如何創建新的蒙戈的ObjectId

Question

我試圖生成供將來使用一個新的蒙戈ObjectId對象：

var objectId = new Mongoose.Schema.Types.ObjectId(); 

但不斷收到：

{ 
    "instance": "ObjectID", 
    "validators": [], 
    "setters": [], 
    "getters": [], 
    "_index": null 
} 

我怎樣才能真正產生獨特的ObjectId無創建任何模式？

Answer 1

解決我的問題：

var objectId = new Mongoose.Types.ObjectId(); 

希望這會有所幫助別人。

Answer 2

This is它是如何在BSON生成，並且貓鼬其實是使用BSON-JS LIB：

/** 
* Machine id. 
* 
* Create a random 3-byte value (i.e. unique for this 
* process). Other drivers use a md5 of the machine id here, but 
* that would mean an asyc call to gethostname, so we don't bother. 
* @ignore 
*/ 
var MACHINE_ID = parseInt(Math.random() * 0xffffff, 10); 

// Regular expression that checks for hex value 
var checkForHexRegExp = new RegExp('^[0-9a-fA-F]{24}$'); 

// Check if buffer exists 
try { 
if (Buffer && Buffer.from) var hasBufferType = true; 
} catch (err) { 
hasBufferType = false; 
} 

/** 
* Create a new ObjectID instance 
* 
* @class 
* @param {(string|number)} id Can be a 24 byte hex string, 12 byte binary string or a Number. 
* @property {number} generationTime The generation time of this ObjectId instance 
* @return {ObjectID} instance of ObjectID. 
*/ 
var ObjectID = function ObjectID(id) { 
// Duck-typing to support ObjectId from different npm packages 
if (id instanceof ObjectID) return id; 
if (!(this instanceof ObjectID)) return new ObjectID(id); 

this._bsontype = 'ObjectID'; 

// The most common usecase (blank id, new objectId instance) 
if (id == null || typeof id === 'number') { 
    // Generate a new id 
    this.id = this.generate(id); 
    // If we are caching the hex string 
    if (ObjectID.cacheHexString) this.__id = this.toString('hex'); 
    // Return the object 
    return; 
} 

// Check if the passed in id is valid 
var valid = ObjectID.isValid(id); 

// Throw an error if it's not a valid setup 
if (!valid && id != null) { 
    throw new Error(
    'Argument passed in must be a single String of 12 bytes or a string of 24 hex characters' 
    ); 
} else if (valid && typeof id === 'string' && id.length === 24 && hasBufferType) { 
    return new ObjectID(new Buffer(id, 'hex')); 
} else if (valid && typeof id === 'string' && id.length === 24) { 
    return ObjectID.createFromHexString(id); 
} else if (id != null && id.length === 12) { 
    // assume 12 byte string 
    this.id = id; 
} else if (id != null && id.toHexString) { 
    // Duck-typing to support ObjectId from different npm packages 
    return id; 
} else { 
    throw new Error(
    'Argument passed in must be a single String of 12 bytes or a string of 24 hex characters' 
    ); 
} 

if (ObjectID.cacheHexString) this.__id = this.toString('hex'); 
}; 

// Allow usage of ObjectId as well as ObjectID 
// var ObjectId = ObjectID; 

// Precomputed hex table enables speedy hex string conversion 
var hexTable = []; 
for (var i = 0; i < 256; i++) { 
hexTable[i] = (i <= 15 ? '0' : '') + i.toString(16); 
} 

/** 
* Return the ObjectID id as a 24 byte hex string representation 
* 
* @method 
* @return {string} return the 24 byte hex string representation. 
*/ 
ObjectID.prototype.toHexString = function() { 
if (ObjectID.cacheHexString && this.__id) return this.__id; 

var hexString = ''; 
if (!this.id || !this.id.length) { 
    throw new Error(
    'invalid ObjectId, ObjectId.id must be either a string or a Buffer, but is [' + 
     JSON.stringify(this.id) + 
     ']' 
    ); 
} 

if (this.id instanceof _Buffer) { 
    hexString = convertToHex(this.id); 
    if (ObjectID.cacheHexString) this.__id = hexString; 
    return hexString; 
} 

for (var i = 0; i < this.id.length; i++) { 
    hexString += hexTable[this.id.charCodeAt(i)]; 
} 

if (ObjectID.cacheHexString) this.__id = hexString; 
return hexString; 
}; 

