Fix the outer source not found error in both Method sources and Threshold sources in creating a new score set and calibration.

src/mavedb/lib/external_publications.py

@@ -564,4 +564,13 @@ def _fetch(self, url: str, return_format: str = "json") -> Any:
             return []
 
         response.raise_for_status()
-        return json.loads(response.text) if return_format == "json" else response.text
+
+        if return_format == "json":
+            if not response.text or not response.text.strip():
+                return []
+            try:
+                return json.loads(response.text)
+            except json.JSONDecodeError:
+                return []
+
+        return response.text

src/mavedb/lib/identifiers.py

@@ -216,7 +216,10 @@ async def fetch_biorxiv_article(identifier: str) -> Optional[RxivContentDetail]:
     Fetch an existing bioRxiv article from Rxiv
     """
     fetch = Rxiv("https://api.biorxiv.org", "biorxiv")
-    articles = fetch.content_detail(identifier=identifier)
+    try:
+        articles = fetch.content_detail(identifier=identifier)
+    except Exception:
+        return None
     try:
         return articles[-1]
     except IndexError:
@@ -228,7 +231,10 @@ async def fetch_medrxiv_article(identifier: str) -> Optional[RxivContentDetail]:
     Fetch an existing medRxiv article from Rxiv
     """
     fetch = Rxiv("https://api.biorxiv.org", "medrxiv")
-    articles = fetch.content_detail(identifier=identifier)
+    try:
+        articles = fetch.content_detail(identifier=identifier)
+    except Exception:
+        return None
     try:
         return articles[-1]
     except IndexError: