dashboards_mirror_survey_stack/src/viewCreator.js

Library allowing to retrieve, reorganize and keep up to date SurveyStack data in a mongoDB mirror as well as serving it efficiently.

const { MongoClient, ObjectId } = require('mongodb');

async function createAView( { connectionURL, viewName, db="dashboards", sourceCollection, aggregationPipeline } ) {
    const client = new MongoClient(connectionURL);
    let viewCreation = {
        viewName: viewName
    };

    try {
        // we need to erase the view if it previously existed first, as is seems there is no way of updating the view instead
        await client.connect();
        let drop = await client
            .db(db)
            .dropCollection(viewName)
        ;
    } catch(e) {
        if ( e.code == 26 ) {
            // an error 26 will be generated when the namespace we want to drop isn't found, meaning the collection is new
            viewCreation.previouslyExisted = false;
        } else {
            viewCreation.previouslyExisted = true;
            viewCreation.cleaningError = e;
        };
    }
    ;

    try {
        // once the preexistence problem is dealth with, we can directly create the view
        viewCreation.result = await client
            .db(db)
            .createCollection(
                viewName,
                {
                    viewOn: sourceCollection,
                    pipeline: aggregationPipeline
                }
            );
        viewCreation.errored = false;
    } catch(error) {
        viewCreation.error = error;
        viewCreation.errored = true;
    } finally {
        await client.close();
    };
    return viewCreation;
};

// let experiment1 = createAView( connectionURL, dataExplorerView.name, "dashboards",dataExplorerView.sourceCollection, dataExplorerView.pipeline ).catch(console.error);

/**
 * Creates a set of views, based on provided object with the needed parameters
 * @param {  [name:string, sourceCollection:string, pipeline:  mongoDBPipeline] } viewsList -- List of objects describing views, each one provides the target name, the pipeline and the source colletion.
 * @param {string} connectionURL -- MongoDB connection URI.
 * @param {string} db -- Database Name.
 * @returns {} 
 */
async function createAllViews( { viewsList, connectionURL, db = "dashboards" } ) {
    let index = 0;
    let results = [];
    while( index < viewsList.length ) {
        let currentView = viewsList[index];
        let currentResult = await createAView( { connectionURL:connectionURL, viewName: currentView.name, db:db, sourceCollection:currentView.sourceCollection, aggregationPipeline:currentView.pipeline } );
        results.push(currentResult); 

        index ++;
    };
    return results;
};

exports.createAllViews = createAllViews;
exports.createAView = createAView;