/** 
* Update the ObjectID index used in generating new ObjectID's on the driver 
* 
* @method 
* @return {number} returns next index value. 
* @ignore 
*/ 
ObjectID.prototype.get_inc = function() { 
return (ObjectID.index = (ObjectID.index + 1) % 0xffffff); 
}; 

/** 
* Update the ObjectID index used in generating new ObjectID's on the driver 
* 
* @method 
* @return {number} returns next index value. 
* @ignore 
*/ 
ObjectID.prototype.getInc = function() { 
return this.get_inc(); 
}; 

/** 
* Generate a 12 byte id buffer used in ObjectID's 
* 
* @method 
* @param {number} [time] optional parameter allowing to pass in a second based timestamp. 
* @return {Buffer} return the 12 byte id buffer string. 
*/ 
ObjectID.prototype.generate = function(time) { 
if ('number' !== typeof time) { 
    time = ~~(Date.now()/1000); 
} 

// Use pid 
var pid = 
    (typeof process === 'undefined' || process.pid === 1 
    ? Math.floor(Math.random() * 100000) 
    : process.pid) % 0xffff; 
var inc = this.get_inc(); 
// Buffer used 
var buffer = new Buffer(12); 
// Encode time 
buffer[3] = time & 0xff; 
buffer[2] = (time >> 8) & 0xff; 
buffer[1] = (time >> 16) & 0xff; 
buffer[0] = (time >> 24) & 0xff; 
// Encode machine 
buffer[6] = MACHINE_ID & 0xff; 
buffer[5] = (MACHINE_ID >> 8) & 0xff; 
buffer[4] = (MACHINE_ID >> 16) & 0xff; 
// Encode pid 
buffer[8] = pid & 0xff; 
buffer[7] = (pid >> 8) & 0xff; 
// Encode index 
buffer[11] = inc & 0xff; 
buffer[10] = (inc >> 8) & 0xff; 
buffer[9] = (inc >> 16) & 0xff; 
// Return the buffer 
return buffer; 
}; 

/** 
* Converts the id into a 24 byte hex string for printing 
* 
* @param {String} format The Buffer toString format parameter. 
* @return {String} return the 24 byte hex string representation. 
* @ignore 
*/ 
ObjectID.prototype.toString = function(format) { 
// Is the id a buffer then use the buffer toString method to return the format 
if (this.id && this.id.copy) { 
    return this.id.toString(typeof format === 'string' ? format : 'hex'); 
} 

// if(this.buffer) 
return this.toHexString(); 
}; 

/** 
* Converts to a string representation of this Id. 
* 
* @return {String} return the 24 byte hex string representation. 
* @ignore 
*/ 
ObjectID.prototype.inspect = ObjectID.prototype.toString; 

/** 
* Converts to its JSON representation. 
* 
* @return {String} return the 24 byte hex string representation. 
* @ignore 
*/ 
ObjectID.prototype.toJSON = function() { 
return this.toHexString(); 
}; 

/** 
* Compares the equality of this ObjectID with `otherID`. 
* 
* @method 
* @param {object} otherID ObjectID instance to compare against. 
* @return {boolean} the result of comparing two ObjectID's 
*/ 
ObjectID.prototype.equals = function equals(otherId) { 
// var id; 

if (otherId instanceof ObjectID) { 
    return this.toString() === otherId.toString(); 
} else if (
    typeof otherId === 'string' && 
    ObjectID.isValid(otherId) && 
    otherId.length === 12 && 
    this.id instanceof _Buffer 
) { 
    return otherId === this.id.toString('binary'); 
} else if (typeof otherId === 'string' && ObjectID.isValid(otherId) && otherId.length === 24) { 
    return otherId.toLowerCase() === this.toHexString(); 
} else if (typeof otherId === 'string' && ObjectID.isValid(otherId) && otherId.length === 12) { 
    return otherId === this.id; 
} else if (otherId != null && (otherId instanceof ObjectID || otherId.toHexString)) { 
    return otherId.toHexString() === this.toHexString(); 
} else { 
    return false; 
} 
}; 

