DADI API Data Connector

This repository specifies the interface required to build a database connector for DADI API.

Exports

Data connectors must export a constructor function at the root level. The constructor receives an optional object with config parameter overrides, and it should have the following methods in its prototype chain.

const MyDataConnector = function (options) {
  this.config = Object.assign({}, config, options)
}

MyDataConnector.prototype.connect = function ({database, collection}) {
  // ...
}

module.exports = MyDataConnector

Methods

• connect()
• find()
• insert()
• update()
• delete()
• stats()
• index()
• getIndexes()
• dropDatabases()

---

connect({database, collection})

Establishes a connection to the database. API calls it both when establishing a connection for the first time and also when attempting a reconnection.

Parameters:

• database {String}: the name of the database file to use
• collection {Object}: the name of the collection to use

Return value:

• Promise resolved with undefined if the connection is successful
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection could not be established

Events emitted:

• DB_CONNECTED: when the database connection is established
• DB_ERROR: when the database connection is closed or times out; an optional error object can be sent as a parameter
• DB_RECONNECTED: when the database connection is re-established

---

find({ query, collection, options = {}, schema, settings })

Finds documents in a collection.

Parameters:

• query {Object}: the query to perform
• collection {String}: the name of the collection to query
• options {QueryOptions}: a set of query options, such as offset, limit, sort, fields
• schema {Object}: the JSON schema for the collection
• settings {Object}: the settings block of the collection schema

Return value:

• Promise resolved with an object containing:
  • results: An array with the matching documents
  • metadata: A metadata object, with the format used by @dadi/metadata
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

insert({data, collection, options = {}, schema, settings = {}})

Creates documents in a collection.

Parameters:

• data {Object}: a single document or an Array of documents to insert
• collection {String}: the name of the collection to query
• schema {Object}: the JSON schema for the collection
• settings {Object}: the settings block of the collection schema

Return value:

• Promise resolved with an object containing an array with the inserted documents
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

update({query, collection, update, options = {}, schema})

Updates documents in a collection.

Parameters:

• query {Object}: the query that selects documents for update
• collection {String}: the name of the collection to update
• update {Object}: the update for the documents matching the query
• options {QueryOptions}: a set of query options, such as offset, limit, sort, fields
• schema {Object}: the JSON schema for the collection

Return value:

• Promise resolved with an object containing a matchedCount property, with a count of the number of documents affected by the update operation
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

delete({query, collection, schema})

Deletes documents from a collection.

Parameters:

• query {Object}: the query that selects documents for deletion
• collection {String}: the name of the collection to delete from
• schema {Object}: the JSON schema for the collection

Return value:

• Promise resolved with an object containing a deletedCount property, with a count of the number of documents affected by the delete operation
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

stats(collection, options)

Gets statistics about the collection.

Parameters:

• collection {String}: the name of the collection to get stats for
• options {QueryOptions}: a set of query options, such as offset, limit, sort, fields

Return value:

• Promise resolved with an object containing the following properties:
  • count
  • size
  • averageObjectSize
  • storageSize
  • indexes
  • totalIndexSize
  • indexSizes
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

index(collection, indexes)

Creates indexes in the collection.

Parameters:

• collection {String}: the name of the collection to add indexes to
• indexes {Object}: an array of indexes to create for the collection

Return value:

• Promise resolved with an an array of objects representing the indexes, with the name of the collection and the name of the index in the collection and index properties respectively
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

getIndexes(collection)

Retrieves indexes from a collection.

Parameters:

• collection {String}: the name of the collection to get indexes for

Return value:

• Promise resolved with an an array of objects representing the indexes, each with the name of the index in an name property
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

dropDatabase(collection)

Removes a collection from a database or drops the database completely.

Parameters:

• collection {String}: the name of the collection to drop from the database. Use null to drop the database.

Return value:

• Promise resolved with undefined
• Promise rejected with an Error object, with a message of DB_DISCONNECTED, if the connection to the database is unavailable

---

Configuration

DADI API uses one primary configuration file to modify the behaviour of certain functions. In addition to the primary configuration file it also needs a configuration file for the data connector that is being used.

Configuration Files

The configuration files for your API Connector must be placed in the same directory as the primary API configuration file, which is commonly config/.

The naming convention for API Connector configuration files follows the format nameOfConnector.<environment>.json

For example:

• nameOfConnector.development.json
• nameOfConnector.test.json
• nameOfConnector.production.json

The configuration file should contain an configurable properties that a user needs to connect to and configure the underlying data store.

For example:

{
  "database": {
    "host": "127.0.0.1",
    "port": 2101,
    "autosaveInterval": 1000
  }
}

Licence

DADI is a data centric development and delivery stack, built specifically in support of the principles of API first and COPE.

Copyright notice
(C) 2017 DADI+ Limited support@dadi.tech
All rights reserved

This product is part of DADI.
DADI is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version ("the GPL").

If you wish to use DADI outside the scope of the GPL, please contact us at info@dadi.co for details of alternative licence arrangements.

This product may be distributed alongside other components available under different licences (which may not be GPL). See those components themselves, or the documentation accompanying them, to determine what licences are applicable.

DADI is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

The GNU General Public License (GPL) is available at http://www.gnu.org/licenses/gpl-3.0.en.html.
A copy can be found in the file GPL.md distributed with these files.

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