我有一个WebApi / MVC应用程序,我正在为它开发一个angular2客户端(以取代MVC)。我在理解Angular如何保存文件时遇到了一些麻烦。

请求是可以的(与MVC一起工作很好,我们可以记录接收到的数据),但我不知道如何保存下载的数据(我主要遵循与本文相同的逻辑)。我确信这是愚蠢的简单,但到目前为止,我根本没有领会它。

组件函数的代码如下。我尝试了不同的替代方案,blob方式应该是我所理解的方式,但URL中没有createObjectURL函数。我甚至不能在窗口中找到URL的定义,但显然它存在。如果我使用FileSaver.js模块,我得到同样的错误。所以我猜这是最近改变的或者还没有实现的东西。我如何触发文件保存在A2?

downloadfile(type: string){

    let thefile = {};
    this.pservice.downloadfile(this.rundata.name, type)
        .subscribe(data => thefile = new Blob([data], { type: "application/octet-stream" }), //console.log(data),
                    error => console.log("Error downloading the file."),
                    () => console.log('Completed file download.'));

    let url = window.URL.createObjectURL(thefile);
    window.open(url);
}

为了完整起见,获取数据的服务如下所示,但它所做的唯一一件事是发出请求并在没有映射的情况下传递数据:

downloadfile(runname: string, type: string){
   return this.authHttp.get( this.files_api + this.title +"/"+ runname + "/?file="+ type)
            .catch(this.logAndPassOn);
}

当前回答

对于那些使用Redux模式

我在文件保存器中添加了@Hector Cuevas的名字,在他的回答中。使用Angular2 v. 2.3.1,我不需要添加@types/file-saver。

以PDF格式下载日志为例。

日记账操作

public static DOWNLOAD_JOURNALS = '[Journals] Download as PDF';
public downloadJournals(referenceId: string): Action {
 return {
   type: JournalActions.DOWNLOAD_JOURNALS,
   payload: { referenceId: referenceId }
 };
}

public static DOWNLOAD_JOURNALS_SUCCESS = '[Journals] Download as PDF Success';
public downloadJournalsSuccess(blob: Blob): Action {
 return {
   type: JournalActions.DOWNLOAD_JOURNALS_SUCCESS,
   payload: { blob: blob }
 };
}

期刊效应

@Effect() download$ = this.actions$
    .ofType(JournalActions.DOWNLOAD_JOURNALS)
    .switchMap(({payload}) =>
        this._journalApiService.downloadJournal(payload.referenceId)
        .map((blob) => this._actions.downloadJournalsSuccess(blob))
        .catch((err) => handleError(err, this._actions.downloadJournalsFail(err)))
    );

@Effect() downloadJournalSuccess$ = this.actions$
    .ofType(JournalActions.DOWNLOAD_JOURNALS_SUCCESS)
    .map(({payload}) => saveBlobAs(payload.blob, 'journal.pdf'))

期刊服务

public downloadJournal(referenceId: string): Observable<any> {
    const url = `${this._config.momentumApi}/api/journals/${referenceId}/download`;
    return this._http.getBlob(url);
}

HTTP服务

public getBlob = (url: string): Observable<any> => {
    return this.request({
        method: RequestMethod.Get,
        url: url,
        responseType: ResponseContentType.Blob
    });
};

轴颈减速器 虽然这只设置了我们应用程序中使用的正确状态,但我仍然想添加它来显示完整的模式。

case JournalActions.DOWNLOAD_JOURNALS: {
  return Object.assign({}, state, <IJournalState>{ downloading: true, hasValidationErrors: false, errors: [] });
}

case JournalActions.DOWNLOAD_JOURNALS_SUCCESS: {
  return Object.assign({}, state, <IJournalState>{ downloading: false, hasValidationErrors: false, errors: [] });
}

我希望这对你有帮助。

其他回答

下载和显示PDF文件,一个非常相似的代码剪辑如下:

  private downloadFile(data: Response): void {
    let blob = new Blob([data.blob()], { type: "application/pdf" });
    let url = window.URL.createObjectURL(blob);
    window.open(url);
  }

  public showFile(fileEndpointPath: string): void {
    let reqOpt: RequestOptions = this.getAcmOptions();  //  getAcmOptions is our helper method. Change this line according to request headers you need.
    reqOpt.responseType = ResponseContentType.Blob;
    this.http
      .get(fileEndpointPath, reqOpt)
      .subscribe(
        data => this.downloadFile(data),
        error => alert("Error downloading file!"),
        () => console.log("OK!")
      );
  }

对于那些使用Redux模式

我在文件保存器中添加了@Hector Cuevas的名字,在他的回答中。使用Angular2 v. 2.3.1,我不需要添加@types/file-saver。

以PDF格式下载日志为例。

日记账操作

public static DOWNLOAD_JOURNALS = '[Journals] Download as PDF';
public downloadJournals(referenceId: string): Action {
 return {
   type: JournalActions.DOWNLOAD_JOURNALS,
   payload: { referenceId: referenceId }
 };
}

public static DOWNLOAD_JOURNALS_SUCCESS = '[Journals] Download as PDF Success';
public downloadJournalsSuccess(blob: Blob): Action {
 return {
   type: JournalActions.DOWNLOAD_JOURNALS_SUCCESS,
   payload: { blob: blob }
 };
}

