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

go.mod

@@ -2,7 +2,7 @@ module gitea.maximumdirect.net/ejr/weatherfeeder
 
 go 1.25
 
-require gitea.maximumdirect.net/ejr/feedkit v0.7.2
+require gitea.maximumdirect.net/ejr/feedkit v0.8.0
 
 require (
 	github.com/klauspost/compress v1.17.2 // indirect

go.sum

@@ -1,5 +1,5 @@
-gitea.maximumdirect.net/ejr/feedkit v0.7.2 h1:hTg302SgSi7tw11lNzuc+3g7MvHT6jQQziuo2NoARt8=
+gitea.maximumdirect.net/ejr/feedkit v0.8.0 h1:JdEEy6T3AQ97alLNYcQ3crN3tOEZPLMBD0Qr/MH5/dw=
-gitea.maximumdirect.net/ejr/feedkit v0.7.2/go.mod h1:U6xC9xZLN3cL4yi7YBVyzGoHYRLJXusFCAKlj2kdYYQ=
+gitea.maximumdirect.net/ejr/feedkit v0.8.0/go.mod h1:U6xC9xZLN3cL4yi7YBVyzGoHYRLJXusFCAKlj2kdYYQ=
 github.com/klauspost/compress v1.17.2 h1:RlWWUY/Dr4fL8qk9YG7DTZ7PDgME2V4csBXA8L/ixi4=
 github.com/klauspost/compress v1.17.2/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=

internal/sources/common/config.go

@@ -1,104 +0,0 @@
-// FILE: ./internal/sources/common/config.go
-package common
-
-import (
-	"fmt"
-	"strings"
-
-	"gitea.maximumdirect.net/ejr/feedkit/config"
-)
-
-// This file centralizes small, boring config-validation patterns shared across
-// weatherfeeder source drivers.
-//
-// Goal: keep driver constructors (New*Source) easy to read and consistent, while
-// keeping driver-specific options in cfg.Params (feedkit remains domain-agnostic).
-
-// HTTPSourceConfig is the standard "HTTP-polling source" config shape used across drivers.
-type HTTPSourceConfig struct {
-	Name      string
-	URL       string
-	UserAgent string
-}
-
-// RequireHTTPSourceConfig enforces weatherfeeder's standard HTTP source config:
-//
-//   - cfg.Name must be present
-//   - cfg.Params must be present
-//   - params.url must be present (accepts "url" or "URL")
-//   - params.user_agent must be present (accepts "user_agent" or "userAgent")
-//
-// We intentionally require a User-Agent for *all* sources, even when upstreams
-// do not strictly require one. This keeps config uniform across providers.
-func RequireHTTPSourceConfig(driver string, cfg config.SourceConfig) (HTTPSourceConfig, error) {
-	if strings.TrimSpace(cfg.Name) == "" {
-		return HTTPSourceConfig{}, fmt.Errorf("%s: name is required", driver)
-	}
-	if cfg.Params == nil {
-		return HTTPSourceConfig{}, fmt.Errorf("%s %q: params are required (need params.url and params.user_agent)", driver, cfg.Name)
-	}
-
-	url, ok := cfg.ParamString("url", "URL")
-	if !ok {
-		return HTTPSourceConfig{}, fmt.Errorf("%s %q: params.url is required", driver, cfg.Name)
-	}
-
-	ua, ok := cfg.ParamString("user_agent", "userAgent")
-	if !ok {
-		return HTTPSourceConfig{}, fmt.Errorf("%s %q: params.user_agent is required", driver, cfg.Name)
-	}
-
-	return HTTPSourceConfig{
-		Name:      cfg.Name,
-		URL:       url,
-		UserAgent: ua,
-	}, nil
-}
-
-// --- The helpers below remain useful for future drivers; they are not required
-// --- by the observation sources after adopting RequireHTTPSourceConfig.
-
-// RequireName ensures cfg.Name is present and non-whitespace.
-func RequireName(driver string, cfg config.SourceConfig) error {
-	if strings.TrimSpace(cfg.Name) == "" {
-		return fmt.Errorf("%s: name is required", driver)
-	}
-	return nil
-}
-
-// RequireParams ensures cfg.Params is non-nil. The "want" string should be a short
-// description of required keys, e.g. "need params.url and params.user_agent".
-func RequireParams(driver string, cfg config.SourceConfig, want string) error {
-	if cfg.Params == nil {
-		return fmt.Errorf("%s %q: params are required (%s)", driver, cfg.Name, want)
-	}
-	return nil
-}
-
-// RequireURL returns the configured URL for a source.
-// Canonical key is "url"; we also accept "URL" as a convenience.
-func RequireURL(driver string, cfg config.SourceConfig) (string, error) {
-	if cfg.Params == nil {
-		return "", fmt.Errorf("%s %q: params are required (need params.url)", driver, cfg.Name)
-	}
-
-	u, ok := cfg.ParamString("url", "URL")
-	if !ok {
-		return "", fmt.Errorf("%s %q: params.url is required", driver, cfg.Name)
-	}
-	return u, nil
-}
-
-// RequireUserAgent returns the configured User-Agent for a source.
-// Canonical key is "user_agent"; we also accept "userAgent" as a convenience.
-func RequireUserAgent(driver string, cfg config.SourceConfig) (string, error) {
-	if cfg.Params == nil {
-		return "", fmt.Errorf("%s %q: params are required (need params.user_agent)", driver, cfg.Name)
-	}
-
-	ua, ok := cfg.ParamString("user_agent", "userAgent")
-	if !ok {
-		return "", fmt.Errorf("%s %q: params.user_agent is required", driver, cfg.Name)
-	}
-	return ua, nil
-}

