Add ParseImagePath for chi wildcard and upstream fetcher with SSRF protection

internal/imgcache/urlparser_test.go

@@ -162,6 +162,63 @@ func TestParseImageURL(t *testing.T) {
 	}
 }
 
+func TestParseImagePath(t *testing.T) {
+	// ParseImagePath is for chi wildcard capture (no /v1/image/ prefix)
+	tests := []struct {
+		name    string
+		input   string
+		want    *ParsedURL
+		wantErr bool
+	}{
+		{
+			name:  "chi wildcard capture",
+			input: "cdn.example.com/photos/cat.jpg/800x600.webp",
+			want: &ParsedURL{
+				Host:   "cdn.example.com",
+				Path:   "/photos/cat.jpg",
+				Size:   Size{Width: 800, Height: 600},
+				Format: FormatWebP,
+			},
+		},
+		{
+			name:  "with leading slash from chi",
+			input: "/cdn.example.com/photos/cat.jpg/800x600.webp",
+			want: &ParsedURL{
+				Host:   "cdn.example.com",
+				Path:   "/photos/cat.jpg",
+				Size:   Size{Width: 800, Height: 600},
+				Format: FormatWebP,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ParseImagePath(tt.input)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ParseImagePath() error = %v, wantErr %v", err, tt.wantErr)
+
+				return
+			}
+			if err != nil {
+				return
+			}
+			if got.Host != tt.want.Host {
+				t.Errorf("Host = %q, want %q", got.Host, tt.want.Host)
+			}
+			if got.Path != tt.want.Path {
+				t.Errorf("Path = %q, want %q", got.Path, tt.want.Path)
+			}
+			if got.Size != tt.want.Size {
+				t.Errorf("Size = %v, want %v", got.Size, tt.want.Size)
+			}
+			if got.Format != tt.want.Format {
+				t.Errorf("Format = %q, want %q", got.Format, tt.want.Format)
+			}
+		})
+	}
+}
+
 func TestParsedURL_ToImageRequest(t *testing.T) {
 	parsed := &ParsedURL{
 		Host:   "cdn.example.com",