/** 
* Returns the generation date (accurate up to the second) that this ID was generated. 
* 
* @method 
* @return {date} the generation date 
*/ 
ObjectID.prototype.getTimestamp = function() { 
var timestamp = new Date(); 
var time = this.id[3] | (this.id[2] << 8) | (this.id[1] << 16) | (this.id[0] << 24); 
timestamp.setTime(Math.floor(time) * 1000); 
return timestamp; 
}; 

/** 
* @ignore 
*/ 
ObjectID.index = ~~(Math.random() * 0xffffff); 

/** 
* @ignore 
*/ 
ObjectID.createPk = function createPk() { 
return new ObjectID(); 
}; 

/** 
* Creates an ObjectID from a second based number, with the rest of the ObjectID zeroed out. Used for comparisons or sorting the ObjectID. 
* 
* @method 
* @param {number} time an integer number representing a number of seconds. 
* @return {ObjectID} return the created ObjectID 
*/ 
ObjectID.createFromTime = function createFromTime(time) { 
var buffer = new Buffer([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]); 
// Encode time into first 4 bytes 
buffer[3] = time & 0xff; 
buffer[2] = (time >> 8) & 0xff; 
buffer[1] = (time >> 16) & 0xff; 
buffer[0] = (time >> 24) & 0xff; 
// Return the new objectId 
return new ObjectID(buffer); 
}; 

// Lookup tables 
//var encodeLookup = 'abcdef'.split(''); 
var decodeLookup = []; 
i = 0; 
while (i < 10) decodeLookup[0x30 + i] = i++; 
while (i < 16) decodeLookup[0x41 - 10 + i] = decodeLookup[0x61 - 10 + i] = i++; 

var _Buffer = Buffer; 
var convertToHex = function(bytes) { 
return bytes.toString('hex'); 
}; 

/** 
* Creates an ObjectID from a hex string representation of an ObjectID. 
* 
* @method 
* @param {string} hexString create a ObjectID from a passed in 24 byte hexstring. 
* @return {ObjectID} return the created ObjectID 
*/ 
ObjectID.createFromHexString = function createFromHexString(string) { 
// Throw an error if it's not a valid setup 
if (typeof string === 'undefined' || (string != null && string.length !== 24)) { 
    throw new Error(
    'Argument passed in must be a single String of 12 bytes or a string of 24 hex characters' 
    ); 
} 

// Use Buffer.from method if available 
if (hasBufferType) return new ObjectID(new Buffer(string, 'hex')); 

// Calculate lengths 
var array = new _Buffer(12); 
var n = 0; 
var i = 0; 

while (i < 24) { 
    array[n++] = (decodeLookup[string.charCodeAt(i++)] << 4) | decodeLookup[string.charCodeAt(i++)]; 
} 

return new ObjectID(array); 
}; 

/** 
* Checks if a value is a valid bson ObjectId 
* 
* @method 
* @return {boolean} return true if the value is a valid bson ObjectId, return false otherwise. 
*/ 
ObjectID.isValid = function isValid(id) { 
if (id == null) return false; 

if (typeof id === 'number') { 
    return true; 
} 

if (typeof id === 'string') { 
    return id.length === 12 || (id.length === 24 && checkForHexRegExp.test(id)); 
} 

if (id instanceof ObjectID) { 
    return true; 
} 

if (id instanceof _Buffer) { 
    return true; 
} 

// Duck-Typing detection of ObjectId like objects 
if (id.toHexString) { 
    return id.id.length === 12 || (id.id.length === 24 && checkForHexRegExp.test(id.id)); 
} 

return false; 
}; 

/** 
* @ignore 
*/ 
Object.defineProperty(ObjectID.prototype, 'generationTime', { 
enumerable: true, 
get: function() { 
    return this.id[3] | (this.id[2] << 8) | (this.id[1] << 16) | (this.id[0] << 24); 
}, 
set: function(value) { 
    // Encode time into first 4 bytes 
    this.id[3] = value & 0xff; 
    this.id[2] = (value >> 8) & 0xff; 
    this.id[1] = (value >> 16) & 0xff; 
    this.id[0] = (value >> 24) & 0xff; 
} 
}); 

export default ObjectID; 

只需做以下

import './path/to/file/objectid.js' 


var newMongoCompatibleUUID = ObjectID().toHexString()