Added: unsign form route (#75)

Author: signebedi

libreforms_fastapi/app/__init__.py

@@ -1084,10 +1084,14 @@ async def api_form_sign(
     except SignatureError as e:
         raise HTTPException(status_code=403, detail=f"{e}")
 
+    except InsufficientPermissions as e:
+        raise HTTPException(status_code=403, detail=f"{e}")
 
     except DocumentAlreadyHasValidSignature as e:
         raise HTTPException(status_code=200, detail=f"{e}")
 
+    except NoChangesProvided as e:
+        raise HTTPException(status_code=200, detail=f"{e}")
 
     # Send email
     if config.SMTP_ENABLED:
@@ -1118,6 +1122,95 @@ async def api_form_sign(
         "document_id": document_id, 
     }
 
+
+@app.patch("/api/form/unsign/{form_name}/{document_id}", dependencies=[Depends(api_key_auth)])
+async def api_form_sign(
+    form_name:str,
+    document_id:str,
+    background_tasks: BackgroundTasks,
+    request: Request,
+    session: SessionLocal = Depends(get_db),
+    key: str = Depends(X_API_KEY),
+):
+    if form_name not in get_form_names():
+        raise HTTPException(status_code=404, detail=f"Form '{form_name}' not found")
+
+    # Ugh, I'd like to find a more efficient way to get the user data. But alas, that
+    # the sqlalchemy-signing table is not optimized alongside the user model...
+    user = session.query(User).filter_by(api_key=key).first()
+
+    # Here we validate the user groups permit this level of access to the form
+    try:
+        user.validate_permission(form_name=form_name, required_permission="sign_own")
+    except Exception as e:
+        raise HTTPException(status_code=403, detail=f"{e}")
+        
+    metadata={
+        doc_db.last_editor_field: user.username,
+    }
+
+    # Add the remote addr host if enabled
+    if config.COLLECT_USAGE_STATISTICS:
+        metadata[doc_db.ip_address_field] = request.client.host
+
+    try:
+        # Process the request as needed
+        success = doc_db.sign_document(
+            form_name=form_name, 
+            document_id=document_id,
+            metadata=metadata,
+            username=user.username,
+            public_key=user.public_key,
+            private_key_path=user.private_key_ref,
+            unsign=True,
+        )
+
+    # Unlike other methods, like get_one_document or fuzzy_search_documents, this method raises exceptions when 
+    # it fails to ensure the user knows their operation was not successful.
+    except DocumentDoesNotExist as e:
+        raise HTTPException(status_code=404, detail=f"{e}")
+
+    except DocumentIsDeleted as e:
+        raise HTTPException(status_code=410, detail=f"{e}")
+
+    except SignatureError as e:
+        raise HTTPException(status_code=403, detail=f"{e}")
+
+    except InsufficientPermissions as e:
+        raise HTTPException(status_code=403, detail=f"{e}")
+
+    except NoChangesProvided as e:
+        raise HTTPException(status_code=200, detail=f"{e}")
+
+    # Send email
+    if config.SMTP_ENABLED:
+        background_tasks.add_task(
+            mailer.send_mail, 
+            subject="Form Unsigned", 
+            content=f"This email servers to notify you that a form was unsigned at {config.DOMAIN} by the user registered at this email address. The form's document ID is '{document_id}'. If you believe this was a mistake, or did not intend to sign this form, please contact your system administrator.", 
+            to_address=user.email,
+        )
+
+    # Write this query to the TransactionLog
+    if config.COLLECT_USAGE_STATISTICS:
+
+        endpoint = request.url.path
+        remote_addr = request.client.host
+
+        background_tasks.add_task(
+            write_api_call_to_transaction_log, 
+            api_key=key, 
+            endpoint=endpoint, 
+            remote_addr=remote_addr, 
+            query_params={},
+        )
+
+    return {
+        "message": "Form successfully unsigned", 
+        "document_id": document_id, 
+    }
+
+
 # Approve form
 # This is a metadata-only field. It should not impact the data, just the metadata - namely, to afix 
 # an approval - in the format of a digital signature - to the form. 

