Merge pull request #54 from sw360/links-and-embedded-parsing

Convenience functions for HAL _embedded and _links parsing

Author: tngraf

ChangeLog.md

@@ -5,6 +5,16 @@
 
 # SW360 Base Library for Python
 
+## NEXT
+
+* new helper functions `get_linked_id()` and `get_embedded()` to help parsing the
+  `obj["_links"]` and `obj["_embedded"]` sections of HAL responses.
+* All `get_*()` and `update_*()` methods now return a `SW360Response` which is a dict
+  subclass. So you can still use the result as a normal dict, existing code should work
+  unchanged. The new class however also provides the convenience methods `linked_id()`,
+  `linked_ids()`, `embedded_list()`, and `embedded_lists()` to easily access the HAL
+  sections of the response.
+
 ## V1.12.0.dev1
 
 * Support Keycloak (OpenID) token generation.

sw360/__init__.py

@@ -9,6 +9,7 @@
 
 __version__ = (1, 11, 2)
 
+from .base import SW360Response
 from .sw360_api import SW360
 from .sw360error import SW360Error
 from .sw360keycloak import SW360Keycloak
@@ -18,5 +19,6 @@
     "SW360",
     "SW360Error",
     "SW360OAuth2",
-    "SW360Keycloak"
+    "SW360Keycloak",
+    "SW360Response",
 ]

sw360/base.py

@@ -1,7 +1,8 @@
 # -------------------------------------------------------------------------------
-# Copyright (c) 2023-2025 Siemens
+# Copyright (c) 2023-2026 Siemens
 # All Rights Reserved.
 # Authors: thomas.graf@siemens.com
+# Authors: gernot.hillier@siemens.com
 #
 # Licensed under the MIT license.
 # SPDX-License-Identifier: MIT
@@ -15,6 +16,76 @@
 from .sw360error import SW360Error
 
 
+class SW360Response(Dict[str, Any]):
+    """A regular dict response with convenience methods for HAL traversal.
+
+    Behaves identically to a plain ``dict`` for backward compatibility, but
+    adds ``linked_id()``, ``linked_ids()``, ``embedded_list()``, and
+    ``embedded_lists()`` for comfortable access to ``_links`` and
+    ``_embedded`` sections.
+    """
+
+    def linked_id(self, link_key: str = "self") -> Optional[str]:
+        """Extract a resource ID from a ``_links`` entry.
+
+        Convenience shortcut for ``BaseMixin.get_linked_id(self, link_key)``.
+
+        :param link_key: the link relation key, defaults to ``"self"``
+        :return: the resource ID, or ``None`` if not available
+        """
+        return BaseMixin.get_linked_id(self, link_key)
+
+    def linked_ids(self) -> Dict[str, str]:
+        """Return all linked resource IDs as a dict.
+
+        Iterates all entries in ``_links`` and resolves each href to its
+        resource ID, returning a mapping of link key to ID. Useful for
+        inspecting which linked resources are available.
+
+        :return: dict mapping each link key to its resource ID
+        """
+        links = self.get("_links")
+        if not isinstance(links, dict):
+            return {}
+        return {
+            key: BaseMixin.get_id_from_href(entry["href"])
+            for key, entry in links.items()
+            if isinstance(entry, dict) and isinstance(entry.get("href"), str)
+        }
+
+    def embedded_list(self, key: str) -> List["SW360Response"]:
+        """Retrieve a specific embedded resource list.
+
+        Like ``BaseMixin.get_embedded()``, but each item in the returned
+        list is wrapped in ``SW360Response`` so that ``.linked_id()`` and
+        other convenience methods are available on the items.
+
+        :param key: the embedded resource key, e.g. ``"releases"``
+        :return: list of embedded resources as ``SW360Response`` objects,
+            or ``[]`` if not present
+        """
+        return [SW360Response(item) for item in BaseMixin.get_embedded(self, key)]
+
+    def embedded_lists(self) -> Dict[str, List["SW360Response"]]:
+        """Return all embedded resource lists as a dict.
+
+        Iterates all entries in ``_embedded`` and wraps each item in
+        ``SW360Response``. Useful for inspecting which embedded resources
+        are available.
+
+        :return: dict mapping each embedded key to its list of
+            ``SW360Response`` objects
+        """
+        embedded = self.get("_embedded")
+        if not isinstance(embedded, dict):
+            return {}
+        return {
+            key: [SW360Response(item) for item in items]
+            for key, items in embedded.items()
+            if isinstance(items, list)
+        }
+
+
 class BaseMixin():
     """Python interface to the Siemens SW360 platform
 
@@ -48,13 +119,13 @@ def __init__(self, url: str, token: str, oauth2: bool = False) -> None:
 
         self.force_no_session = False
 
-    def api_get(self, url: str = "") -> Optional[Dict[str, Any]]:
+    def api_get(self, url: str = "") -> Optional[SW360Response]:
         """Request `url` from REST API and return json answer.
 
