[IMP] attachment_zipped_download: provide ir.attachment.action_download mixin

This helps to download multiple attachments from any models.

attachment_zipped_download/models/ir_attachment_action_download.py

@@ -0,0 +1,55 @@
+# Copyright 2023 Foodles (https://www.foodles.com/)
+# @author Pierre Verkest <pierreverkest84@gmail.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+from odoo import _, models
+
+
+class IrAttachmentActionDownloadMixin(models.AbstractModel):
+
+    _name = "ir.attachment.action_download"
+    _description = """
+        Mixin to help download attachments linked to record(s).
+    """
+
+    def _get_downloadable_attachments(self):
+        """Give a chance to easily overwrite this method
+        on sub modules to limit restict attachement able to downlaods
+
+        In some case we probably want the user download some specific
+        document that are probably related to the current model
+
+        By default return all attachment link the the record.
+        """
+        return self.env["ir.attachment"].search(
+            [("res_model", "=", self._name), ("res_id", "in", self.ids)]
+        )
+
+    def action_download_attachments(self):
+        """Return action to:
+        * emit a warning message if no attachment found
+        * download a file if only 1 file found
+        * zip and download the list of attachment returns by `_get_downloadable_attachments`
+        """
+        attachments = self._get_downloadable_attachments()
+        if not attachments:
+            title = _("No attachment!")
+            message = _("There is no document found to download.")
+            return {
+                "type": "ir.actions.client",
+                "tag": "display_notification",
+                "params": {
+                    "type": "warning",
+                    "title": title,
+                    "message": message,
+                    "sticky": True,
+                },
+            }
+
+        if len(attachments) == 1:
+            return {
+                "target": "self",
+                "type": "ir.actions.act_url",
+                "url": "/web/content/%s?download=1" % attachments.id,
+            }
+        else:
+            return attachments.action_attachments_download()