feat: use an in memory rtree to find the timezone

cmd/update.go

@@ -0,0 +1,121 @@
+/*
+Copyright © 2021 NAME HERE <EMAIL ADDRESS>
+
+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 cmd
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/noandrea/geo2tz/v2/helpers"
+	"github.com/noandrea/geo2tz/v2/web"
+	"github.com/spf13/cobra"
+)
+
+const (
+	// geo data url
+	LatestReleaseURL = "https://github.com/evansiroky/timezone-boundary-builder/releases/latest"
+)
+
+// updateCmd represents the build command
+var updateCmd = &cobra.Command{
+	Use:   "update VERSION",
+	Short: "Download the timezone data from the latest release or a specific version",
+	Example: `To build from the latest version:
+geo2tz update latest
+
+To build from a specific version:
+geo2tz update 2023d
+`,
+	Args: cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		versionName := args[0]
+		return update(versionName, web.Settings.Tz.DatabaseName)
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(updateCmd)
+	updateCmd.Flags().StringVar(&web.Settings.Tz.DatabaseName, "db", web.TZDBFile, "Destination database filename")
+	updateCmd.Flags().StringVar(&web.Settings.Tz.VersionFile, "version-file", web.TZVersionFile, "Version file")
+}
+
+func update(versionName, targetFile string) (err error) {
+	var release = web.NewTzRelease(versionName)
+	// do we need the latest version?
+	if versionName == "latest" {
+		release, err = getLatest()
+		if err != nil {
+			return
+		}
+	}
+	if err := fetchAndCacheFile(targetFile, release.GeoDataURL); err != nil {
+		return err
+	}
+	helpers.SaveJSON(release, web.Settings.Tz.VersionFile)
+	return
+}
+
+func fetchAndCacheFile(filename string, url string) (err error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	f, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	n, err := io.Copy(f, resp.Body)
+	if err != nil {
+		return err
+	}
+	if n != resp.ContentLength {
+		fmt.Println(n, resp.ContentLength)
+	}
+	return
+}
+
+func getLatest() (web.TzRelease, error) {
+	// create http client
+	client := &http.Client{
+		Timeout: 1 * time.Second,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			// don't follow redirects
+			return http.ErrUseLastResponse
+		},
+	}
+	r, err := client.Head(LatestReleaseURL)
+	if err != nil {
+		err = fmt.Errorf("failed to get release url: %w", err)
+		return web.TzRelease{}, err
+	}
+	defer r.Body.Close()
+	// get the tag name
+	releaseURL, err := r.Location()
+	if err != nil {
+		err = fmt.Errorf("failed to get release url: %w", err)
+		return web.TzRelease{}, err
+	}
+	v := web.NewTzRelease(releaseURL.Path[strings.LastIndex(releaseURL.Path, "/")+1:])
+	return v, nil
+}

db/db.go

@@ -0,0 +1,14 @@
+package db
+
+import "errors"
+
+type TzDBIndex interface {
+	Lookup(lat, lon float64) (string, error)
+	Size() int
+}
+
+var (
+	// ErrNotFound is returned when a timezone is not found
+	ErrNotFound = errors.New("timezone not found")
+	ErrInternal = errors.New("shape without tzID")
+)