microsoft · mxschmitt · Sep 15, 2021 · Sep 15, 2021 · Sep 15, 2021
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -49,6 +49,13 @@ pre-commit run --all-files
 
 For more details look at the [CI configuration](./blob/master/.github/workflows/ci.yml).
 
+Collect coverage
+
+```sh
+pytest --browser chromium --cov-report html --cov=playwright
+open htmlcov/index.html
+```
+
 ### Regenerating APIs
 
 ```bash

diff --git a/README.md b/README.md
@@ -4,9 +4,9 @@ Playwright is a Python library to automate [Chromium](https://www.chromium.org/H
 
 |          | Linux | macOS | Windows |
 |   :---   | :---: | :---: | :---:   |
-| Chromium <!-- GEN:chromium-version -->95.0.4636.0<!-- GEN:stop --> | ✅ | ✅ | ✅ |
+| Chromium <!-- GEN:chromium-version -->96.0.4641.0<!-- GEN:stop --> | ✅ | ✅ | ✅ |
 | WebKit <!-- GEN:webkit-version -->15.0<!-- GEN:stop --> | ✅ | ✅ | ✅ |
-| Firefox <!-- GEN:firefox-version -->91.0<!-- GEN:stop --> | ✅ | ✅ | ✅ |
+| Firefox <!-- GEN:firefox-version -->92.0<!-- GEN:stop --> | ✅ | ✅ | ✅ |
 
 ## Documentation
 

diff --git a/playwright/_impl/_api_structures.py b/playwright/_impl/_api_structures.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import sys
-from typing import List, Optional, Union
+from typing import Dict, List, Optional, Union
 
 if sys.version_info >= (3, 8):  # pragma: no cover
     from typing import Literal, TypedDict
@@ -139,3 +139,12 @@ class SecurityDetails(TypedDict):
     subjectName: Optional[str]
     validFrom: Optional[float]
     validTo: Optional[float]
+
+
+class NameValue(TypedDict):
+    name: str
+    value: str
+
+
+HeadersArray = List[NameValue]
+Headers = Dict[str, str]
diff --git a/playwright/_impl/_browser_type.py b/playwright/_impl/_browser_type.py
@@ -38,7 +38,6 @@
     ForcedColors,
     ReducedMotion,
     locals_to_params,
-    not_installed_error,
 )
 from playwright._impl._transport import WebSocketTransport
 from playwright._impl._wait_helper import throw_on_timeout
@@ -86,12 +85,7 @@ async def launch(
     ) -> Browser:
         params = locals_to_params(locals())
         normalize_launch_params(params)
-        try:
-            return from_channel(await self._channel.send("launch", params))
-        except Exception as e:
-            if "npx playwright install" in str(e):
-                raise not_installed_error(f'"{self.name}" browser was not found.')
-            raise e
+        return from_channel(await self._channel.send("launch", params))
 
     async def launch_persistent_context(
         self,
@@ -144,16 +138,11 @@ async def launch_persistent_context(
         params = locals_to_params(locals())
         await normalize_context_params(self._connection._is_sync, params)
         normalize_launch_params(params)
-        try:
-            context = from_channel(
-                await self._channel.send("launchPersistentContext", params)
-            )
-            context._options = params
-            return context
-        except Exception as e:
-            if "npx playwright install" in str(e):
-                raise not_installed_error(f'"{self.name}" browser was not found.')
