diff --git a/pkg/c8y/utils.go b/pkg/c8y/utils.go index e247f2c3..f3979344 100644 --- a/pkg/c8y/utils.go +++ b/pkg/c8y/utils.go @@ -12,10 +12,12 @@ import ( "strings" ) -func prepareMultipartRequest(method string, url string, values map[string]io.Reader) (req *http.Request, err error) { +// Prepare multipart form-data request which uses io.Pipe to buffer reading the message to ensure files won't be read entirely into memory +func prepareMultipartRequest(method string, url string, values map[string]io.Reader) (*http.Request, error) { + pr, pw := io.Pipe() + // Prepare a form that you will submit to that URL. - var b bytes.Buffer - w := multipart.NewWriter(&b) + w := multipart.NewWriter(pw) // Sort formdata keys keys := make([]string, 0, len(values)) @@ -24,51 +26,57 @@ func prepareMultipartRequest(method string, url string, values map[string]io.Rea } sort.Strings(keys) - for _, key := range keys { - r := values[key] - if key == "filename" { - // Ignore filename as it is used to name the uploaded file - continue - } + go func() { + var err error + for _, key := range keys { + r := values[key] + if key == "filename" { + // Ignore filename as it is used to name the uploaded file + continue + } - var fw io.Writer - if x, ok := r.(io.Closer); ok { - defer x.Close() - } - // Add an image file - if x, ok := r.(*os.File); ok { + var fw io.Writer + if x, ok := r.(io.Closer); ok { + defer x.Close() + } + // Add an image file + if x, ok := r.(*os.File); ok { - // Check if manual filename field was provided, otherwise use the basename - filename := filepath.Base(x.Name()) - if manual_filename, ok := values["filename"]; ok { - if b, rErr := io.ReadAll(manual_filename); rErr == nil { - filename = string(b) - } else { - err = rErr + // Check if manual filename field was provided, otherwise use the basename + filename := filepath.Base(x.Name()) + if manual_filename, ok := values["filename"]; ok { + if b, rErr := io.ReadAll(manual_filename); rErr == nil { + filename = string(b) + } else { + pw.CloseWithError(rErr) + return + } + } + if fw, err = w.CreateFormFile(key, filename); err != nil { + pw.CloseWithError(err) + return + } + } else { + // Add other fields + if fw, err = w.CreateFormField(key); err != nil { + pw.CloseWithError(err) + return } } - if fw, err = w.CreateFormFile(key, filename); err != nil { - return - } - } else { - // Add other fields - if fw, err = w.CreateFormField(key); err != nil { + if _, err = io.Copy(fw, r); err != nil { + pw.CloseWithError(err) return } } - if _, err = io.Copy(fw, r); err != nil { - return nil, err - } - - } - // Don't forget to close the multipart writer. - // If you don't close it, your request will be missing the terminating boundary. - w.Close() + // Don't forget to close the multipart writer. + // If you don't close it, your request will be missing the terminating boundary. + pw.CloseWithError(w.Close()) + }() // Now that you have a form, you can submit it to your handler. - req, err = http.NewRequest(method, url, &b) - if err != nil { - return + req, rErr := http.NewRequest(method, url, pr) + if rErr != nil { + return req, rErr } // Don't forget to set the content type, this will contain the boundary. req.Header.Set("Content-Type", w.FormDataContentType())