[mod] upgrade httpx 0.21.2

httpx 0.21.2 and httpcore 0.14.4 fix multiple issues:
* https://github.com/encode/httpx/releases/tag/0.21.2
* https://github.com/encode/httpcore/releases/tag/0.14.4

so most of the workarounds in searx.network have been removed.

4 files changed, 48 insertions, 112 deletions

diff --git a/requirements.txt b/requirements.txt
index e42c1fb7..f6308044 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,9 +7,9 @@ lxml==4.7.1
 pygments==2.11.0
 python-dateutil==2.8.2
 pyyaml==6.0
-httpx[http2]==0.19.0
+httpx[http2]==0.21.2
 Brotli==1.0.9
 uvloop==0.16.0
-httpx-socks[asyncio]==0.4.1
+httpx-socks[asyncio]==0.7.2
 langdetect==1.0.9
 setproctitle==1.2.2
diff --git a/searx/network/client.py b/searx/network/client.py
index cd1e4146..6858ac05 100644
--- a/searx/network/client.py
+++ b/searx/network/client.py
@@ -6,8 +6,6 @@ import asyncio
 import logging
 import threading
 
-import anyio
-import httpcore
 import httpx
 from httpx_socks import AsyncProxyTransport
 from python_socks import parse_proxy_url, ProxyConnectionError, ProxyTimeoutError, ProxyError
@@ -27,31 +25,10 @@ logger = logger.getChild('searx.network.client')
 LOOP = None
 SSLCONTEXTS = {}
 TRANSPORT_KWARGS = {
-    # use anyio :
-    # * https://github.com/encode/httpcore/issues/344
-    # * https://github.com/encode/httpx/discussions/1511
-    'backend': 'anyio',
     'trust_env': False,
 }
 
 
-# pylint: disable=protected-access
-async def close_connections_for_url(connection_pool: httpcore.AsyncConnectionPool, url: httpcore._utils.URL):
-
-    origin = httpcore._utils.url_to_origin(url)
-    logger.debug('Drop connections for %r', origin)
-    connections_to_close = connection_pool._connections_for_origin(origin)
-    for connection in connections_to_close:
-        await connection_pool._remove_from_pool(connection)
-        try:
-            await connection.aclose()
-        except httpx.NetworkError as e:
-            logger.warning('Error closing an existing connection', exc_info=e)
-
-
-# pylint: enable=protected-access
-
-
 def get_sslcontexts(proxy_url=None, cert=None, verify=True, trust_env=True, http2=False):
     key = (proxy_url, cert, verify, trust_env, http2)
     if key not in SSLCONTEXTS:
@@ -62,75 +39,25 @@ def get_sslcontexts(proxy_url=None, cert=None, verify=True, trust_env=True, http
 class AsyncHTTPTransportNoHttp(httpx.AsyncHTTPTransport):
     """Block HTTP request"""
 
-    async def handle_async_request(self, method, url, headers=None, stream=None, extensions=None):
+    async def handle_async_request(self, request):
         raise httpx.UnsupportedProtocol('HTTP protocol is disabled')
 
 
 class AsyncProxyTransportFixed(AsyncProxyTransport):
     """Fix httpx_socks.AsyncProxyTransport
 
-    Map python_socks exceptions to httpx.ProxyError / httpx.ConnectError
-
-    Map socket.gaierror to httpx.ConnectError
-
-    Note: AsyncProxyTransport inherit from AsyncConnectionPool
+    Map python_socks exceptions to httpx.ProxyError exceptions
     """
 
