Caching SearXNG

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SearXNG installs itself on /usr/local/searxng/searxng-src, with the main source code in searxng-src directory.

Interesting files are...

  1. webapp.py in /usr/local/searxng/searxng-src/searx/webapp.py : def search()
  2. __init__.py in /usr/local/searxng/searxng-src/searx/search/__init__.py : class Search

A cache implentation here...

  • making a directory in the searx folder named cache
  • make a sub-folder for every possible character in the cache directory, for instance a to z and 0 to 9

  • the cache files are named by and are indentical to the search term
  • check if the filename exists when a search is performed
  • if there is a match read in the local file instead and defer the search
  • send the keywords to cache maintainers so they can update the cache. They can then crawl the search engines and build a more comprehensive cache over time.
  • the user updates their cache, by downloading a distributed database.

Benefits: Why do this?

Imagine a man in the middle that knows your search term before you and performed the search prior and then returned had the result ready. The result is the same, except it would very much faster. That is what a cache could do, it could also allow for a more comprehensive search. I could perform searches across all the search engines, compile and store that data on disk and when I searched the same term again, the result would be optimized.

Moreover, this turns searXNG into a full search engine built from caching results, searches are against a local file, so it speeds up searching significantly and offline searching is possible if the cache gets big enough.

Searx is privacy focused search engine, so disclosure to end user that however anonymous, caching requires keywords/search term sharing. That is how the cache is built.

Proposed searXNG options:

  • use cache
  • update the cache daily

File in question: __init__.py

class Search:

"""Search information container"""

__slots__ = "search_query", "result_container", "start_time", "actual_timeout"

def search_multiple_requests(self, requests):

# pylint: disable=protected-access

search_id = str(uuid4())

for engine_name, query, request_params in requests:

_search = copy_current_request_context(PROCESSORS[engine_name].search)

th = threading.Thread( # pylint: disable=invalid-name

target=_search,

args=(query, request_params, self.result_container, self.start_time, self.actual_timeout),

name=search_id,

)

th._timeout = False

th._engine_name = engine_name

th.start()

for th in threading.enumerate(): # pylint: disable=invalid-name

if th.name == search_id:

remaining_time = max(0.0, self.actual_timeout - (default_timer() - self.start_time))

th.join(remaining_time)

if th.is_alive():

th._timeout = True

self.result_container.add_unresponsive_engine(th._engine_name, 'timeout')

PROCESSORS[th._engine_name].logger.error('engine timeout')

def search_multiple_requests2(self, requests):

# pylint: disable=protected-access

search_id = str(uuid4())

mock_result_container = ResultContainer()

mock_results = [{'url': f'Mock Result {i}', 'content': ''} for i in range(1, 6)]

threads = []

for engine_name, _, _ in requests:

th = threading.Thread(

target=self.mock_search_function,

args=(engine_name, mock_results, mock_result_container),

name=search_id,

)

th._timeout = False

th._engine_name = engine_name

th.start()

threads.append(th)

remaining_time = None

for th in threads:

if th.name == search_id:

if remaining_time is None:

remaining_time = self.actual_timeout - (default_timer() - self.start_time)

th.join(remaining_time)

if th.is_alive():

th._timeout = True

self.result_container.add_unresponsive_engine(th._engine_name, 'timeout')

PROCESSORS[th._engine_name].logger.error('engine timeout')

# Wait for all threads to finish, even if some have timed out

for th in threads:

th.join()

# Copy the mock results to the actual result_container

self.result_container = mock_result_container

def mock_search_function(self, engine_name, mock_results, result_container):

# This is a mock search function

time.sleep(0.1) # Simulate some processing time

result_container.extend(engine_name, mock_results)

def search_standard(self):

"""

Update self.result_container, self.actual_timeout

"""

requests, self.actual_timeout = self._get_requests()

cache_dir = 'cache'

query_file_path = os.path.join(cache_dir, self.search_query.query)

# send all search-request

if requests:

# Check if the file exists in the cache directory

if os.path.isfile(query_file_path):

self.search_multiple_requests2(requests)

else:

self.search_multiple_requests(requests)

# return results, suggestions, answers and infoboxes

return True

  

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