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index.js
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index.js
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'use strict';
var mongoose = require('mongoose');
var EventEmitter = require('events').EventEmitter;
var Promise = require('bluebird');
// Setup contexter
var contexter = new EventEmitter();
contexter.mongoose = Mongoose;
contexter.model = model;
contexter.attach = attach;
module.exports = contexter;
function Mongoose(context) {
// Create seperate mongoose instance
var instance = new mongoose.Mongoose();
// Overload createConnection method to add context
var __createConnection = instance.createConnection;
instance.createConnection = function(uri, options) {
// Create actual connection and attach context to returned db
var db = __createConnection.apply(this, arguments);
return attach(context, db);
};
// Attach context to mongoose instance
return attach(context, instance);
}
function model(context, db, name, schema, collection, skipInit) {
var args,model;
// Create model
if (typeof db === 'string') {
// Create model with default mongoose if no db specified
args = Array.prototype.slice.call(arguments, 1);
model = mongoose.model.apply(mongoose, args);
} else {
// Create model with specified db otherwise
args = Array.prototype.slice.call(arguments, 2);
model = db.model.apply(db, args);
}
// Attach context to created model
return model ? attach(context, model) : model;
}
function attach(context, target) {
// Ignore if not target specifed
if (!target)
return target;
// Update existing context if target already contextualized
if (target.hasOwnProperty('$setContext')) {
target.$setContext(context);
return target;
}
// Create closure for specified context
var __context = context;
// Overload constructor for Model functions
var extTarget = target;
if (typeof target === 'function') {
extTarget = function () {
// Invoke original constructor
var inst = target.apply(this, arguments);
// Instantiate results with context
return instantiate(inst, __context);
};
}
// Add $getContext method to return attached context
extTarget.$getContext = function () {
return __context;
};
// Add $setContext method to replace attached context
extTarget.$setContext = function (context) {
if (__context !== context) {
__context = context;
contexter.emit('contextChanged', extTarget);
}
};
if (target instanceof mongoose.Mongoose || target instanceof mongoose.Connection) {
// Overload model method for Mongoose instances and connections
var __model = target.model;
target.model = function() {
// Invoke original model and attach context to returned result
var model = __model.apply(this, arguments);
return model ? attach(context, model) : model;
}
} else {
// Overload properties and methods for models and queries to attach context
// and associated methods on returned results
var key;
for (key in target) {
if (typeof target[key] === 'function') {
// Overload methods
switch (key) {
case 'create':
// Overload returned promise to attach context on completion
extTarget[key] = overloadPromise(key, extTarget);
break;
case 'exec':
case 'geoNear':
case 'geoSearch':
// Overload returned promise to attach context on completion
extTarget[key] = overloadPromise(key);
break;
case 'model':
if (target instanceof mongoose.Query) {
// Overload Query.model to attach context to returned model
extTarget.model = attach(__context, target.model);
} else {
// Overload Model.model to attach context to returned model
extTarget.model = function () {
var __method = target.model;
return function () {
var model = __method.apply(target, arguments);
return attach(__context, model);
};
}();
}
break;
case 'populate':
if (target instanceof mongoose.Query) {
// Attach context to query returned by Query.populate
extTarget.populate = overloadQuery(key);
} else {
// Overload promise returned by model.populate to attach context on completion
extTarget.populate = overloadPromise(key);
}
break;
case 'count':
case 'distinct':
case 'find':
case 'findById':
case 'findByIdAndRemove':
case 'findByIdAndUpdate':
case 'findOne':
case 'findOneAndRemove':
case 'findOneAndUpdate':
case 'remove':
case 'update':
// Overload method to attach context to returned query
extTarget[key] = overloadQuery(key);
break;
case '$where':
case 'all':
case 'and':
case 'batchSize':
case 'box':
case 'cast':
case 'center':
case 'centerSphere':
case 'circle':
case 'collection':
case 'comment':
case 'elemMatch':
case 'equals':
case 'exists':
case 'geometry':
case 'gt':
case 'gte':
case 'hint':
