feat(feishu): support downloading external images from interactive cards

Previously only Feishu-hosted images (img_key, icon_key) could be
downloaded. Now external URLs in src field are also downloaded via
HTTP and made available to the LLM.

- extractCardImageKeys now returns two slices: Feishu keys and external URLs
- Add downloadExternalImage to download images from HTTP URLs
- Update downloadInboundMedia to handle both Feishu API and HTTP downloads
- Update tests for new function signature

pkg/channels/feishu/common.go

@@ -87,66 +87,61 @@ func stripMentionPlaceholders(content string, mentions []*larkim.MentionEvent) s
 
 // extractCardImageKeys recursively extracts all image keys from a Feishu interactive card.
 // Image keys are used to download images from Feishu API.
-// Only Feishu-hosted keys are returned (img_xxx, icon_xxx); external URLs are filtered out.
-func extractCardImageKeys(rawContent string) []string {
+// Returns two slices: Feishu-hosted keys and external URLs.
+func extractCardImageKeys(rawContent string) (feishuKeys []string, externalURLs []string) {
 	if rawContent == "" {
-		return nil
+		return nil, nil
 	}
 
 	var card map[string]any
 	if err := json.Unmarshal([]byte(rawContent), &card); err != nil {
-		return nil
+		return nil, nil
 	}
 
-	var keys []string
-	extractImageKeysRecursive(card, &keys)
-	return keys
+	extractImageKeysRecursive(card, &feishuKeys, &externalURLs)
+	return feishuKeys, externalURLs
 }
 
-// isFeishuImageKey returns true if the string is a Feishu-hosted image key
-// (not an external URL). Feishu keys typically start with img_, icon_, or file_.
-func isFeishuImageKey(s string) bool {
-	if s == "" {
-		return false
-	}
-	// Filter out external URLs
-	if strings.HasPrefix(s, "http://") || strings.HasPrefix(s, "https://") {
-		return false
-	}
-	return true
+// isExternalURL returns true if the string is an external HTTP/HTTPS URL.
+func isExternalURL(s string) bool {
+	return strings.HasPrefix(s, "http://") || strings.HasPrefix(s, "https://")
 }
 
 // extractImageKeysRecursive traverses card structure to find all image keys.
-// Only Feishu-hosted keys are collected; external URLs are skipped.
-func extractImageKeysRecursive(v any, keys *[]string) {
+// Collects both Feishu-hosted keys and external URLs separately.
+func extractImageKeysRecursive(v any, feishuKeys, externalURLs *[]string) {
 	switch val := v.(type) {
 	case map[string]any:
 		// Check if this is an img element
 		if tag, ok := val["tag"].(string); ok {
 			switch tag {
 			case "img":
-				// Try img_key first (most common, always Feishu-hosted)
+				// Try img_key first (always Feishu-hosted)
 				if imgKey, ok := val["img_key"].(string); ok && imgKey != "" {
-					*keys = append(*keys, imgKey)
+					*feishuKeys = append(*feishuKeys, imgKey)
 				}
-				// Also try src, but only if it's a Feishu-hosted key (not external URL)
-				if src, ok := val["src"].(string); ok && src != "" && isFeishuImageKey(src) {
-					*keys = append(*keys, src)
+				// Check src - could be Feishu key or external URL
+				if src, ok := val["src"].(string); ok && src != "" {
+					if isExternalURL(src) {
+						*externalURLs = append(*externalURLs, src)
+					} else {
+						*feishuKeys = append(*feishuKeys, src)
+					}
 				}
 			case "icon":
 				// Icon elements use icon_key
 				if iconKey, ok := val["icon_key"].(string); ok && iconKey != "" {
-					*keys = append(*keys, iconKey)
+					*feishuKeys = append(*feishuKeys, iconKey)
 				}
 			}
 		}
 		// Recurse into all nested structures
 		for _, child := range val {
-			extractImageKeysRecursive(child, keys)
+			extractImageKeysRecursive(child, feishuKeys, externalURLs)
 		}
 	case []any:
 		for _, item := range val {
-			extractImageKeysRecursive(item, keys)
+			extractImageKeysRecursive(item, feishuKeys, externalURLs)
 		}
 	}
 }

