jsApplication is the general prototype of the application at its highest level.
Let's examine some methods that can be used for customization.
It is a class whose only method is getDataAccess(), which returns an instance of jsConnectionPool, a simple class that creates a DataAccess by invoking a method of jsDbList and adds it to a pool, which, in this case, is a simple list of connections.
When a connection (jsPooledConnection) is released (with the release method), it becomes available to be returned by subsequent calls to getDataAccess().
If you wanted to implement a more sophisticated logic, such as always keeping a fixed number of connections open or permanently releasing unused connections after a certain period, you can create a class derived from JsConnectionPool and ensure that createConnectionPool returns an instance of it.
Returns an object that has as many properties as there are folders to allow access to anonymous clients, not yet authenticated. It is used to add authentication middleware to all routes that require it.
This is a route to which all errors are redirected. Any logging functionalities should be inserted here.
This route adds the close and finish events to the current request so that they can, when invoked, release the connection from the connection pool by invoking its release method.
Creates a jsEnvironment from an instance of Identity, a class declared in jsToken. It is the responsibility of the authentication process to create a valid Identity, a Token, and communicate it to the client so that it can make subsequent requests in the authenticated state.
An environment contains the session variables of a specific user and is cached when the session is created to speed up its subsequent interactions.
Creates a PostData class (or its derivative) to use for saving a DataSet. The created class must then be initialized with the init method.
This default method creates a BusinessPostData class, but it can be modified, for example, to not handle business logic and save data without any control because perhaps the data has already been checked elsewhere.
createPostData also sets the default class for optimistic locking, such as:
new OptimisticLocking(['lt', 'lu'], ['ct', 'cu', 'lt', 'lu'])where the fields used for optimistic locking will be, respectively:
- for modification: lt, lu
- for creation: ct, cu, lt, lu
The stamp fields of the environment are ct and lt, and when the environment calculates them.
The prepareForPosting method of the OptimisticLocking class is used to calculate the locking fields whenever a DataRow needs to be saved to the database. The prepareForPosting method, in turn, invokes the field(fieldName) method of the Environment class for each field indicated in the configuration, respectively, for insertion or modification depending on the state of the row to be saved.
By default, the Environment class uses ct and lt as stamp fields, while the values of the cu and lu fields are set in the createEnvironment method of jsApplication, equal to the value identity.name. It is possible to customize this value.
Creates a specific DataSet identified by tableName and editType. By default, it reads a JSON file from the ./client/dataset folder and deserializes it into a jsDataSet.
Creates an anonymous environment based on an input Identity. By default, it simply creates a new environment through the constructor.
Creates a context based on the token, anonymous if the token is not present or is an anonymous token.
The context (Context) is always created as anonymous, then during authentication, it recalculates the environment and marks the context as no longer anonymous. To do this, you can invoke the _doLogin method of the module routes/_authUtils.