Add support for ZSTD compression (#11161)

Author: KGuillaume-chaps

.pre-commit-config.yaml

@@ -55,6 +55,10 @@ repos:
   rev: v1.5.0
   hooks:
   - id: yesqa
+    additional_dependencies:
+      - flake8-docstrings==1.6.0
+      - flake8-no-implicit-concat==0.3.4
+      - flake8-requirements==1.7.8
 - repo: https://github.com/PyCQA/isort
   rev: '6.0.1'
   hooks:

CHANGES/11161.feature.rst

@@ -0,0 +1,2 @@
+Add support for Zstandard (aka Zstd) compression
+-- by :user:`KGuillaume-chaps`.

CONTRIBUTORS.txt

@@ -218,6 +218,7 @@ Justin Foo
 Justin Turner Arthur
 Kay Zheng
 Kevin Samuel
+Kilian Guillaume
 Kimmo Parviainen-Jalanko
 Kirill Klenov
 Kirill Malovitsa

aiohttp/_http_parser.pyx

@@ -437,7 +437,7 @@ cdef class HttpParser:
         if enc is not None:
             self._content_encoding = None
             enc = enc.lower()
-            if enc in ('gzip', 'deflate', 'br'):
+            if enc in ('gzip', 'deflate', 'br', 'zstd'):
                 encoding = enc
 
         if self._cparser.type == cparser.HTTP_REQUEST:

aiohttp/client_reqrep.py

@@ -44,7 +44,7 @@
     InvalidURL,
     ServerFingerprintMismatch,
 )
-from .compression_utils import HAS_BROTLI
+from .compression_utils import HAS_BROTLI, HAS_ZSTD
 from .formdata import FormData
 from .hdrs import CONTENT_TYPE
 from .helpers import (
@@ -105,7 +105,15 @@
 
 
 def _gen_default_accept_encoding() -> str:
-    return "gzip, deflate, br" if HAS_BROTLI else "gzip, deflate"
+    encodings = [
+        "gzip",
+        "deflate",
+    ]
+    if HAS_BROTLI:
+        encodings.append("br")
+    if HAS_ZSTD:
+        encodings.append("zstd")
+    return ", ".join(encodings)
 
 
 @frozen_dataclass_decorator

aiohttp/compression_utils.py

@@ -21,6 +21,18 @@
 except ImportError:
     HAS_BROTLI = False
 
+if sys.version_info >= (3, 14):
+    import compression.zstd  # noqa: I900
+
+    HAS_ZSTD = True
+else:
+    try:
+        import zstandard
+
+        HAS_ZSTD = True
+    except ImportError:
+        HAS_ZSTD = False
+
 MAX_SYNC_CHUNK_SIZE = 1024
 
 
@@ -276,3 +288,22 @@ def flush(self) -> bytes:
         if hasattr(self._obj, "flush"):
             return cast(bytes, self._obj.flush())
         return b""
+
+
+class ZSTDDecompressor:
+    def __init__(self) -> None:
+        if not HAS_ZSTD:
+            raise RuntimeError(
+                "The zstd decompression is not available. "
+                "Please install `zstandard` module"
+            )
+        if sys.version_info >= (3, 14):
+            self._obj = compression.zstd.ZstdDecompressor()
+        else:
+            self._obj = zstandard.ZstdDecompressor()
+
+    def decompress_sync(self, data: bytes) -> bytes:
+        return self._obj.decompress(data)
+
+    def flush(self) -> bytes:
+        return b""

aiohttp/http_parser.py

@@ -26,7 +26,13 @@
 
 from . import hdrs
 from .base_protocol import BaseProtocol
-from .compression_utils import HAS_BROTLI, BrotliDecompressor, ZLibDecompressor
+from .compression_utils import (
+    HAS_BROTLI,
+    HAS_ZSTD,
+    BrotliDecompressor,
+    ZLibDecompressor,
+    ZSTDDecompressor,
+)
 from .helpers import (
     _EXC_SENTINEL,
     DEBUG,
@@ -527,7 +533,7 @@ def parse_headers(
         enc = headers.get(hdrs.CONTENT_ENCODING)
         if enc:
             enc = enc.lower()
-            if enc in ("gzip", "deflate", "br"):
+            if enc in ("gzip", "deflate", "br", "zstd"):
                 encoding = enc
 
         # chunking
@@ -930,14 +936,21 @@ def __init__(self, out: StreamReader, encoding: Optional[str]) -> None:
         self.encoding = encoding
         self._started_decoding = False
 
-        self.decompressor: Union[BrotliDecompressor, ZLibDecompressor]
+        self.decompressor: Union[BrotliDecompressor, ZLibDecompressor, ZSTDDecompressor]
         if encoding == "br":
             if not HAS_BROTLI:
                 raise ContentEncodingError(
                     "Can not decode content-encoding: brotli (br). "
                     "Please install `Brotli`"
                 )
             self.decompressor = BrotliDecompressor()
+        elif encoding == "zstd":
+            if not HAS_ZSTD:
+                raise ContentEncodingError(
+                    "Can not decode content-encoding: zstandard (zstd). "
+                    "Please install `zstandard`"
+                )
+            self.decompressor = ZSTDDecompressor()
         else:
             self.decompressor = ZLibDecompressor(encoding=encoding)
 

docs/client_quickstart.rst

@@ -190,6 +190,10 @@ You can enable ``brotli`` transfer-encodings support,
 just install `Brotli <https://pypi.org/project/Brotli/>`_
 or `brotlicffi <https://pypi.org/project/brotlicffi/>`_.
 
+You can enable ``zstd`` transfer-encodings support,
+install `zstandard <https://pypi.org/project/zstandard/>`_.
+If you are using Python >= 3.14, no dependency should be required.
+
 JSON Request
 ============
 

docs/spelling_wordlist.txt

@@ -382,3 +382,5 @@ www
 xxx
 yarl
 zlib
+zstandard
+zstd

requirements/lint.in

@@ -14,3 +14,4 @@ trustme
 uvloop; platform_system != "Windows"
 valkey
 zlib_ng
+zstandard; implementation_name == "cpython"