pkg/channels/feishu/common_test.go

@@ -293,82 +293,114 @@ func TestStripMentionPlaceholders(t *testing.T) {
 
 func TestExtractCardImageKeys(t *testing.T) {
 	tests := []struct {
-		name    string
-		content string
-		want    []string
+		name              string
+		content           string
+		wantFeishuKeys    []string
+		wantExternalURLs  []string
 	}{
 		{
-			name:    "empty content",
-			content: "",
-			want:    nil,
+			name:              "empty content",
+			content:           "",
+			wantFeishuKeys:    nil,
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "invalid JSON",
-			content: "not json",
-			want:    nil,
+			name:              "invalid JSON",
+			content:           "not json",
+			wantFeishuKeys:    nil,
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "card with no images",
-			content: `{"schema":"2.0","body":{"elements":[{"tag":"markdown","content":"text"}]}}`,
-			want:    nil,
+			name:              "card with no images",
+			content:           `{"schema":"2.0","body":{"elements":[{"tag":"markdown","content":"text"}]}}`,
+			wantFeishuKeys:    nil,
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "single image with img_key",
-			content: `{"elements":[{"tag":"img","img_key":"img_abc123"}]}`,
-			want:    []string{"img_abc123"},
+			name:              "single image with img_key",
+			content:           `{"elements":[{"tag":"img","img_key":"img_abc123"}]}`,
+			wantFeishuKeys:    []string{"img_abc123"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "single image with src",
-			content: `{"elements":[{"tag":"img","src":"img_xyz789"}]}`,
-			want:    []string{"img_xyz789"},
+			name:              "single image with src as Feishu key",
+			content:           `{"elements":[{"tag":"img","src":"img_xyz789"}]}`,
+			wantFeishuKeys:    []string{"img_xyz789"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "multiple images",
-			content: `{"elements":[{"tag":"img","img_key":"img_1"},{"tag":"div","text":{"content":"text"}},{"tag":"img","img_key":"img_2"}]}`,
-			want:    []string{"img_1", "img_2"},
+			name:              "multiple images",
+			content:           `{"elements":[{"tag":"img","img_key":"img_1"},{"tag":"div","text":{"content":"text"}},{"tag":"img","img_key":"img_2"}]}`,
+			wantFeishuKeys:    []string{"img_1", "img_2"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "nested image in columns",
-			content: `{"elements":[{"tag":"div","columns":[{"tag":"img","img_key":"img_col1"},{"tag":"img","img_key":"img_col2"}]}]}`,
-			want:    []string{"img_col1", "img_col2"},
+			name:              "nested image in columns",
+			content:           `{"elements":[{"tag":"div","columns":[{"tag":"img","img_key":"img_col1"},{"tag":"img","img_key":"img_col2"}]}]}`,
+			wantFeishuKeys:    []string{"img_col1", "img_col2"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "image in action",
-			content: `{"elements":[{"tag":"action","actions":[{"tag":"img","img_key":"img_action"}]}]}`,
-			want:    []string{"img_action"},
+			name:              "image in action",
+			content:           `{"elements":[{"tag":"action","actions":[{"tag":"img","img_key":"img_action"}]}]}`,
+			wantFeishuKeys:    []string{"img_action"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "icon element",
-			content: `{"elements":[{"tag":"icon","icon_key":"icon_123"}]}`,
