Feat : Capture Cross Iframe and Responsive Capture Features by yashmahamulkar-bs · Pull Request #211 · percy/percy-selenium-python

yashmahamulkar-bs · 2026-03-15T21:56:44Z

This pull request introduces significant improvements to the percy/snapshot.py module, focusing on enhanced support for responsive and cross-origin iframe snapshotting, as well as better configuration via environment variables. The changes also include utility refactoring and improved test compatibility.

Responsive Snapshot and Cross-Origin Iframe Enhancements:

Added comprehensive support for capturing and stitching cross-origin iframes into DOM snapshots, including context management for iframe switching, serialization, and resource deduplication. (percy/snapshot.py)
Improved responsive snapshot capture by introducing new environment variable controls (PERCY_RESPONSIVE_CAPTURE_MIN_HEIGHT, PERCY_RESPONSIVE_CAPTURE_RELOAD_PAGE), fetching responsive widths from the Percy server, and handling window resizing and reload logic more robustly. (percy/snapshot.py) [1] [2]

Refactoring and Utility Improvements:

Refactored utility functions for environment variable parsing and window resize event handling, and restructured code to use context managers for safe iframe switching. (percy/snapshot.py) [1] [2]
Streamlined the main snapshotting logic to consistently inject the Percy DOM script and pass it to downstream functions, ensuring consistent behavior across both regular and responsive snapshots. (percy/snapshot.py)

Testing and Compatibility:

Updated test imports to use the correct WebDriver class from Selenium, improving compatibility with recent Selenium versions. (tests/test_driver_metadata.py)

Copilot

Pull request overview

This PR expands percy/snapshot.py to support cross-origin iframe stitching into DOM snapshots and improves responsive snapshot capture behavior/configuration (including new env-var toggles and fetching responsive widths from the Percy CLI). It also updates Selenium-related test imports/behavior for compatibility and adds targeted unit/integration-ish tests around the new functionality.

Changes:

Add cross-origin iframe capture + stitching into srcdoc, including safe iframe context switching and resource deduplication.
Rework responsive snapshot capture to fetch computed widths from /percy/widths-config, add reload/min-height controls, and refactor resize handling.
Update/extend tests to accommodate the new snapshot request patterns and Selenium WebDriver imports.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 7 comments.

File	Description
`percy/snapshot.py`	Implements cross-origin iframe processing/stitching and refactors responsive snapshot capture to use CLI-provided widths and new env-var controlled behaviors.
`tests/test_snapshot.py`	Updates snapshot assertions to be more robust against httpretty request ordering/duplication; adds new tests for responsive reload/min-height and iframe stitching.
`tests/test_driver_metadata.py`	Updates Selenium WebDriver import/patch targets for improved compatibility with newer Selenium versions.

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yashmahamulkar-bs · 2026-03-16T05:35:53Z

percy/snapshot.py

+        window._percyResizeHandler = () => { window.resizeCount++; };
+        window.removeEventListener('resize', window._percyResizeHandler);


percy/snapshot.py

+        page_origin = _get_origin(driver.current_url)
+        iframes = driver.find_elements("tag name", "iframe")
+        if iframes and percy_dom_script:
+            processed_frames = []
+            for frame in iframes:
+                frame_src = frame.get_attribute('src')
+                if _is_unsupported_iframe_src(frame_src):
+                    continue
+
+                try:
+                    frame_origin = _get_origin(urljoin(driver.current_url, frame_src))
+                except Exception as e:
+                    log(f"Skipping iframe \"{frame_src}\": {e}", "debug")
+                    continue
+
+                if frame_origin == page_origin:
+                    continue
+
+                result = process_frame(driver, frame, kwargs, percy_dom_script)
+                if result:
+                    processed_frames.append(result)
+
+            if processed_frames:
+                dom_snapshot = stitch_cors_iframes(dom_snapshot, processed_frames)


yashmahamulkar-bs · 2026-03-16T05:39:03Z

percy/snapshot.py

+            target_height = driver.execute_script(
+                f"return window.outerHeight - window.innerHeight + {min_height}")
+            log(
+                f'Calculated height for responsive capture using minHeight: {target_height}',
+                'debug')


percy/snapshot.py

yashmahamulkar-bs · 2026-03-16T06:56:49Z

percy/snapshot.py


 # pylint: disable=too-many-arguments, too-many-branches, too-many-locals
 def create_region(
+    *,


yashmahamulkar-bs · 2026-03-16T06:56:57Z

tests/test_snapshot.py

    @patch('selenium.webdriver.Chrome')
    def test_posts_snapshots_to_the_local_percy_server_for_responsive_dom_chrome(self, MockChrome):
        os.environ['RESONSIVE_CAPTURE_SLEEP_TIME'] = '1'


tests/test_snapshot.py

rahulXbrowserstack

Check test this thing once
We have

iPhone 13 → width: 390px, height: 663px
Samsung S22 → width: 360px, height: 649px
Now, when a mobile device is selected, its DOM will be captured at the specific device height.

If the same widths (390px or 360px) are used in desktop configs, then:

The default desktop height will be applied, OR
If minHeight is set and the PERCY_RESPONSIVE_CAPTURE_MIN_HEIGHT flag is enabled, then that minHeight will be used instead.

rahulXbrowserstack

also add the enhancement in the label of this PR, as this will ease to track the changes across versions

yashmahamulkar-bs added 6 commits March 11, 2026 12:07

added new features

965c2d3

Adding Cross Iframe feature

88e3cc9

adding cross iframe stich feature:

d0a9520

fixing lints

da20d79

fixing linting issue

4fb5086

fixing linting issue

bf30d28

yashmahamulkar-bs requested a review from a team as a code owner March 15, 2026 21:56

yashmahamulkar-bs requested review from Shivanshu-07, Copilot and ninadbstack March 15, 2026 21:56

Copilot started reviewing on behalf of yashmahamulkar-bs March 15, 2026 21:57 View session

Copilot AI reviewed Mar 15, 2026

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yashmahamulkar-bs added 6 commits March 16, 2026 11:50

Resolving copilot reviews

a684f63

fixing copilot reviews

4241fd7

fixing lint

6595916

fixing test issues

d44531f

fixing test issues

25ce0e4

fixing lint issues

4b77d63

yashmahamulkar-bs changed the title ~~Add Cross Iframe features~~ Feat : Add Cross Iframe features and Responsive Capture Features Mar 16, 2026

yashmahamulkar-bs changed the title ~~Feat : Add Cross Iframe features and Responsive Capture Features~~ Feat : Capture Cross Iframe and Responsive Capture Features Mar 16, 2026

yashmahamulkar-bs added 2 commits March 16, 2026 20:54

using cli changes for cross origin iframe

0bec057

fixing lint

c32595d

yashmahamulkar-bs requested a review from rahulXbrowserstack March 17, 2026 10:32

changes in height logic

e987e03

rahulXbrowserstack approved these changes Mar 18, 2026

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rahulXbrowserstack reviewed Mar 18, 2026

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yashmahamulkar-bs requested a review from rishigupta1599 March 18, 2026 10:25

rahulXbrowserstack reviewed Mar 18, 2026

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yashmahamulkar-bs added the ✨ enhancement New feature or request label Mar 18, 2026

rishigupta1599 approved these changes Mar 18, 2026

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Alpha Release 2.1.4

a730a99

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Feat : Capture Cross Iframe and Responsive Capture Features#211

Feat : Capture Cross Iframe and Responsive Capture Features#211
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		window._percyResizeHandler = () => { window.resizeCount++; };
		window.removeEventListener('resize', window._percyResizeHandler);

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