181 lines
3.4 KiB
Go
181 lines
3.4 KiB
Go
package nominatim
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"reflect"
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"strconv"
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)
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type Nominatim struct {
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siteName string
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}
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var (
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ErrorMissingSiteName = errors.New("siteName must be defined")
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)
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func New(siteName string) (*Nominatim, error) {
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if siteName == "" {
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return nil, ErrorMissingSiteName
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}
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return &Nominatim{
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siteName: siteName,
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}, nil
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}
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// Search for coordinates based on q
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// API endpoint: https://nominatim.openstreetmap.org/search
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func (n *Nominatim) Search(q string) (*SearchResults, error) {
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url := fmt.Sprintf("https://nominatim.openstreetmap.org/search?q=%s&format=jsonv2", url.QueryEscape(q))
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req, err := http.NewRequest("GET", url, nil)
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if err != nil {
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return nil, err
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}
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req.Header.Set("User-Agent", n.siteName)
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return nil, fmt.Errorf("%s", resp.Status)
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}
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return nil, err
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}
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result := SearchResults{}
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err = json.Unmarshal(body, &result)
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if err != nil {
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return nil, err
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}
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return &result, nil
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}
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// Reverse search for location based on lat and lon
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// API endpoint: https://nominatim.openstreetmap.org/reverse
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func (n *Nominatim) Reverse(lat, lon float64) (*ReverseResult, error) {
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url := fmt.Sprintf("https://nominatim.openstreetmap.org/reverse?lat=%.16f&lon=%.16f&format=jsonv2", lat, lon)
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req, err := http.NewRequest("GET", url, nil)
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if err != nil {
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return nil, err
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}
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req.Header.Set("User-Agent", n.siteName)
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return nil, fmt.Errorf("%s", resp.Status)
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}
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return nil, err
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}
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result := ReverseResult{}
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err = json.Unmarshal(body, &result)
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if err != nil {
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return nil, err
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}
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if allFieldsNil(result) {
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return nil, fmt.Errorf("no result")
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}
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return &result, nil
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}
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type LookupResult struct {
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Coordinates
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Location string `json:"location"`
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}
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// Lookup location coordinates based on q
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func (n *Nominatim) Lookup(q string) (*LookupResult, error) {
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r, err := n.Search(q)
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if err != nil {
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return nil, err
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}
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if len(*r) == 0 {
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return nil, fmt.Errorf("no result")
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}
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firstResult := (*r)[0]
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lon, err := strconv.ParseFloat(*firstResult.Longitude, 64)
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if err != nil {
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return nil, err
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}
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lat, err := strconv.ParseFloat(*firstResult.Latitude, 64)
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if err != nil {
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return nil, err
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}
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return &LookupResult{
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Location: *firstResult.Name,
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Coordinates: Coordinates{
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Latitude: lat,
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Longitude: lon,
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},
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}, nil
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}
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// Lookup location name based on lat and lon
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func (n *Nominatim) ReverseLookup(lat, lon float64) (*LookupResult, error) {
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r, err := n.Reverse(lat, lon)
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if err != nil {
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return nil, err
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}
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return &LookupResult{
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Location: *r.Name,
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Coordinates: Coordinates{
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Latitude: lat,
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Longitude: lon,
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},
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}, nil
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}
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// Check if all fields on s is nil
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func allFieldsNil(s interface{}) bool {
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v := reflect.ValueOf(s)
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// Check if the passed value is a struct
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if v.Kind() != reflect.Struct {
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return false
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}
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// Iterate through all fields in the struct
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for i := 0; i < v.NumField(); i++ {
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field := v.Field(i)
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// Check if the field is a pointer and is nil
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if field.Kind() == reflect.Ptr && !field.IsNil() {
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return false
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}
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}
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return true
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}
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