OnResponse().DoFunc panic

[xenogenesi]

I used the yui minify example as base, from the content type I catch any json, do some business with it and then go on.

I believe the panic is caused by the GET of a very large file (like 4GB large, not .json) or maybe even a chunked request, anybody had the same problem? suggestions?

2018/11/29 20:19:35 [090] INFO: Received response 304 Not Modified
2018/11/29 20:19:35 [090] INFO: Copying response to client 304 Not Modified [304]
2018/11/29 20:19:35 [090] INFO: Copied 0 bytes to client error=<nil>
2018/11/29 20:20:19 http: panic serving 192.168.2.40:57825: runtime error: invalid memory address or nil pointer dereference
goroutine 566 [running]:
net/http.(*conn).serve.func1(0xc420440960)
	/usr/lib/go-1.10/src/net/http/server.go:1726 +0xd0
panic(0x6a7880, 0x889010)
	/usr/lib/go-1.10/src/runtime/panic.go:502 +0x229
main.main.func1(0x0, 0xc4202a6b40, 0x0)
	/home/alex/tmp/golang/gops4proxy/main.go:64 +0x46
github.com/elazarl/goproxy.FuncRespHandler.Handle(0x714028, 0x0, 0xc4202a6b40, 0xc42038fe30)
	/home/alex/go/src/github.com/elazarl/goproxy/actions.go:35 +0x3a
github.com/elazarl/goproxy.(*ProxyConds).Do.func1(0x0, 0xc4202a6b40, 0xc42011f830)
	/home/alex/go/src/github.com/elazarl/goproxy/dispatcher.go:284 +0x163
github.com/elazarl/goproxy.FuncRespHandler.Handle(0xc4200f19e0, 0x0, 0xc4202a6b40, 0x0)
	/home/alex/go/src/github.com/elazarl/goproxy/actions.go:35 +0x3a
github.com/elazarl/goproxy.(*ProxyHttpServer).filterResponse(0xc42012c000, 0x0, 0xc4202a6b40, 0x7375a0)
	/home/alex/go/src/github.com/elazarl/goproxy/proxy.go:73 +0x50
github.com/elazarl/goproxy.(*ProxyHttpServer).ServeHTTP(0xc42012c000, 0x73a680, 0xc42012a540, 0xc420414700)
	/home/alex/go/src/github.com/elazarl/goproxy/proxy.go:119 +0x789
net/http.serverHandler.ServeHTTP(0xc420080f70, 0x73a680, 0xc42012a540, 0xc420414700)
	/usr/lib/go-1.10/src/net/http/server.go:2697 +0xbc
net/http.(*conn).serve(0xc420440960, 0x73a900, 0xc4200112c0)
	/usr/lib/go-1.10/src/net/http/server.go:1830 +0x651
created by net/http.(*Server).Serve
	/usr/lib/go-1.10/src/net/http/server.go:2798 +0x27b

main.go::

 62          proxy.Verbose = *verbose
 63          proxy.OnResponse().DoFunc(func(resp *http.Response, ctx *goproxy.ProxyCtx) *http.Response {
 64                  contentType := resp.Header.Get("Content-Type")
 65                  if strings.HasPrefix(contentType, "application/json") {
 66                          // 
 67                          ctx.Logf("** contentType: %s", string(contentType))
 68                          bodyContent, _ := ioutil.ReadAll(resp.Body)
	...
130                          }
131                          resp.Body = ioutil.NopCloser(bytes.NewReader(bodyContent))
132                  }
133                  return resp
134          })
135          log.Fatal(http.ListenAndServe(*addr, proxy))