期刊效应

@Effect() download$ = this.actions$
    .ofType(JournalActions.DOWNLOAD_JOURNALS)
    .switchMap(({payload}) =>
        this._journalApiService.downloadJournal(payload.referenceId)
        .map((blob) => this._actions.downloadJournalsSuccess(blob))
        .catch((err) => handleError(err, this._actions.downloadJournalsFail(err)))
    );

@Effect() downloadJournalSuccess$ = this.actions$
    .ofType(JournalActions.DOWNLOAD_JOURNALS_SUCCESS)
    .map(({payload}) => saveBlobAs(payload.blob, 'journal.pdf'))

期刊服务

public downloadJournal(referenceId: string): Observable<any> {
    const url = `${this._config.momentumApi}/api/journals/${referenceId}/download`;
    return this._http.getBlob(url);
}

HTTP服务

public getBlob = (url: string): Observable<any> => {
    return this.request({
        method: RequestMethod.Get,
        url: url,
        responseType: ResponseContentType.Blob
    });
};

轴颈减速器 虽然这只设置了我们应用程序中使用的正确状态,但我仍然想添加它来显示完整的模式。

case JournalActions.DOWNLOAD_JOURNALS: {
  return Object.assign({}, state, <IJournalState>{ downloading: true, hasValidationErrors: false, errors: [] });
}

case JournalActions.DOWNLOAD_JOURNALS_SUCCESS: {
  return Object.assign({}, state, <IJournalState>{ downloading: false, hasValidationErrors: false, errors: [] });
}

我希望这对你有帮助。

下面的代码适用于我

让HTML像这样:

<button type="button" onclick="startDownload(someData)">Click to download!</button>

JS如下:

let someData = {};
someData.name = 'someName';
someData.fileurl= 'someUrl';

function startDownload(someData){
    let link = document.createElement('a');
    link.href = someData.fileurl; //data is object received as response
    link.download = someData.fileurl.substr(someData.fileurl.lastIndexOf('/') + 1);
    link.click();
}

我使用的是Angular 4的4.3 httpClient对象。我修改了我在Js的技术博客中找到的答案,它创建了一个链接对象,用它来下载,然后销毁它。

客户:

doDownload(id: number, contentType: string) {
    return this.http
        .get(this.downloadUrl + id.toString(), { headers: new HttpHeaders().append('Content-Type', contentType), responseType: 'blob', observe: 'body' })
}

downloadFile(id: number, contentType: string, filename:string)  {

    return this.doDownload(id, contentType).subscribe(  
        res => { 
            var url = window.URL.createObjectURL(res);
            var a = document.createElement('a');
            document.body.appendChild(a);
            a.setAttribute('style', 'display: none');
            a.href = url;
            a.download = filename;
            a.click();
            window.URL.revokeObjectURL(url);
            a.remove(); // remove the element
        }, error => {
            console.log('download error:', JSON.stringify(error));
        }, () => {
            console.log('Completed file download.')
        }); 

} 

这个的值。downloadUrl之前已经设置为指向api。我用这个来下载附件,所以我知道id,内容类型和文件名: 我使用MVC api返回文件:

 [ResponseCache(Location = ResponseCacheLocation.None, NoStore = true)]
    public FileContentResult GetAttachment(Int32 attachmentID)
    { 
        Attachment AT = filerep.GetAttachment(attachmentID);            
        if (AT != null)
        {
            return new FileContentResult(AT.FileBytes, AT.ContentType);  
        }
        else
        { 
            return null;
        } 
    } 

附件类看起来像这样:

 public class Attachment
{  
    public Int32 AttachmentID { get; set; }
    public string FileName { get; set; }
    public byte[] FileBytes { get; set; }
    public string ContentType { get; set; } 
}

filerep存储库从数据库返回文件。

希望这能帮助到一些人:)

问题是可观察对象运行在另一个上下文中,所以当你尝试创建URL var时,你有一个空对象,而不是你想要的blob。

解决这个问题的众多方法之一如下:

this._reportService.getReport().subscribe(data => this.downloadFile(data)),//console.log(data),
                 error => console.log('Error downloading the file.'),
                 () => console.info('OK');

当请求准备好时,它将调用函数"downloadFile",定义如下:

downloadFile(data: Response) {
  const blob = new Blob([data], { type: 'text/csv' });
  const url= window.URL.createObjectURL(blob);
  window.open(url);
}

这个blob已经被完美地创建了,所以URL变量,如果没有打开新的窗口,请检查你已经导入'rxjs/Rx';

import 'rxjs/Rx' ;

我希望这能帮助到你。