Loopback-component-storage：如何在上传到Amazon S3之前将图像转换为缩略图

3 回答

• 2

  你可以完成你正在尝试的，但它需要三个步骤 .

  首先，使用loopback-component-storage在本地上传文件 . 一旦你有了它，你可以根据自己的喜好创建尽可能多的图像调整 . 但是你需要给图像一些独特的名称以避免碰撞 .

  其次，使用AWS Node SDK将这些新映像推送到S3存储桶 .

  最后，删除本地文件以自行清理 .

  这很简单 . 看看我把这个问题拼凑起来解决这些问题：

  https://github.com/dashby3000/recipe-s3-image-uploader

  干杯!

  丹尼斯

  回复于 2024-04-29T21:57:07+08:00
• 0

  感谢名单 . @Dennis回答 . 我发现自己也是其他方式，我发布它 .

  Container.js

  var fs = require('fs');
      //Formidable to modify the form obtained as requests.
      var IncomingForm = require('formidable');
      //Imager for sending and modifying image to amazon
      var Imager = require('imager');
  
      Container.beforeRemote('upload', function(ctx,  modelInstance, next){
         var app       = Container.app;
         var container = ctx.req.params.container;
         //IF u have large image then. use this to avoid timeout..    
         ctx.req.connection.setTimeout(16000);
  
         //Checking if the container name is valid or not..
         var Customer = app.models.Customer;
         //http://apidocs.strongloop.com/loopback/#persistedmodel-exists
         //Now manually uploading to the provider and first converting the file to the thumbnail..
         upload(app, ctx.req, ctx.res, function(err, data){
           console.log("Image loaded successfully..");
         });                      
  
      });//beforeRemote
  
  
  
  
  
  
  
  
      //For handling the upload 
      var upload = function(app, req, res, options, cb) {
          var storageService =  app.dataSources.presImage.connector;
          if (!cb && 'function' === typeof options) {
               cb = options;
               options = {};
          }
          if (storageService.getFilename && !options.getFilename) {
             options.getFilename = storageService.getFilename;
          }
          if (storageService.acl && !options.acl) {
             options.acl = storageService.acl;
          }
          if (storageService.allowedContentTypes && !options.allowedContentTypes) {
             options.allowedContentTypes = storageService.allowedContentTypes;
          }
          if (storageService.maxFileSize && !options.maxFileSize) {
             options.maxFileSize = storageService.maxFileSize;
          }
          return handler(app, storageService.client, req, res, options, cb);
      }
  
  
     //Using handler for form parsing.. 
     var handler = function (app, provider, req, res, options, cb) {
          if (!cb && 'function' === typeof options) {
          cb = options;
          options = {};
          }
  
          if (!options.maxFileSize) {
          options.maxFileSize = defaultOptions.maxFileSize;
          }
  
          var form = new IncomingForm(options);
  
          var fields = {};
          var files = [];
  
  
            form
              .on('field', function(field, value) {
                fields[field] = value;
              })
              .on('file', function(field, file) {
                //Now upload the file to the amazon server.. 
                uploadToCloud(app,  fields.container, res, cb);
              })
              .on('end', function(name, file) {
                  console.log("END-> File fetched from user phone.\n");
              });
  
            form.parse(req);
      }
  
  
  
  
  
     var uploadToCloud = function(app,  container, res, callback ){
        var fileName, extension;
        var time = new Date();
        time = time.getTime();
        fileName = '' + container + '_' + time;
  
        imagerConfig = {
           variants: {
              items: {
                rename: function (filename) {
                   return fileName + "." + extension;
                },
  
                resize: {
                   thumb: "200x200",
                   original: "100%"
                }
            }
         },
  
        storage: {
          S3: {
            key: 'AMAZON KEY',
            secret: 'AMAZON SECRET',
            bucket: 'YOUR BUCKET NAME HERE',
            storageClass: 'REDUCED_REDUNDANCY',
            secure: false
          }
        },
        debug: true
      }
  
      CHECK IF FILE IS IMAGE ONLY..
      var pattern = /^image\/(.+)$/;
      extension = pattern.exec(path.type);
      try{
          if(extension.length){
               extension = extension[1];
          }else{
               throw "Error. Only image type file is permitted";
          }   
        }catch(err){
             throw "Error getting extension of file..";
        }
  
  
        if(!extension || extension == 'jpeg'){
             extension = "jpg";   
        }
  
        imager = new Imager(imagerConfig, 'S3') // or 'S3' for amazon
        imager.upload([path], function (err, cdnUri, files) {
             // do your stuff
             if(err) throw err; 
             console.log("Successfully saved to the amazon server..");
             var fileArr = [];
             for(var i=0; i < files.length; i++){
                  //Preparing the order object..
                  fileArr.push({
                      name: files[i],
                      container: container
                  }); 
              }
  
              //Sending the result fast..
              //Dont wait for image to get upload..
              res.send({
                 result:{
                    files:{
                      file:fileArr
                    }
                 } 
              }); //res.status  
              callback();
              //Now deleting the original file here...path is "os.tmp()"
  
         }, 'items');
  
     }//uploadToCloud..
  

  Datasource.json

  {
    "db": {
      "host": "",
      "port": 0,
      "database": "",
      "password": "",
      "name": "db",
      "connector": "memory",
      "user": ""
    },
    "Image": {
      "name": "Image",
      "connector": "loopback-component-storage",
      "provider": "amazon",
      "key": "YOUR AMAZON KEY",
      "keyId": "YOUR AMAZON KEY ID",
      "maxFileSize": "15728640"
    }
  }
  

  回复于 2024-04-29T21:57:07+08:00
• 5

  你检查了Strongloop挂钩https://docs.strongloop.com/display/public/LB/Adding+logic+to+models吗？您可以在调用存储组件之前尝试创建Hook

  回复于 2024-04-29T21:57:07+08:00