Edge Case fixes, bug fixes, and UI Cleanup.

Page Importer/app.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import csv
 import datetime as dt
+import hashlib
 import io
 import re
 from dataclasses import replace
@@ -13,6 +14,7 @@ from page_importer.models import ScrapeOptions, ScrapedPost
 from page_importer.scraper import Scraper
 from page_importer.wxr import build_wxr
 
+
 def load_csv(file_data: bytes) -> tuple[list[str], list[dict[str, str]]]:
     text = file_data.decode("utf-8-sig", errors="replace")
     reader = csv.DictReader(io.StringIO(text))
@@ -20,6 +22,20 @@ def load_csv(file_data: bytes) -> tuple[list[str], list[dict[str, str]]]:
     return reader.fieldnames or [], rows
 
 
+def build_upload_fingerprint(file_data: bytes) -> str:
+    return hashlib.sha256(file_data).hexdigest()
+
+
+def sync_uploaded_file_state(session_state: dict[str, object], upload_fingerprint: str) -> None:
+    previous_fingerprint = session_state.get("uploaded_csv_fingerprint")
+    if previous_fingerprint == upload_fingerprint:
+        return
+
+    for key in ("results", "input_rows", "input_headers", "scrape_context"):
+        session_state.pop(key, None)
+    session_state["uploaded_csv_fingerprint"] = upload_fingerprint
+
+
 def render_app() -> None:
     st.title("Page Importer")
     st.caption("Scrape blog posts from CSV URLs and export a WordPress WXR file.")
@@ -47,7 +63,10 @@ def render_app() -> None:
         st.info("Upload a CSV to begin.")
         return
 
-    headers, rows = load_csv(uploaded.getvalue())
+    uploaded_bytes = uploaded.getvalue()
+    sync_uploaded_file_state(st.session_state, build_upload_fingerprint(uploaded_bytes))
+
+    headers, rows = load_csv(uploaded_bytes)
     if not rows:
         st.error("The CSV did not contain any rows.")
         return
@@ -88,6 +107,7 @@ def render_app() -> None:
         results = scrape_rows(rows, context, phase_label="Scraping")
         st.session_state["results"] = results
         st.session_state["input_rows"] = rows
+        st.session_state["input_headers"] = headers
         st.session_state["scrape_context"] = context
 
     results = st.session_state.get("results", [])
@@ -176,7 +196,9 @@ def render_app() -> None:
         st.write(f"**Author:** {selected.author or '(missing)'}")
         st.write(f"**Post Type:** {selected.post_type}")
         st.write(selected.body_html, unsafe_allow_html=True)
-        render_export_sidebar(successful, rows, headers)
+        stored_rows = st.session_state.get("input_rows", rows)
+        stored_headers = st.session_state.get("input_headers", headers)
+        render_export_sidebar(successful, stored_rows, stored_headers)
 
 
 def build_scrape_context(