gridfs/models/File.model.js

  1. /**
  2.  * @module flitter-gridfs/models/File
  3.  */
  5. const Model = require('flitter-orm/src/model/Model')
  7. const path = require('path')
  8. const fs = require('fs')
  9. const Mongo = require('mongodb')
  11. /**
  12.  * Model to represent a stored file.
  13.  * @extends {module:flitter-orm/src/model/Model~Model}
  14.  */
  15. class GridFile extends Model {
  16.     /**
  17.      * Defines the services required by this model.
  18.      * @returns {Array<string>}
  19.      */
  20.     static get services() {
  21.         return [...super.services, 'gridfs']
  22.     }
  24.     /**
  25.      * Defines the schema used by this model.
  26.      * @returns {object}
  27.      */
  28.     static get schema() {
  29.         return {
  30.             name: String,
  31.             content_type: String,
  32.             created_on: {type: Date, default: () => new Date},
  33.             file_id: String,
  34.             data: {type: String, default: '{}'},
  35.         }
  36.     }
  38.     /**
  39.      * Get the GridFS files collection.
  40.      * @returns {Promise<mongodb/Collection>}
  41.      */
  42.     static async files() {
  43.         return this.gridfs.mongo_db.collection('fs.files')
  44.     }
  46.     /**
  47.      * Convert an object ID string to a MongoDB ObjectId.
  48.      * @param {string} id
  49.      * @returns {mongodb/ObjectId}
  50.      */
  51.     static object_id(id) {
  52.         return Mongo.ObjectId(id)
  53.     }
  55.     /**
  56.      * Get a file record by ID string from the grid files collection.
  57.      * @param {string} id
  58.      * @returns {Promise<object>} - resolves to the retrieved file record object
  59.      */
  60.     static async one(id) {
  61.         const files = await this.files()
  62.         return files.findOne({_id: this.object_id(id)})
  63.     }
  65.     /**
  66.      * Get the GridFSBucket used by the model.
  67.      * @returns {mongodb/GridFS/Bucket} - the GridFS bucket
  68.      */
  69.     grid() {
  70.         return this.gridfs.mongo_bucket
  71.     }
  73.     /**
  74.      * Save a file to the grid from a local file.
  75.      * @param {string} filepath - path of the file to be uploaded
  76.      * @param {string} [filename] - name of the file to save, defaults to the model's this.name
  77.      * @returns {Promise<void>}
  78.      */
  79.     write_from_file({filepath, filename}){
  80.         const grid = this.grid()
  81.         filename = filename ? filename : this.name
  82.         filepath = path.resolve(filepath)
  84.         return new Promise((resolve, reject) => {
  85.             fs.createReadStream(filepath)
  86.                 .pipe(grid.openUploadStream(filename))
  87.                 .on('error', (e) => reject(e))
  88.                 .on('finish', (file) => {
  89.                     this.file_id = file._id.toString()
  90.                     this.save().then(resolve)
  91.                 })
  92.         })
  93.     }
  95.     /**
  96.      * Retrieve the model's file from the Grid and store it to the local filesystem.
  97.      * @param {string} filepath - path to which the file should be saved
  98.      * @returns {Promise<void>}
  99.      */
  100.     write_to_file({filepath}){
  101.         filepath = path.resolve(filepath)
  102.         return new Promise((resolve, reject) => {
  103.             this.get_read_stream()
  104.                 .pipe(fs.createWriteStream(filepath))
  105.                 .on('error', e => reject(e))
  106.                 .on('finish', () => resolve())
  107.         })
  108.     }
  110.     /**
  111.      * Get the read stream for the model's stored Grid file.
  112.      * @returns {mongodb/GridFS/GridFSBucketReadStream}
  113.      */
  114.     get_read_stream(){
  115.         const grid = this.grid()
  116.         return grid.openDownloadStream(this.constructor.object_id(this.file_id))
  117.     }
  119.     /**
  120.      * Send this model's stored Grid file as data for the specified response.
  121.      * @param {express/Response} response - the response to send to
  122.      * @returns {boolean | void}
  123.      */
  124.     send_to_response(response){
  125.         const stream = this.get_read_stream()
  126.         response.set({
  127.             'Content-Disposition': `inline; filename="${this.name}"`
  128.         })
  129.         return stream.pipe(response)
  130.     }
  131. }
  133. module.exports = exports = GridFile
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