sails-postgresql/helpers/drop.js

a PostgreSQL adapter for Waterline and Sails.js

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//  ╚═════╝ ╚═╝  ╚═╝ ╚═════╝ ╚═╝
//

module.exports = require('machine').build({


  friendlyName: 'Drop',


  description: 'Remove a table from the database.',


  inputs: {

    datastore: {
      description: 'The datastore to use for connections.',
      extendedDescription: 'Datastores represent the config and manager required to obtain an active database connection.',
      required: true,
      type: 'ref'
    },

    tableName: {
      description: 'The name of the table to destroy.',
      required: true,
      example: 'users'
    },

    meta: {
      friendlyName: 'Meta (custom)',
      description: 'Additional stuff to pass to the driver.',
      extendedDescription: 'This is reserved for custom driver-specific extensions.',
      type: 'ref'
    }

  },


  exits: {

    success: {
      description: 'The table was destroyed successfully.'
    },

    badConnection: {
      friendlyName: 'Bad connection',
      description: 'A connection either could not be obtained or there was an error using the connection.'
    }

  },


  fn: function drop(inputs, exits) {
    // Dependencies
    var _ = require('@sailshq/lodash');
    var Helpers = require('./private');


    // Set a flag if a leased connection from outside the adapter was used or not.
    var leased = _.has(inputs.meta, 'leasedConnection');


    //  ╔═╗╦ ╦╔═╗╔═╗╦╔═  ┌─┐┌─┐┬─┐  ┌─┐  ┌─┐┌─┐  ┌─┐┌─┐┬ ┬┌─┐┌┬┐┌─┐
    //  ║  ╠═╣║╣ ║  ╠╩╗  ├┤ │ │├┬┘  ├─┤  ├─┘│ ┬  └─┐│  ├─┤├┤ │││├─┤
    //  ╚═╝╩ ╩╚═╝╚═╝╩ ╩  └  └─┘┴└─  ┴ ┴  ┴  └─┘  └─┘└─┘┴ ┴└─┘┴ ┴┴ ┴
    // This is a unique feature of Postgres. It may be passed in on a query
    // by query basis using the meta input or configured on the datastore. Default
    // to use the public schema.
    var schemaName = 'public';
    if (inputs.meta && inputs.meta.schemaName) {
      schemaName = inputs.meta.schemaName;
    } else if (inputs.datastore.config && inputs.datastore.config.schemaName) {
      schemaName = inputs.datastore.config.schemaName;
    }


    //  ╔═╗╔═╗╔═╗╦ ╦╔╗╔  ┌─┐┌─┐┌┐┌┌┐┌┌─┐┌─┐┌┬┐┬┌─┐┌┐┌
    //  ╚═╗╠═╝╠═╣║║║║║║  │  │ │││││││├┤ │   │ ││ ││││
    //  ╚═╝╩  ╩ ╩╚╩╝╝╚╝  └─┘└─┘┘└┘┘└┘└─┘└─┘ ┴ ┴└─┘┘└┘
    // Spawn a new connection to run the queries on.
    Helpers.connection.spawnOrLeaseConnection(inputs.datastore, inputs.meta, function spawnConnectionCb(err, connection) {
      if (err) {
        return exits.badConnection(err);
      }


      //  ╔═╗╔═╗╔═╗╔═╗╔═╗╔═╗  ┌┬┐┌─┐┌┐ ┬  ┌─┐  ┌┐┌┌─┐┌┬┐┌─┐
      //  ║╣ ╚═╗║  ╠═╣╠═╝║╣    │ ├─┤├┴┐│  ├┤   │││├─┤│││├┤
      //  ╚═╝╚═╝╚═╝╩ ╩╩  ╚═╝   ┴ ┴ ┴└─┘┴─┘└─┘  ┘└┘┴ ┴┴ ┴└─┘
      var tableName;
      try {
        tableName = Helpers.schema.escapeTableName(inputs.tableName, schemaName);
      } catch (e) {
        // Release the connection on error
        Helpers.connection.releaseConnection(connection, leased, function releaseConnectionCb() {
          return exits.error(e);
        });
        return;
      }

      // Build native query
      var query = 'DROP TABLE IF EXISTS ' + tableName + ';';


      //  ╦═╗╦ ╦╔╗╔  ┌┬┐┬─┐┌─┐┌─┐  ┌─┐ ┬ ┬┌─┐┬─┐┬ ┬
      //  ╠╦╝║ ║║║║   ││├┬┘│ │├─┘  │─┼┐│ │├┤ ├┬┘└┬┘
      //  ╩╚═╚═╝╝╚╝  ─┴┘┴└─└─┘┴    └─┘└└─┘└─┘┴└─ ┴
      Helpers.query.runNativeQuery(connection, query, [], function runNativeQueryCb(err) {
        // Always release the connection back to the pool
        Helpers.connection.releaseConnection(connection, leased, function releaseConnectionCb() {
          if (err) {
            return exits.error(err);
          }

          return exits.success();
        }); // </ releaseConnection >
      }); // </ runNativeQuery >
    }); // </ spawnConnection >
  }
});