猫鼬原型:如何动态插入URL?

问题描述：

我尝试为猫鼬模式创建原型. 数据库包含一行，其中包含图片列表.

I try to create a prototype for a mongoose schema. The database contains a row with a list of pictures.

示例:

{
  "_id": ObjectId("55814a9799677ba44e7826d1"),
  "album": "album1",
  "pictures": [
    "1434536659272.jpg",
    "1434536656464.jpg",
    "1434535467767.jpg"
  ],
  "__v": 0
}

知道如何使用示例原型为每张图片注入URL，以及之后如何才能以JSOn格式(用于API)从集合中获取所有数据(带有图片和url)，将是非常棒的.

It will be awesome to know how i can inject an URL for each pictures with for example a prototype and how after i can get all the datas from the collection (with pictures and url) in JSOn format (for an API).

我测试了许多不同的方法，但是没有用.

I tested many different approach but it doesn't work.

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var PicturesSchema = new Schema({
    album: { type: String, required: true, trim: true },
    pictures: { type: Array, required: false, trim: true }
});

var Pictures = mongoose.model('Pictures', PicturesSchema);

// Not working
Pictures.prototype.getPics = function(){
    return 'https://s3.amazonaws.com/xxxxx/'+ this.pictures;
}

module.exports = Pictures;

如何为每个图片虚拟"注入URL(我不想将URL存储在数据库中)?

How I can inject "virtually" the URL for each pictures (I don't want to store the url in the DB) ?

答

以下是使用一个实例的示例方法:

var mongoose = require('mongoose');
var Schema   = mongoose.Schema;

var PicturesSchema = new Schema({
  album    : { type : String, required : true,  trim : true },
  pictures : { type : Array,  required : false, trim : true }
});

// Make sure this is declared before declaring the model itself.
PicturesSchema.methods.getPics = function() {
  // `this` is the document; because `this.pictures` is an array,
  // we use Array.prototype.map() to map each picture to an URL.
  return this.pictures.map(function(picture) {
    return 'https://s3.amazonaws.com/xxxxx/'+ picture;
  });
};

var Pictures = mongoose.model('Pictures', PicturesSchema);

// Demo:
var pictures = new Pictures({
  album    : 'album1',
  pictures : [
    '1434536659272.jpg',
    '1434536656464.jpg',
    '1434535467767.jpg'
  ]
});

console.log( pictures.getPics() );

如果您希望URL成为文档对象的一部分(例如，用作JSON响应)，请使用虚拟" 代替:

If you want the URL's to be part of the document object (for instance, to use as JSON response), use a "virtual" instead:

...
PicturesSchema.virtual('pictureUrls').get(function() {
  return this.pictures.map(function(picture) {
    return 'https://s3.amazonaws.com/xxxxx/'+ picture;
  });
});
...

// Demo:
console.log('%j', pictures.toJSON({ virtuals : true }) );

猫鼬原型:如何动态插入URL?

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