我是Angular的初学者,我想知道如何创建Angular 5文件上传部分,我试图找到任何教程或文档,但我在任何地方都看不到任何东西。对此有什么想法吗?我尝试了ng4-files,但它不适用于Angular 5
当前回答
就我个人而言,我使用ngx-material-file-input作为前端,Firebase作为后端。更准确地说,后端是与Cloud Firestore结合的Cloud Storage for Firebase。下面是一个示例,它限制文件不大于20 MB,并且只接受某些文件扩展名。我还使用Cloud Firestore来存储上传文件的链接,但你可以跳过这个。
contact.component.html
<mat-form-field>
<!--
Accept only files in the following format: .doc, .docx, .jpg, .jpeg, .pdf, .png, .xls, .xlsx. However, this is easy to bypass, Cloud Storage rules has been set up on the back-end side.
-->
<ngx-mat-file-input
[accept]="[
'.doc',
'.docx',
'.jpg',
'.jpeg',
'.pdf',
'.png',
'.xls',
'.xlsx'
]"
(change)="uploadFile($event)"
formControlName="fileUploader"
multiple
aria-label="Here you can add additional files about your project, which can be helpeful for us."
placeholder="Additional files"
title="Additional files"
type="file"
>
</ngx-mat-file-input>
<mat-icon matSuffix>folder</mat-icon>
<mat-hint
>Accepted formats: DOC, DOCX, JPG, JPEG, PDF, PNG, XLS and XLSX,
maximum files upload size: 20 MB.
</mat-hint>
<!--
Non-null assertion operators are required to let know the compiler that this value is not empty and exists.
-->
<mat-error
*ngIf="contactForm.get('fileUploader')!.hasError('maxContentSize')"
>
This size is too large,
<strong
>maximum acceptable upload size is
{{
contactForm.get('fileUploader')?.getError('maxContentSize')
.maxSize | byteFormat
}}</strong
>
(uploaded size:
{{
contactForm.get('fileUploader')?.getError('maxContentSize')
.actualSize | byteFormat
}}).
</mat-error>
</mat-form-field>
ts(大小验证器部分)
import { FileValidator } from 'ngx-material-file-input';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
/**
* @constructor
* @description Creates a new instance of this component.
* @param {formBuilder} - an abstraction class object to create a form group control for the contact form.
*/
constructor(
private angularFirestore: AngularFirestore,
private angularFireStorage: AngularFireStorage,
private formBuilder: FormBuilder
) {}
public maxFileSize = 20971520;
public contactForm: FormGroup = this.formBuilder.group({
fileUploader: [
'',
Validators.compose([
FileValidator.maxContentSize(this.maxFileSize),
Validators.maxLength(512),
Validators.minLength(2)
])
]
})
ts(文件上传器部分)
import { AngularFirestore } from '@angular/fire/firestore';
import {
AngularFireStorage,
AngularFireStorageReference,
AngularFireUploadTask
} from '@angular/fire/storage';
import { catchError, finalize } from 'rxjs/operators';
import { throwError } from 'rxjs';
public downloadURL: string[] = [];
/**
* @description Upload additional files to Cloud Firestore and get URL to the files.
* @param {event} - object of sent files.
* @returns {void}
*/
public uploadFile(event: any): void {
// Iterate through all uploaded files.
for (let i = 0; i < event.target.files.length; i++) {
const randomId = Math.random()
.toString(36)
.substring(2); // Create random ID, so the same file names can be uploaded to Cloud Firestore.
const file = event.target.files[i]; // Get each uploaded file.
// Get file reference.
const fileRef: AngularFireStorageReference = this.angularFireStorage.ref(
randomId
);
// Create upload task.
const task: AngularFireUploadTask = this.angularFireStorage.upload(
randomId,
file
);
// Upload file to Cloud Firestore.
task
.snapshotChanges()
.pipe(
finalize(() => {
fileRef.getDownloadURL().subscribe((downloadURL: string) => {
this.angularFirestore
.collection(process.env.FIRESTORE_COLLECTION_FILES!) // Non-null assertion operator is required to let know the compiler that this value is not empty and exists.