-			want:    []string{"icon_123"},
+			name:              "icon element",
+			content:           `{"elements":[{"tag":"icon","icon_key":"icon_123"}]}`,
+			wantFeishuKeys:    []string{"icon_123"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "complex card with text and images",
-			content: `{"header":{"title":{"content":"Title"}},"elements":[{"tag":"div","text":{"content":"Description"}},{"tag":"img","img_key":"img_main"}]}`,
-			want:    []string{"img_main"},
+			name:              "complex card with text and images",
+			content:           `{"header":{"title":{"content":"Title"}},"elements":[{"tag":"div","text":{"content":"Description"}},{"tag":"img","img_key":"img_main"}]}`,
+			wantFeishuKeys:    []string{"img_main"},
+			wantExternalURLs:  nil,
 		},
 		{
-			name:    "external URL in src is filtered out",
-			content: `{"elements":[{"tag":"img","src":"https://example.com/image.png"}]}`,
-			want:    nil,
+			name:              "external URL in src",
+			content:           `{"elements":[{"tag":"img","src":"https://example.com/image.png"}]}`,
+			wantFeishuKeys:    nil,
+			wantExternalURLs:  []string{"https://example.com/image.png"},
 		},
 		{
-			name:    "mixed Feishu keys and external URLs",
-			content: `{"elements":[{"tag":"img","img_key":"img_feishu"},{"tag":"img","src":"https://cdn.example.com/external.jpg"},{"tag":"img","src":"img_another"}]}`,
-			want:    []string{"img_feishu", "img_another"},
+			name:              "mixed Feishu keys and external URLs",
+			content:           `{"elements":[{"tag":"img","img_key":"img_feishu"},{"tag":"img","src":"https://cdn.example.com/external.jpg"},{"tag":"img","src":"img_another"}]}`,
+			wantFeishuKeys:    []string{"img_feishu", "img_another"},
+			wantExternalURLs:  []string{"https://cdn.example.com/external.jpg"},
+		},
+		{
+			name:              "multiple external URLs",
+			content:           `{"elements":[{"tag":"img","src":"https://a.com/1.png"},{"tag":"img","src":"http://b.com/2.jpg"}]}`,
+			wantFeishuKeys:    nil,
+			wantExternalURLs:  []string{"https://a.com/1.png", "http://b.com/2.jpg"},
 		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got := extractCardImageKeys(tt.content)
-			if len(got) != len(tt.want) {
-				t.Errorf("extractCardImageKeys() = %v, want %v", got, tt.want)
+			gotFeishuKeys, gotExternalURLs := extractCardImageKeys(tt.content)
+
+			// Compare Feishu keys
+			if len(gotFeishuKeys) != len(tt.wantFeishuKeys) {
+				t.Errorf("extractCardImageKeys() feishuKeys = %v, want %v", gotFeishuKeys, tt.wantFeishuKeys)
 				return
 			}
-			for i, v := range got {
-				if v != tt.want[i] {
-					t.Errorf("extractCardImageKeys()[%d] = %q, want %q", i, v, tt.want[i])
+			for i, v := range gotFeishuKeys {
+				if v != tt.wantFeishuKeys[i] {
+					t.Errorf("extractCardImageKeys() feishuKeys[%d] = %q, want %q", i, v, tt.wantFeishuKeys[i])
+				}
+			}
+
+			// Compare external URLs
+			if len(gotExternalURLs) != len(tt.wantExternalURLs) {
+				t.Errorf("extractCardImageKeys() externalURLs = %v, want %v", gotExternalURLs, tt.wantExternalURLs)
+				return
+			}
+			for i, v := range gotExternalURLs {
+				if v != tt.wantExternalURLs[i] {
+					t.Errorf("extractCardImageKeys() externalURLs[%d] = %q, want %q", i, v, tt.wantExternalURLs[i])
 				}
 			}
 		})

