disallow saving a process model file if it has changed w/ burnettk

spiffworkflow-backend/src/spiffworkflow_backend/api.yml

@@ -1245,6 +1245,13 @@ paths:
     put:
       operationId: spiffworkflow_backend.routes.process_models_controller.process_model_file_update
       summary: save the contents to the given file
+      parameters:
+        - name: file_contents_hash
+          in: query
+          required: true
+          description: The hash of the file contents that originally came with the file.
+          schema:
+            type: string
       tags:
         - Process Model Files
       requestBody:

spiffworkflow-backend/src/spiffworkflow_backend/models/file.py

@@ -1,13 +1,10 @@
-"""File."""
+from __future__ import annotations
 from dataclasses import dataclass
+from typing import Any
 from dataclasses import field
 from datetime import datetime
 from typing import Optional
 
-import marshmallow
-from marshmallow import INCLUDE
-from marshmallow import Schema
-
 from spiffworkflow_backend.helpers.spiff_enum import SpiffEnum
 from spiffworkflow_backend.models.spec_reference import SpecReference
 
@@ -77,7 +74,7 @@ class File:
     references: Optional[list[SpecReference]] = None
     file_contents: Optional[bytes] = None
     process_model_id: Optional[str] = None
-    process_group_id: Optional[str] = None
+    file_contents_hash: Optional[str] = None
 
     def __post_init__(self) -> None:
         """__post_init__."""
@@ -102,28 +99,9 @@ class File:
         )
         return instance
 
-
-class FileSchema(Schema):
-    """FileSchema."""
-
-    class Meta:
-        """Meta."""
-
-        model = File
-        fields = [
-            "id",
-            "name",
-            "content_type",
-            "last_modified",
-            "type",
-            "size",
-            "data_store",
-            "user_uid",
-            "url",
-            "file_contents",
-            "references",
-            "process_group_id",
-            "process_model_id",
-        ]
-        unknown = INCLUDE
-        references = marshmallow.fields.List(marshmallow.fields.Nested("SpecReferenceSchema"))
+    @property
+    def serialized(self) -> dict[str, Any]:
+        dictionary = self.__dict__
+        if isinstance(self.file_contents, bytes):
+            dictionary['file_contents'] = self.file_contents.decode('utf-8')
+        return dictionary

spiffworkflow-backend/src/spiffworkflow_backend/models/process_model.py

@@ -87,7 +87,7 @@ class ProcessModelInfoSchema(Schema):
     display_order = marshmallow.fields.Integer(allow_none=True)
     primary_file_name = marshmallow.fields.String(allow_none=True)
     primary_process_id = marshmallow.fields.String(allow_none=True)
-    files = marshmallow.fields.List(marshmallow.fields.Nested("FileSchema"))
+    files = marshmallow.fields.List(marshmallow.fields.Nested("File"))
     fault_or_suspend_on_exception = marshmallow.fields.String()
     exception_notification_addresses = marshmallow.fields.List(marshmallow.fields.String)
     metadata_extraction_paths = marshmallow.fields.List(

spiffworkflow-backend/src/spiffworkflow_backend/routes/process_models_controller.py

@@ -1,4 +1,5 @@
 """APIs for dealing with process groups, process models, and process instances."""
+from hashlib import sha256
 import json
 import os
 import re
@@ -18,7 +19,6 @@ from werkzeug.datastructures import FileStorage
 
 from spiffworkflow_backend.exceptions.api_error import ApiError
 from spiffworkflow_backend.interfaces import IdToProcessGroupMapping
-from spiffworkflow_backend.models.file import FileSchema
 from spiffworkflow_backend.models.process_group import ProcessGroup
 from spiffworkflow_backend.models.process_instance_report import (
     ProcessInstanceReportModel,
@@ -245,10 +245,9 @@ def process_model_list(
     return make_response(jsonify(response_json), 200)
 
