MySqlPersistence<T>

Implements: IReferenceable, IUnreferenceable, IConfigurable, IOpenable, ICleanable

Description

The MySqlPersistence class allows you to create persistence components that store data in MySQL databases using the official driver.

Important points

• This is the most basic persistence component that is only able to store data items of any type. Specific CRUD operations over the data items must be implemented in child classes by accessing this._db or this._collection properties.

Configuration parameters

• table: (optional) MySQL table name
• schema: (optional) MySQL schema name

connection(s):

• discovery_key: (optional) key to retrieve the connection from IDiscovery
• host: host name or IP address
• port: port number (default: 27017)
• uri: resource URI or connection string with all parameters in it

credential(s):

• store_key: (optional) key to retrieve the credentials from ICredentialStore
• username: (optional) username
• password: (optional) user’s password

options:

• connect_timeout: (optional) number of milliseconds to wait before timing out when connecting a new client (default: 0)

Note: the options below are currently not supported.

• idle_timeout: (optional) number of milliseconds a client must sit idle in the pool and not be checked out (default: 10000)
• max_pool_size: (optional) maximum number of clients the pool should contain (default: 10)

References

• *:logger:*:*:1.0 - (optional) ILogger components to pass log messages
• *:discovery:*:*:1.0 - (optional) IDiscovery services
• *:credential-store:*:*:1.0 - (optional) ICredentialStore to resolve credentials

Constructors

Creates a new instance of the persistence component.

MySqlPersistence(String? tableName, String? schemaName)

• tableName: string - (optional) table name.
• schemaName: string - (optional) a schema name.

Fields

Instance methods

clear

Clears a component’s state.

Future clear(IContext? context) async

• context: IContext - (optional) a context to trace execution through a call chain.

clearSchema

Clears all auto-created objects

void clearSchema()

close

Closes a component and frees the used resources.

Future close(IContext? context) async

• context: IContext - (optional) a context to trace execution through a call chain.

configure

Configures component by passing configuration parameters.

void configure(ConfigParams config)

• config:: ConfigParams - configuration parameters to be set.

convertFromPublic_

Converts object value from public to internal format.

dynamic convertFromPublic_(dynamic value)

• value: dynamic - object in public format to convert.
• returns: dynamic - converted object in internal format.

convertToPublic_

Converts object value from internal to public format.

dynamic convertToPublic_(dynamic value)

• value: dynamic - object in internal format to convert.
• returns: dynamic - converted object in public format.

create

Creates a data item.

Future<T?> create(IContext? context, T item) async

• context: IContext - (optional) a context to trace execution through a call chain.
• item: T - item to be created.
• returns: Future<T?> - created item

createSchema_

Checks if a table exists and if not, it creates the necessary database objects.

Future createSchema_(IContext? context) async

• context: IContext - (optional) a context to trace execution through a call chain.

defineSchema_

Defines database schema via auto create objects or convenience methods.

void defineSchema_()

deleteByFilter

Deletes data items that match to a given filter. This method shall be called by a public deleteByFilter method from child class that receives FilterParams and converts them into a filter function.

Future deleteByFilter_(IContext? context, String? filter) async

• context: IContext - (optional) a context to trace execution through a call chain.
• filter: String - (optional) filter function to filter items.

ensureIndex

Adds index definition to create it on opening.

void ensureIndex_(String name, Map keys, Map? options)

• keys: Map - index keys (fields)
• options: Map - index options

ensureSchema_

Adds a statement to schema definition.

void ensureSchema_(String schemaStatement)

• schemaStatement: string - statement to be added to the schema

generateColumns

Generates a list of column names to use in SQL statements like: “column1,column2,column3”.

String generateColumns_(values)

• values: array with column values or a key-value map
• returns: string - generated list of column names

generateParameters_

Generates a list of value parameters to use in SQL statements like: "$1,$2,$3".

String generateParameters_(values)

• values: array with values or a key-value map
• returns: string - generated list of value parameters

generateSetParameters_

Generates a list of column sets to use in UPDATE statements like: column1=$1,column2=$2

String generateSetParameters_(Map values)

• values: key-value map with columns and values
• returns: string - generated list of column sets

generateValues_

Generates a list of column parameters.

List generateValues_(Map values)

• values: Map - key-value map with columns and values
• returns: List - generated list of column values

getCountByFilter

Gets a number of data items retrieved by a given filter.

This method shall be called by a public getCountByFilter method from the child class that receives FilterParams and converts them into a filter function.

protected getCountByFilter(context: IContext, filter: any): Promise<number>

• context: IContext - (optional) a context to trace execution through a call chain.
• filter: any - (optional) JSON object filter
• returns: Promise<number> - number of filtered items.

getListByFilter

Gets a list of data items retrieved by a given filter and sorted according to sort parameters.

