[httpx] replace searx.poolrequests by searx.network

settings.yml:

* outgoing.networks:
   * can contains network definition
   * propertiers: enable_http, verify, http2, max_connections, max_keepalive_connections,
     keepalive_expiry, local_addresses, support_ipv4, support_ipv6, proxies, max_redirects, retries
   * retries: 0 by default, number of times searx retries to send the HTTP request (using different IP & proxy each time)
   * local_addresses can be "192.168.0.1/24" (it supports IPv6)
   * support_ipv4 & support_ipv6: both True by default
     see https://github.com/searx/searx/pull/1034
* each engine can define a "network" section:
   * either a full network description
   * either reference an existing network

* all HTTP requests of engine use the same HTTP configuration (it was not the case before, see proxy configuration in master)

searx/engines/__init__.py

@@ -27,7 +27,7 @@ from searx import settings
 from searx import logger
 from searx.data import ENGINES_LANGUAGES
 from searx.exceptions import SearxEngineResponseException
-from searx.poolrequests import get, get_proxy_cycles
+from searx.network import get, initialize as initialize_network, set_context_network_name
 from searx.utils import load_module, match_language, get_engine_from_settings, gen_useragent
 
 
@@ -89,8 +89,6 @@ def load_engine(engine_data):
                 engine.categories = []
             else:
                 engine.categories = list(map(str.strip, param_value.split(',')))
-        elif param_name == 'proxies':
-            engine.proxies = get_proxy_cycles(param_value)
         else:
             setattr(engine, param_name, param_value)
 
@@ -289,9 +287,11 @@ def load_engines(engine_list):
 
 def initialize_engines(engine_list):
     load_engines(engine_list)
+    initialize_network(engine_list, settings['outgoing'])
 
     def engine_init(engine_name, init_fn):
         try:
+            set_context_network_name(engine_name)
             init_fn(get_engine_from_settings(engine_name))
         except SearxEngineResponseException as exc:
             logger.warn('%s engine: Fail to initialize // %s', engine_name, exc)