TestXxx(t *testing.T) {
+	now := time.Now()
+	then := now.Add(time.Duration(-24) * time.Hour)
+
+	values, err := coindesk.GetPriceValues(context.Background(), coindesk.BTC, then, now)
+	if err != nil {
+		t.Errorf("test failure: %v", err)
+	}
+	_ = values
+	fmt.Println()
+
+	tickers, err := coindesk.GetAssetTickers(context.Background(), coindesk.BTC, coindesk.ETH)
+	if err != nil {
+		t.Errorf("test failure: %v", err)
+	}
+	_ = tickers
+	fmt.Println()
+}

coindesk/model.go

@@ -0,0 +1,112 @@
+package coindesk
+
+import (
+	"encoding/json"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Asset is a cryptocurrency, like Bitcoin, Ethereum, etc.
+type Asset string
+
+const (
+	// BTC is the Bitcoin asset.
+	BTC Asset = "BTC"
+	// ETH is the Ethereum asset.
+	ETH Asset = "ETH"
+)
+
+// Response represents the general top-level format of Coindesk API responses.
+type Response[T any] struct {
+	StatusCode int    `json:"statusCode"`
+	Message    string `json:"message"`
+	Data       T      `json:"data"`
+}
+
+// PriceValues contains a series of timestamped prices for a particular asset.
+type PriceValues struct {
+	ISO            Asset            `json:"iso"`
+	Name           string           `json:"name"`
+	Slug           string           `json:"slug"`
+	IngestionStart Date             `json:"ingestionStart"`
+	Entries        []TimestampPrice `json:"entries"`
+}
+
+// AssetTickers is a map from an asset to its ticker data.
+type AssetTickers map[Asset]AssetTicker
+
+// AssetTicker is a snapshot of pricing data for an asset.
+type AssetTicker struct {
+	ISO    Asset  `json:"iso"`
+	Name   string `json:"name"`
+	Slug   string `json:"slug"`
+	Change struct {
+		Percent float64 `json:"percent"`
+		Value   float64 `json:"value"`
+	} `json:"change"`
+	OHLC struct {
+		Opening Price `json:"o"`
+		High    Price `json:"h"`
+		Low     Price `json:"l"`
+		Closing Price `json:"c"`
+	} `json:"ohlc"`
+	CirculatingSupply float64   `json:"circulatingSupply"`
+	MarketCap         Price     `json:"marketCap"`
+	Timestamp         Timestamp `json:"ts"`
+}
+
+// TimestampPrice represents a JSON array with two elements: an integer Unix
+// timestamp expressed in milliseconds, and a floating-point USD price.
+type TimestampPrice struct {
+	Timestamp Timestamp
+	Price     Price
+}
+
+func (t *TimestampPrice) UnmarshalJSON(b []byte) error {
+	a := []interface{}{&t.Timestamp, &t.Price}
+	return json.Unmarshal(b, &a)
+}
+
+// Timestamp represents an integer Unix timestamp expressed in milliseconds
+// which has been converted into a Golang time.Time object.
+type Timestamp time.Time
+
+func (t *Timestamp) UnmarshalJSON(b []byte) error {
+	s := string(b)
+	n := len(s)
+	secsStr := s[0 : n-3]
+	millisStr := s[n-3:]
+	secs, err := strconv.ParseInt(secsStr, 10, 64)
+	if err != nil {
+		return err
+	}
+	millis, err := strconv.ParseInt(millisStr, 10, 64)
+	if err != nil {
+		return err
+	}
+
+	converted := time.Unix(secs, millis*1e6)
+	*t = Timestamp(converted)
+
+	return nil
+}
+
+// Price represents the USD price of an asset.
+type Price float64
+
+// Date represents a date-only string which has been converted into a Golang
+// time.Time object.
+type Date time.Time
+
+func (d *Date) UnmarshalJSON(b []byte) error {
+	s := string(b)
+	s, _ = strings.CutPrefix(s, "\"")
+	s, _ = strings.CutSuffix(s, "\"")
+	t, err := time.Parse(time.DateOnly, s)
+	if err != nil {
+		return err
+	}
+	*d = Date(t)
+	return nil
+}

coindesk/requests.go

@@ -0,0 +1,48 @@
+package coindesk
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/carlmjohnson/requests"
+)
+
+// GetPriceValues gets timestamped prices for a particular asset.
+func GetPriceValues(
+	ctx context.Context, asset Asset, startDate, endDate time.Time,
+) (resp Response[PriceValues], err error) {
+	const basePath = "v2/tb/price/values"
+	const timeFormat = "2006-01-02T15:04"
+	err = requests.New(commonConfig).
+		Path(fmt.Sprintf("%s/%s", basePath, asset)).
+		Param("start_date", startDate.Format(timeFormat)).
+		Param("end_date", endDate.Format(timeFormat)).
+		ToJSON(&resp).
+		Fetch(ctx)
+	return
+}
+
+// GetAssetTickers gets tickers for a set of assets.
+func GetAssetTickers(ctx context.Context, assets ...Asset) (resp Response[AssetTickers], err error) {
+	const basePath = "v2/tb/price/ticker"
+	var strAssets []string
+	for _, asset := range assets {
+		strAssets = append(strAssets, string(asset))
+	}
+	err = requests.New(commonConfig).
+		Path(basePath).
+		Param("assets", strings.Join(strAssets, ",")).
+		ToJSON(&resp).
+		Fetch(ctx)
+	return
+}
+
+const baseUrl = "https://production.api.coindesk.com"
+
+func commonConfig(rb *requests.Builder) {
+	rb.
+		BaseURL(baseUrl).
+		Accept("application/json;charset=utf-8")
+}