-            raise e
+        context = from_channel(
+            await self._channel.send("launchPersistentContext", params)
+        )
+        context._options = params
+        return context
 
     async def connect_over_cdp(
         self,

diff --git a/playwright/_impl/_helper.py b/playwright/_impl/_helper.py
@@ -36,6 +36,7 @@
 )
 from urllib.parse import urljoin
 
+from playwright._impl._api_structures import NameValue
 from playwright._impl._api_types import Error, TimeoutError
 
 if sys.version_info >= (3, 8):  # pragma: no cover
@@ -69,15 +70,10 @@ class ErrorPayload(TypedDict, total=False):
     value: Any
 
 
-class Header(TypedDict):
-    name: str
-    value: str
-
-
 class ContinueParameters(TypedDict, total=False):
     url: Optional[str]
     method: Optional[str]
-    headers: Optional[List[Header]]
+    headers: Optional[List[NameValue]]
     postData: Optional[str]
 
 
@@ -234,20 +230,6 @@ def is_safe_close_error(error: Exception) -> bool:
     )
 
 
-def not_installed_error(message: str) -> Exception:
-    return Error(
-        f"""
-================================================================================
-{message}
-Please complete Playwright installation via running
-
-    "python -m playwright install"
-
-================================================================================
-"""
-    )
-
-
 to_snake_case_regex = re.compile("((?<=[a-z0-9])[A-Z]|(?!^)[A-Z](?=[a-z]))")
 
 

diff --git a/playwright/_impl/_input.py b/playwright/_impl/_input.py
@@ -80,6 +80,9 @@ async def dblclick(
     ) -> None:
         await self.click(x, y, delay=delay, button=button, clickCount=2)
 
+    async def wheel(self, deltaX: float, deltaY: float) -> None:
+        await self._channel.send("mouseWheel", locals_to_params(locals()))
+
 
 class Touchscreen:
     def __init__(self, channel: Channel) -> None:

diff --git a/playwright/_impl/_network.py b/playwright/_impl/_network.py
@@ -16,12 +16,15 @@
 import base64
 import json
 import mimetypes
+from collections import defaultdict
 from pathlib import Path
 from types import SimpleNamespace
 from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Union, cast
 from urllib import parse
 
 from playwright._impl._api_structures import (
+    Headers,
+    HeadersArray,
     RemoteAddr,
     RequestSizes,
     ResourceTiming,
@@ -34,7 +37,7 @@
     from_nullable_channel,
 )
 from playwright._impl._event_context_manager import EventContextManagerImpl
-from playwright._impl._helper import ContinueParameters, Header, locals_to_params
+from playwright._impl._helper import ContinueParameters, locals_to_params
 from playwright._impl._wait_helper import WaitHelper
 
 if TYPE_CHECKING:  # pragma: no cover
@@ -64,8 +67,8 @@ def __init__(
             "responseStart": -1,
             "responseEnd": -1,
         }
-        self._headers: List[Header] = self._initializer["headers"]
-        self._all_headers_future: Optional[asyncio.Future[List[Header]]] = None
+        self._provisional_headers = RawHeaders(self._initializer["headers"])
+        self._all_headers_future: Optional[asyncio.Future[RawHeaders]] = None
 
     def __repr__(self) -> str:
         return f"<Request url={self.url!r} method={self.method!r}>"
@@ -115,10 +118,6 @@ def post_data_buffer(self) -> Optional[bytes]:
             return None
         return base64.b64decode(b64_content)
 
-    @property
-    def headers(self) -> Dict[str, str]:
-        return headers_array_to_object(self._headers, True)
-
     async def response(self) -> Optional["Response"]:
         return from_nullable_channel(await self._channel.send("response"))
 
@@ -145,25 +144,27 @@ def failure(self) -> Optional[str]:
     def timing(self) -> ResourceTiming:
         return self._timing
 
-    async def all_headers(self) -> Dict[str, str]:
-        return headers_array_to_object(await self._get_headers_if_needed(), True)
+    @property
+    def headers(self) -> Headers:
+        return self._provisional_headers.headers()
 
-    async def headers_array(self) -> List[List[str]]:
-        return list(
-            map(
-                lambda header: [header["name"], header["value"]],
-                await self._get_headers_if_needed(),
-            )
-        )
+    async def all_headers(self) -> Headers:
+        return (await self._actual_headers()).headers()
+
+    async def headers_array(self) -> HeadersArray:
+        return (await self._actual_headers()).headers_array()
+
+    async def header_value(self, name: str) -> Optional[str]:
+        return (await self._actual_headers()).get(name)
 