This method shall be called by a public getListByFilter method from a child class that receives FilterParams and converts them into a filter function.

protected getListByFilter(context: IContext, filter: any, sort: any, select: any): Promise<T[]>

• context: IContext - (optional) a context to trace execution through a call chain.
• filter: any - (optional) filter function to filter items
• sort: any - (optional) sorting parameters
• select: any - (optional) projection parameters (not used yet)
• returns: Promise<T[]> - data list of results by filter.

getOneRandom

Gets a random item from items that match to a given filter.

This method shall be called by a public getOneRandom method from a child class that receives FilterParams and converts them into a filter function.

protected getOneRandom(context: IContext, filter: any): Promise<T>

• context: IContext - (optional) a context to trace execution through a call chain.
• filter: any - (optional) a filter JSON object
• returns: Promise<T> - a random item.

getPageByFilter

Gets a page of data items retrieved by a given filter and sorted according to sort parameters.

This method shall be called by a public getPageByFilter method from the a child class that receives FilterParams and converts them into a filter function.

protected getPageByFilter(context: IContext, filter: any, paging: PagingParams, sort: any, select: any): Promise<DataPage>

• context: IContext - (optional) a context to trace execution through a call chain.
• filter: any - (optional) filter for JSON objects.
• paging: PagingParams - (optional) paging parameters
• sort: any - (optional) sorting JSON object
• select: any - (optional) projection JSON object
• returns: Promise<DataPage> - a data page of result by filter

isOpen

Checks if the component is opened.

public isOpen(): boolean

• returns: boolean - True if the component has been opened and False otherwise.

open

Opens the component.

public open(context: IContext): Promise<void>

• context: IContext - (optional) transaction id used to trace execution through the call chain.

quoteIdentifier

Adds single quotes to a string.

protected quoteIdentifier(value: string): string

• value: string - string where quotes need to be added
• returns: string - string with added quotes

quotedTableName

Joins schema and database name in dot notation

protected quotedTableName(): string

• returns: string - string with added quotes

setReferences

Sets references to dependent components.

public setReferences(references: IReferences): void

• references: IReferences - references to locate the component dependencies.

unsetReferences

Unsets (clears) previously set references to dependent components.

public unsetReferences(): void

Examples

export class MyMySqlPersistence extends MySqlPersistence<MyData> {
    public constructor() {
        super("mydata");
    }

    protected defineSchema(): void {
        this.clearSchema();
        this.ensureSchema('CREATE TABLE `' + this._tableName + '` (id VARCHAR(32) PRIMARY KEY, `name` VARCHAR(50), `content` TEXT)');
        this.ensureIndex(this._tableName + '_key', { name: 1 }, { unique: true });
    }

    public async set(context: IContext, item: MyData): Promise<MyData> {
        if (item == null) {
            return null;
        }

        let row = this.convertFromPublic(item);
        let columns = this.generateColumns(row);
        let params = this.generateParameters(row);
        let setParams = this.generateSetParameters(row);
        let values = this.generateValues(row);
        values.push(...values);
        values.push(item.id);

        let query = "INSERT INTO " + this.quotedTableName() + " (" + columns + ") VALUES (" + params + ")";
        query += " ON DUPLICATE KEY UPDATE " + setParams;
        query += "; SELECT * FROM " + this.quotedTableName() + " WHERE id=?";

        let newItem = await new Promise<any>((resolve, reject) => {
            this._client.query(query, values, (err, result) => {
                if (err != null) {
                    reject(err);
                    return;
                }
                let item = result && result.length == 2 && result[1].length == 1
                    ? result[1][0] : null;
                resolve(item);
            });
        });

        newItem = this.convertToPublic(newItem);
        return newItem;
    }

    public async getOneByName(context: IContext, name: string): Promise<MyData> {
        let query = "SELECT * FROM " + this.quotedTableName() + " WHERE name=?";
        let params = [name];

        let item = await new Promise<any>((resolve, reject) => {
            this._client.query(query, params, (err, result) => {
                if (err != null) {
                    reject(err);
                    return;
                }
                let item = result ? result[0] || null : null;
                resolve(item);
            });
        });

        item = this.convertToPublic(item);
        return item;
    }
}

let persistence = new MyMySqlPersistence();
persistence.configure(ConfigParams.fromTuples(
    "connection.host", "localhost",
    "connection.port", 5432,
    "credential.username", "mysql",
    "credential.password", "mysql",
    "connection.database", "mytestobjects"
));

await persitence.open("123",);
let item = await persistence.set("123", { name: "ABC" });
item = await persistence.getByName("123", "ABC");
console.log(item);                   // Result: { name: "ABC" }