Secure send: hand somebody a password without leaving it in a chat window

plugins/securesend/plugin.py

@@ -0,0 +1,76 @@
+"""Securesend plugin main class.
+
+One-view expiring links for handing someone a credential, encrypted in the browser
+"""
+
+import json
+import logging
+from pathlib import Path
+from typing import List, Dict, Optional, Type
+
+from flask import Flask, Blueprint
+
+from shopdb.plugins.base import BasePlugin, PluginMeta
+
+from .models import SecureSecret
+from .api import securesend_bp
+
+logger = logging.getLogger(__name__)
+
+
+class SecuresendPlugin(BasePlugin):
+    """Securesend plugin.
+
+    One-view expiring links for handing someone a credential, encrypted in the
+    browser. The key travels in the URL fragment and never reaches the server,
+    so what is stored here is ciphertext nobody on this side can read.
+    """
+
+    def __init__(self):
+        manifest_path = Path(__file__).parent / 'manifest.json'
+        with open(manifest_path) as f:
+            self._manifest = json.load(f)
+
+    @property
+    def meta(self) -> PluginMeta:
+        return PluginMeta(
+            name=self._manifest['name'],
+            version=self._manifest['version'],
+            description=self._manifest['description'],
+            author=self._manifest.get('author', ''),
+            dependencies=self._manifest.get('dependencies', []),
+            core_version=self._manifest.get('core_version', '>=0.1.0'),
+            api_prefix=self._manifest.get('api_prefix'),
+        )
+
+    def get_blueprint(self) -> Optional[Blueprint]:
+        return securesend_bp
+
+    def get_models(self) -> List[Type]:
+        return [SecureSecret]
+
+    def get_permissions(self) -> List:
+        """One permission, on CREATION only.
+
+        There is deliberately no read permission: the recipient of a secret
+        usually has no account here, and the unguessable token is what
+        authorises the read. Adding a permission to that side would make the
+        feature useless for the case it exists for - handing a credential to
+        somebody while you are on a call with them.
+
+        No delete permission either. A secret is spent by being read or by
+        expiring, and both remove the row; a hand-delete route would only add a
+        way to destroy the audit trail of a secret that had not been read yet.
+        """
+        return [
+            ('securesend.create', 'Create shared secret links', 'securesend'),
+        ]
+
+    def init_app(self, app: Flask, db_instance) -> None:
+        logger.info(f'Securesend plugin initialized (v{self.meta.version})')
+
+    def on_install(self, app: Flask) -> None:
+        # NO ASSET TYPE. The scaffold assumes a plugin extends Asset, and this
+        # one does not: a shared credential is a short-lived event, not a thing
+        # the site owns and inventories.
+        logger.info('Securesend plugin installed')