fix: Handle missing Civitai API response fields gracefully

Fix KeyError when 'hashes', 'name', or 'model' fields are missing from
Civitai API responses. Use .get() with defaults instead of direct dict
access in:

- LoraMetadata.from_civitai_info()
- CheckpointMetadata.from_civitai_info()
- EmbeddingMetadata.from_civitai_info()
- RecipeScanner._get_hash_from_civitai()
- DownloadManager._process_download()

Fixes #820

py/services/download_manager.py

@@ -496,7 +496,9 @@ class DownloadManager:
                 return {"success": False, "error": "No mirror URL found"}
 
             # 3. Prepare download
-            file_name = file_info["name"]
+            file_name = file_info.get("name", "")
+            if not file_name:
+                return {"success": False, "error": "No filename found in file info"}
             save_path = os.path.join(save_dir, file_name)
 
             # 5. Prepare metadata based on model type

py/services/recipe_scanner.py

@@ -1351,8 +1351,9 @@ class RecipeScanner:
                     
             # Get hash from the first file
             for file_info in version_info.get('files', []):
-                if file_info.get('hashes', {}).get('SHA256'):
-                    return file_info['hashes']['SHA256'], False  # Return hash with False for isDeleted flag
+                sha256_hash = (file_info.get('hashes') or {}).get('SHA256')
+                if sha256_hash:
+                    return sha256_hash, False  # Return hash with False for isDeleted flag
                     
             logger.debug(f"No SHA256 hash found in version info for ID: {model_version_id}")
             return None, False

py/utils/models.py

@@ -143,27 +143,27 @@ class LoraMetadata(BaseModelMetadata):
     @classmethod
     def from_civitai_info(cls, version_info: Dict, file_info: Dict, save_path: str) -> 'LoraMetadata':
         """Create LoraMetadata instance from Civitai version info"""
-        file_name = file_info['name']
+        file_name = file_info.get('name', '')
         base_model = determine_base_model(version_info.get('baseModel', ''))
-        
+
         # Extract tags and description if available
         tags = []
         description = ""
-        if 'model' in version_info:
-            if 'tags' in version_info['model']:
-                tags = version_info['model']['tags']
-            if 'description' in version_info['model']:
-                description = version_info['model']['description']
-        
+        model_data = version_info.get('model') or {}
+        if 'tags' in model_data:
+            tags = model_data['tags']
+        if 'description' in model_data:
+            description = model_data['description']
+
         return cls(
             file_name=os.path.splitext(file_name)[0],
-            model_name=version_info.get('model').get('name', os.path.splitext(file_name)[0]),
+            model_name=model_data.get('name', os.path.splitext(file_name)[0]),
             file_path=save_path.replace(os.sep, '/'),
             size=file_info.get('sizeKB', 0) * 1024,
             modified=datetime.now().timestamp(),
-            sha256=file_info['hashes'].get('SHA256', '').lower(),
+            sha256=(file_info.get('hashes') or {}).get('SHA256', '').lower(),
             base_model=base_model,
-            preview_url=None,  # Will be updated after preview download
+            preview_url='',  # Will be updated after preview download
             preview_nsfw_level=0, # Will be updated after preview download
             from_civitai=True,
             civitai=version_info,
@@ -179,28 +179,28 @@ class CheckpointMetadata(BaseModelMetadata):
     @classmethod
     def from_civitai_info(cls, version_info: Dict, file_info: Dict, save_path: str) -> 'CheckpointMetadata':
         """Create CheckpointMetadata instance from Civitai version info"""
-        file_name = file_info['name']
+        file_name = file_info.get('name', '')
         base_model = determine_base_model(version_info.get('baseModel', ''))
         sub_type = version_info.get('type', 'checkpoint')
-        
+
         # Extract tags and description if available
         tags = []
         description = ""
-        if 'model' in version_info:
-            if 'tags' in version_info['model']:
-                tags = version_info['model']['tags']
-            if 'description' in version_info['model']:
-                description = version_info['model']['description']
-        
+        model_data = version_info.get('model') or {}
+        if 'tags' in model_data:
+            tags = model_data['tags']
+        if 'description' in model_data:
+            description = model_data['description']
+
         return cls(
             file_name=os.path.splitext(file_name)[0],
-            model_name=version_info.get('model').get('name', os.path.splitext(file_name)[0]),
+            model_name=model_data.get('name', os.path.splitext(file_name)[0]),
             file_path=save_path.replace(os.sep, '/'),
             size=file_info.get('sizeKB', 0) * 1024,
             modified=datetime.now().timestamp(),
-            sha256=file_info['hashes'].get('SHA256', '').lower(),
+            sha256=(file_info.get('hashes') or {}).get('SHA256', '').lower(),
             base_model=base_model,
-            preview_url=None,  # Will be updated after preview download
+            preview_url='',  # Will be updated after preview download
             preview_nsfw_level=0,
             from_civitai=True,
             civitai=version_info,
@@ -217,28 +217,28 @@ class EmbeddingMetadata(BaseModelMetadata):
     @classmethod
     def from_civitai_info(cls, version_info: Dict, file_info: Dict, save_path: str) -> 'EmbeddingMetadata':
         """Create EmbeddingMetadata instance from Civitai version info"""
-        file_name = file_info['name']
+        file_name = file_info.get('name', '')
         base_model = determine_base_model(version_info.get('baseModel', ''))
         sub_type = version_info.get('type', 'embedding')
-        
+
         # Extract tags and description if available
         tags = []
         description = ""
-        if 'model' in version_info:
-            if 'tags' in version_info['model']:
-                tags = version_info['model']['tags']
-            if 'description' in version_info['model']:
-                description = version_info['model']['description']
-        
+        model_data = version_info.get('model') or {}
+        if 'tags' in model_data:
+            tags = model_data['tags']
+        if 'description' in model_data:
+            description = model_data['description']
+
         return cls(
             file_name=os.path.splitext(file_name)[0],
-            model_name=version_info.get('model').get('name', os.path.splitext(file_name)[0]),
+            model_name=model_data.get('name', os.path.splitext(file_name)[0]),
             file_path=save_path.replace(os.sep, '/'),
             size=file_info.get('sizeKB', 0) * 1024,
             modified=datetime.now().timestamp(),
-            sha256=file_info['hashes'].get('SHA256', '').lower(),
+            sha256=(file_info.get('hashes') or {}).get('SHA256', '').lower(),
             base_model=base_model,
-            preview_url=None,  # Will be updated after preview download
+            preview_url='',  # Will be updated after preview download
             preview_nsfw_level=0,
             from_civitai=True,
             civitai=version_info,