3 files changed, 92 insertions, 2 deletions

diff --git a/apps/web/lib/sanitize.test.ts b/apps/web/lib/sanitize.test.ts
index 266b8af..f47db80 100644
--- a/apps/web/lib/sanitize.test.ts
+++ b/apps/web/lib/sanitize.test.ts
@@ -44,4 +44,50 @@ describe("sanitizeEntryContent", () => {
     const input = "<pre><code>const x = 1</code></pre>"
     expect(sanitizeEntryContent(input)).toBe(input)
   })
+
+  it("strips 1x1 tracking pixel images", () => {
+    const input = '<p>content</p><img src="https://tracker.example.com/pixel.gif" width="1" height="1">'
+    expect(sanitizeEntryContent(input)).toBe("<p>content</p>")
+  })
+
+  it("strips images with zero dimensions", () => {
+    const input = '<img src="https://tracker.example.com/pixel.gif" width="0" height="0">'
+    expect(sanitizeEntryContent(input)).toBe("")
+  })
+
+  it("strips images where only width is a tracking dimension", () => {
+    const input = '<img src="https://tracker.example.com/pixel.gif" width="1">'
+    expect(sanitizeEntryContent(input)).toBe("")
+  })
+
+  it("strips images where only height is a tracking dimension", () => {
+    const input = '<img src="https://tracker.example.com/pixel.gif" height="2">'
+    expect(sanitizeEntryContent(input)).toBe("")
+  })
+
+  it("preserves normal-sized images", () => {
+    const input = '<img src="https://example.com/photo.jpg" width="800" height="600">'
+    const result = sanitizeEntryContent(input)
+    expect(result).toContain("src=")
+    expect(result).toContain("width=")
+    expect(result).toContain("height=")
+  })
+
+  it("preserves images without dimension attributes", () => {
+    const input = '<img src="https://example.com/photo.jpg" alt="a photo">'
+    const result = sanitizeEntryContent(input)
+    expect(result).toContain("src=")
+    expect(result).toContain("alt=")
+  })
+
+  it("strips 3x3 tracking pixel at threshold boundary", () => {
+    const input = '<img src="https://tracker.example.com/pixel.gif" width="3" height="3">'
+    expect(sanitizeEntryContent(input)).toBe("")
+  })
+
+  it("preserves images just above tracking pixel threshold", () => {
+    const input = '<img src="https://example.com/icon.png" width="4" height="4">'
+    const result = sanitizeEntryContent(input)
+    expect(result).toContain("src=")
+  })
 })
diff --git a/apps/web/lib/sanitize.ts b/apps/web/lib/sanitize.ts
index b63cee1..3a85016 100644
--- a/apps/web/lib/sanitize.ts
+++ b/apps/web/lib/sanitize.ts
@@ -1,5 +1,19 @@
 import sanitizeHtml from "sanitize-html"
 
+const TRACKING_PIXEL_DIMENSION_THRESHOLD = 3
+
+function isTrackingPixel(tagName: string, attributes: Record<string, string>): boolean {
+  if (tagName !== "img") return false
+
+  const width = parseInt(attributes.width, 10)
+  const height = parseInt(attributes.height, 10)
+
+  if (!isNaN(width) && width <= TRACKING_PIXEL_DIMENSION_THRESHOLD) return true
+  if (!isNaN(height) && height <= TRACKING_PIXEL_DIMENSION_THRESHOLD) return true
+
+  return false
+}
+
 const SANITIZE_OPTIONS: sanitizeHtml.IOptions = {
   allowedTags: [
     "h1",
@@ -36,6 +50,7 @@ const SANITIZE_OPTIONS: sanitizeHtml.IOptions = {
     img: ["src", "alt", "title", "width", "height"],
   },
   allowedSchemes: ["http", "https"],
+  exclusiveFilter: (frame) => isTrackingPixel(frame.tag, frame.attribs),
 }
 
 export function sanitizeEntryContent(htmlContent: string): string {
diff --git a/services/worker/internal/parser/parser.go b/services/worker/internal/parser/parser.go
index 203a943..b5307e8 100644
--- a/services/worker/internal/parser/parser.go
+++ b/services/worker/internal/parser/parser.go
@@ -174,13 +174,42 @@ func resolveGloballyUniqueIdentifier(feedItem *gofeed.Item) string {
 	return fmt.Sprintf("sha256:%x", hashBytes)
 }
 
+func stripTrackingParameters(rawURL string) string {
+	trimmedURL := strings.TrimSpace(rawURL)
+
+	if !strings.HasPrefix(trimmedURL, "http://") && !strings.HasPrefix(trimmedURL, "https://") {
+		return trimmedURL
+	}
+
+	parsedURL, parseError := url.Parse(trimmedURL)
+
+	if parseError != nil {
+		return trimmedURL
+	}
+
+	queryParameters := parsedURL.Query()
+	filteredParameters := url.Values{}
+
+	for parameterName, parameterValues := range queryParameters {
+		loweredName := strings.ToLower(parameterName)
+
+		if !trackingQueryParameters[loweredName] {
+			filteredParameters[parameterName] = parameterValues
+		}
+	}
+
+	parsedURL.RawQuery = canonicalizeQueryString(filteredParameters)
+
+	return parsedURL.String()
+}
+
 func resolveEntryURL(feedItem *gofeed.Item) string {
 	if feedItem.Link != "" {
-		return feedItem.Link
+		return stripTrackingParameters(feedItem.Link)
 	}
 
 	if feedItem.GUID != "" && strings.HasPrefix(feedItem.GUID, "http") {
-		return feedItem.GUID
+		return stripTrackingParameters(feedItem.GUID)
 	}
 
 	return ""