Update api_clients/umls_client.py

api_clients/umls_client.py

@@ -0,0 +1,45 @@
+# api_clients/umls_client.py
+"""
+Client for the NLM Unified Medical Language System (UMLS) API.
+Handles the complex ticket-based authentication.
+"""
+import aiohttp
+from lxml import html
+from .config import UMLS_API_KEY, UMLS_AUTH_URL, UMLS_BASE_URL, REQUEST_HEADERS
+
+class UMLSClient:
+    def __init__(self, session: aiohttp.ClientSession):
+        self.session = session
+        self.service_ticket = None
+
+    async def authenticate(self):
+        """Gets a single-use service ticket for API requests."""
+        if not UMLS_API_KEY:
+            print("Warning: UMLS_API_KEY not found. UMLS features will be disabled.")
+            return False
+        params = {'apikey': UMLS_API_KEY}
+        async with self.session.post(UMLS_AUTH_URL, data=params, headers=REQUEST_HEADERS) as resp:
+            if resp.status == 201:
+                response_text = await resp.text()
+                self.service_ticket = html.fromstring(response_text).find('.//form').get('action')
+                return True
+            else:
+                print(f"Error authenticating with UMLS: {resp.status}")
+                return False
+
+    async def get_cui_for_term(self, term: str):
+        """Searches for a Concept Unique Identifier (CUI) for a given term."""
+        if not await self.authenticate():
+            return None
+
+        query = {'string': term, 'ticket': self.service_ticket}
+        url = f"{UMLS_BASE_URL}/search/current"
+        
+        async with self.session.get(url, params=query, headers=REQUEST_HEADERS) as resp:
+            if resp.status == 200:
+                data = await resp.json()
+                results = data.get('result', {}).get('results', [])
+                return results[0] if results else None
+            else:
+                print(f"Error searching UMLS for term '{term}': {resp.status}")
+                return None