case 'in':
case 'intersects':
case 'lean':
case 'limit':
case 'lt':
case 'lte':
case 'maxDistance':
case 'maxScan':
case 'maxTime':
case 'maxscan':
case 'merge':
case 'mod':
case 'model':
case 'ne':
case 'near':
case 'nearSphere':
case 'nin':
case 'nor':
case 'or':
case 'polygon':
case 'read':
case 'regex':
case 'select':
case 'setOptions':
case 'size':
case 'skip':
case 'slaveOk':
case 'slice':
case 'snapshot':
case 'sort':
case 'tailable':
case 'toConstructor':
case 'where':
case 'within':
// Overload method to attach context to returned results
extTarget[key] = function () {
var __method = target[key];
return function () {
return attach(__context, __method.apply(target, arguments));
}
}();
break;
default:
if (extTarget !== target) {
// Reroute to invoke original method with original target
extTarget[key] = function () {
var __method = target[key];
return function () {
return __method.apply(target, arguments);
}
}();
}
break;
}
} else if (extTarget !== target) {
// Overload all properties with getter and setter methods to
// to get/set properties on original target
Object.defineProperty(extTarget, key, function () {
var __key = key;
return {
get: function () {
return target[__key];
},
set: function (val) {
target[__key] = val;
}
};
}());
}
}
}
// Model or Query contextualization completed
contexter.emit('contextualized', extTarget);
return extTarget;
// Local functions
function overloadPromise(method, self) {
var __target = self || target;
var __method = target[method];
return function () {
var i, cb, args = [];
// Extract original callback (if any) from arguments
for (i = 0; i < arguments.length; i++) {
if (typeof arguments[i] === 'function') {
cb = arguments[i];
break;
} else {
args.push(arguments[i]);
}
}
// Insert custom callback and promise to attach context to returned results
// before passing data on to original caller
var __deferred = Promise.defer();
args.push(function () {
if (this)
this.$getContext = extTarget.$getContext;
addContext(arguments);
if (cb)
cb.apply(this, arguments);
__deferred.resolve.apply(__deferred, Array.prototype.slice.call(arguments,1));
});
// Invoke original method
__method.apply(__target, args);
return __deferred.promise;
}
}
function overloadQuery(method, callback) {
var __method = target[method];
return function () {
var i, cb, args = [];
// Extract original callback (if any) from arguments
for (i = 0; i < arguments.length; i++) {
if (typeof arguments[i] === 'function') {
cb = arguments[i];
break;
} else {
args.push(arguments[i]);
}
}
// Replace callback (if any) to attach context to results
// before invoking original callback
if (cb) {
args.push(function () {
if (this)
this.$getContext = extTarget.$getContext;
if (callback)
callback.apply(this, arguments);
else
addContext(arguments);
cb.apply(this, arguments);
});
}
// Invoke original method
var query = __method.apply(target, args);
// Attach context to results if method returns a query
if (query instanceof mongoose.Query)
query = attach(__context, query);
return query;
}
}
function addContext(results) {
// Instantiate any document instances in results
for (var i = 1; i < results.length; i++) {
if (Array.isArray(results[i])) {
results[i].forEach(function (arg) {
if (arg instanceof mongoose.Model)
instantiate(arg, __context);
})
} else if (results[i] instanceof mongoose.Model) {
instantiate(results[i], __context);
}
}
}
}
function instantiate(inst, context) {
var __context = null;
if (inst.hasOwnProperty('$setContext')) {
// Replace existing context
inst.$setContext(context);
} else {
// Attach new context and associated methods
__context = context;
inst.$getContext = function () {
return __context;
};
inst.$setContext = function (context) {
if (__context !== context) {
__context = context;
contexter.emit('contextChanged', inst);
}
};
// Overload model method to attach context to returned results
if (typeof inst.model === 'function') {
var __model = inst.model;
inst.model = function () {
return attach(__context, __model.apply(this, arguments));
};
}
// Overload update method to attach context to returned results
if (typeof inst.update === 'function') {
var __update = inst.update;
inst.update = function () {
return attach(__context, __update.apply(this, arguments));
}
}
}
// Instantiate sub-documents
inst.schema.eachPath(function (name, type) {
if (type instanceof mongoose.Schema.Types.DocumentArray)
inst[name].forEach(function (subdoc) {
instantiate(subdoc, context);
})
});
// Instanciation completed
if (__context)
contexter.emit('instantiated', inst);
return inst;
}