pkg/channels/feishu/feishu_64.go

@@ -550,13 +550,21 @@ func (c *FeishuChannel) downloadInboundMedia(
 
 	case larkim.MsgTypeInteractive:
 		// Extract and download images embedded in interactive cards
-		imageKeys := extractCardImageKeys(rawContent)
-		for _, imageKey := range imageKeys {
+		feishuKeys, externalURLs := extractCardImageKeys(rawContent)
+		// Download Feishu-hosted images via API
+		for _, imageKey := range feishuKeys {
 			ref := c.downloadResource(ctx, messageID, imageKey, "image", ".jpg", store, scope)
 			if ref != "" {
 				refs = append(refs, ref)
 			}
 		}
+		// Download external images via HTTP
+		for _, imageURL := range externalURLs {
+			ref := c.downloadExternalImage(ctx, imageURL, store, scope)
+			if ref != "" {
+				refs = append(refs, ref)
+			}
+		}
 
 	case larkim.MsgTypeFile, larkim.MsgTypeAudio, larkim.MsgTypeMedia:
 		fileKey := extractFileKey(rawContent)
@@ -676,6 +684,100 @@ func (c *FeishuChannel) downloadResource(
 	return ref
 }
 
+// downloadExternalImage downloads an image from an external URL and stores it in MediaStore.
+// Returns the media reference on success, or empty string on failure.
+func (c *FeishuChannel) downloadExternalImage(
+	ctx context.Context,
+	imageURL string,
+	store media.MediaStore,
+	scope string,
+) string {
+	// Create HTTP request with context
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, imageURL, nil)
+	if err != nil {
+		logger.ErrorCF("feishu", "Failed to create request for external image", map[string]any{
+			"url":   imageURL,
+			"error": err.Error(),
+		})
+		return ""
+	}
+
+	// Download image
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		logger.ErrorCF("feishu", "Failed to download external image", map[string]any{
+			"url":   imageURL,
+			"error": err.Error(),
+		})
+		return ""
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		logger.ErrorCF("feishu", "External image download failed with status", map[string]any{
+			"url":    imageURL,
+			"status": resp.StatusCode,
+		})
+		return ""
+	}
+
+	// Determine filename from URL path
+	filename := filepath.Base(imageURL)
+	if filename == "" || filename == "." || filename == "/" {
+		filename = "external_image"
+	}
+	// Ensure we have an extension for images
+	if filepath.Ext(filename) == "" {
+		filename += ".jpg"
+	}
+
+	// Write to the shared picoclaw_media directory using a unique name to avoid collisions.
+	mediaDir := filepath.Join(os.TempDir(), "picoclaw_media")
+	if mkdirErr := os.MkdirAll(mediaDir, 0o700); mkdirErr != nil {
+		logger.ErrorCF("feishu", "Failed to create media directory", map[string]any{
+			"error": mkdirErr.Error(),
+		})
+		return ""
+	}
+	ext := filepath.Ext(filename)
+	localPath := filepath.Join(mediaDir, utils.SanitizeFilename(fmt.Sprintf("ext_%d%s", rand.Int63(), ext)))
+
+	out, err := os.Create(localPath)
+	if err != nil {
+		logger.ErrorCF("feishu", "Failed to create temp file for external image", map[string]any{
+			"path":  localPath,
+			"error": err.Error(),
+		})
+		return ""
+	}
+
+	if _, err := io.Copy(out, resp.Body); err != nil {
+		out.Close()
+		os.Remove(localPath)
+		logger.ErrorCF("feishu", "Failed to write external image to file", map[string]any{
+			"error": err.Error(),
+		})
+		return ""
+	}
+	out.Close()
+
+	// Store in MediaStore
+	ref, err := store.Store(localPath, media.MediaMeta{
+		Filename: filename,
+		Source:   "feishu_external",
+	}, scope)
+	if err != nil {
+		logger.ErrorCF("feishu", "Failed to store external image", map[string]any{
+			"url":   imageURL,
+			"error": err.Error(),
+		})
+		os.Remove(localPath)
+		return ""
+	}
+
+	return ref
+}
+
 // appendMediaTags appends media type tags to content (like Telegram's "[image: photo]").
 // For interactive cards, media tags are not appended because content is raw JSON
 // and appending would produce invalid JSON format.