Storing User Input

Introduction
The Rocket.Chat Apps-Engine provides persistenceRead: IPersistenceRead andpersistence: IPersistence to help you read and write data from or to the RocketChat database.
We can get persistenceRead: IPersistenceRead through the following way:
// Get a persistence reader if you are using it in a method
// Here `this` means the main App class instance
const persistenceRead = this.getAccessors().reader.getPersistenceReader();
​
// Some methods provideds `read: IRead` parameter, so that you get a persistence
// reader through this parameter too.
const persistenceRead = read.getPersistenceRead();
For persistence: IPersistence, you can only obtain it through parameter approach, which means you can not persist data within a method (typically is an event handler that you are going to implement) if the method doesn't have a persistence: IPersistence parameter.
function someMethod(context, read: IRead, persistence: IPersistence) {
    console.log(persistence); // The only way to fetch a persistence writer object
}
Example
Below is a complete example to show how we can manage persistence methods with a class. Consider that you are going to persist some messages. You can create a class called MessagePersistence. Then you can add a series of static methods as shown below to add/remove/query data from the database.
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import { IPersistence, IPersistenceRead } from '@rocket.chat/apps-engine/definition/accessors';
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import { RocketChatAssociationModel, RocketChatAssociationRecord } from '@rocket.chat/apps-engine/definition/metadata';
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import { IRoom } from '@rocket.chat/apps-engine/definition/rooms';
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​
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export class MessagePersistence {
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    // add a record
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    public static async persist(persis: IPersistence, room: IRoom, id: string): Promise<boolean> {
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        const associations: Array<RocketChatAssociationRecord> = [
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, 'message'), 
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            new RocketChatAssociationRecord(RocketChatAssociationModel.ROOM, room.id),
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, id),
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        ];
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​
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        try {
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            await persis.updateByAssociations(associations, { id }, true);
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        } catch (err) {
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            console.warn(err);
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            return false;
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        }
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​
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        return true;
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    }
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​
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    // query all records within the "scope" - message
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    public static async findAll(persis: IPersistenceRead): Promise<Array<string>> {
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        const associations: Array<RocketChatAssociationRecord> = [
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, 'message'),
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        ];
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​
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        let result: Array<string> = [];
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        try {
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            const records: Array<{ id: string }> = (await persis.readByAssociations(associations)) as Array<{ id: string }>;
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​
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            if (records.length) {
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                result = records.map(({ id }) => id);
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            }
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        } catch (err) {
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            console.warn(err);
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        }
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​
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        return result;
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    }
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​
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    // query all records by room within the "scope" - message
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    public static async findByRoom(persis: IPersistenceRead, room: IRoom): Promise<Array<string>> {
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        const associations: Array<RocketChatAssociationRecord> = [
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, 'message'),
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            new RocketChatAssociationRecord(RocketChatAssociationModel.ROOM, room.id),
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        ];
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​
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        let result: Array<string> = [];
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        try {
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            const records: Array<{ id: string }> = (await persis.readByAssociations(associations)) as Array<{ id: string }>;
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​
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            if (records.length) {
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                result = records.map(({ id }) => id);
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            }
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        } catch (err) {
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            console.warn(err);
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        }
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​
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        return result;
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    }
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​
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    // remove all records by room within the "scope" - message
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    public static async removeByRoom(persis: IPersistence, room: IRoom): Promise<boolean> {
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        const associations: Array<RocketChatAssociationRecord> = [
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, 'message'),
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            new RocketChatAssociationRecord(RocketChatAssociationModel.ROOM, room.id),
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        ];
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​
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        try {
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            await persis.removeByAssociations(associations);
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        } catch (err) {
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            console.warn(err);
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            return false;
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        }
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​
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        return true;
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    }
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​
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    // remove all records by id within the "scope" - message
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    public static async removeById(persis: IPersistence, id: string): Promise<boolean> {
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        const associations: Array<RocketChatAssociationRecord> = [
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, 'message'),
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, id),
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        ];
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​
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        try {
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            await persis.removeByAssociations(associations);
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        } catch (err) {
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            console.warn(err);
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            return false;
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        }
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​
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        return true;
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    }
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​
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    // remove all records within the "scope" - message
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    public static async clear(persis): Promise<boolean> {
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        const associations: Array<RocketChatAssociationRecord> = [
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            new RocketChatAssociationRecord(RocketChatAssociationModel.MISC, 'message'),
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        ];
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​
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        try {
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            await persis.removeByAssociations(associations);
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        } catch (err) {
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            console.warn(err);
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            return false;
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        }
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​
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        return true;
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    }
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}
With this, you can now implement app data persistence in your apps, by managing your app's internal state and handling user inputs!
Last modified 9d ago