Angular - POST上传的文件

Question

我正在使用Angular、TypeScript 将文件连同 JSON 数据一起发送到服务器。

下面是我的代码：

import {Component, View, NgFor, FORM_DIRECTIVES, FormBuilder, ControlGroup} from 'angular2/angular2';
import {Http, Response, Headers} from 'http/http';


@Component({ selector: 'file-upload' })
@View({
directives: [FORM_DIRECTIVES],
template: `
<h3>File Upload</h3>

<div>
     Select file:
    <input type="file" (change)="changeListener($event)">
</div>

`
})
export class FileUploadCmp {

public file: File;
public url: string;
headers: Headers;


constructor(public http: Http) {
    console.log('file upload Initialized');
    //set the header as multipart        
    this.headers = new Headers();
    this.headers.set('Content-Type', 'multipart/form-data');
    this.url = 'http://localhost:8080/test';
}

//onChange file listener
changeListener($event): void {
    this.postFile($event.target);
}

//send post file to server 
postFile(inputValue: any): void {

    var formData = new FormData();
    formData.append("name", "Name");
    formData.append("file",  inputValue.files[0]);

    this.http.post(this.url +,
      formData ,
        {
            headers: this.headers

        });
}

}

如何将formData 转换为字符串并将其发送到服务器？我记得在AngularJS (v1) 中你会使用transformRequest。

Answer 1

您的 http 服务文件：

import { Injectable } from "@angular/core";
import { ActivatedRoute, Router } from '@angular/router';
import { Http, Headers, Response, Request, RequestMethod, URLSearchParams, RequestOptions } from "@angular/http";
import {Observable} from 'rxjs/Rx';
import { Constants } from './constants';
declare var $: any;

@Injectable()
export class HttpClient {
  requestUrl: string;
  responseData: any;
  handleError: any;

  constructor(private router: Router, 
  private http: Http, 
  private constants: Constants, 
  ) {
    this.http = http;
  }

  postWithFile (url: string, postData: any, files: File[]) {

    let headers = new Headers();
    let formData:FormData = new FormData();
    formData.append('files', files[0], files[0].name);
    // For multiple files
    // for (let i = 0; i < files.length; i++) {
    //     formData.append(`files[]`, files[i], files[i].name);
    // }

    if(postData !=="" && postData !== undefined && postData !==null){
      for (var property in postData) {
          if (postData.hasOwnProperty(property)) {
              formData.append(property, postData[property]);
          }
      }
    }
    var returnReponse = new Promise((resolve, reject) => {
      this.http.post(this.constants.root_dir + url, formData, {
        headers: headers
      }).subscribe(
          res => {
            this.responseData = res.json();
            resolve(this.responseData);
          },
          error => {
            this.router.navigate(['/login']);
            reject(error);
          }
      );
    });
    return returnReponse;
  }
}

调用你的函数（组件文件）：

onChange(event) {
    let file = event.srcElement.files;
    let postData = {field1:"field1", field2:"field2"}; // Put your form data variable. This is only example.
    this._service.postWithFile(this.baseUrl + "add-update",postData,file).then(result => {
        console.log(result);
    });
}

您的 html 代码：

<input type="file" class="form-control" name="documents" (change)="onChange($event)" [(ngModel)]="stock.documents" #documents="ngModel">

Answer 2

查看我的代码，但请注意。我使用 async/await，因为最新的 Chrome beta 可以读取任何 es6 代码，这些代码是通过 TypeScript 编译获得的。因此，您必须将 asyncs/await 替换为 .then()。

