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Add closed shadow DOM capture via CDP #33

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Add closed shadow DOM capture via CDP #33

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98 changes: 98 additions & 0 deletions src/main/java/io/percy/playwright/Percy.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,9 @@
import com.microsoft.playwright.*;
import com.microsoft.playwright.options.Cookie;
import com.microsoft.playwright.options.ViewportSize;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;


/**
Expand Down Expand Up @@ -303,6 +306,10 @@ public JSONObject snapshot(String name, Map<String, Object> options) {
String percyDomScript = fetchPercyDOM();
page.evaluate(percyDomScript);

// Expose closed shadow roots via CDP before serialization so
// PercyDOM.serialize() can access them through the WeakMap
exposeClosedShadowRoots(page);

List<Cookie> cookies = new ArrayList<>();
try {
cookies = page.context().cookies();
Expand Down Expand Up @@ -902,6 +909,97 @@ Map<String, Object> getSerializedDOM(
return mutableSnapshot;
}

// -------------------------------------------------------------------------
// Closed Shadow DOM via CDP
// -------------------------------------------------------------------------

/**
* Use CDP to discover closed shadow roots and expose them to PercyDOM.serialize().
* Closed shadow roots are inaccessible from JS (element.shadowRoot === null),
* but CDP's DOM domain can pierce them.
*/
private void exposeClosedShadowRoots(Page page) {
CDPSession cdpSession = null;
try {
cdpSession = page.context().newCDPSession(page);
} catch (Exception err) {
log("CDP session unavailable: " + err.getMessage(), "debug");
return;
}

try {
cdpSession.send("DOM.enable");

JsonObject docParams = new JsonObject();
docParams.addProperty("depth", -1);
docParams.addProperty("pierce", true);
JsonElement docResult = cdpSession.send("DOM.getDocument", docParams);
JsonObject root = docResult.getAsJsonObject().getAsJsonObject("root");

List<JsonObject> closedPairs = new ArrayList<>();
walkNodes(root, closedPairs);

if (closedPairs.isEmpty()) {
return;
}

log("Found " + closedPairs.size() + " closed shadow root(s), exposing via CDP", "debug");

page.evaluate("() => { window.__percyClosedShadowRoots = window.__percyClosedShadowRoots || new WeakMap(); }");

for (JsonObject pair : closedPairs) {
JsonObject resolveHost = new JsonObject();
resolveHost.addProperty("backendNodeId", pair.get("hostBackendNodeId").getAsInt());
JsonElement hostResult = cdpSession.send("DOM.resolveNode", resolveHost);
String hostObjectId = hostResult.getAsJsonObject().getAsJsonObject("object").get("objectId").getAsString();

JsonObject resolveShadow = new JsonObject();
resolveShadow.addProperty("backendNodeId", pair.get("shadowBackendNodeId").getAsInt());
JsonElement shadowResult = cdpSession.send("DOM.resolveNode", resolveShadow);
String shadowObjectId = shadowResult.getAsJsonObject().getAsJsonObject("object").get("objectId").getAsString();

JsonObject callParams = new JsonObject();
callParams.addProperty("functionDeclaration",
"function(shadowRoot) { window.__percyClosedShadowRoots.set(this, shadowRoot); }");
callParams.addProperty("objectId", hostObjectId);
JsonArray args = new JsonArray();
JsonObject arg = new JsonObject();
arg.addProperty("objectId", shadowObjectId);
args.add(arg);
callParams.add("arguments", args);
cdpSession.send("Runtime.callFunctionOn", callParams);
}
} catch (Exception err) {
log("Could not expose closed shadow roots via CDP: " + err.getMessage(), "debug");
} finally {
if (cdpSession != null) {
try { cdpSession.detach(); } catch (Exception ignored) { }
}
}
}

private void walkNodes(JsonObject node, List<JsonObject> closedPairs) {
if (node.has("contentDocument")) return;

if (node.has("shadowRoots")) {
for (JsonElement srElem : node.getAsJsonArray("shadowRoots")) {
JsonObject sr = srElem.getAsJsonObject();
if (sr.has("shadowRootType") && "closed".equals(sr.get("shadowRootType").getAsString())) {
JsonObject pair = new JsonObject();
pair.addProperty("hostBackendNodeId", node.get("backendNodeId").getAsInt());
pair.addProperty("shadowBackendNodeId", sr.get("backendNodeId").getAsInt());
closedPairs.add(pair);
}
walkNodes(sr, closedPairs);
}
}
if (node.has("children")) {
for (JsonElement childElem : node.getAsJsonArray("children")) {
walkNodes(childElem.getAsJsonObject(), closedPairs);
}
}
}

// -------------------------------------------------------------------------
// Logging
// -------------------------------------------------------------------------
Expand Down
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