ravel
Version:
Ravel Rapid Application Development Framework
89 lines (86 loc) • 6.74 kB
JavaScript
;
const Metadata = require('../../util/meta');
const ApplicationError = require('../../util/application_error');
/**
* The `@transaction` decorator for opening a transaction on a `Routes` or
* `Resource` handler method. Facilitates transaction-per-request.
* Can also be applied at the class-level to open connections for all handlers
* in that `Route` or `Resource` class.
*
* Connections are available within the handler as an object `ctx.transaction`, which
* contains connections as values and `DatabaseProvider` names as keys. Connections
* will be closed automatically when the endpoint responds (do not close them yourself),
* and will automatically roll-back changes if a `DatabaseProvider` supports it (generally
* a SQL-only feature).
*
* @param {...String} args - A list of database provider names to open connections for.
*
* @example
* // Note: decorator works the same way on Routes or Resource classes
* const Routes = require('ravel').Routes;
* const mapping = Routes.mapping;
*
* class MyRoutes extends Routes {
* constructor () {
* super('/');
* }
*
* // @mapping(Routes.GET, 'app')
* // @transaction // open all connections within this handler
* async appHandler (ctx) {
* // ctx.transaction is an object containing
* // keys for DatabaseProviders and values
* // for their open connections
* }
*
* // @mapping(Routes.GET, 'something')
* // @transaction('mysql', 'rethinkdb') // open one or more specific connections within this handler
* async somethingHandler (ctx) {
* // can use ctx.transaction.mysql
* // can use ctx.transaction.rethinkdb
* }
* }
* @example
* // Note: decorator works the same way on Routes or Resource classes
* const Resource = require('ravel').Resource;
*
* // @transaction('mysql') // all handlers will have ctx.transaction.mysql
* class MyResource extends Resource {
* constructor () {
* super('/');
* }
*
* async post (ctx) {
* // can use ctx.transaction.mysql
* }
* }
*/
function transaction(...args) {
// handle @transaction at the method-level without arguments
if (args.length === 3 && typeof args[0].constructor === 'function') {
Metadata.putMethodMeta(args[0], args[1], '@transaction', 'providers', []);
} else if (args.length === 1 && typeof args[0] === 'function') {
// handle @transaction at the class-level without arguments
Metadata.putClassMeta(args[0].prototype, '@transaction', 'providers', []);
} else {
// handle @transaction() at the class and method-level with arguments
return function (target, key) {
args.forEach(name => {
if (typeof name !== 'string') {
throw new ApplicationError.IllegalValue(
'Values supplied to @transaction decorator must be strings, and must match ' +
'the name of a registered database provider');
}
});
if (key === undefined) {
Metadata.putClassMeta(target.prototype, '@transaction', 'providers', args);
} else {
Metadata.putMethodMeta(target, key, '@transaction', 'providers', args);
}
};
}
}
/*!
* Export the `@transaction` decorator
*/
module.exports = transaction;