-    async def handle_async_request(self, method, url, headers=None, stream=None, extensions=None):
-        retry = 2
-        while retry > 0:
-            retry -= 1
-            try:
-                return await super().handle_async_request(
-                    method, url, headers=headers, stream=stream, extensions=extensions
-                )
-            except (ProxyConnectionError, ProxyTimeoutError, ProxyError) as e:
-                raise httpx.ProxyError from e
-            except OSError as e:
-                # socket.gaierror when DNS resolution fails
-                raise httpx.ConnectError from e
-            except httpx.NetworkError as e:
-                # httpx.WriteError on HTTP/2 connection leaves a new opened stream
-                # then each new request creates a new stream and raise the same WriteError
-                await close_connections_for_url(self, url)
-                raise e
-            except anyio.ClosedResourceError as e:
-                await close_connections_for_url(self, url)
-                raise httpx.CloseError from e
-            except httpx.RemoteProtocolError as e:
-                # in case of httpx.RemoteProtocolError: Server disconnected
-                await close_connections_for_url(self, url)
-                logger.warning('httpx.RemoteProtocolError: retry', exc_info=e)
-                # retry
-
-
-class AsyncHTTPTransportFixed(httpx.AsyncHTTPTransport):
-    """Fix httpx.AsyncHTTPTransport"""
-
-    async def handle_async_request(self, method, url, headers=None, stream=None, extensions=None):
-        retry = 2
-        while retry > 0:
-            retry -= 1
-            try:
-                return await super().handle_async_request(
-                    method, url, headers=headers, stream=stream, extensions=extensions
-                )
-            except OSError as e:
-                # socket.gaierror when DNS resolution fails
-                raise httpx.ConnectError from e
-            except httpx.NetworkError as e:
-                # httpx.WriteError on HTTP/2 connection leaves a new opened stream
-                # then each new request creates a new stream and raise the same WriteError
-                await close_connections_for_url(self._pool, url)
-                raise e
-            except anyio.ClosedResourceError as e:
-                await close_connections_for_url(self._pool, url)
-                raise httpx.CloseError from e
-            except httpx.RemoteProtocolError as e:
-                # in case of httpx.RemoteProtocolError: Server disconnected
-                await close_connections_for_url(self._pool, url)
-                logger.warning('httpx.RemoteProtocolError: retry', exc_info=e)
-                # retry
+    async def handle_async_request(self, request):
+        try:
+            return await super().handle_async_request(request)
+        except ProxyConnectionError as e:
+            raise httpx.ProxyError("ProxyConnectionError: " + e.strerror, request=request) from e
+        except ProxyTimeoutError as e:
+            raise httpx.ProxyError("ProxyTimeoutError: " + e.args[0], request=request) from e
+        except ProxyError as e:
+            raise httpx.ProxyError("ProxyError: " + e.args[0], request=request) from e
 
 
 def get_transport_for_socks_proxy(verify, http2, local_address, proxy_url, limit, retries):
@@ -157,9 +84,7 @@ def get_transport_for_socks_proxy(verify, http2, local_address, proxy_url, limit
         verify=verify,
         http2=http2,
         local_address=local_address,
-        max_connections=limit.max_connections,
-        max_keepalive_connections=limit.max_keepalive_connections,
-        keepalive_expiry=limit.keepalive_expiry,
+        limits=limit,
         retries=retries,
         **TRANSPORT_KWARGS,
     )
@@ -167,13 +92,13 @@ def get_transport_for_socks_proxy(verify, http2, local_address, proxy_url, limit
 
 def get_transport(verify, http2, local_address, proxy_url, limit, retries):
     verify = get_sslcontexts(None, None, True, False, http2) if verify is True else verify
-    return AsyncHTTPTransportFixed(
+    return httpx.AsyncHTTPTransport(
         # pylint: disable=protected-access
         verify=verify,
         http2=http2,
-        local_address=local_address,
-        proxy=httpx._config.Proxy(proxy_url) if proxy_url else None,
         limits=limit,
+        proxy=httpx._config.Proxy(proxy_url) if proxy_url else None,
+        local_address=local_address,
         retries=retries,
         **TRANSPORT_KWARGS,
     )
diff --git a/searx/network/network.py b/searx/network/network.py
index 9e14e14b..43140b44 100644
--- a/searx/network/network.py
+++ b/searx/network/network.py
@@ -213,15 +213,18 @@ class Network:
         await asyncio.gather(*[close_client(client) for client in self._clients.values()], return_exceptions=False)
 
