tags.py 文件源码

def create(self, ctx, name: TagName, *, content: commands.clean_content):
        """Creates a new tag owned by you.

        This tag is server-specific and cannot be used in other servers.
        For global tags that others can use, consider using the tag box.

        Note that server moderators can delete your tag.
        """

        # due to our denormalized design, I need to insert the tag in two different
        # tables, make sure it's in a transaction so if one of the inserts fail I
        # can act upon it
        query = """WITH tag_insert AS (
                        INSERT INTO tags (name, content, owner_id, location_id)
                        VALUES ($1, $2, $3, $4)
                        RETURNING id
                    )
                    INSERT INTO tag_lookup (name, owner_id, location_id, tag_id)
                    VALUES ($1, $3, $4, (SELECT id FROM tag_insert));
                """

        # since I'm checking for the exception type and acting on it, I need
        # to use the manual transaction blocks

        tr = ctx.db.transaction()
        await tr.start()

        try:
            await ctx.db.execute(query, name, content, ctx.author.id, ctx.guild.id)
        except asyncpg.UniqueViolationError:
            await tr.rollback()
            await ctx.send('This tag already exists.')
        except:
            await tr.rollback()
            await ctx.send('Could not create tag.')
        else:
            await tr.commit()
            await ctx.send(f'Tag {name} successfully created.')