输入更改处理程序：

/**
 * @param fileInput
 */
public psdTemplateSelectionHandler (fileInput: any){
    let FileList: FileList = fileInput.target.files;

    for (let i = 0, length = FileList.length; i < length; i++) {
        this.psdTemplates.push(FileList.item(i));
    }

    this.progressBarVisibility = true;
}

提交处理程序：

public async psdTemplateUploadHandler (): Promise<any> {
    let result: any;

    if (!this.psdTemplates.length) {
        return;
    }

    this.isSubmitted = true;

    this.fileUploadService.getObserver()
        .subscribe(progress => {
            this.uploadProgress = progress;
        });

    try {
        result = await this.fileUploadService.upload(this.uploadRoute, this.psdTemplates);
    } catch (error) {
        document.write(error)
    }

    if (!result['images']) {
        return;
    }

    this.saveUploadedTemplatesData(result['images']);
    this.redirectService.redirect(this.redirectRoute);
}

文件上传服务。该服务还存储了上传进度 in progress$ 属性，在其他地方，您可以订阅它并每 500 毫秒获取一次新值。

import { Component } from 'angular2/core';
import { Injectable } from 'angular2/core';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/share';

@Injectable()
export class FileUploadService {
/**
 * @param Observable<number>
 */
private progress$: Observable<number>;

/**
 * @type {number}
 */
private progress: number = 0;

private progressObserver: any;

constructor () {
    this.progress$ = new Observable(observer => {
        this.progressObserver = observer
    });
}

/**
 * @returns {Observable<number>}
 */
public getObserver (): Observable<number> {
    return this.progress$;
}

/**
 * Upload files through XMLHttpRequest
 *
 * @param url
 * @param files
 * @returns {Promise<T>}
 */
public upload (url: string, files: File[]): Promise<any> {
    return new Promise((resolve, reject) => {
        let formData: FormData = new FormData(),
            xhr: XMLHttpRequest = new XMLHttpRequest();

        for (let i = 0; i < files.length; i++) {
            formData.append("uploads[]", files[i], files[i].name);
        }

        xhr.onreadystatechange = () => {
            if (xhr.readyState === 4) {
                if (xhr.status === 200) {
                    resolve(JSON.parse(xhr.response));
                } else {
                    reject(xhr.response);
                }
            }
        };

        FileUploadService.setUploadUpdateInterval(500);

        xhr.upload.onprogress = (event) => {
            this.progress = Math.round(event.loaded / event.total * 100);

            this.progressObserver.next(this.progress);
        };

        xhr.open('POST', url, true);
        xhr.send(formData);
    });
}

/**
 * Set interval for frequency with which Observable inside Promise will share data with subscribers.
 *
 * @param interval
 */
private static setUploadUpdateInterval (interval: number): void {
    setInterval(() => {}, interval);
}
}

Answer 3

关注这个问题Github - Request/Upload progress handling via @angular/http，angular2 http 还不支持文件上传。

对于非常基本的文件上传，我创建了这样的服务功能作为解决方法（使用Тимофей's answer）：

  uploadFile(file:File):Promise<MyEntity> {
    return new Promise((resolve, reject) => {

        let xhr:XMLHttpRequest = new XMLHttpRequest();
        xhr.onreadystatechange = () => {
            if (xhr.readyState === 4) {
                if (xhr.status === 200) {
                    resolve(<MyEntity>JSON.parse(xhr.response));
                } else {
                    reject(xhr.response);
                }
            }
        };

        xhr.open('POST', this.getServiceUrl(), true);

        let formData = new FormData();
        formData.append("file", file, file.name);
        xhr.send(formData);
    });
}

Answer 4

首先，您必须创建自己的内联 TS-Class，因为目前尚不支持 FormData 类：

var data : {
  name: string;
  file: File;
} = {
  name: "Name",
  file: inputValue.files[0]
  };

然后你用 JSON.stringify(data) 把它发送到服务器

let opts: RequestOptions = new RequestOptions();
opts.method = RequestMethods.Post;
opts.headers = headers;
this.http.post(url,JSON.stringify(data),opts);

Answer 5

在我的项目中，我使用 XMLHttpRequest 发送 multipart/form-data。 我认为它适合你。

和uploader 代码

let xhr = new XMLHttpRequest();
xhr.open('POST', 'http://www.example.com/rest/api', true);
xhr.withCredentials = true;
xhr.send(formData);

这里是示例：https://github.com/wangzilong/angular2-multipartForm