Keep asset and snippet filenames the same (if possible)

InvenTree/report/models.py

@@ -7,12 +7,14 @@ from __future__ import unicode_literals
 
 import os
 import sys
+import logging
 
 import datetime
 
 from django.db import models
 from django.conf import settings
 
+from django.core.files.storage import FileSystemStorage
 from django.core.validators import FileExtensionValidator
 
 import stock.models
@@ -29,6 +31,35 @@ except OSError as err:
     sys.exit(1)
 
 
+logger = logging.getLogger(__name__)
+
+
+class ReportFileUpload(FileSystemStorage):
+    """
+    Custom implementation of FileSystemStorage class.
+
+    When uploading a report (or a snippet / asset / etc),
+    it is often important to ensure the filename is not arbitrarily *changed*,
+    if the name of the uploaded file is identical to the currently stored file.
+
+    For example, a snippet or asset file is referenced in a template by filename,
+    and we do not want that filename to change when we upload a new *version*
+    of the snippet or asset file.
+    
+    This uploader class performs the following pseudo-code function:
+
+    - If the model is *new*, proceed as normal
+    - If the model is being updated:
+        a) If the new filename is *different* from the existing filename, proceed as normal
+        b) If the new filename is *identical* to the existing filename, we want to overwrite the existing file
+    """
+
+    def get_available_name(self, name, max_length=None):
+
+        print("Name:", name)
+        return super().get_available_name(name, max_length)
+
+
 def rename_template(instance, filename):
 
     return instance.rename_file(filename)
@@ -235,7 +266,19 @@ def rename_snippet(instance, filename):
 
     filename = os.path.basename(filename)
 
-    return os.path.join('report', 'snippets', filename)
+    path = os.path.join('report', 'snippets', filename)
+
+    # If the snippet file is the *same* filename as the one being uploaded,
+    # delete the original one from the media directory
+    if str(filename) == str(instance.snippet):
+        fullpath = os.path.join(settings.MEDIA_ROOT, path)
+        fullpath = os.path.abspath(fullpath)
+       
+        if os.path.exists(fullpath):
+            logger.info(f"Deleting existing snippet file: '{filename}'")
+            os.remove(fullpath)
+
+    return path
 
 
 class ReportSnippet(models.Model):
@@ -259,7 +302,19 @@ def rename_asset(instance, filename):
 
     filename = os.path.basename(filename)
 
-    return os.path.join('report', 'assets', filename)
+    path = os.path.join('report', 'assets', filename)
+
+    # If the asset file is the *same* filename as the one being uploaded,
+    # delete the original one from the media directory
+    if str(filename) == str(instance.asset):
+        fullpath = os.path.join(settings.MEDIA_ROOT, path)
+        fullpath = os.path.abspath(fullpath)
+
+        if os.path.exists(fullpath):
+            logger.info(f"Deleting existing asset file: '{filename}'")
+            os.remove(fullpath)
+
+    return path
 
 
 class ReportAsset(models.Model):