         :param url: the url to be requested
         :type url: string
-        :return: JSON data
-        :rtype: JSON
+        :return: JSON data as dict with convenience methods for HAL traversal
+        :rtype: SW360Response
         :raises SW360Error: if there is a negative HTTP response
         """
 
@@ -70,7 +141,11 @@ def api_get(self, url: str = "") -> Optional[Dict[str, Any]]:
         if response.ok:
             if response.status_code == 204:  # 204 = no content
                 return None
-            return response.json()
+            parsed = response.json()
+            if isinstance(parsed, dict):
+                return SW360Response(parsed)
+            else:
+                return parsed
 
         raise SW360Error(response, url)
 
@@ -137,16 +212,16 @@ def api_post(
 
         raise SW360Error(response, url)
 
-    def api_patch(self, url: str = "", json: Any = {}) -> Optional[Dict[str, Any]]:
+    def api_patch(self, url: str = "", json: Any = {}) -> Optional[SW360Response]:
         """
         Send a PATCH request to the specified URL with the provided json data.
 
         :param url: The URL to send the PATCH request to.
         :type url: str
         :param json: The dictionary containing json data to be sent in the request.
         :type json: Dict[str, Any]
-        :return: The JSON response received from the server, if any.
-        :rtype: Optional[Dict[str, Any]]
+        :return: The JSON response as dict with convenience methods for HAL traversal
+        :rtype: Optional[SW360Response]
         :raises SW360Error: If the HTTP response indicates an error.
         """
         if (not self.force_no_session) and self.session is None:
@@ -162,7 +237,11 @@ def api_patch(self, url: str = "", json: Any = {}) -> Optional[Dict[str, Any]]:
             if response.status_code == 204:  # 204 = no content
                 return None
             if response.content:
-                return response.json()
+                parsed = response.json()
+                if isinstance(parsed, dict):
+                    return SW360Response(parsed)
+                else:
+                    return parsed
             else:
                 return None
 
@@ -241,3 +320,65 @@ def get_id_from_href(cls, href: str) -> str:
         pos = href.rfind("/")
         identifier = href[(pos + 1):]
         return identifier
+
+    @classmethod
+    def get_linked_id(cls, data: Dict[str, Any], link_key: str = "self") -> Optional[str]:
+        """Extract the resource ID from a HAL ``_links`` entry.
+
+        Looks up ``data["_links"][link_key]["href"]`` and returns the last
+        path segment, which is the resource identifier in the SW360 REST API.
+
+        It defaults to the "self" link, but can be used for any link relation key
+        like "sw360:component" or "sw360:project". The "sw360:" prefix can be
+        omitted in the `link_key` argument.
+
+        :param data: a JSON response dict containing a ``_links`` section
+        :param link_key: the link relation key, e.g. ``"self"`` or
+            ``"sw360:component"``
+        :return: the extracted resource ID, or ``None`` if the path does not
+            exist
+        :rtype: Optional[str]
+        """
+        links = data.get("_links")
+        if not isinstance(links, dict):
+            return None
+
+        if link_key in links:
+            entry = links.get(link_key)
+        else:
+            entry = links.get("sw360:" + link_key)
+        if not isinstance(entry, dict):
+            return None
+
+        href = entry.get("href")
+        if not isinstance(href, str):
+            return None
+
+        return cls.get_id_from_href(href)
+
+    @classmethod
+    def get_embedded(cls, data: Dict[str, Any], key: str) -> List[Dict[str, Any]]:
+        """Safely retrieve an embedded resource list from a HAL response.
+
+        Returns ``data["_embedded"][key]`` if it exists and is a list,
+        otherwise returns an empty list. The "sw360:" prefix can be omitted
+        in the `key` argument.
+
+        :param data: a JSON response dict potentially containing an
+            ``_embedded`` section
+        :param key: the embedded resource key, e.g. ``"sw360:releases"``
+        :return: the list of embedded resources, or ``[]`` if not present
+        :rtype: List[Dict[str, Any]]
+        """
+        embedded = data.get("_embedded")
+        if not isinstance(embedded, dict):
+            return []
+
+        if key in embedded:
+            items = embedded.get(key)
+        else:
+            items = embedded.get("sw360:" + key)
+        if not isinstance(items, list):
+            return []
+
+        return items