nodebook-nbql/lib/knexify.js

Filter query language for nodebook

// Knexify
var _ = require('lodash'),
    resourceContext = require('./context'),
    processFilter, buildWhere, whereType;

_.mixin(require('./lodash-stmt'));

processFilter = function processFilter(filter, context) {
  var joins = [],
      addJoin,
      expandAlias,
      processProperty;

  addJoin = function addJoin(join) {
    if (joins.indexOf(join) === -1) {
      joins.push(join);
    }
  };

  expandAlias = function expandAlias(property) {
    // expand property aliases into their proper paths
    if (context.propAliases && context.propAliases[property]) {
      property = context.propAliases[property];
    }
    return property;
  };

  processProperty = function processProperty(property) {
    var parts;

    property = expandAlias(property);

    // separate properties with '.'
    parts = property.split('.');

    // if length is 1, only column name exists, add table name
    if (parts.length === 1) {
      property = context.name ? context.name + '.' + property : property;
    }

    // Collect relations back into an array.
    // note: lazy way for building joins and include params
    if (parts.length > 1) {
      addJoin(parts[0]);
    }
    return property;
  };

  // loop through and process all the properties
  _.eachStatement(filter.statements, function (statement) {
    statement.prop = processProperty(statement.prop);
  });

  filter.joins = joins;

  return filter;
};

// detect where type
whereType = function whereType(statement, index) {
  var whereFunc = 'andWhere';
  if (index === 0) {
    whereFunc = 'where';
  } else if (statement.func === 'or') {
    whereFunc = 'orWhere';
  }

  if (statement.value === null) {
    if (statement.func === 'or') {
      whereFunc = statement.op === 'IS NOT' ? 'orWhereNotNull' : 'orWhereNull';
    } else {
      whereFunc = statement.op === 'IS NOT' ? 'whereNotNull' : 'whereNull';
    }
  }
  return whereFunc;
};

// build where
buildWhere = function buildWhere(qb, statements) {
  _.eachStatement(
    statements,
    function single(statement, index) {
      qb[whereType(statement, index)](statement.prop, statement.op, statement.value);
    },
    function group(statement, index) {
      qb[whereType(statement, index)](function (_qb) {
        buildWhere(_qb, statement.group);
      });
    }
  );
};

// knexify
// converts a 'filter' from a set of statements from JSON to a set of 'where' calls on a queryBuilder object

module.exports = function knexify(qb, filter) {
  filter = processFilter(filter, resourceContext[qb._single.table]);
  buildWhere(qb, filter.statements);
  return qb;
};

// used only for testing
module.exports._buildWhere = buildWhere;