下载PDF文件,Angular 6和Web API

Question

我想使用Angular 6和Web API下载PDF.这是代码实现,

mycomponent.ts

download(myObj: any) {
    this.testService.downloadDoc(myObj.id).subscribe(result => {

        var url = window.URL.createObjectURL(result);
        window.open(url);
        console.log("download result ", result);
    });
}

myService.ts

downloadDoc(Id: string): Observable<any> {
    let url = this.apiUrl + "api/myApi/download/" + Id;
    return this.http.get(url, { responseType: "blob" });
}

Web API服务

[HttpGet("download/{DocId}")]
    public async Task<HttpResponseMessage> GetDocument(string docId)
    {
        var docDetails = await _hoaDocs.GetDocumentDetails(docId).ConfigureAwait(false);
        var dataBytes = docDetails.Stream;
        var dataStream = new MemoryStream(dataBytes);

        var response = new HttpResponseMessage
        {
            StatusCode = HttpStatusCode.OK,
            Content = new StreamContent(dataStream)
        };

        response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
        {
            FileName = docDetails.File_Name
        };
        response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");

        return response;
    }

当我执行上面的代码时,它没有下载PDF,这是在控制台中记录的结果对象

download result  
Blob(379) {size: 379, type: "application/json"}
size:379
type:"application/json"
__proto__:Blob

Answer 1

import { Injectable } from "@angular/core";
declare var $;

@Injectable()
export class DownloadFileService {

   save(file, fileName) {
       if (window.navigator.msSaveOrOpenBlob) {
        // IE specific download.
        navigator.msSaveBlob(file, fileName);
    } else {
        const downloadLink = document.createElement("a");
        downloadLink.style.display = "none";
        document.body.appendChild(downloadLink);
        downloadLink.setAttribute("href", window.URL.createObjectURL(file));
        downloadLink.setAttribute("download", fileName);
        downloadLink.click();
        document.body.removeChild(downloadLink);
     }
   }
}

Answer 2

我假设您正在使用.Net Core。

您返回的类型是HttpResponseMessage。对于.Net Core及更高版本，应为IActionResult。

因此，就您而言，您将返回

return File(<filepath-or-stream>, <content-type>)

要么

您必须在Startup.cs文件中做一个小的更改：

services.AddMvc().AddWebApiConventions();

然后，我不确定这里是否100％，但是您也必须更改路由：

routes.MapWebApiRoute("DefaultApi", "api/{controller}/{id?}");