Moved HTTP polling helpers upstream into feedkit, and updated to feedkit v0.8.0

internal/sources/openweather/observation.go

@@ -9,19 +9,20 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	owcommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/openweather"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
 )
 
 type ObservationSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewObservationSource(cfg config.SourceConfig) (*ObservationSource, error) {
 	const driver = "openweather_observation"
 
-	hs, err := common.NewHTTPSource(driver, cfg, "application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -42,10 +43,13 @@ func (s *ObservationSource) Poll(ctx context.Context) ([]event.Event, error) {
 		return nil, fmt.Errorf("%s %q: %w", s.http.Driver, s.http.Name, err)
 	}
 
-	raw, meta, err := s.fetchRaw(ctx)
+	raw, meta, changed, err := s.fetchRaw(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if !changed {
+		return nil, nil
+	}
 
 	var effectiveAt *time.Time
 	if !meta.ParsedTimestamp.IsZero() {
@@ -75,20 +79,23 @@ type openWeatherMeta struct {
 	ParsedTimestamp time.Time `json:"-"`
 }
 
-func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, openWeatherMeta, error) {
-	raw, err := s.http.FetchJSON(ctx)
+func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, openWeatherMeta, bool, error) {
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, openWeatherMeta{}, err
+		return nil, openWeatherMeta{}, false, err
+	}
+	if !changed {
+		return nil, openWeatherMeta{}, false, nil
 	}
 
 	var meta openWeatherMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
-		return raw, openWeatherMeta{}, nil
+		return raw, openWeatherMeta{}, true, nil
 	}
 
 	if meta.Dt > 0 {
 		meta.ParsedTimestamp = time.Unix(meta.Dt, 0).UTC()
 	}
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }