I have some changes related to other thing but suddenly when i am downloading file from api

i am getting below error

@Injectable()
export class FileDownloadService {
    
 constructor(private httpClient: HttpClient) { }


  public downloadFile(data: HttpResponse<Blob>) {
    const contentDisposition = data.headers.get('content-disposition');
    const filename = this.getFilenameFromContentDisposition(contentDisposition);
    const blob = data.body;
    const url = window.URL.createObjectURL(blob);
    const anchor = document.createElement("a");
    anchor.download = filename;
    anchor.href = url;
    anchor.click();
  }

  private getFilenameFromContentDisposition(contentDisposition: string): string {
    const regex = /filename=(?<filename>[^,;] );/g;
    const match = regex.exec(contentDisposition);
    const filename = match.groups['filename'];
    return filename;
  }

}

controller:

 download() {
   
    this.dataService.download(this.fileName)
        .pipe(takeUntil(this.unsubscribe$))
        .subscribe({
          next: (blobresponse: any) => {  
              this.downloadService.downloadFile(blobresponse);      
            }, error: (error:any) => { }
        });   
 }

Error:

1. ERROR TypeError: Cannot read properties of null (reading 'groups') at FileDownloadService.getFilenameFromContentDisposition (:4200/main.js:1323:32) at FileDownloadService.downloadFile (:4200/main.js:1312:31) at Object.next (:4200/src_app_views_account_account_module_ts.js:1367:38) at ConsumerObserver.next (:4200/vendor.js:90420:33) at SafeSubscriber._next (:4200/vendor.js:90389:26) at SafeSubscriber.next (:4200/vendor.js:90360:18) at :4200/vendor.js:91984:181 at OperatorSubscriber._next (:4200/vendor.js:91542:21) at OperatorSubscriber.next (:4200/vendor.js:90360:18) at subscribe.innerComplete (:4200/vendor.js:92213:28) defaultErrorLogger @ vendor.js:sourcemap:130591

Not donwloading file entire application..I have chehcked api but response (file) is coming from api.. Please let me know what i did wrong..it is perfectly fine last week..pls suggest me i am checking from last 24 hrs. but no where find solution..

EDIT: API response Added

EDIT: May be issue with contentdecoposition

CodePudding user response：

You have to do the null check:

private getFilenameFromContentDisposition(contentDisposition: string): string {
    const regex = /filename=(?<filename>[^,;] );/g;
    const match = regex.exec(contentDisposition);
    let filename = null; // or any other value you consider default
    if (typeof match !== 'undefined' && match !== null) {
        filename = match.groups['filename'];
    } 
    return filename; 
}

CodePudding user response：

In .net 6 some i have inlcuded corepolicy. now code working..it may help some other net 6..Thank you @dmitryro

 services.AddCors(options =>
            {

                options.AddDefaultPolicy(builder => builder
                 .AllowAnyMethod()
                 .AllowAnyHeader()
                  .WithExposedHeaders("Content-Disposition")    ----This line i have added
                 .SetIsOriginAllowed(origin => true) // allow any origin
                 .AllowCredentials());
            });