internal/sources/common/http.go

@@ -1,76 +0,0 @@
-// FILE: ./internal/sources/common/http_source.go
-package common
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"net/http"
-
-	"gitea.maximumdirect.net/ejr/feedkit/config"
-	"gitea.maximumdirect.net/ejr/feedkit/transport"
-)
-
-// HTTPSource is a tiny, reusable "HTTP polling spine" for weatherfeeder sources.
-//
-// It centralizes the boring parts:
-//   - standard config shape (url + user_agent) via RequireHTTPSourceConfig
-//   - a default http.Client with timeout
-//   - FetchBody / headers / max-body safety limit
-//   - consistent error wrapping (driver + source name)
-//
-// Individual drivers remain responsible for:
-//   - decoding minimal metadata (for Event.ID / EffectiveAt)
-//   - constructing the event envelope (kind/schema/payload)
-type HTTPSource struct {
-	Driver    string
-	Name      string
-	URL       string
-	UserAgent string
-	Accept    string
-	Client    *http.Client
-}
-
-// NewHTTPSource builds an HTTPSource using weatherfeeder's standard HTTP source
-// config (params.url + params.user_agent) and a default HTTP client.
-func NewHTTPSource(driver string, cfg config.SourceConfig, accept string) (*HTTPSource, error) {
-	c, err := RequireHTTPSourceConfig(driver, cfg)
-	if err != nil {
-		return nil, err
-	}
-
-	return &HTTPSource{
-		Driver:    driver,
-		Name:      c.Name,
-		URL:       c.URL,
-		UserAgent: c.UserAgent,
-		Accept:    accept,
-		Client:    transport.NewHTTPClient(transport.DefaultHTTPTimeout),
-	}, nil
-}
-
-// FetchBytes fetches the URL and returns the raw response body bytes.
-func (s *HTTPSource) FetchBytes(ctx context.Context) ([]byte, error) {
-	client := s.Client
-	if client == nil {
-		// Defensive: allow tests or callers to nil out Client; keep behavior sane.
-		client = transport.NewHTTPClient(transport.DefaultHTTPTimeout)
-	}
-
-	b, err := transport.FetchBody(ctx, client, s.URL, s.UserAgent, s.Accept)
-	if err != nil {
-		return nil, fmt.Errorf("%s %q: %w", s.Driver, s.Name, err)
-	}
-	return b, nil
-}
-
-// FetchJSON fetches the URL and returns the raw body as json.RawMessage.
-// json.Unmarshal accepts json.RawMessage directly, so callers can decode minimal
-// metadata without keeping both []byte and RawMessage in their own structs.
-func (s *HTTPSource) FetchJSON(ctx context.Context) (json.RawMessage, error) {
-	b, err := s.FetchBytes(ctx)
-	if err != nil {
-		return nil, err
-	}
-	return json.RawMessage(b), nil
-}

internal/sources/nws/alerts.go

@@ -9,6 +9,7 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
@@ -22,14 +23,14 @@ import (
 // Output schema:
 //   - standards.SchemaRawNWSAlertsV1
 type AlertsSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewAlertsSource(cfg config.SourceConfig) (*AlertsSource, error) {
 	const driver = "nws_alerts"
 
