fix(screenshot): derive the screenshot type from the path extension like the Node.js client (#2021)

Author: yury-s

playwright/src/main/java/com/microsoft/playwright/impl/ElementHandleImpl.java

@@ -36,9 +36,6 @@
 import static com.microsoft.playwright.impl.Serialization.*;
 import static com.microsoft.playwright.impl.Utils.*;
 import static com.microsoft.playwright.impl.Utils.addFilePathUploadParams;
-import static com.microsoft.playwright.options.ScreenshotType.JPEG;
-import static com.microsoft.playwright.options.ScreenshotType.PNG;
-import static com.microsoft.playwright.options.ScreenshotType.WEBP;
 
 public class ElementHandleImpl extends JSHandleImpl implements ElementHandle {
   private final FrameImpl frame;
@@ -270,20 +267,8 @@ public byte[] screenshot(ScreenshotOptions options) {
     if (options == null) {
       options = new ScreenshotOptions();
     }
-    if (options.type == null) {
-      options.type = PNG;
-      if (options.path != null) {
-        String fileName = options.path.getFileName().toString();
-        int extStart = fileName.lastIndexOf('.');
-        if (extStart != -1) {
-          String extension = fileName.substring(extStart).toLowerCase();
-          if (".jpeg".equals(extension) || ".jpg".equals(extension)) {
-            options.type = JPEG;
-          } else if (".webp".equals(extension)) {
-            options.type = WEBP;
-          }
-        }
-      }
+    if (options.type == null && options.path != null) {
+      options.type = Utils.screenshotTypeForPath(options.path);
     }
     JsonObject params = gson().toJsonTree(options).getAsJsonObject();
     params.remove("path");

playwright/src/main/java/com/microsoft/playwright/impl/PageImpl.java

@@ -33,9 +33,6 @@
 import static com.microsoft.playwright.impl.Serialization.gson;
 import static com.microsoft.playwright.impl.Serialization.parseError;
 import static com.microsoft.playwright.impl.Utils.*;
-import static com.microsoft.playwright.options.ScreenshotType.JPEG;
-import static com.microsoft.playwright.options.ScreenshotType.PNG;
-import static com.microsoft.playwright.options.ScreenshotType.WEBP;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.nio.file.Files.readAllBytes;
 import static java.util.Arrays.asList;
@@ -1273,20 +1270,8 @@ private byte[] screenshotImpl(ScreenshotOptions options) {
     if (options == null) {
       options = new ScreenshotOptions();
     }
-    if (options.type == null) {
-      options.type = PNG;
-      if (options.path != null) {
-        String fileName = options.path.getFileName().toString();
-        int extStart = fileName.lastIndexOf('.');
-        if (extStart != -1) {
-          String extension = fileName.substring(extStart).toLowerCase();
-          if (".jpeg".equals(extension) || ".jpg".equals(extension)) {
-            options.type = JPEG;
-          } else if (".webp".equals(extension)) {
-            options.type = WEBP;
-          }
-        }
-      }
+    if (options.type == null && options.path != null) {
+      options.type = Utils.screenshotTypeForPath(options.path);
     }
     JsonObject params = gson().toJsonTree(options).getAsJsonObject();
     params.remove("path");

playwright/src/main/java/com/microsoft/playwright/impl/Utils.java

@@ -23,13 +23,15 @@
 import com.microsoft.playwright.options.ClientCertificate;
 import com.microsoft.playwright.options.FilePayload;
 import com.microsoft.playwright.options.HttpHeader;
+import com.microsoft.playwright.options.ScreenshotType;
 
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
+import java.net.URLConnection;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.*;
@@ -246,6 +248,21 @@ static void mkParentDirs(Path file) {
     }
   }
 
+  /** The screenshot type for a path when no type is given, from its extension, like the Node.js client. */
+  static ScreenshotType screenshotTypeForPath(Path path) {
+    String fileName = path.getFileName().toString();
+    int extStart = fileName.lastIndexOf('.');
+    String extension = extStart == -1 ? "" : fileName.substring(extStart + 1).toLowerCase();
+    switch (extension) {
+      case "png": return ScreenshotType.PNG;
+      case "jpg":
+      case "jpeg": return ScreenshotType.JPEG;
+      case "webp": return ScreenshotType.WEBP;
+      default:
+        throw new PlaywrightException("path: unsupported mime type \"" + URLConnection.guessContentTypeFromName(fileName) + "\"");
+    }
+  }
+
   static void writeToFile(byte[] buffer, Path path) {
     mkParentDirs(path);
     try (FileOutputStream out = new FileOutputStream(path.toFile())) {

playwright/src/test/java/com/microsoft/playwright/TestPageScreenshot.java

@@ -352,4 +352,29 @@ private byte[] expectedScreenshot(BrowserType browserType, String name) throws I
     Path path = Paths.get("src/test/resources/expectations");
     return Files.readAllBytes(path.resolve(name + "-" + browserType.name() + ".png"));
   }
+
+  @PlaywrightTest
+  void pathOptionShouldDetectJpeg(Page page, @TempDir Path tmpDir) throws IOException {
+    Path outputPath = tmpDir.resolve("screenshot.jpg");
+    byte[] buffer = page.screenshot(new Page.ScreenshotOptions().setPath(outputPath));
+    assertEquals(asList(0xFF, 0xD8, 0xFF), asList(buffer[0] & 0xFF, buffer[1] & 0xFF, buffer[2] & 0xFF));
+    assertArrayEquals(buffer, Files.readAllBytes(outputPath));
+  }
+
+  @PlaywrightTest
+  void shouldPreferTypeOverPathExtension(Page page, @TempDir Path tmpDir) {
+    Path outputPath = tmpDir.resolve("screenshot.png");
+    byte[] buffer = page.screenshot(new Page.ScreenshotOptions().setPath(outputPath).setType(ScreenshotType.JPEG));
+    assertEquals(asList(0xFF, 0xD8, 0xFF), asList(buffer[0] & 0xFF, buffer[1] & 0xFF, buffer[2] & 0xFF));
+  }
+
+  @PlaywrightTest
+  void pathOptionShouldThrowForUnsupportedExtension(Page page, @TempDir Path tmpDir) {
+    PlaywrightException e = assertThrows(PlaywrightException.class,
+      () -> page.screenshot(new Page.ScreenshotOptions().setPath(tmpDir.resolve("screenshot.txt"))));
+    assertTrue(e.getMessage().contains("path: unsupported mime type \"text/plain\""), e.getMessage());
+    e = assertThrows(PlaywrightException.class,
+      () -> page.locator("body").screenshot(new Locator.ScreenshotOptions().setPath(tmpDir.resolve("screenshot.txt"))));
+    assertTrue(e.getMessage().contains("path: unsupported mime type \"text/plain\""), e.getMessage());
+  }
 }