     @staticmethod
-    def get_kwargs_clients(kwargs):
+    def extract_kwargs_clients(kwargs):
         kwargs_clients = {}
         if 'verify' in kwargs:
             kwargs_clients['verify'] = kwargs.pop('verify')
         if 'max_redirects' in kwargs:
             kwargs_clients['max_redirects'] = kwargs.pop('max_redirects')
+        if 'allow_redirects' in kwargs:
+            # see https://github.com/encode/httpx/pull/1808
+            kwargs['follow_redirects'] = kwargs.pop('allow_redirects')
         return kwargs_clients
 
-    def is_valid_respones(self, response):
+    def is_valid_response(self, response):
         # pylint: disable=too-many-boolean-expressions
         if (
             (self.retry_on_http_error is True and 400 <= response.status_code <= 599)
@@ -231,34 +234,40 @@ class Network:
             return False
         return True
 
-    async def request(self, method, url, **kwargs):
+    async def call_client(self, stream, method, url, **kwargs):
         retries = self.retries
+        was_disconnected = False
+        kwargs_clients = Network.extract_kwargs_clients(kwargs)
         while retries >= 0:  # pragma: no cover
-            kwargs_clients = Network.get_kwargs_clients(kwargs)
             client = await self.get_client(**kwargs_clients)
             try:
-                response = await client.request(method, url, **kwargs)
-                if self.is_valid_respones(response) or retries <= 0:
+                if stream:
+                    response = client.stream(method, url, **kwargs)
+                else:
+                    response = await client.request(method, url, **kwargs)
+                if self.is_valid_response(response) or retries <= 0:
                     return response
-            except (httpx.RequestError, httpx.HTTPStatusError) as e:
+            except httpx.RemoteProtocolError as e:
+                if not was_disconnected:
+                    # the server has closed the connection:
+                    # try again without decreasing the retries variable & with a new HTTP client
+                    was_disconnected = True
+                    await client.aclose()
+                    self._logger.warning('httpx.RemoteProtocolError: the server has disconnected, retrying')
+                    continue
                 if retries <= 0:
                     raise e
-            retries -= 1
-
-    async def stream(self, method, url, **kwargs):
-        retries = self.retries
-        while retries >= 0:  # pragma: no cover
-            kwargs_clients = Network.get_kwargs_clients(kwargs)
-            client = await self.get_client(**kwargs_clients)
-            try:
-                response = client.stream(method, url, **kwargs)
-                if self.is_valid_respones(response) or retries <= 0:
-                    return response
             except (httpx.RequestError, httpx.HTTPStatusError) as e:
                 if retries <= 0:
                     raise e
             retries -= 1
 
+    async def request(self, method, url, **kwargs):
+        return await self.call_client(False, method, url, **kwargs)
+
+    async def stream(self, method, url, **kwargs):
+        return await self.call_client(True, method, url, **kwargs)
+
     @classmethod
     async def aclose_all(cls):
         await asyncio.gather(*[network.aclose() for network in NETWORKS.values()], return_exceptions=False)
diff --git a/tests/unit/network/test_network.py b/tests/unit/network/test_network.py
index d25a0d77..4253e69a 100644
--- a/tests/unit/network/test_network.py
+++ b/tests/unit/network/test_network.py
@@ -76,13 +76,15 @@ class TestNetwork(SearxTestCase):
             'verify': True,
             'max_redirects': 5,
             'timeout': 2,
+            'allow_redirects': True,
         }
-        kwargs_client = Network.get_kwargs_clients(kwargs)
+        kwargs_client = Network.extract_kwargs_clients(kwargs)
 
         self.assertEqual(len(kwargs_client), 2)
-        self.assertEqual(len(kwargs), 1)
+        self.assertEqual(len(kwargs), 2)
 
         self.assertEqual(kwargs['timeout'], 2)
+        self.assertEqual(kwargs['follow_redirects'], True)
 
         self.assertTrue(kwargs_client['verify'])
         self.assertEqual(kwargs_client['max_redirects'], 5)