 	// NWS alerts responses are GeoJSON-ish; allow fallback to plain JSON as well.
-	hs, err := common.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -43,10 +44,13 @@ func (s *AlertsSource) Name() string { return s.http.Name }
 func (s *AlertsSource) Kind() event.Kind { return event.Kind("alert") }
 
 func (s *AlertsSource) Poll(ctx context.Context) ([]event.Event, error) {
-	raw, meta, err := s.fetchRaw(ctx)
+	raw, meta, changed, err := s.fetchRaw(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if !changed {
+		return nil, nil
+	}
 
 	// EffectiveAt policy for alerts:
 	// Prefer the collection-level "updated" timestamp (best dedupe signal).
@@ -97,16 +101,19 @@ type alertsMeta struct {
 	ParsedLatestFeatureTime time.Time `json:"-"`
 }
 
-func (s *AlertsSource) fetchRaw(ctx context.Context) (json.RawMessage, alertsMeta, error) {
+func (s *AlertsSource) fetchRaw(ctx context.Context) (json.RawMessage, alertsMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, alertsMeta{}, err
+		return nil, alertsMeta{}, false, err
+	}
+	if !changed {
+		return nil, alertsMeta{}, false, nil
 	}
 
 	var meta alertsMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
 		// If metadata decode fails, still return raw; Poll will fall back to Source:EmittedAt.
-		return raw, alertsMeta{}, nil
+		return raw, alertsMeta{}, true, nil
 	}
 
 	// Top-level updated (preferred).
@@ -143,5 +150,5 @@ func (s *AlertsSource) fetchRaw(ctx context.Context) (json.RawMessage, alertsMet
 	}
 	meta.ParsedLatestFeatureTime = latest
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }

internal/sources/nws/forecast_hourly.go

@@ -9,6 +9,7 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
@@ -22,14 +23,14 @@ import (
 // Output schema (current implementation):
 //   - standards.SchemaRawNWSHourlyForecastV1
 type HourlyForecastSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewHourlyForecastSource(cfg config.SourceConfig) (*HourlyForecastSource, error) {
 	const driver = "nws_forecast_hourly"
 
 	// NWS forecast endpoints are GeoJSON (and sometimes also advertise json-ld/json).
-	hs, err := common.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -43,10 +44,13 @@ func (s *HourlyForecastSource) Name() string { return s.http.Name }
 func (s *HourlyForecastSource) Kind() event.Kind { return event.Kind("forecast") }
 
 func (s *HourlyForecastSource) Poll(ctx context.Context) ([]event.Event, error) {
-	raw, meta, err := s.fetchRaw(ctx)
+	raw, meta, changed, err := s.fetchRaw(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if !changed {
+		return nil, nil
+	}
 
 	// EffectiveAt is optional; for forecasts it’s most naturally the run “issued” time.
 	// NWS gridpoint forecasts expose generatedAt (preferred) and updateTime/updated.
@@ -94,16 +98,19 @@ type hourlyForecastMeta struct {
 	ParsedUpdateTime  time.Time `json:"-"`
 }
 
-func (s *HourlyForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, hourlyForecastMeta, error) {
+func (s *HourlyForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, hourlyForecastMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, hourlyForecastMeta{}, err
+		return nil, hourlyForecastMeta{}, false, err
+	}
+	if !changed {
+		return nil, hourlyForecastMeta{}, false, nil
 	}
 
 	var meta hourlyForecastMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
 		// If metadata decode fails, still return raw; Poll will fall back to Source:EmittedAt.
-		return raw, hourlyForecastMeta{}, nil
+		return raw, hourlyForecastMeta{}, true, nil
 	}
 
 	// generatedAt (preferred)
@@ -125,5 +132,5 @@ func (s *HourlyForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, h
 		}
 	}
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }

internal/sources/nws/forecast_narrative.go

@@ -9,6 +9,7 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
@@ -22,14 +23,14 @@ import (
 // Output schema:
 //   - standards.SchemaRawNWSNarrativeForecastV1
 type NarrativeForecastSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewNarrativeForecastSource(cfg config.SourceConfig) (*NarrativeForecastSource, error) {
 	const driver = "nws_forecast_narrative"
 
 	// NWS forecast endpoints are GeoJSON (and sometimes also advertise json-ld/json).
-	hs, err := common.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -43,10 +44,13 @@ func (s *NarrativeForecastSource) Name() string { return s.http.Name }
 func (s *NarrativeForecastSource) Kind() event.Kind { return event.Kind("forecast") }
 
 func (s *NarrativeForecastSource) Poll(ctx context.Context) ([]event.Event, error) {
-	raw, meta, err := s.fetchRaw(ctx)
+	raw, meta, changed, err := s.fetchRaw(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if !changed {
+		return nil, nil
+	}
 
