Solve custom section issue with sessions

Now correctly uses st.session_state instead of a local file.

app.py

@@ -27,7 +27,11 @@ st.title("Skops space creator for sklearn")
 
 PLACEHOLDER = "[More Information Needed]"
 PLOT_PREFIX = "__plot__:"
-custom_sections: dict[str, str] = {}
+
+# store session state
+if "custom_sections" not in st.session_state:
+    st.session_state.custom_sections = {}
+
 tmp_repo = Path(mkdtemp(prefix="skops-"))
 left_col, right_col = st.columns([1, 2])
 
@@ -36,32 +40,11 @@ CUSTOM_SECTIONS_CACHE_FILE = ".custom-sections.json"
 
 
 def _clear_custom_section_cache():
-    with open(CUSTOM_SECTIONS_CACHE_FILE, "w") as f:
-        f.write("")
-
-
-def _load_custom_section_cache():
-    global custom_sections
-
-    # in case file doesn't exist yet, create it
-    if not os.path.exists(CUSTOM_SECTIONS_CACHE_FILE):
-        Path(CUSTOM_SECTIONS_CACHE_FILE).touch()
-
-    with open(CUSTOM_SECTIONS_CACHE_FILE, "r") as f:
-        try:
-            custom_sections = json.load(f)
-        except ValueError:
-            pass
-
-
-def _write_custom_section_cache():
-    with open(CUSTOM_SECTIONS_CACHE_FILE, "w") as f:
-        json.dump(custom_sections, f)
+    st.session_state.custom_sections.clear()
 
 
 def _remove_custom_section(key):
-    del custom_sections[key]
-    _write_custom_section_cache()
+    del st.session_state.custom_sections[key]
 
 
 def _clear_repo(path):
@@ -157,8 +140,8 @@ def _create_model_card():
     if citation:
         model_card.add(**{"Citation": citation})
 
-    if custom_sections:
-        for key, val in custom_sections.items():
+    if st.session_state.custom_sections:
+        for key, val in st.session_state.custom_sections.items():
             if not key:
                 continue
 
@@ -256,8 +239,7 @@ def add_custom_section():
     if not section_name or not section_content:
         return
 
-    custom_sections[section_name] = section_content
-    _write_custom_section_cache()
+    st.session_state.custom_sections[section_name] = section_content
 
 
 def add_custom_plot():
@@ -275,8 +257,7 @@ def add_custom_plot():
     with open(file_path, "wb") as f:
         f.write(plot_file.getvalue())
 
-    custom_sections[str(PLOT_PREFIX + plot_name)] = file_path
-    _write_custom_section_cache()
+    st.session_state.custom_sections[str(PLOT_PREFIX + plot_name)] = file_path
 
 
 with left_col:
@@ -339,6 +320,7 @@ with left_col:
         height=5,
     )
 
+    # ADD A CUSTOM SECTIONS
     with st.form("custom-section", clear_on_submit=True):
         section_name = st.text_input(
             "Section name (use '/' for subsections, e.g. 'Model description/My new"
@@ -352,6 +334,7 @@ with left_col:
             "Create new section", on_click=add_custom_section
         )
 
+    # ADD A PLOT
     with st.form("custom-plots", clear_on_submit=True):
         plot_name = st.text_input(
             "Section name (use '/' for subsections, e.g. 'Model description/My new"
@@ -362,8 +345,7 @@ with left_col:
 
         submit_new_plot = st.form_submit_button("Add plot", on_click=add_custom_plot)
 
-    _load_custom_section_cache()
-    for key in custom_sections:
+    for key in st.session_state.custom_sections:
         if not key:
             continue
 
@@ -378,9 +360,9 @@ with left_col:
                 f"Remove section '{key}'", on_click=_remove_custom_section, args=(key,)
             )
 
-    if custom_sections:
+    if st.session_state.custom_sections:
         st.button(
-            f"Remove all ({len(custom_sections)}) custom elements",
+            f"Remove all ({len(st.session_state.custom_sections)}) custom elements",
             on_click=_clear_custom_section_cache,
         )