.add({ downloadURL: downloadURL });
this.downloadURL.push(downloadURL);
});
}),
catchError((error: any) => {
return throwError(error);
})
)
.subscribe();
}
}
storage.rules
rules_version = '2';
service firebase.storage {
match /b/{bucket}/o {
match /{allPaths=**} {
allow read; // Required in order to send this as attachment.
// Allow write files Firebase Storage, only if:
// 1) File is no more than 20MB
// 2) Content type is in one of the following formats: .doc, .docx, .jpg, .jpeg, .pdf, .png, .xls, .xlsx.
allow write: if request.resource.size <= 20 * 1024 * 1024
&& (request.resource.contentType.matches('application/msword')
|| request.resource.contentType.matches('application/vnd.openxmlformats-officedocument.wordprocessingml.document')
|| request.resource.contentType.matches('image/jpg')
|| request.resource.contentType.matches('image/jpeg')
|| request.resource.contentType.matches('application/pdf')
|| request.resource.contentType.matches('image/png')
|| request.resource.contentType.matches('application/vnd.ms-excel')
|| request.resource.contentType.matches('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'))
}
}
}
其他回答
我使用的是Angular 5.2.11, 我喜欢Gregor Doroschenko提供的解决方案,但是我注意到上传的文件是零字节的,我必须做一个小小的改变才能让它为我工作。
postFile(fileToUpload: File): Observable<boolean> {
const endpoint = 'your-destination-url';
return this.httpClient
.post(endpoint, fileToUpload, { headers: yourHeadersConfig })
.map(() => { return true; })
.catch((e) => this.handleError(e));
}
下面几行(formData)对我不起作用。
const formData: FormData = new FormData();
formData.append('fileKey', fileToUpload, fileToUpload.name);
https://github.com/amitrke/ngrke/blob/master/src/app/services/fileupload.service.ts
使用Angular和nodejs上传文件的完整示例(express)
HTML代码
<div class="form-group">
<label for="file">Choose File</label><br/>
<input type="file" id="file" (change)="uploadFile($event.target.files)" multiple>
</div>
TS组件代码
uploadFile(files) {
console.log('files', files)
var formData = new FormData();
for(let i =0; i < files.length; i++){
formData.append("files", files[i], files[i]['name']);
}
this.httpService.httpPost('/fileUpload', formData)
.subscribe((response) => {
console.log('response', response)
},
(error) => {
console.log('error in fileupload', error)
})
}
Node Js代码
上传火灾控制器
function start(req, res) {
fileUploadService.fileUpload(req, res)
.then(fileUploadServiceResponse => {
res.status(200).send(fileUploadServiceResponse)
})
.catch(error => {
res.status(400).send(error)
})
}
module.exports.start = start
使用multer上传服务
const multer = require('multer') // import library
const moment = require('moment')
const q = require('q')
const _ = require('underscore')
const fs = require('fs')
const dir = './public'
/** Store file on local folder */
let storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, 'public')
},
filename: function (req, file, cb) {
let date = moment(moment.now()).format('YYYYMMDDHHMMSS')
cb(null, date + '_' + file.originalname.replace(/-/g, '_').replace(/ /g, '_'))
}
})
/** Upload files */
let upload = multer({ storage: storage }).array('files')
/** Exports fileUpload function */
module.exports = {
fileUpload: function (req, res) {
let deferred = q.defer()
/** Create dir if not exist */
if (!fs.existsSync(dir)) {
fs.mkdirSync(dir)
console.log(`\n\n ${dir} dose not exist, hence created \n\n`)
}
upload(req, res, function (err) {
if (req && (_.isEmpty(req.files))) {
deferred.resolve({ status: 200, message: 'File not attached', data: [] })
} else {
if (err) {
deferred.reject({ status: 400, message: 'error', data: err })
} else {
deferred.resolve({
status: 200,
message: 'File attached',
filename: _.pluck(req.files,
'filename'),
data: req.files
})
}
}
})
return deferred.promise
}
}
下面是一个上传文件到api的例子:
