Merge pull request #46 from knhash/change-detection

feat: add change detection module

internal/assets/templates.go

@@ -23,6 +23,7 @@ var (
 	RedditCardsHorizontalTemplate = compileTemplate("reddit-horizontal-cards.html", "widget-base.html")
 	RedditCardsVerticalTemplate   = compileTemplate("reddit-vertical-cards.html", "widget-base.html")
 	ReleasesTemplate              = compileTemplate("releases.html", "widget-base.html")
+	ChangeDetectionTemplate       = compileTemplate("change-detection.html", "widget-base.html")
 	VideosTemplate                = compileTemplate("videos.html", "widget-base.html", "video-card-contents.html")
 	VideosGridTemplate            = compileTemplate("videos-grid.html", "widget-base.html", "video-card-contents.html")
 	StocksTemplate                = compileTemplate("stocks.html", "widget-base.html")

internal/assets/templates/change-detection.html

@@ -0,0 +1,17 @@
+{{ template "widget-base.html" . }}
+
+{{ define "widget-content" }}
+<ul class="list list-gap-14 collapsible-container" data-collapse-after="{{ .CollapseAfter }}">
+    {{ range .ChangeDetections }}
+    <li>
+        <a class="size-h4 block text-truncate color-highlight" href="{{ .URL }}" target="_blank" rel="noreferrer">{{ .Title }}</a>
+        <ul class="list-horizontal-text">
+            <li {{ dynamicRelativeTimeAttrs .LastChanged }}></li>
+            <li class="shrink min-width-0"><a class="visited-indicator" href="{{ .DiffURL }}" target="_blank" rel="noreferrer">diff:{{ .PreviousHash }}</a></li>
+        </ul>
+    </li>
+    {{ else }}
+    <li>No watches configured</li>
+    {{ end}}
+</ul>
+{{ end }}

internal/feed/changedetection.go

@@ -0,0 +1,139 @@
+package feed
+
+import (
+	"fmt"
+	"log/slog"
+	"net/http"
+	"sort"
+	"strings"
+	"time"
+)
+
+type ChangeDetectionWatch struct {
+	Title        string
+	URL          string
+	LastChanged  time.Time
+	DiffURL      string
+	PreviousHash string
+}
+
+type ChangeDetectionWatches []ChangeDetectionWatch
+
+func (r ChangeDetectionWatches) SortByNewest() ChangeDetectionWatches {
+	sort.Slice(r, func(i, j int) bool {
+		return r[i].LastChanged.After(r[j].LastChanged)
+	})
+
+	return r
+}
+
+type changeDetectionResponseJson struct {
+	Title        string `json:"title"`
+	URL          string `json:"url"`
+	LastChanged  int64  `json:"last_changed"`
+	DateCreated  int64  `json:"date_created"`
+	PreviousHash string `json:"previous_md5"`
+}
+
+func FetchWatchUUIDsFromChangeDetection(instanceURL string, token string) ([]string, error) {
+	request, _ := http.NewRequest("GET", fmt.Sprintf("%s/api/v1/watch", instanceURL), nil)
+
+	if token != "" {
+		request.Header.Add("x-api-key", token)
+	}
+
+	uuidsMap, err := decodeJsonFromRequest[map[string]struct{}](defaultClient, request)
+
+	if err != nil {
+		return nil, fmt.Errorf("could not fetch list of watch UUIDs: %v", err)
+	}
+
+	uuids := make([]string, 0, len(uuidsMap))
+
+	for uuid := range uuidsMap {
+		uuids = append(uuids, uuid)
+	}
+
+	return uuids, nil
+}
+
+func FetchWatchesFromChangeDetection(instanceURL string, requestedWatchIDs []string, token string) (ChangeDetectionWatches, error) {
+	watches := make(ChangeDetectionWatches, 0, len(requestedWatchIDs))
+
+	if len(requestedWatchIDs) == 0 {
+		return watches, nil
+	}
+
+	requests := make([]*http.Request, len(requestedWatchIDs))
+
+	for i, repository := range requestedWatchIDs {
+		request, _ := http.NewRequest("GET", fmt.Sprintf("%s/api/v1/watch/%s", instanceURL, repository), nil)
+
+		if token != "" {
+			request.Header.Add("x-api-key", token)
+		}
+
+		requests[i] = request
+	}
+
+	task := decodeJsonFromRequestTask[changeDetectionResponseJson](defaultClient)
+	job := newJob(task, requests).withWorkers(15)
+	responses, errs, err := workerPoolDo(job)
+
+	if err != nil {
+		return nil, err
+	}
+
+	var failed int
+
+	for i := range responses {
+		if errs[i] != nil {
+			failed++
+			slog.Error("Failed to fetch or parse change detection watch", "error", errs[i], "url", requests[i].URL)
+			continue
+		}
+
+		watchJson := responses[i]
+
+		watch := ChangeDetectionWatch{
+			URL:     watchJson.URL,
+			DiffURL: fmt.Sprintf("%s/diff/%s?from_version=%d", instanceURL, requestedWatchIDs[i], watchJson.LastChanged-1),
+		}
+
+		if watchJson.LastChanged == 0 {
+			watch.LastChanged = time.Unix(watchJson.DateCreated, 0)
+		} else {
+			watch.LastChanged = time.Unix(watchJson.LastChanged, 0)
+		}
+
+		if watchJson.Title != "" {
+			watch.Title = watchJson.Title
+		} else {
+			watch.Title = strings.TrimPrefix(strings.Trim(stripURLScheme(watchJson.URL), "/"), "www.")
+		}
+
+		if watchJson.PreviousHash != "" {
+			var hashLength = 8
+
+			if len(watchJson.PreviousHash) < hashLength {
+				hashLength = len(watchJson.PreviousHash)
+			}
+
+			watch.PreviousHash = watchJson.PreviousHash[0:hashLength]
+		}
+
+		watches = append(watches, watch)
+	}
+
+	if len(watches) == 0 {
+		return nil, ErrNoContent
+	}
+
+	watches.SortByNewest()
+
+	if failed > 0 {
+		return watches, fmt.Errorf("%w: could not get %d watches", ErrPartialContent, failed)
+	}
+
+	return watches, nil
+}