 	// EffectiveAt is optional; for forecasts it’s most naturally the run “issued” time.
 	// NWS gridpoint forecasts expose generatedAt (preferred) and updateTime/updated.
@@ -94,16 +98,19 @@ type narrativeForecastMeta struct {
 	ParsedUpdateTime  time.Time `json:"-"`
 }
 
-func (s *NarrativeForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, narrativeForecastMeta, error) {
+func (s *NarrativeForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, narrativeForecastMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, narrativeForecastMeta{}, err
+		return nil, narrativeForecastMeta{}, false, err
+	}
+	if !changed {
+		return nil, narrativeForecastMeta{}, false, nil
 	}
 
 	var meta narrativeForecastMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
 		// If metadata decode fails, still return raw; Poll will fall back to Source:EmittedAt.
-		return raw, narrativeForecastMeta{}, nil
+		return raw, narrativeForecastMeta{}, true, nil
 	}
 
 	// generatedAt (preferred)
@@ -125,5 +132,5 @@ func (s *NarrativeForecastSource) fetchRaw(ctx context.Context) (json.RawMessage
 		}
 	}
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }

internal/sources/nws/observation.go

@@ -9,6 +9,7 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
@@ -16,13 +17,13 @@ import (
 
 // ObservationSource polls an NWS station observation endpoint and emits a RAW observation Event.
 type ObservationSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewObservationSource(cfg config.SourceConfig) (*ObservationSource, error) {
 	const driver = "nws_observation"
 
-	hs, err := common.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -35,10 +36,13 @@ func (s *ObservationSource) Name() string { return s.http.Name }
 func (s *ObservationSource) Kind() event.Kind { return event.Kind("observation") }
 
 func (s *ObservationSource) Poll(ctx context.Context) ([]event.Event, error) {
-	raw, meta, err := s.fetchRaw(ctx)
+	raw, meta, changed, err := s.fetchRaw(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if !changed {
+		return nil, nil
+	}
 
 	// EffectiveAt is optional; for observations it’s naturally the observation timestamp.
 	var effectiveAt *time.Time
@@ -72,16 +76,19 @@ type observationMeta struct {
 	ParsedTimestamp time.Time `json:"-"`
 }
 
-func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, observationMeta, error) {
+func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, observationMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, observationMeta{}, err
+		return nil, observationMeta{}, false, err
+	}
+	if !changed {
+		return nil, observationMeta{}, false, nil
 	}
 
 	var meta observationMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
 		// If metadata decode fails, still return raw; envelope will fall back to Source:EffectiveAt.
-		return raw, observationMeta{}, nil
+		return raw, observationMeta{}, true, nil
 	}
 
 	tsStr := strings.TrimSpace(meta.Properties.Timestamp)
@@ -91,5 +98,5 @@ func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, obse
 		}
 	}
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }

internal/sources/nws/observation_test.go

@@ -0,0 +1,63 @@
+package nws
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"gitea.maximumdirect.net/ejr/feedkit/config"
+	"gitea.maximumdirect.net/ejr/feedkit/event"
+)
+
+func TestObservationSourcePollReturnsNoEventsOn304(t *testing.T) {
+	var call int
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		call++
+		switch call {
+		case 1:
+			w.Header().Set("ETag", `"obs-v1"`)
+			_, _ = w.Write([]byte(`{"id":"obs-1","properties":{"timestamp":"2026-03-28T12:00:00Z"}}`))
+		case 2:
+			if got := r.Header.Get("If-None-Match"); got != `"obs-v1"` {
+				t.Fatalf("second request If-None-Match = %q", got)
+			}
+			w.WriteHeader(http.StatusNotModified)
+		default:
+			t.Fatalf("unexpected call count %d", call)
+		}
+	}))
+	defer srv.Close()
+
+	src, err := NewObservationSource(config.SourceConfig{
+		Name:   "NWSObservationTest",
+		Driver: "nws_observation",
+		Mode:   config.SourceModePoll,
+		Params: map[string]any{
+			"url":        srv.URL,
+			"user_agent": "test-agent",
+		},
+	})
+	if err != nil {
+		t.Fatalf("NewObservationSource() error = %v", err)
+	}
+
+	first, err := src.Poll(context.Background())
+	if err != nil {
+		t.Fatalf("first Poll() error = %v", err)
+	}
+	if len(first) != 1 {
+		t.Fatalf("first Poll() len = %d, want 1", len(first))
+	}
+	if first[0].Kind != event.Kind("observation") {
+		t.Fatalf("first Poll() kind = %q", first[0].Kind)
+	}
+
+	second, err := src.Poll(context.Background())
+	if err != nil {
+		t.Fatalf("second Poll() error = %v", err)
+	}
+	if len(second) != 0 {
+		t.Fatalf("second Poll() len = %d, want 0", len(second))
+	}
+}

internal/sources/openmeteo/forecast.go

@@ -8,6 +8,7 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/openmeteo"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
@@ -15,13 +16,13 @@ import (
 
