Add client Brotli support (#5227) (#7100)

(cherry picked from commit 28ea32d)

backport ref
#5227 (comment)

Co-authored-by: Dmitry Erlikh <derlih@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

CHANGES/5219.feature

@@ -0,0 +1 @@
+Add client brotli compression support (optional with runtime check)

aiohttp/client_reqrep.py

@@ -49,6 +49,7 @@
     set_result,
 )
 from .http import SERVER_SOFTWARE, HttpVersion10, HttpVersion11, StreamWriter
+from .http_parser import HAS_BROTLI
 from .log import client_logger
 from .streams import StreamReader
 from .typedefs import (
@@ -84,6 +85,10 @@
 json_re = re.compile(r"^application/(?:[\w.+-]+?\+)?json")
 
 
+def _gen_default_accept_encoding() -> str:
+    return "gzip, deflate, br" if HAS_BROTLI else "gzip, deflate"
+
+
 @attr.s(auto_attribs=True, frozen=True, slots=True)
 class ContentDisposition:
     type: Optional[str]
@@ -229,7 +234,7 @@ class ClientRequest:
 
     DEFAULT_HEADERS = {
         hdrs.ACCEPT: "*/*",
-        hdrs.ACCEPT_ENCODING: "gzip, deflate",
+        hdrs.ACCEPT_ENCODING: _gen_default_accept_encoding(),
     }
 
     body = b""

docs/glossary.rst

@@ -27,6 +27,19 @@
 
       https://pypi.python.org/pypi/asyncio/
 
+   Brotli
+
+      Brotli is a generic-purpose lossless compression algorithm that
+      compresses data using a combination of a modern variant
+      of the LZ77 algorithm, Huffman coding and second order context modeling,
+      with a compression ratio comparable to the best currently available
+      general-purpose compression methods. It is similar in speed with deflate
+      but offers more dense compression.
+
+      The specification of the Brotli Compressed Data Format is defined :rfc:`7932`
+
+      https://pypi.org/project/Brotli/
+
    callable
 
       Any object that can be called. Use :func:`callable` to check

docs/index.rst

@@ -170,6 +170,12 @@ Dependencies
 
      $ pip install aiodns
 
+- *Optional* :term:`Brotli` for brotli (:rfc:`7932`) client compression support.
+
+  .. code-block:: bash
+
+     $ pip install Brotli
+
 
 Communication channels
 ======================

docs/spelling_wordlist.txt

@@ -38,6 +38,7 @@ BodyPartReader
 boolean
 botocore
 brotli
+Brotli
 brotlipy
 bugfix
 Bugfixes

tests/test_client_request.py

@@ -17,6 +17,7 @@
     ClientRequest,
     ClientResponse,
     Fingerprint,
+    _gen_default_accept_encoding,
     _merge_ssl_params,
 )
 from aiohttp.helpers import PY_310
@@ -319,7 +320,7 @@ def test_headers(make_request) -> None:
 
     assert "CONTENT-TYPE" in req.headers
     assert req.headers["CONTENT-TYPE"] == "text/plain"
-    assert req.headers["ACCEPT-ENCODING"] == "gzip, deflate"
+    assert req.headers["ACCEPT-ENCODING"] == "gzip, deflate, br"
 
 
 def test_headers_list(make_request) -> None:
@@ -1287,3 +1288,15 @@ def test_loose_cookies_types(loop) -> None:
         req.update_cookies(cookies=loose_cookies_type)
 
     loop.run_until_complete(req.close())
+
+
+@pytest.mark.parametrize(
+    "has_brotli,expected",
+    [
+        (False, "gzip, deflate"),
+        (True, "gzip, deflate, br"),
+    ],
+)
+def test_gen_default_accept_encoding(has_brotli, expected) -> None:
+    with mock.patch("aiohttp.client_reqrep.HAS_BROTLI", has_brotli):
+        assert _gen_default_accept_encoding() == expected

tests/test_web_functional.py

@@ -7,6 +7,7 @@
 from typing import Optional
 from unittest import mock
 
+import brotli
 import pytest
 from multidict import CIMultiDictProxy, MultiDict
 from yarl import URL
@@ -1078,11 +1079,22 @@ async def handler(request):
     await resp.release()
 
 
-async def test_response_with_precompressed_body_gzip(aiohttp_client) -> None:
+@pytest.mark.parametrize(
+    "compressor,encoding",
+    [
+        (zlib.compressobj(wbits=16 + zlib.MAX_WBITS), "gzip"),
+        (zlib.compressobj(wbits=zlib.MAX_WBITS), "deflate"),
+        # Actually, wrong compression format, but
+        # should be supported for some legacy cases.
+        (zlib.compressobj(wbits=-zlib.MAX_WBITS), "deflate"),
+    ],
+)
+async def test_response_with_precompressed_body(
+    aiohttp_client, compressor, encoding
+) -> None:
     async def handler(request):
-        headers = {"Content-Encoding": "gzip"}
-        zcomp = zlib.compressobj(wbits=16 + zlib.MAX_WBITS)
-        data = zcomp.compress(b"mydata") + zcomp.flush()
+        headers = {"Content-Encoding": encoding}
+        data = compressor.compress(b"mydata") + compressor.flush()
         return web.Response(body=data, headers=headers)
 
     app = web.Application()
@@ -1093,17 +1105,15 @@ async def handler(request):
     assert 200 == resp.status
     data = await resp.read()
     assert b"mydata" == data
-    assert resp.headers.get("Content-Encoding") == "gzip"
+    assert resp.headers.get("Content-Encoding") == encoding
 
     await resp.release()
 
 
-async def test_response_with_precompressed_body_deflate(aiohttp_client) -> None:
+async def test_response_with_precompressed_body_brotli(aiohttp_client) -> None:
     async def handler(request):
-        headers = {"Content-Encoding": "deflate"}
-        zcomp = zlib.compressobj(wbits=zlib.MAX_WBITS)
-        data = zcomp.compress(b"mydata") + zcomp.flush()
-        return web.Response(body=data, headers=headers)
+        headers = {"Content-Encoding": "br"}
+        return web.Response(body=brotli.compress(b"mydata"), headers=headers)
 
     app = web.Application()
     app.router.add_get("/", handler)
@@ -1113,31 +1123,11 @@ async def handler(request):
     assert 200 == resp.status
     data = await resp.read()
     assert b"mydata" == data
-    assert resp.headers.get("Content-Encoding") == "deflate"
+    assert resp.headers.get("Content-Encoding") == "br"
 
     await resp.release()
 
 
-async def test_response_with_precompressed_body_deflate_no_hdrs(aiohttp_client) -> None:
-    async def handler(request):
-        headers = {"Content-Encoding": "deflate"}
-        # Actually, wrong compression format, but
-        # should be supported for some legacy cases.
-        zcomp = zlib.compressobj(wbits=-zlib.MAX_WBITS)
-        data = zcomp.compress(b"mydata") + zcomp.flush()
-        return web.Response(body=data, headers=headers)
-
-    app = web.Application()
-    app.router.add_get("/", handler)
-    client = await aiohttp_client(app)
-
-    resp = await client.get("/")
-    assert 200 == resp.status
-    data = await resp.read()
-    assert b"mydata" == data
-    assert resp.headers.get("Content-Encoding") == "deflate"
-
-
 async def test_bad_request_payload(aiohttp_client) -> None:
     async def handler(request):
         assert request.method == "POST"