only use one http session in the main function

src/stock-symbol-scraper/main.py

@@ -61,8 +61,9 @@ def get_str_from_td(td: Tag) -> str:
     return str(content).strip()
 
 
-async def all_trs_from_page(url: str) -> ResultSet:
-    async with ClientSession() as session:
+async def all_trs_from_page(url: str, session: ClientSession = None) -> ResultSet:
+    if session is None:
+        session = ClientSession()
     async with session.get(url) as response:
         html = await response.text()
     soup = BeautifulSoup(html, 'html.parser')
@@ -76,24 +77,27 @@ async def all_trs_from_page(url: str) -> ResultSet:
         raise UnexpectedMarkupError
 
 
-async def all_data_from_category(category: str) -> list[row_type]:
+async def all_data_from_category(category: str, session: ClientSession = None) -> list[row_type]:
     log.info(f"Getting companies starting with '{category}'")
+    if session is None:
+        session = ClientSession()
     data: list[row_type] = []
     page = 1
-    trs = await all_trs_from_page(f'{BASE_URL}{category}')
+    trs = await all_trs_from_page(f'{BASE_URL}{category}', session)
     while len(trs) > 0:
-        log.info(f"Scraping page {page}")
+        log.info(f"Scraping '{category}' page {page}")
         data.extend(data_from_rows(trs))
         page += 1
-        trs = await all_trs_from_page(f'{BASE_URL}{category}/{page}')
+        trs = await all_trs_from_page(f'{BASE_URL}{category}/{page}', session)
     return data
 
 
 async def get_all_data(asynchronous: bool = False) -> list[row_type]:
+    async with ClientSession() as session:
         if asynchronous:
-        results = await asyncio.gather(*(all_data_from_category(category) for category in CATEGORIES))
+            results = await asyncio.gather(*(all_data_from_category(category, session) for category in CATEGORIES))
         else:
-        results = [await all_data_from_category(category) for category in CATEGORIES]
+            results = [await all_data_from_category(category, session) for category in CATEGORIES]
     data = []
     for result in results:
         data.extend(result)