我想用HTML显示从mongodb检索到的图像。
我的控制台数据是：
{原始名称：“ dhoni.jpg”，文件名：“ file-1558517416483。”，contentType：“ image / jpeg”} contentType：“图片/ jpeg” 文件名：“ file-1558517416483”。 原名：“ dhoni.jpg” 原始：对象
这是我的控制台输出数据。我想在HTML中显示图片。如何实现。
如何获取图像并显示在html页面中。
//server.js:
let express = require('express');
let app = express();
let bodyParser = require('body-parser');
let mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/files');
let conn = mongoose.connection;
let multer = require('multer');
let GridFsStorage = require('multer-gridfs-storage');
let Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;
let gfs = Grid(conn.db);
let port = 3000;
// Setting up the root route
app.get('/', (req, res) => {
res.send('Welcome to the express server');
});
// Allows cross-origin domains to access this API
app.use((req, res, next) => {
res.append('Access-Control-Allow-Origin' , 'http://localhost:4200');
res.append('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
res.append("Access-Control-Allow-Headers", "Origin, Accept,Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers");
res.append('Access-Control-Allow-Credentials', true);
next();
});
// BodyParser middleware
app.use(bodyParser.json());
// Setting up the storage element
let storage = GridFsStorage({
gfs : gfs,
filename: (req, file, cb) => {
let date = Date.now();
// The way you want to store your file in database
cb(null, file.fieldname + '-' + date + '.');
},
// Additional Meta-data that you want to store
metadata: function(req, file, cb) {
cb(null, { originalname: file.originalname });
},
root: 'ctFiles' // Root collection name
});
// Multer configuration for single file uploads
let upload = multer({
storage: storage
}).single('file');
// Route for file upload
app.post('/upload', (req, res) => {
upload(req,res, (err) => {
if(err){
res.json({error_code:1,err_desc:err});
return;
}
res.json({error_code:0, error_desc: null, file_uploaded: true});
});
});
// Downloading a single file
app.get('/file/:filename', (req, res) => {
gfs.collection('ctFiles'); //set collection name to lookup into
/** First check if file exists */
gfs.files.find({filename: req.params.filename}).toArray(function(err, files){
console.log("add");
if(!files || files.length === 0){
return res.status(404).json({
responseCode: 1,
responseMessage: "error"
});
}
// create read stream
var readstream = gfs.createReadStream({
filename: files[0].filename,
root: "ctFiles"
});
// set the proper content type
res.set('Content-Type', files[0].contentType)
// Return response
return readstream.pipe(res);
});
});
// Route for getting all the files
app.get('/files', (req, res) => {
let filesData;
let count = 0;
gfs.collection('ctFiles'); // set the collection to look up into
gfs.files.find({}).toArray((err, files) => {
// Error checking
if(!files || files.length === 0){
return res.status(404).json({
responseCode: 1,
responseMessage: "error"
});
}
// Loop through all the files and fetch the necessary information
files.forEach((file) => {
filesData = {
originalname: file.metadata.originalname,
filename: file.filename,
contentType: file.contentType
}
});
res.json(filesData);
});
});
app.listen(port, (req, res) => {
console.log("Server started on port: " + port);
});
<!--app.component.html:-->
<div class="row">
<div class="col-md-4">
<br>
<form>
<div class="form-group">
<label for="multiple">Choose file(s)</label>
<input type="file" class="form-control" name="multiple" ng2FileSelect [uploader]="uploader" multiple />
</div>
</form>
</div>
</div>
<div class="col-md-8">
File(s) Selected: {{ uploader?.queue?.length }}
<table class="table">
<thead>
<tr>
<th width="50%">Name</th>
<th>Size</th>
<th>Progress</th>
<th>Status</th>
<th>Actions</th>
</tr>
</thead>
<tbody>
<tr *ngFor="let item of uploader.queue">
<td><strong>{{ item.file.name }}</strong></td>
<td nowrap>{{ item.file.size/1024/1024 | number:'.2' }} MB</td>
<td>
<div class="progress" style="margin-bottom: 0;">
<div class="progress-bar" role="progressbar" [ngStyle]="{ 'width': item.progress + '%' }"></div>
</div>
</td>
<td class="text-center">
<span *ngIf="item.isSuccess"><i class="fa fa-check"></i></span>
<span *ngIf="item.isCancel"><i class="fa fa-ban"></i></span>
<span *ngIf="item.isError"><i class="fa fa-times"></i></span>
</td>
<td nowrap>
<button type="button" class="btn btn-success btn-xs"
(click)="item.upload()" [disabled]="item.isReady || item.isUploading || item.isSuccess">
<span class="fa fa-upload"></span> Upload
</button>
<button type="button" class="btn btn-warning btn-xs"
(click)="item.cancel()" [disabled]="!item.isUploading">
<span class="fa fa-ban"></span> Cancel
</button>
<button type="button" class="btn btn-danger btn-xs"
(click)="item.remove()">
<span class="fa fa-trash"></span> Remove
</button>
</td>
</tr>
</tbody>
</table>
</div>
app.component.ts:
import { FilesService } from './../files.service';
import { Component, OnInit } from '@angular/core';
import { FileUploader } from 'ng2-file-upload';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {
constructor(private FileService: FilesService) { }
private files = [];
private url = 'http://localhost:3000/upload';
private uploader: FileUploader;
ngOnInit() {
this.uploader = new FileUploader({url: this.url});
this.FileService.showFileNames().subscribe(response => {
console.log(response.json());
this.files = response.json();
});
}
}
file.service.ts:
import { Injectable } from '@angular/core';
import { Http, Headers, ResponseContentType } from '@angular/http';
@Injectable()
export class FilesService {
constructor(private http: Http) { }
showFileNames() {
return this.http.get('http://127.0.0.1:3000/files');
}
}