ISSUE-9507: ADD `application/gzip,application/octet-stream` accept header when downloading chart

Signed-off-by: Matt Clegg <m@cle.gg>

pkg/downloader/chart_downloader.go

@@ -97,6 +97,8 @@ func (c *ChartDownloader) DownloadTo(ref, version, dest string) (string, *proven
 		return "", nil, err
 	}
 
+	c.Options = append(c.Options, getter.WithAcceptHeader("application/gzip,application/octet-stream"))
+
 	data, err := g.Get(u.String(), c.Options...)
 	if err != nil {
 		return "", nil, err

pkg/getter/getter.go

@@ -38,6 +38,7 @@ type options struct {
 	unTar                 bool
 	insecureSkipVerifyTLS bool
 	plainHTTP             bool
+	acceptHeader          string
 	username              string
 	password              string
 	passCredentialsAll    bool
@@ -60,6 +61,13 @@ func WithURL(url string) Option {
 	}
 }
 
+// WithAcceptHeader sets the request's Accept header as some REST APIs serve multiple content types
+func WithAcceptHeader(header string) Option {
+	return func(opts *options) {
+		opts.acceptHeader = header
+	}
+}
+
 // WithBasicAuth sets the request's Authorization header to use the provided credentials
 func WithBasicAuth(username, password string) Option {
 	return func(opts *options) {

pkg/getter/httpgetter.go

@@ -53,6 +53,10 @@ func (g *HTTPGetter) get(href string) (*bytes.Buffer, error) {
 		return nil, err
 	}
 
+	if g.opts.acceptHeader != "" {
+		req.Header.Set("Accept", g.opts.acceptHeader)
+	}
+
 	req.Header.Set("User-Agent", version.GetUserAgent())
 	if g.opts.userAgent != "" {
 		req.Header.Set("User-Agent", g.opts.userAgent)