improvement: in watch mode, use hash in graphics filenames to force browser refresh

Author: phfaist

flm/main/feature_graphics_collection.py

@@ -858,12 +858,27 @@ def prepare_collect_graphics(self, source_info, resolved_src_url, counter):
             )
             target_ext = converter_info['target_ext']
 
-            target_fname = self.collect_graphics_filename_template_obj.substitute({
-                'basename': os.path.basename(resolved_src_url),
-                'basenoext': basenoext,
-                'ext': target_ext,
-                'counter': counter,
-            })
+            input_hash = None
+            if source_type == 'file':
+                with open(resolved_src_url, 'rb') as f:
+                    input_hash = hashlib.file_digest(f, 'sha256').hexdigest()
+
+            try:
+                target_fname = self.collect_graphics_filename_template_obj.substitute({
+                    'basename': os.path.basename(resolved_src_url),
+                    'basenoext': basenoext,
+                    'ext': target_ext,
+                    'counter': counter,
+                    'hash': input_hash if input_hash is not None else 'NOHASH',
+                    'hash6': input_hash[:6] if input_hash is not None else 'NOHASH',
+                })
+            except KeyError as e:
+                raise ValueError(
+                    f"Invalid file name template in feature_graphics_collection: ‘"
+                    + self.collect_graphics_filename_template
+                    + f"’ refers to invalid key ‘{e.args[0]}’"
+                )
+                    
             target_path = os.path.join(
                 self.reference_output_dir,
                 self.collect_graphics_to_output_folder,
@@ -880,6 +895,7 @@ def prepare_collect_graphics(self, source_info, resolved_src_url, counter):
                 'source_url': source_url,
                 'src_url_resolved': resolved_src_url,
                 'converter_info': converter_info,
+                'input_hash': input_hash,
                 'target_path': target_path,
                 'target_relative_path': target_relative_path,
                 'from_ext': ext,
@@ -902,10 +918,7 @@ def collect_graphics(self, source_key, collect_info, *, cache_info):
 
             logger.debug('converter_info = %r', converter_info)
 
-            input_hash = None
-            if source_type == 'file':
-                with open(src_url, 'rb') as f:
-                    input_hash = hashlib.file_digest(f, 'sha256').hexdigest()
+            input_hash = collect_info['input_hash']
 
             if os.path.exists(target_path):
                 # check if the input file was updated since last run

flm/main/watch.py

@@ -120,6 +120,11 @@ def workflow_postprocess_actions_fn(rendered_content, document, render_context):
         inline_default_config = None
         if computed_format == 'html':
             inline_default_config = { 'flm': {
+                'features': {
+                    'flm.main.feature_graphics_collection': {
+                        'collect_graphics_filename_template': "gr${counter}-${hash6}${ext}"
+                    }
+                },
                 'renderer': {
                     'html': {
                         'include_node_data_attrs_fn': include_node_data_attrs_fn_src_line_col,