 
-def process_model_file_update(modified_process_model_identifier: str, file_name: str) -> flask.wrappers.Response:
-    """Process_model_file_update."""
+def process_model_file_update(modified_process_model_identifier: str, file_name: str, file_contents_hash: str) -> flask.wrappers.Response:
     message = f"User: {g.user.username} clicked save for"
-    return _create_or_update_process_model_file(modified_process_model_identifier, message, 200)
+    return _create_or_update_process_model_file(modified_process_model_identifier, message, 200, file_contents_hash=file_contents_hash)
 
 
 def process_model_file_delete(modified_process_model_identifier: str, file_name: str) -> flask.wrappers.Response:
@@ -293,7 +292,6 @@ def process_model_file_create(
 
 
 def process_model_file_show(modified_process_model_identifier: str, file_name: str) -> Any:
-    """Process_model_file_show."""
     process_model_identifier = modified_process_model_identifier.replace(":", "/")
     process_model = _get_process_model(process_model_identifier)
     files = SpecFileService.get_files(process_model, file_name)
@@ -309,8 +307,10 @@ def process_model_file_show(modified_process_model_identifier: str, file_name: s
     file = files[0]
     file_contents = SpecFileService.get_data(process_model, file.name)
     file.file_contents = file_contents
+    file_contents_hash = sha256(file_contents).hexdigest()
+    file.file_contents_hash = file_contents_hash
     file.process_model_id = process_model.id
-    return FileSchema().dump(file)
+    return make_response(jsonify(file), 200)
 
 
 #   {
@@ -477,6 +477,7 @@ def _create_or_update_process_model_file(
     modified_process_model_identifier: str,
     message_for_git_commit: str,
     http_status_to_return: int,
+    file_contents_hash: Optional[str],
 ) -> flask.wrappers.Response:
     """_create_or_update_process_model_file."""
     process_model_identifier = modified_process_model_identifier.replace(":", "/")
@@ -498,6 +499,16 @@ def _create_or_update_process_model_file(
             status_code=400,
         )
 
+    current_file_contents_bytes = SpecFileService.get_data(process_model, request_file.filename)
+    if current_file_contents_bytes and file_contents_hash:
+        current_file_contents_hash = sha256(current_file_contents_bytes).hexdigest()
+        if current_file_contents_hash != file_contents_hash:
+            raise ApiError(
+                error_code="process_model_file_has_changed",
+                message=f"Process model file: {request_file.filename} was already changed by someone else. Please reload before making changes.",
+                status_code=409,
+            )
+
     file = None
     try:
         file = SpecFileService.update_file(process_model, request_file.filename, request_file_contents)
@@ -514,8 +525,4 @@ def _create_or_update_process_model_file(
     file.process_model_id = process_model.id
     _commit_and_push_to_git(f"{message_for_git_commit} {process_model_identifier}/{file.name}")
 
-    return Response(
-        json.dumps(FileSchema().dump(file)),
-        status=http_status_to_return,
-        mimetype="application/json",
-    )
+    return make_response(jsonify(file), http_status_to_return)

spiffworkflow-backend/src/spiffworkflow_backend/services/spec_file_service.py

@@ -175,7 +175,6 @@ class SpecFileService(FileSystemService):
 
     @classmethod
     def update_file(cls, process_model_info: ProcessModelInfo, file_name: str, binary_data: bytes) -> File:
-        """Update_file."""
         SpecFileService.assert_valid_file_name(file_name)
         cls.validate_bpmn_xml(file_name, binary_data)
 

spiffworkflow-frontend/src/interfaces.ts

@@ -114,6 +114,7 @@ export interface ProcessFile {
   size: number;
   type: string;
   file_contents?: string;
+  file_contents_hash?: string;
 }
 
 export interface ProcessInstanceMetadata {

spiffworkflow-frontend/src/routes/ProcessModelEditDiagram.tsx

@@ -206,6 +206,9 @@ export default function ProcessModelEditDiagram() {
       httpMethod = 'POST';
     } else {
       url += `/${fileNameWithExtension}`;
+      if (processModelFile && processModelFile.file_contents_hash) {
+        url += `?file_contents_hash=${processModelFile.file_contents_hash}`;
+      }
     }
     if (!fileNameWithExtension) {
       handleShowFileNameEditor();