Add DistanceMatrix API

distance.go

@@ -0,0 +1,63 @@
+package maps
+
+import (
+	"fmt"
+	"net/url"
+	"time"
+)
+
+func (c Client) DistanceMatrix(orig, dest []Location, opts *DistanceMatrixOpts) (*DistanceMatrixResponse, error) {
+	var d DistanceMatrixResponse
+	if err := c.doDecode(baseURL+distancematrix(orig, dest, opts), &d); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}
+
+func distancematrix(orig, dest []Location, opts *DistanceMatrixOpts) string {
+	p := url.Values{}
+	p.Set("origins", encodeLocations(orig))
+	p.Set("destinations", encodeLocations(dest))
+	opts.update(p)
+	return "distancematrix/json?" + p.Encode()
+}
+
+type DistanceMatrixOpts struct {
+	Language, Units string
+	Mode, Avoid     *string
+	DepartureTime   time.Time
+}
+
+func (o *DistanceMatrixOpts) update(p url.Values) {
+	if o == nil {
+		return
+	}
+	if o.Mode != nil {
+		p.Set("mode", *o.Mode)
+	}
+	if o.Language != "" {
+		p.Set("language", o.Language)
+	}
+	if o.Avoid != nil {
+		p.Set("avoid", *o.Avoid)
+	}
+	if o.Units != "" {
+		p.Set("units", o.Units)
+	}
+	if !o.DepartureTime.IsZero() {
+		p.Set("departure_time", fmt.Sprintf("%d", o.DepartureTime.Unix()))
+	}
+}
+
+type DistanceMatrixResponse struct {
+	Status               string   `json:"status"`
+	OriginAddresses      []string `json:"origin_addresses"`
+	DestinationAddresses []string `json:"destination_addresses"`
+	Rows                 []struct {
+		Elements []struct {
+			Status   string   `json:"status"`
+			Duration Duration `json:"duration"`
+			Distance Distance `json:"distance"`
+		} `json:"elements"`
+	} `json:"rows"`
+}

maps.go

@@ -107,3 +107,7 @@ func encodeLatLngs(ll []LatLng) string {
 func Float64(f float64) *float64 {
 	return &f
 }
+
+func String(s string) *string {
+	return &s
+}

maps_test.go

@@ -159,3 +159,20 @@ func TestGeocode(t *testing.T) {
 	}
 	t.Logf("%v", r)
 }
+
+func TestDistanceMatrix(t *testing.T) {
+	c := NewClient("")
+	orig := []Location{Address("Vancouver, BC"), Address("Seattle")}
+	dst := []Location{Address("San Francisco"), Address("Victoria, BC")}
+	opts := &DistanceMatrixOpts{
+		Mode:     String(ModeBicycling),
+		Language: "fr-FR",
+	}
+	t.Logf("%s", baseURL+distancematrix(orig, dst, opts))
+	r, err := c.DistanceMatrix(orig, dst, opts)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	t.Logf("%v", r)
+
+}