-    async def _get_headers_if_needed(self) -> List[Header]:
+    async def _actual_headers(self) -> "RawHeaders":
         if not self._all_headers_future:
             self._all_headers_future = asyncio.Future()
             response = await self.response()
             if not response:
-                return self._headers
+                return self._provisional_headers
             headers = await response._channel.send("rawRequestHeaders")
-            self._all_headers_future.set_result(headers)
+            self._all_headers_future.set_result(RawHeaders(headers))
         return await self._all_headers_future
 
 
@@ -256,10 +257,10 @@ def __init__(
         self._request._timing["connectEnd"] = timing["connectEnd"]
         self._request._timing["requestStart"] = timing["requestStart"]
         self._request._timing["responseStart"] = timing["responseStart"]
-        self._headers = headers_array_to_object(
-            cast(List[Header], self._initializer["headers"]), True
+        self._provisional_headers = RawHeaders(
+            cast(HeadersArray, self._initializer["headers"])
         )
-        self._raw_headers_future: Optional[asyncio.Future[List[Header]]] = None
+        self._raw_headers_future: Optional[asyncio.Future[RawHeaders]] = None
         self._finished_future: asyncio.Future[bool] = asyncio.Future()
 
     def __repr__(self) -> str:
@@ -284,25 +285,26 @@ def status_text(self) -> str:
         return self._initializer["statusText"]
 
     @property
-    def headers(self) -> Dict[str, str]:
-        return self._headers.copy()
+    def headers(self) -> Headers:
+        return self._provisional_headers.headers()
 
-    async def all_headers(self) -> Dict[str, str]:
-        return headers_array_to_object(await self._get_headers_if_needed(), True)
+    async def all_headers(self) -> Headers:
+        return (await self._actual_headers()).headers()
 
-    async def headers_array(self) -> List[List[str]]:
-        return list(
-            map(
-                lambda header: [header["name"], header["value"]],
-                await self._get_headers_if_needed(),
-            )
-        )
+    async def headers_array(self) -> HeadersArray:
+        return (await self._actual_headers()).headers_array()
+
+    async def header_value(self, name: str) -> Optional[str]:
+        return (await self._actual_headers()).get(name)
+
+    async def header_values(self, name: str) -> List[str]:
+        return (await self._actual_headers()).get_all(name)
 
-    async def _get_headers_if_needed(self) -> List[Header]:
+    async def _actual_headers(self) -> "RawHeaders":
         if not self._raw_headers_future:
             self._raw_headers_future = asyncio.Future()
-            headers = cast(List[Header], await self._channel.send("rawResponseHeaders"))
-            self._raw_headers_future.set_result(headers)
+            headers = cast(HeadersArray, await self._channel.send("rawResponseHeaders"))
+            self._raw_headers_future.set_result(RawHeaders(headers))
         return await self._raw_headers_future
 
     async def server_addr(self) -> Optional[RemoteAddr]:
@@ -420,12 +422,32 @@ def _on_close(self) -> None:
         self.emit(WebSocket.Events.Close)
 
 
-def serialize_headers(headers: Dict[str, str]) -> List[Header]:
+def serialize_headers(headers: Dict[str, str]) -> HeadersArray:
     return [{"name": name, "value": value} for name, value in headers.items()]
 
 
-def headers_array_to_object(headers: List[Header], lower_case: bool) -> Dict[str, str]:
-    return {
-        (header["name"].lower() if lower_case else header["name"]): header["value"]
-        for header in headers
-    }
+class RawHeaders:
+    def __init__(self, headers: HeadersArray) -> None:
+        self._headers_array = headers
+        self._headers_map: Dict[str, Dict[str, bool]] = defaultdict(dict)
+        for header in headers:
+            self._headers_map[header["name"].lower()][header["value"]] = True
+
+    def get(self, name: str) -> Optional[str]:
+        values = self.get_all(name)
+        if not values:
+            return None
+        separator = "\n" if name.lower() == "set-cookie" else ", "
+        return separator.join(values)
+
+    def get_all(self, name: str) -> List[str]:
+        return list(self._headers_map[name.lower()].keys())
+
+    def headers(self) -> Dict[str, str]:
+        result = {}
+        for name in self._headers_map.keys():
+            result[name] = cast(str, self.get(name))
+        return result
+
+    def headers_array(self) -> HeadersArray:
+        return self._headers_array