Consume a different Yahoo! API

The old one stopped working a few days ago.

cmd/commands/fetch.go

@@ -25,7 +25,7 @@ import (
 	"github.com/sboehler/knut/lib/model"
 	"github.com/sboehler/knut/lib/model/price"
 	"github.com/sboehler/knut/lib/model/registry"
-	"github.com/sboehler/knut/lib/quotes/yahoo"
+	"github.com/sboehler/knut/lib/quotes/yahoo2"
 	"github.com/sboehler/knut/lib/syntax"
 	"github.com/shopspring/decimal"
 	"github.com/sourcegraph/conc/pool"
@@ -62,7 +62,7 @@ func (r *fetchRunner) run(cmd *cobra.Command, args []string) {
 
 const fetchConcurrency = 5
 
-func (r *fetchRunner) execute(cmd *cobra.Command, args []string) error {
+func (r *fetchRunner) execute(_ *cobra.Command, args []string) error {
 	reg := registry.New()
 	configs, err := r.readConfig(args[0])
 	if err != nil {
@@ -133,13 +133,13 @@ func (r *fetchRunner) readFile(ctx *registry.Registry, filepath string) (res map
 
 func (r *fetchRunner) fetchPrices(reg *registry.Registry, cfg fetchConfig, t0, t1 time.Time, results map[time.Time]*model.Price) error {
 	var (
-		c                 = yahoo.New()
-		quotes            []yahoo.Quote
+		c                 = yahoo2.New()
+		quotes            []yahoo2.Quote
 		commodity, target *model.Commodity
 		err               error
 	)
 	if quotes, err = c.Fetch(cfg.Symbol, t0, t1); err != nil {
-		return err
+		return fmt.Errorf("error fetching symbol %s: %v", cfg.Symbol, err)
 	}
 	if commodity, err = reg.Commodities().Get(cfg.Commodity); err != nil {
 		return err

lib/quotes/yahoo/yahoo.go

@@ -12,6 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package yahoo implements fetching pricing data from Yahoo!. The method
+// in this packages stopped working around 2024-09-11, see package yahoo2
+// for an updated version that uses a different API.
 package yahoo
 
 import (

lib/quotes/yahoo2/yahoo2.go

@@ -0,0 +1,146 @@
+// Copyright 2021 Silvio Böhler
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package yahoo2
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"path"
+	"time"
+)
+
+const yahooURL string = "https://query2.finance.yahoo.com/v8/finance/chart"
+
+// Quote represents a quote on a given day.
+type Quote struct {
+	Date     time.Time
+	Open     float64
+	High     float64
+	Low      float64
+	Close    float64
+	AdjClose float64
+	Volume   int
+}
+
+// Client is a client for Yahoo! quotes.
+type Client struct {
+	url string
+}
+
+// New creates a new client with the default URL.
+func New() Client {
+	return Client{yahooURL}
+}
+
+// Fetch fetches a set of quotes
+func (c *Client) Fetch(sym string, t0, t1 time.Time) ([]Quote, error) {
+	u, err := createURL(c.url, sym, t0, t1)
+	if err != nil {
+		return nil, fmt.Errorf("error creating URL for symbol %s: %w", sym, err)
+	}
+	resp, err := http.Get(u.String())
+	if err != nil {
+		return nil, fmt.Errorf("error fetching data from URL %s: %w", u.String(), err)
+	}
+	defer resp.Body.Close()
+	quote, err := decodeResponse(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("error decoding response for symbol %s (url: %s): %w", sym, u, err)
+	}
+	return quote, nil
+}
+
+// createURL creates a URL for the given root URL and parameters.
+func createURL(rootURL, sym string, t0, t1 time.Time) (*url.URL, error) {
+	u, err := url.Parse(rootURL)
+	if err != nil {
+		return u, err
+	}
+	u.Path = path.Join(u.Path, url.PathEscape(sym))
+	u.RawQuery = url.Values{
+		"events":   {"history"},
+		"interval": {"1d"},
+		"period1":  {fmt.Sprint(t0.Unix())},
+		"period2":  {fmt.Sprint(t1.Unix())},
+	}.Encode()
+	return u, nil
+}
+
+// decodeResponse takes a reader for the response and returns
+// the parsed quotes.
+func decodeResponse(r io.Reader) ([]Quote, error) {
+	d := json.NewDecoder(r)
+	var body jbody
+	if err := d.Decode(&body); err != nil {
+		return nil, err
+	}
+	result := body.Chart.Result[0]
+	loc, err := time.LoadLocation(result.Meta.ExchangeTimezoneName)
+	if err != nil {
+		return nil, fmt.Errorf("unknown time zone: %s", result.Meta.ExchangeTimezoneName)
+	}
+	var res []Quote
+	for i, ts := range body.Chart.Result[0].Timestamp {
+		date := time.Unix(int64(ts), 0).In(loc)
+		q := Quote{
+			Date:     time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, time.UTC),
+			Open:     result.Indicators.Quote[0].Open[i],
+			Close:    result.Indicators.Quote[0].Close[i],
+			High:     result.Indicators.Quote[0].High[i],
+			Low:      result.Indicators.Quote[0].Low[i],
+			AdjClose: result.Indicators.Adjclose[0].Adjclose[i],
+			Volume:   result.Indicators.Quote[0].Volume[i],
+		}
+		res = append(res, q)
+	}
+	return res, nil
+}
+
+type jbody struct {
+	Chart jchart `json:"chart"`
+}
+type jchart struct {
+	Result []jresult `json:"result"`
+}
+
+type jresult struct {
+	Meta       jmeta       `json:"meta"`
+	Timestamp  []int       `json:"timestamp"`
+	Indicators jindicators `json:"indicators"`
+}
+
+type jmeta struct {
+	ExchangeTimezoneName string `json:"exchangeTimezoneName"`
+}
+
+type jindicators struct {
+	Quote    []jquote    `json:"quote"`
+	Adjclose []jadjclose `json:"adjclose"`
+}
+
+type jquote struct {
+	Volume []int     `json:"volume"`
+	High   []float64 `json:"high"`
+	Close  []float64 `json:"close"`
+	Low    []float64 `json:"low"`
+	Open   []float64 `json:"open"`
+}
+
+type jadjclose struct {
+	Adjclose []float64 `json:"adjclose"`
+}