Corrupt file or an invalid file : when trying to open downloaded pbix file using Power BI Rest API.

[Anonymous]

Hello,

I am unable to open .pbix file when downloaded using Power BI Rest API, I have use Export report from group endpoint to donload the file. 

I have NodeJS as backend handling the API request. 

daoObj.exportReport( groupId, reportId, token).then(function (status) {  

                      res.status(200).send(status);

}, function (error) {

             ocalogger.error(tenantId, '>>> Error exporting report: ' + reportId + ': ', error);

            deferred.reject(error);

});

 exportReport: function ( groupId, reportId, accessToken) {

        var deferred = QRef.defer();

        const url = config.apiRoot + 'groups/' + groupId + '/reports/' + reportId + '/Export';

        const headers = {

            'Authorization': 'Bearer ' + accessToken

        };

        request.get({ url: url,  headers: headers}, function (err, response, body) {

            if(response.statusCode === 200){

                deferred.resolve(response.body);

            }else{                

                if (err) {

                    deferred.reject(err);

                } else if (parsedBody.error) {

                    deferred.reject(parsedBody.error.message);

                } else {

                    // If successful, return the access token.

                    deferred.resolve(response.body);

                }

            }

        });

        return deferred.promise;

    }

The front end is ReactJS and I am using "file-saver" npm package to download the file.

handleExportReportEvent = (reportData) =>{
var self = this;
var reqBody = {};
reqBody.workspaceId = reportData.workspaceId;
reqBody.reportId = reportData.reportId;
this.props.exportReport(reqBody).then(() =>{
var blobObj = new Blob([self.props.exportReportObj.exportReportData] );
 FileSaver.saveAs(blobObj,  "report.pbix");
})
}

I am able to download the file, but when I try to open with the latest Power BI Desktop application, I am receving

"The report.pbix file is corrupt or an invalid file".

Please let me know where I am making a mistake