angularjs – transformResponse headers参数($resource)中缺少

我该如何解决？

API的响应标头

HTTP/1.1 201 Created
Server: Apache-Coyote/1.1
x-content-type-options: nosniff
x-xss-protection: 1; mode=block
Cache-Control: no-cache,no-store,max-age=0,must-revalidate
Pragma: no-cache
Expires: 0
x-frame-options: DENY
Access-Control-Allow-Origin: http://localhost:9000
access-control-allow-methods: POST,PUT,GET,DELETE,OPTIONS
access-control-allow-headers: Content-Type
Access-Control-Allow-Credentials: true
Content-Disposition: attachment; filename="testCall.pcap"
FileName: testCall.pcap
Content-Type: application/pcap

transformResponse的标题

Pragma: no-cache
Content-Type: application/pcap
Cache-Control: no-cache,must-revalidate
Expires: 0

app.factory("MyService",function ($resource,ENV,_) {
    return {
        testCall: $resource(ENV.apiEndpoint + "/test-call",{},{
            launch: {
                method: 'POST',isArray: false,headers:{'Accept':'application/octet-stream'},responseType: 'blob',cache: false,transformResponse: function(data,headers){
                    var filename = headers('Content-Disposition'); //headers('FileName')
                    var contentType = headers('Content-Type');

                    var file = new Blob([data],{
                        type: contentType
                    });

                    var fileURL = URL.createObjectURL(file);
                    var a         = document.createElement('a');
                    a.href        = fileURL;
                    a.target      = '_blank';
                    a.download    = filename;
                    document.body.appendChild(a);
                    a.click();
                }
            }
        }),searchOptions: $resource(ENV.apiEndpoint + "//search-options")
    };
});