libreforms_fastapi/utils/document_database.py

@@ -398,7 +398,7 @@ def update_document(
         if len(dropping_unchanged_data.keys()) == 0:
             raise NoChangesProvided(form_name, document_id)
 
-        print("\n\n\nDropping Unchanged Fields: ", dropping_unchanged_data)
+        # print("\n\n\nDropping Unchanged Fields: ", dropping_unchanged_data)
 
         # Build the journal
         journal = document['metadata'].get(self.journal_field)
@@ -441,6 +441,7 @@ def sign_document(
         metadata={}, 
         exclude_deleted=True,
         verify_on_sign=True,
+        unsign=False,
     ):
         """
         Manage signatures existing form in specified form's database.
@@ -464,25 +465,41 @@ def sign_document(
                 self.logger.warning(f"Document for {form_name} with document_id {document_id} is deleted and was not updated")
             raise DocumentIsDeleted(form_name, document_id)
 
-        # Before we even begin, we verify whether a signature exists and only proceed if it doesn't. Otherwise, 
-        # we raise a DocumentAlreadyHasValidSignature exception. The idea here is to avoid spamming signatures if
-        # there has been no substantive change to the data since a past signature. This will allow the logic here
-        # to proceed if there is no signature, or if the data has changed since the last signature.
-        has_document_already_been_signed = verify_record_signature(record=document, username=username, env=self.env, public_key=public_key, private_key_path=private_key_path)
-
-        if has_document_already_been_signed:
-            raise DocumentAlreadyHasValidSignature(form_name, document_id, username)
-
-        # Now we afix the signature
-        try:
-            r, signature = sign_record(record=document, username=username, env=self.env, private_key_path=private_key_path)
-
-            if verify_on_sign:
-                verify = verify_record_signature(record=r, username=username, env=self.env, public_key=public_key, private_key_path=private_key_path)
-                assert (verify)
-                # print ("\n\n\n", a)
-        except:
-            raise SignatureError(form_name, document_id, username)
+        if username != document['metadata'][self.created_by_field]:
+            if self.use_logger:
+                self.logger.warning(f"Insufficient permissions to {'unsign' if unsign else 'sign'} document for {form_name} with document_id {document_id}")
+            raise InsufficientPermissions(form_name, document_id, username)
+
+        # If we are trying to unsign the document, then we remove the signature, update the document, and return.
+        if unsign:
+            
+            # If the document is not signed, raise a no changes exception
+            if not document['metadata'][self.signature_field]:
+                raise NoChangesProvided(form_name, document_id)
+
+            signature = None
+
+        else:
+
+            # Before we even begin, we verify whether a signature exists and only proceed if it doesn't. Otherwise, 
+            # we raise a DocumentAlreadyHasValidSignature exception. The idea here is to avoid spamming signatures if
+            # there has been no substantive change to the data since a past signature. This will allow the logic here
+            # to proceed if there is no signature, or if the data has changed since the last signature.
+            has_document_already_been_signed = verify_record_signature(record=document, username=username, env=self.env, public_key=public_key, private_key_path=private_key_path)
+
+            if has_document_already_been_signed:
+                raise DocumentAlreadyHasValidSignature(form_name, document_id, username)
+
+            # Now we afix the signature
+            try:
+                r, signature = sign_record(record=document, username=username, env=self.env, private_key_path=private_key_path)
+
+                if verify_on_sign:
+                    verify = verify_record_signature(record=r, username=username, env=self.env, public_key=public_key, private_key_path=private_key_path)
+                    assert (verify)
+                    # print ("\n\n\n", a)
+            except:
+                raise SignatureError(form_name, document_id, username)
 
         current_timestamp = datetime.now(self.timezone)