pouchdb.js

/**
 * PouchDB backend
 */
"use strict";

var async = require('async');
var _ = require('lodash');

/**
 * Creates a PouchDB Backend
 */
function PouchDBBackend(db, prefix) {
  this.db = db;
  this.prefix = prefix || 'acl';
}

Object.defineProperties(PouchDBBackend.prototype, {
	/**
	 * Begins a transaction
	 */
	begin: {
    value: function () {
	    return [];
    }
	},
	/**
	 * Ends a transaction.
	 */
	end: {
		value: function (transaction, cb) {
			async.series(transaction, cb);
		}
	},
	/**
	 * Cleans the whole storage
	 */
	clean: {
		value: function (cb) {
			this.db.destroy().then(function () {
				cb(null);
			}).catch(function (error) {
				cb(error);
			});
		}
	},
	/**
	 * Gets the contents at the bucket's key.
	 */
	get: {
		value: function (bucket, key, cb) {
			this.db.get(this._bucketKey(bucket, key), function (err, doc) {
				if (err && err.status === 404) {
					cb(null, []);
				} else if (err) {
					cb(err);
				} else {
					cb(null, _.without(_.keys(doc), "_rev", "_id"));
				}
			});
		}
	},
	/**
	 * Returns the union of the values in the given keys.
	 */
	union: {
		value: function (bucket, keys, cb) {
	    var self = this;

      var fns = keys.map(function (key) {
        return function (cb) {
          self.get(bucket, key, function (err, doc) {
            if (err) {
              cb(err);
            } else {
              cb(null, doc);
            }
          });
        };
      });

	    async.parallel(fns, function (err, results) {
	      if (err) {
	        cb(err);
	      } else {
          var keyArrays = [];
          results.forEach(function(doc){
            keyArrays.push.apply(keyArrays, _.keys(doc));
          });
	        cb(null, _.without(_.union(keyArrays),"_rev","_id"));
	      }
	    });
		}
	},
	/**
	 * Adds values to a given key inside a bucket.
	 */
	add: {
		value: function (transaction, bucket, key, values) {
			var self = this;
			transaction.push(function (cb) {
        var kb = self._bucketKey(bucket, key),
  				  valueArray = makeArray(values),
	          newDoc = {};
				valueArray.forEach(function (value) { newDoc[value] = true; });

				self.db.get(kb, function (err, doc) {
					if (err && err.status === 404) {
						self.db.put(newDoc, kb, cb);
					} else if (err) {
						cb(err);
					} else {
						self.db.put(newDoc, kb, doc['_rev'], cb);
					}
				});
			});
		}
	},
	/**
	 * Delete the given key(s) at the bucket
	 */
	del: {
		value: function (transaction, bucket, keys) {
			var	self = this;

	    transaction.push(function (cb) {
        var keyArray = makeArray(keys), kbs = this._bucketKey(bucket, keyArray);

	      var fns = kbs.map(function (kb) {
	        return function (innerCb) {
						self.db.get(kb, function (err, doc) {
							if (err) {
								innerCb(err);
							} else {
								self.db.remove(doc, innerCb);
							}
						})
	        };
	      });

	      async.parallel(fns, cb);
	    });
		}
	},
	/**
	 * Removes values from a given key inside a bucket.
	 */
	remove: {
		value: function (transaction, bucket, key, values) {
			var self = this;

			transaction.push(function (cb) {
        var valueArray = makeArray(values),
  				  kb = self._bucketKey(bucket, key);

				self.db.get(kb, function (err, doc) {
					values.forEach(function (value) {
						delete doc[value];
					});

					self.db.put(doc, cb);
				});
			});
		}
	},
	/**
	 * Private key generator function.
	 */
	_bucketKey: {
		value: function(bucket, keys) {
	    if (Array.isArray(keys)) {
	      return keys.map(function (key) {
	        return this.prefix+'_'+bucket+'@'+key;
	      }, this);
	    } else {
	      return this.prefix+'_'+bucket+'@'+keys;
	    }
	  }
	}
});

function makeArray(arr) {
	return Array.isArray(arr) ? arr : [arr];
}

exports = module.exports = PouchDBBackend;