/ 
OpenResty-0.1.7
River stage zero No dependents
/ OpenResty::Spec::MetaModel

NAME

OpenResty::Spec::MetaModel - Metamodel for OpenResty backends

VERSION

This document describes the 0.02 version of the metamodel used in the OpenResty 0.2.x series.

DESCRIPTION

The metamodel in OpenResty is a set of internal database schemas or tables for storing meta information regarding the user data. They're usually invisible to the outside users and their names are carefully chosen so as to prevent potential naming conflicts with users' objects.

Global metamodel

The global metamodel stores the global (system-wide) information about the OpenResty users.

It sits in a separate PostgreSQL schema named _admin. It owns the following meta tables:

_version

The definition of the _version table is

create table _version (
    version varchar(10)
)

Usually it stores the version of the global metamodel itself. Note that the version of the metamodel is independent of the version number of the whole OpenResty server implementation. For instance, the OpenResty 0.2.x series uses metamodel 0.02 while the versions earlier uses 0.01 instead. This table usually has only 1 row. But it's also fine to keep track of all the version history. The largest version number will be considered the current version of the metamodel in the current user schema.

_accounts

The _accounts table stores the list of all the available OpenResty accounts in the whole system. It has the following definition:

create table _accounts (
    id serial primary key,
    name text unique not null,
    created_on timestamp (0) with time zone
)

The name column specifies the name of the account while the created_on is the creation time of the account.

Local metamodel

Each OpenResty account registered by an outside user has a PostgreSQL schema for storing its models, views, roles, actions, and other user objects. Such schema has the same name as the account name. For instance, account carrie has a corresponding database schema (or namespace) named carrie. The carrie schema has the following meta tables:

_version

The definition of the _version table is

create table _version (
    version varchar(10)
)

It is exactly the same as the _version table in the global metamodel.

_roles

The _roles table stores the meta information of the OpenResty Role objects.

create table _roles (
    id serial primary key,
    name text unique not null,
    login text not null,
    password text,
    description text not null
);

The login column specifies the login method used by the role. Allowed values are 'password', 'anonymous', and 'captcha'.

The password column must be not null when the login column has the value of 'password'. Its values should be null otherwise.

_access

The _access table stores the information of the access rules associated with the OpenResty Role objects.

create table _access (
    id serial primary key,
    role text not null,
    method varchar(10) not null,
    url text not null
);

The role column stores the name of the role which owns the current rule.

Each access rule has two components, HTTP method and the (abbreviated) URL, which are saved in the columns method and url, respectively. An example is that method has a value of 'GET' and url has a value of '/=/model/~/~/~'.

_models

The _models table stores the meta information regarding the OpenResty models.

The definition of _models is

create table _models (
    id serial primary key,
    name text unique not null,
    description text not null
);

The name column stores the names of user models. Every user model is represented by a physical PostgreSQL table under the same schema and the leading character of its name must be case-sensitive letters. Table names leading by an underscore are preserved for meta tables.

The description column stores users' textual description for their models.

Neither name nor description can be null.

_columns

The _columns table stores the meta information regarding OpenResty models' columns.

create table _columns (
    id serial primary key,
    name text not null,
    model text not null,
    label text not null,
    type text not null,
    default_value text,
    indexed text,
    unique(model, name)
);

The name column keeps the names of user models' columns and the model column stores the names of the corresponding models.

The lable column stores the textual label provided by the user who created the column and types of the model columns are stored in the type column.

None of the columns above but default_value and indexed can be null and in addition, the combination of the columns model and name should be unique.

User columns have default values and the corresponding JSON representation is stored in the default_value column. Note that the values for default_value are JSON literals, for instance, "32", ["now()"], and etc.

The indexed column stores the index method applied to the current user column if any; null otherwise. Possible values are 'fulltext', 'btree', 'rtree', 'gist', and 'hash'.

_views

The _views table stores the information of the OpenResty View objects.

create table _views (
    id serial primary key,
    name text unique not null,
    definition text unique not null,
    description text
);

All of the columns have similar meaning as the _model table except that the definition column stores the minisql string defining the functionality of the view.

_actions

The _actions table stores the information of the OpenResty Action objects.

create table _action (
    id serial primary key,
    name text unique not null,
    description text,
    definition text unique not null,
    confirmed_by text
);

Most of the columns are similar to those in the _view table except that the last confirmed_by column specifies the confirmation method used to fire the action. Allowed values for this column are "email", "cellphone", and "captcha".

_feeds

WARNING This part deserves more treatment.

The _feeds table stores the meta information for the OpenResty Feed objects.

create table _feeds (
    id serial primary key,
    name text unique not null,
    description text not null,
    view text not null,
    arguments text not null,
    type text not null,
    snapshot text
);

The arguments column defines the mapping from Feed entries' attributes to the associated View object's columns. The JSON representation is used as the arguments column's value. An example for the case of Atom/RSS feed is:

{title:"title",author:"poster",link:"http://blog.agentzh.org/#post-$id",issued:"created",summary:"content",summary_type:"html"}

For email feeds, it may look like

{title:"title",body:"content",body_type:"html"}

The type column specifies the type of the Feed object, like "RSS 0.9", "RSS 1.0", "RSS 2.0", "Atom", and "email".

The snapshot stores a snapshot of the feeds which are usually automatically updated by OpenResty deamon processes.

AUTHOR

agentzh <agentzh@yahoo.cn>

COPYRIGHT AND LICENSE

Copyright (c) 2008 Yahoo! China EEEE Works, Alibaba Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license can be found at

http://www.gnu.org/licenses/fdl.html