wehub-resource-sync
65 lines
2.3 KiB
Markdown
65 lines
2.3 KiB
Markdown
# Dialogs
|
|
|
|
Browser dialogs (`alert`, `confirm`, `prompt`, `beforeunload`) freeze the JS thread. Two approaches depending on timing.
|
|
|
|
## Detection
|
|
|
|
`page_info()` auto-surfaces any open dialog: if one is pending it returns `{"dialog": {"type", "message", ...}}` instead of the usual viewport dict (because the page's JS is frozen anyway). So if you call `page_info()` after an action and see a `dialog` key, handle it before doing anything else.
|
|
|
|
## Reactive: dismiss via CDP (preferred)
|
|
|
|
Works even when JS is frozen. Handles all dialog types including `beforeunload`.
|
|
|
|
```python
|
|
# Dismiss and read the message
|
|
cdp("Page.handleJavaScriptDialog", accept=True) # accept / click OK
|
|
cdp("Page.handleJavaScriptDialog", accept=False) # cancel / click Cancel
|
|
|
|
# Read what the dialog said (from buffered CDP events)
|
|
events = drain_events()
|
|
for e in events:
|
|
if e["method"] == "Page.javascriptDialogOpening":
|
|
print(e["params"]["type"]) # "alert", "confirm", "prompt", "beforeunload"
|
|
print(e["params"]["message"]) # the dialog text
|
|
```
|
|
|
|
Undetectable by antibot — no JS injected into the page.
|
|
|
|
## Proactive: stub via JS
|
|
|
|
Prevents dialogs from ever appearing. Good when you expect multiple `alert()`/`confirm()` calls in sequence.
|
|
|
|
```python
|
|
js("""
|
|
window.__dialogs__=[];
|
|
window.alert=m=>window.__dialogs__.push(String(m));
|
|
window.confirm=m=>{window.__dialogs__.push(String(m));return true;};
|
|
window.prompt=(m,d)=>{window.__dialogs__.push(String(m));return d||'';};
|
|
""")
|
|
# ... do actions that trigger dialogs ...
|
|
msgs = js("window.__dialogs__||[]")
|
|
```
|
|
|
|
Tradeoffs:
|
|
- Stubs are lost on page navigation -- must re-run the snippet
|
|
- `confirm()` always returns `true` (auto-approves)
|
|
- Detectable by antibot (`window.alert.toString()` reveals non-native code)
|
|
- Does NOT handle `beforeunload`
|
|
|
|
## beforeunload specifically
|
|
|
|
Fires when navigating away from a page with unsaved changes (forms, editors, upload pages). The page freezes until the user clicks Leave/Stay.
|
|
|
|
```python
|
|
# Option A: dismiss after navigating (CDP-level, safe)
|
|
goto_url("https://new-url.com")
|
|
try:
|
|
cdp("Page.handleJavaScriptDialog", accept=True) # click "Leave"
|
|
except:
|
|
pass # no dialog — normal
|
|
|
|
# Option B: prevent before navigating (JS injection, detectable)
|
|
js("window.onbeforeunload=null")
|
|
goto_url("https://new-url.com")
|
|
```
|