mirror of
https://github.com/chubin/wttr.in
synced 2025-01-12 12:08:47 +00:00
99 lines
2.1 KiB
Go
99 lines
2.1 KiB
Go
package ip
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import (
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"errors"
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"os"
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"path"
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"strconv"
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"strings"
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"github.com/chubin/wttr.in/internal/config"
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)
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var (
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ErrNotFound = errors.New("cache entry not found")
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ErrInvalidCacheEntry = errors.New("invalid cache entry format")
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)
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// Location information.
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type Location struct {
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CountryCode string
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Country string
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Region string
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City string
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Latitude float64
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Longitude float64
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}
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// Cache provides access to the IP Geodata cache.
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type Cache struct {
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config *config.Config
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}
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// NewCache returns new cache reader for the specified config.
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func NewCache(config *config.Config) *Cache {
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return &Cache{
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config: config,
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}
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}
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// Read returns location information from the cache, if found,
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// or ErrNotFound if not found. If the entry is found, but its format
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// is invalid, ErrInvalidCacheEntry is returned.
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//
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// Format:
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//
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// [CountryCode];Country;Region;City;[Latitude];[Longitude]
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//
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// Example:
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//
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// DE;Germany;Free and Hanseatic City of Hamburg;Hamburg;53.5736;9.9782
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//
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func (c *Cache) Read(addr string) (*Location, error) {
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bytes, err := os.ReadFile(c.cacheFile(addr))
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if err != nil {
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return nil, ErrNotFound
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}
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return parseCacheEntry(string(bytes))
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}
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// cacheFile retuns path to the cache entry for addr.
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func (c *Cache) cacheFile(addr string) string {
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return path.Join(c.config.Geo.IPCache, addr)
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}
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// parseCacheEntry parses the location cache entry s,
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// and return location, or error, if the cache entry is invalid.
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func parseCacheEntry(s string) (*Location, error) {
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var (
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lat float64 = -1000
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long float64 = -1000
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err error
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)
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parts := strings.Split(s, ";")
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if len(parts) < 4 {
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return nil, ErrInvalidCacheEntry
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}
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if len(parts) >= 6 {
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lat, err = strconv.ParseFloat(parts[4], 64)
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if err != nil {
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return nil, ErrInvalidCacheEntry
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}
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long, err = strconv.ParseFloat(parts[5], 64)
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if err != nil {
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return nil, ErrInvalidCacheEntry
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}
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}
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return &Location{
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CountryCode: parts[0],
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Country: parts[1],
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Region: parts[2],
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City: parts[3],
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Latitude: lat,
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Longitude: long,
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}, nil
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}
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