CouchbasePersistence<T>

Implements: IReferenceable, IUnreferenceable, IConfigurable, IOpenable, ICleanable

Description

The CouchbasePersistence class allows you to create abstract persistence components that store data in a Couchbase database using Couchbase object relational mapping.

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._collection or this._model properties.

Configuration parameters

• bucket: (optional) Couchbase bucket’s 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:
  • auto_create: (optional) automatically create a missing bucket (default: false)
  • auto_index: (optional) automatically create a primary index (default: false)
  • flush_enabled: (optional) bucket flush enabled (default: false)
  • bucket_type: (optional) bucket type (default: couchbase)
  • ram_quota: (optional) RAM quota in MB (default: 100)

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.

public constructor(bucket?: string, collection?:string)

• bucket: string - (optional) bucket’s name.
• collection: string - (optional) collection’s name.

Fields

Instance methods

clear

Clears a component’s state.

public clear(correlationId: string): Promise<void>

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

close

Closes a component and frees used resources.

public close(correlationId: string): Promise<void>

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

configure

Configures a component by passing its configuration parameters.

public configure(config: ConfigParams): void

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

convertFromPublic

Converts an object’s value from public to internal format.

protected convertFromPublic(value: any): any

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

convertFromPublicPartial

Converts the given object from the public partial format.

protected convertFromPublicPartial(value: any): any

• value: any - object to convert from the public partial format.
• returns: any - initial object.

convertToPublic

Converts an objecc from internal to public format.

protected convertToPublic(value: any): any

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

create

Creates a data item.

public create(correlationId: string, item: T): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• item: T - item to be created.
• returns: Promise<T> - created item

createBucketFilter

Creates a filter that includes a collection’s name in it.

protected createBucketFilter(filter: string): string

• filter: string - user-defined filter
• returns: string - filter that includes a collection’s name.

deleteByFilter

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

protected deleteByFilter(correlationId: string, filter: any): Promise<void>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• filter: any - (optional) filter function to filter items.

generateBucketId

Generates a unique id for a specific collection in the bucket.

protected generateBucketId(value: any): string

• value: any - public unique id.
• returns: string - unique bucket id.

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(correlationId: string, filter: any): Promise<number>

• correlationId: string - (optional) transaction id used to trace execution through the 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(correlationId: string, filter: any, sort: any, select: any): Promise<T[]>

• correlationId: string - (optional) transaction id used to trace execution through the 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(correlationId: string, filter: any): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• filter: any - (optional) filter JSON object
• returns: Promise<T> - 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(correlationId: string, filter: any, paging: PagingParams, sort: any, select: any): Promise<DataPage>

• correlationId: string - (optional) transaction id used to trace execution through the 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> - data page of result by filter

isOpen

Checks if the component is open.

public isOpen(): boolean

• returns: boolean - true if the component is open and false otherwise.

open

Opens the component.

public open(correlationId: string): Promise<void>

• correlationId: string - (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

setReferences

Sets references to dependent components.

public setReferences(references: IReferences): void

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

unsetReferences

Unsets (clears) previously set references to dependent components.

public unsetReferences(): void

Examples

class MyCouchbasePersistence extends CouchbasePersistence<MyData> {
  public constructor() {
    super("mydata", "mycollection", new MyDataCouchbaseSchema());
  }

  public getByName(correlationId: string, name: string): Promise<MyData> {
    let criteria = { name: name };
    return new Promise((resolve, reject) => {
       this._model.findOne(criteria, (err, value) => {
           if (err == null) resolve(value);
           else reject(err);
       });
    });
  }

  public set(correlatonId: string, item: MyData, callback: (err) => void): void {
    let criteria = { name: item.name };
    let options = { upsert: true, new: true };
    return new Promise((resolve, reject) => {
       this._model.findOneAndUpdate(criteria, item, options, (err, value) => {
           if (err == null) resolve(value);
           else reject(err);
       });
    });
  }
}

let persistence = new MyCouchbasePersistence();
persistence.configure(ConfigParams.fromTuples(
    "host", "localhost",
    "port", 27017
));

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