 // ForecastSource polls an Open-Meteo hourly forecast endpoint and emits one RAW Forecast Event.
 type ForecastSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewForecastSource(cfg config.SourceConfig) (*ForecastSource, error) {
 	const driver = "openmeteo_forecast"
 
-	hs, err := common.NewHTTPSource(driver, cfg, "application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -34,10 +35,13 @@ func (s *ForecastSource) Name() string { return s.http.Name }
 func (s *ForecastSource) Kind() event.Kind { return event.Kind("forecast") }
 
 func (s *ForecastSource) Poll(ctx context.Context) ([]event.Event, error) {
-	raw, meta, err := s.fetchRaw(ctx)
+	raw, meta, changed, err := s.fetchRaw(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if !changed {
+		return nil, nil
+	}
 
 	// Open-Meteo does not expose a true "issued at" timestamp for forecast runs.
 	// We use current.time when present; otherwise we fall back to the first hourly time
@@ -79,16 +83,19 @@ type forecastMeta struct {
 	ParsedTimestamp time.Time `json:"-"`
 }
 
-func (s *ForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, forecastMeta, error) {
+func (s *ForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, forecastMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, forecastMeta{}, err
+		return nil, forecastMeta{}, false, err
+	}
+	if !changed {
+		return nil, forecastMeta{}, false, nil
 	}
 
 	var meta forecastMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
 		// If metadata decode fails, still return raw; Poll will fall back to Source:EmittedAt.
-		return raw, forecastMeta{}, nil
+		return raw, forecastMeta{}, true, nil
 	}
 
 	ts := strings.TrimSpace(meta.Current.Time)
@@ -106,5 +113,5 @@ func (s *ForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, forecas
 		}
 	}
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }

internal/sources/openmeteo/observation.go

@@ -8,6 +8,7 @@ import (
 
 	"gitea.maximumdirect.net/ejr/feedkit/config"
 	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/openmeteo"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
 	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
@@ -15,13 +16,13 @@ import (
 
 // ObservationSource polls an Open-Meteo endpoint and emits one RAW Observation Event.
 type ObservationSource struct {
-	http *common.HTTPSource
+	http *fksources.HTTPSource
 }
 
 func NewObservationSource(cfg config.SourceConfig) (*ObservationSource, error) {
 	const driver = "openmeteo_observation"
 
-	hs, err := common.NewHTTPSource(driver, cfg, "application/json")
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/json")
 	if err != nil {
 		return nil, err
 	}
@@ -34,10 +35,13 @@ func (s *ObservationSource) Name() string { return s.http.Name }
 func (s *ObservationSource) Kind() event.Kind { return event.Kind("observation") }
 
 func (s *ObservationSource) Poll(ctx context.Context) ([]event.Event, error) {
-	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() {
@@ -72,21 +76,24 @@ type openMeteoMeta struct {
 	ParsedTimestamp time.Time `json:"-"`
 }
 
-func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, openMeteoMeta, error) {
+func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, openMeteoMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
 	if err != nil {
-		return nil, openMeteoMeta{}, err
+		return nil, openMeteoMeta{}, false, err
+	}
+	if !changed {
+		return nil, openMeteoMeta{}, false, nil
 	}
 
 	var meta openMeteoMeta
 	if err := json.Unmarshal(raw, &meta); err != nil {
 		// If metadata decode fails, still return raw; envelope will omit EffectiveAt.
-		return raw, openMeteoMeta{}, nil
+		return raw, openMeteoMeta{}, true, nil
 	}
 
 	if t, err := openmeteo.ParseTime(meta.Current.Time, meta.Timezone, meta.UTCOffsetSeconds); err == nil {
 		meta.ParsedTimestamp = t.UTC()
 	}
 
-	return raw, meta, nil
+	return raw, meta, true, nil
 }

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) {
+func (s *ObservationSource) fetchRaw(ctx context.Context) (json.RawMessage, openWeatherMeta, bool, error) {
-	raw, err := s.http.FetchJSON(ctx)
+	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
 }