步骤1:HTML模板
定义文件类型的简单输入标记。为(change)-event添加一个处理选择文件的函数。
<div class="form-group">
<label for="file">Choose File</label>
<input type="file"
id="file"
(change)="handleFileInput($event.target.files)">
</div>
步骤2:在TypeScript中处理上传
为所选文件定义一个默认变量。
fileToUpload: File | null = null;
创建你在(change)-event中使用的函数:
handleFileInput(files: FileList) {
this.fileToUpload = files.item(0);
}
如果你想处理多文件选择,那么你可以遍历这个文件数组。
现在通过调用file-upload.service创建文件上传函数:
uploadFileToActivity() {
this.fileUploadService.postFile(this.fileToUpload).subscribe(data => {
// do something, if upload success
}, error => {
console.log(error);
});
}
第三步:文件上传服务
通过post方法上传文件,你应该使用FormData,因为这样你可以添加文件到http请求。
postFile(fileToUpload: File): Observable<boolean> {
const endpoint = 'your-destination-url';
const formData: FormData = new FormData();
formData.append('fileKey', fileToUpload, fileToUpload.name);
return this.httpClient
.post(endpoint, formData, { headers: yourHeadersConfig })
.map(() => { return true; })
.catch((e) => this.handleError(e));
}
所以,这是一个非常简单的工作例子,我每天都在工作中使用。
好的,因为这个线程出现在谷歌的第一个结果中,对于其他有同样问题的用户,你不需要像trueboroda指出的那样重新开始,有ng2-file-upload库,它简化了使用angular 6和7上传文件的过程,你所需要做的是:
安装最新的Angular CLI
yarn add global @angular/cli
出于兼容性考虑,请安装rx-compat
npm install rxjs-compat --save
安装ng2-file-upload
npm install ng2-file-upload --save
在你的模块中导入FileSelectDirective指令。
import { FileSelectDirective } from 'ng2-file-upload';
Add it to [declarations] under @NgModule:
declarations: [ ... FileSelectDirective , ... ]
在你的组件中
import { FileUploader } from 'ng2-file-upload/ng2-file-upload';
...
export class AppComponent implements OnInit {
public uploader: FileUploader = new FileUploader({url: URL, itemAlias: 'photo'});
}
模板
<input type="file" name="photo" ng2FileSelect [uploader]="uploader" />
为了更好地理解,你可以查看这个链接: 如何使用Angular 6/7上传文件
在Angular 7/8/9中
来源链接
使用自举表单
<form>
<div class="form-group">
<fieldset class="form-group">
<label>Upload Logo</label>
{{imageError}}
<div class="custom-file fileInputProfileWrap">
<input type="file" (change)="fileChangeEvent($event)" class="fileInputProfile">
<div class="img-space">
<ng-container *ngIf="isImageSaved; else elseTemplate">
<img [src]="cardImageBase64" />
</ng-container>
<ng-template #elseTemplate>
<img src="./../../assets/placeholder.png" class="img-responsive">
</ng-template>
</div>
</div>
</fieldset>
</div>
<a class="btn btn-danger" (click)="removeImage()" *ngIf="isImageSaved">Remove</a>
</form>
在组件类中
fileChangeEvent(fileInput: any) {
this.imageError = null;
if (fileInput.target.files && fileInput.target.files[0]) {
// Size Filter Bytes
const max_size = 20971520;
const allowed_types = ['image/png', 'image/jpeg'];
const max_height = 15200;
const max_width = 25600;
if (fileInput.target.files[0].size > max_size) {
this.imageError =
'Maximum size allowed is ' + max_size / 1000 + 'Mb';
return false;
}
if (!_.includes(allowed_types, fileInput.target.files[0].type)) {
this.imageError = 'Only Images are allowed ( JPG | PNG )';
return false;
}
const reader = new FileReader();
reader.onload = (e: any) => {
const image = new Image();
image.src = e.target.result;
image.onload = rs => {
const img_height = rs.currentTarget['height'];
const img_width = rs.currentTarget['width'];
console.log(img_height, img_width);
if (img_height > max_height && img_width > max_width) {
this.imageError =
'Maximum dimentions allowed ' +
max_height +
'*' +
max_width +
'px';
return false;
} else {
const imgBase64Path = e.target.result;
this.cardImageBase64 = imgBase64Path;
this.isImageSaved = true;
// this.previewImagePath = imgBase64Path;
}
};
};
reader.readAsDataURL(fileInput.target.files[0]);
}
}
removeImage() {
this.cardImageBase64 = null;
this.isImageSaved = false;
}
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