Revize 4e70d22a

Re #8472 - Added get_chain_of_trust method documentation and comments

src/services/certificate_service.py

@@ -129 +129 @@
         return self.certificate_repository.read_all(cert_type)
 
     def get_chain_of_trust(self, from_id: int, to_id: int = -1, exclude_root=True) -> List[Certificate]:
+        """
+        Traverses the certificate hierarchy tree upwards till a certificate with the `to_id` ID is found or till a
+        root CA certificate is found. Root certificates are excluded from the chain by default.
+        :param from_id: ID of the first certificate to be included in the chain of trust
+        :param to_id: ID of the last certificate to be included in the chain of trust
+        :param exclude_root: a flag indicating whether root CA certificate should be excluded
+        :return: a list of certificates representing the chain of trust starting with the certificate given by `from_id`
+        ID
+        """
+        # read the first certificate of the chain
         start_cert = self.certificate_repository.read(from_id)
 
+        # if no cert is found or the current cert is root CA and root CAs should be excluded, then return an empty list
         if start_cert is None or (start_cert.type_id == ROOT_CA_ID and exclude_root):
             return []
 
@@ -139 +150 @@
 
         # TODO could possibly be simplified
         if start_cert.type_id == ROOT_CA_ID:
+            # the first cert found is a root ca
             return chain_of_trust
 
         while True:
             parent_cert = self.certificate_repository.read(current_cert.parent_id)
 
-            # check whether parent certificate
-            if parent_cert is None or parent_cert.type_id == ROOT_CA_ID:
+            # check whether parent certificate exists
+            if parent_cert is None:
+                break
+
+            # check whether the found certificate is a root certificate
+            if parent_cert.type_id == ROOT_CA_ID:
                 if not exclude_root:
+                    # append the found root cert only if root certificates should not be excluded from the CoT
                     chain_of_trust.append(parent_cert)
                 break
 
+            # append the certificate
             chain_of_trust.append(parent_cert)
 
+            # stop iterating over certificates if the id of the found certificate matches `to_id` method parameter
             if parent_cert.certificate_id == to_id:
                 break