修改数据库初始化逻辑，完善权限，废弃flaskenv

migrations/env.py

@@ -1,10 +1,6 @@
-from __future__ import with_statement
-
 import logging
 from logging.config import fileConfig
 
-from sqlalchemy import engine_from_config
-from sqlalchemy import pool
 from flask import current_app
 
 from alembic import context
@@ -13,26 +9,48 @@ from alembic import context
 # access to the values within the .ini file in use.
 config = context.config
 
-# Interpret the configs file for Python logging.
+# Interpret the config file for Python logging.
 # This line sets up loggers basically.
 fileConfig(config.config_file_name)
 logger = logging.getLogger('alembic.env')
 
+
+def get_engine():
+    try:
+        # this works with Flask-SQLAlchemy<3 and Alchemical
+        return current_app.extensions['migrate'].db.get_engine()
+    except TypeError:
+        # this works with Flask-SQLAlchemy>=3
+        return current_app.extensions['migrate'].db.engine
+
+
+def get_engine_url():
+    try:
+        return get_engine().url.render_as_string(hide_password=False).replace(
+            '%', '%%')
+    except AttributeError:
+        return str(get_engine().url).replace('%', '%%')
+
+
 # add your model's MetaData object here
 # for 'autogenerate' support
 # from myapp import mymodel
 # target_metadata = mymodel.Base.metadata
-config.set_main_option(
-    'sqlalchemy.url',
-    str(current_app.extensions['migrate'].db.engine.url).replace('%', '%%'))
-target_metadata = current_app.extensions['migrate'].db.metadata
+config.set_main_option('sqlalchemy.url', get_engine_url())
+target_db = current_app.extensions['migrate'].db
 
-# other values from the configs, defined by the needs of env.py,
+# other values from the config, defined by the needs of env.py,
 # can be acquired:
-# my_important_option = configs.get_main_option("my_important_option")
+# my_important_option = config.get_main_option("my_important_option")
 # ... etc.
 
 
+def get_metadata():
+    if hasattr(target_db, 'metadatas'):
+        return target_db.metadatas[None]
+    return target_db.metadata
+
+
 def run_migrations_offline():
     """Run migrations in 'offline' mode.
 
@@ -47,7 +65,7 @@ def run_migrations_offline():
     """
     url = config.get_main_option("sqlalchemy.url")
     context.configure(
-        url=url, target_metadata=target_metadata, literal_binds=True
+        url=url, target_metadata=get_metadata(), literal_binds=True
     )
 
     with context.begin_transaction():
@@ -72,16 +90,12 @@ def run_migrations_online():
                 directives[:] = []
                 logger.info('No changes in schema detected.')
 
-    connectable = engine_from_config(
-        config.get_section(config.config_ini_section),
-        prefix='sqlalchemy.',
-        poolclass=pool.NullPool,
-    )
+    connectable = get_engine()
 
     with connectable.connect() as connection:
         context.configure(
             connection=connection,
-            target_metadata=target_metadata,
+            target_metadata=get_metadata(),
             process_revision_directives=process_revision_directives,
             **current_app.extensions['migrate'].configure_args
         )