refactored to reduce duplicated code

parsers/drawings.py

@@ -66,6 +66,41 @@ rx_wallet = re.compile(r"""
 
     $                      # Anchor, ensuring the match is at the end of the string
     """, re.VERBOSE | re.IGNORECASE)
+def _set_filesize_and_check(fullpath, model_obj, parser_label, url_prefix="/dwgdataraw"):
+    """Set model_obj.filesize from filesystem and create DataIssue if missing/zero.
+    Returns True if file exists and has size > 0, False otherwise.
+    """
+    try:
+        size = Path(fullpath).stat().st_size
+    except Exception as e:
+        message = f"! Unable to stat file {fullpath}: {e}"
+        print(message)
+        DataIssue.objects.create(parser=parser_label, message=message, url=f"{url_prefix}/{getattr(model_obj, 'dwgpath', '')}")
+        return False
+
+    model_obj.filesize = size
+    model_obj.save()
+    if size <= 0:
+        message = f"! Zero length {parser_label.lower()} file {fullpath}"
+        print(message)
+        DataIssue.objects.create(parser=parser_label, message=message, url=f"{url_prefix}/{getattr(model_obj, 'dwgpath', '')}")
+        return False
+
+    return True
+
+
+def _read_text_file(fullpath):
+    """Read text file robustly, returning a str (falls back to binary decode)."""
+    try:
+        with open(fullpath, "r", encoding="utf-8", errors="replace") as fh:
+            return fh.read()
+    except Exception:
+        try:
+            with open(fullpath, "rb") as fh:
+                return fh.read().decode("utf-8", errors="replace")
+        except Exception as e:
+            print(f"! Unable to read file {fullpath}: {e}")
+            return ""
 
 def parse_tnl_file(dwgfile, path):
     """Is given a line of text 'path' which may or may not contain a recognisable name of a scanned file
@@ -177,15 +212,10 @@ def settherionfileinfo(filetuple):
     thtype, therionfile = filetuple
 
     ff = os.path.join(settings.DRAWINGS_DATA, therionfile.dwgpath)
-    therionfile.filesize = os.stat(ff)[stat.ST_SIZE]
-    if therionfile.filesize <= 0:
-        message = f"! Zero length therion file {ff}"
-        print(message)
-        DataIssue.objects.create(parser="Therion", message=message, url=f"/dwgdataraw/{therionfile.dwgpath}")
+    if not _set_filesize_and_check(ff, therionfile, "Therion"):
         return
-    fin = open(ff, "r")
-    ttext = fin.read()
-    fin.close()
+
+    ttext = _read_text_file(ff)
 
     # The equivalent for a tunnel 'path' would be a .th2 'line wall'  or 'scrap'
     # print(len(re.findall(r"line", ttext)))
@@ -243,15 +273,10 @@ def settnlfileinfo(dwgfile):
     *ref wallet identifiers may be found in at least two different places in tunnel files.
     """
     ff = os.path.join(settings.DRAWINGS_DATA, dwgfile.dwgpath)
-    dwgfile.filesize = os.stat(ff)[stat.ST_SIZE]
-    if dwgfile.filesize <= 0:
-        message = f"! Zero length tunnel file {ff}"
-        print(message)
-        DataIssue.objects.create(parser="Tunnel", message=message, url=f"/dwgdataraw/{dwgfile.dwgpath}")
+    if not _set_filesize_and_check(ff, dwgfile, "Tunnel"):
         return
-    fin = open(ff, "r") # tunnel files are now all utf-8 after fixup 24/10/2025.
-    ttext = fin.read()
-    fin.close()
+
+    ttext = _read_text_file(ff)
 
     dwgfile.npaths = len(rx_skpath.findall(ttext))
     # dwgfile.save()
@@ -286,18 +311,12 @@ def settnlfileinfo(dwgfile):
 def setdrwfileinfo(dwgfile):
     """Read in the drawing file contents and sets values on the dwgfile object,
     but these are SVGs, PDFs or .txt files, so there is no useful format to search for
-    This function is a placeholder in case we thnk of a way to do something
-    to recognise generic survex filenames.
+
     """
     ff = Path(settings.DRAWINGS_DATA) / dwgfile.dwgpath
-    dwgfile.filesize = ff.stat().st_size
-    dwgfile.save()
-    if dwgfile.filesize <= 0:
-        message = f"! Zero length drawing file {ff}"
-        print(message)
-        DataIssue.objects.create(parser="drawings", message=message, url=f"/dwgdataraw/{dwgfile.dwgpath}")
+    if not _set_filesize_and_check(ff, dwgfile, "drawings"):
         return
-
+    # nothing more to parse for generic files
 
 def load_drawings_files():
     """Breadth first search of drawings directory looking for sub-directories and *.xml filesize