feat: preserve Substack widgets in Markdown (fixes #64) (#76)

Author: ma2za

.pre-commit-config.yaml

@@ -1,17 +1,17 @@
-repos:
-  - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v6.0.0
-    hooks:
-      - id: check-yaml
-      - id: end-of-file-fixer
-      - id: trailing-whitespace
-  - repo: https://github.com/psf/black
-    rev: 26.5.1
-    hooks:
-      - id: black
-  - repo: https://github.com/pycqa/isort
-    rev: 8.0.1
-    hooks:
-      - id: isort
-        name: isort (python)
-        args: ["--profile", "black"]
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v6.0.0
+    hooks:
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+  - repo: https://github.com/psf/black
+    rev: 26.5.1
+    hooks:
+      - id: black
+  - repo: https://github.com/pycqa/isort
+    rev: 9.0.1
+    hooks:
+      - id: isort
+        name: isort (python)
+        args: ["--profile", "black"]

substack/api.py

@@ -478,6 +478,7 @@ def update_draft_from_markdown(
         draft_section_id: int = None,
         tags=None,
         dry_run: bool = False,
+        allow_unsupported_change: bool = False,
     ) -> dict:
         """
         Update an existing draft body from Markdown, with optional metadata changes.
@@ -497,12 +498,7 @@ def update_draft_from_markdown(
         if not isinstance(draft_body, dict):
             raise ValueError("Malformed draft body: draft_body must be a JSON object")
 
-        _, unsupported_nodes = document_to_markdown(draft_body)
-        if unsupported_nodes:
-            raise ValueError(
-                "Refusing to update: remote draft contains unsupported Substack nodes. "
-                "Export it first or remove the nodes manually to avoid data loss."
-            )
+        _, remote_unsupported = document_to_markdown(draft_body)
 
         post = Post(
             title=draft.get("title", ""),
@@ -515,6 +511,25 @@ def update_draft_from_markdown(
         )
         post.from_markdown(markdown, api=self)
 
+        _, submitted_unsupported = document_to_markdown(post.draft_body)
+
+        if not allow_unsupported_change:
+            remote_serialized = [
+                json.dumps(n, ensure_ascii=False, separators=(",", ":"), sort_keys=True)
+                for n in remote_unsupported
+            ]
+            submitted_serialized = [
+                json.dumps(n, ensure_ascii=False, separators=(",", ":"), sort_keys=True)
+                for n in submitted_unsupported
+            ]
+            if sorted(remote_serialized) != sorted(submitted_serialized):
+                raise ValueError(
+                    "Refusing to update: remote unsupported nodes are missing, duplicated, stale, or altered. "
+                    "Export the draft first or set allow_unsupported_change=True to proceed."
+                )
+
+        unsupported_nodes = remote_unsupported
+
         update_payload = {"draft_body": json.dumps(post.draft_body)}
 
         if subtitle is not None:

substack/cli.py

@@ -310,6 +310,9 @@ def _drafts_create(api, args):
 
 
 def _drafts_update(api, args):
+    if args.allow_unsupported_change and not args.yes:
+        raise CLIUsageError("--yes is required when using --allow-unsupported-change")
+
     if not args.yes and (args.json_output or not sys.stdin.isatty()):
         raise CLIUsageError("--yes is required in non-interactive or JSON mode")
 
@@ -347,6 +350,7 @@ def _drafts_update(api, args):
         draft_section_id=args.draft_section_id,
         tags=args.tags,
         dry_run=args.dry_run,
+        allow_unsupported_change=args.allow_unsupported_change,
     )
 
     if args.json_output:
@@ -508,6 +512,7 @@ def _build_parser():
     drafts_update.add_argument("--draft-section-id", type=int)
     drafts_update.add_argument("--tag", action="append", dest="tags", metavar="TAG")
     drafts_update.add_argument("--dry-run", action="store_true")
+    drafts_update.add_argument("--allow-unsupported-change", action="store_true")
     drafts_update.add_argument("--yes", action="store_true")
     drafts_update.set_defaults(handler=_drafts_update)