internal/feed/utils.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net/url"
+	"regexp"
 	"slices"
 	"strings"
 )
@@ -78,6 +79,13 @@ func maybeCopySliceWithoutZeroValues[T int | float64](values []T) []T {
 	return values
 }
 
+
+var urlSchemePattern = regexp.MustCompile(`^[a-z]+:\/\/`)
+
+func stripURLScheme(url string) string {
+	return urlSchemePattern.ReplaceAllString(url, "")
+}
+
 func limitStringLength(s string, max int) (string, bool) {
 	asRunes := []rune(s)
 

internal/widget/changedetection.go

@@ -0,0 +1,66 @@
+package widget
+
+import (
+	"context"
+	"html/template"
+	"time"
+
+	"github.com/glanceapp/glance/internal/assets"
+	"github.com/glanceapp/glance/internal/feed"
+)
+
+type ChangeDetection struct {
+	widgetBase       `yaml:",inline"`
+	ChangeDetections feed.ChangeDetectionWatches `yaml:"-"`
+	WatchUUIDs       []string                    `yaml:"watches"`
+	InstanceURL      string                      `yaml:"instance-url"`
+	Token            OptionalEnvString           `yaml:"token"`
+	Limit            int                         `yaml:"limit"`
+	CollapseAfter    int                         `yaml:"collapse-after"`
+}
+
+func (widget *ChangeDetection) Initialize() error {
+	widget.withTitle("Change Detection").withCacheDuration(1 * time.Hour)
+
+	if widget.Limit <= 0 {
+		widget.Limit = 10
+	}
+
+	if widget.CollapseAfter == 0 || widget.CollapseAfter < -1 {
+		widget.CollapseAfter = 5
+	}
+
+	if widget.InstanceURL == "" {
+		widget.InstanceURL = "https://www.changedetection.io"
+	}
+
+	return nil
+}
+
+func (widget *ChangeDetection) Update(ctx context.Context) {
+	if len(widget.WatchUUIDs) == 0 {
+		uuids, err := feed.FetchWatchUUIDsFromChangeDetection(widget.InstanceURL, string(widget.Token))
+
+		if !widget.canContinueUpdateAfterHandlingErr(err) {
+			return
+		}
+
+		widget.WatchUUIDs = uuids
+	}
+
+	watches, err := feed.FetchWatchesFromChangeDetection(widget.InstanceURL, widget.WatchUUIDs, string(widget.Token))
+
+	if !widget.canContinueUpdateAfterHandlingErr(err) {
+		return
+	}
+
+	if len(watches) > widget.Limit {
+		watches = watches[:widget.Limit]
+	}
+
+	widget.ChangeDetections = watches
+}
+
+func (widget *ChangeDetection) Render() template.HTML {
+	return widget.render(widget, assets.ChangeDetectionTemplate)
+}

internal/widget/widget.go

@@ -45,6 +45,8 @@ func New(widgetType string) (Widget, error) {
 		return &TwitchGames{}, nil
 	case "twitch-channels":
 		return &TwitchChannels{}, nil
+	case "change-detection":
+		return &ChangeDetection{}, nil
 	case "repository":
 		return &Repository{}, nil
 	case "search":