Add new WithDisableCompression configuration

This translates down into the (*http.Transport).DisableCompression
setting.

client.go

@@ -343,6 +343,14 @@ func WithRedirects(redirectFunc RedirectFunc) ClientOption {
 	})
 }
 
+// WithDisableCompression configures the HTTP client to not automatically
+// request compressed responses, and disables automatic response decompression.
+func WithDisableCompression(ok bool) ClientOption {
+	return clientOptionFunc(func(opts *clientOptions) {
+		opts.disableCompression = ok
+	})
+}
+
 // RedirectFunc is a function that advises an HTTP client on whether to
 // follow a redirect. The given req is the redirected request, based on
 // the server's previous status code and "Location" header, and the given
@@ -390,6 +398,7 @@ type clientOptions struct {
 	tlsHandshakeTimeout     time.Duration
 	defaultTimeout          time.Duration
 	requestTimeout          time.Duration
+	disableCompression      bool
 }
 
 func (opts *clientOptions) applyDefaults() {

client_test.go

@@ -207,6 +207,7 @@ func TestNewClient_TransportConfig(t *testing.T) {
 			dialCount.Add(1)
 			return defaultDialer.DialContext(ctx, network, addr)
 		}),
+		WithDisableCompression(true),
 	)
 	client3 := makeClient(t, ctx, transportOption) // all defaults, no explicitly configured backend
 
@@ -225,6 +226,7 @@ func TestNewClient_TransportConfig(t *testing.T) {
 	require.Equal(t, int64(1<<20), rtOpts.MaxResponseHeaderBytes)
 	require.Zero(t, rtOpts.IdleConnTimeout)
 	require.True(t, rtOpts.KeepWarm)
+	require.False(t, rtOpts.DisableCompression)
 	// and check that settings were conveyed to round tripper as expected
 	val, ok = latestResults.Load(addr1)
 	require.True(t, ok)
@@ -234,6 +236,7 @@ func TestNewClient_TransportConfig(t *testing.T) {
 	require.Equal(t, 10*time.Second, transport.TLSHandshakeTimeout)
 	require.Equal(t, int64(1<<20), transport.MaxResponseHeaderBytes)
 	require.Zero(t, transport.IdleConnTimeout)
+	require.False(t, transport.DisableCompression)
 
 	// no redirects
 	sendGetRequest(t, ctx, client1, fmt.Sprintf("http://%s/redirect", addr1), expectRedirect("/foo"))
@@ -254,6 +257,7 @@ func TestNewClient_TransportConfig(t *testing.T) {
 	require.Equal(t, int64(1<<20), rtOpts.MaxResponseHeaderBytes)
 	require.Zero(t, rtOpts.IdleConnTimeout)
 	require.False(t, rtOpts.KeepWarm)
+	require.False(t, rtOpts.DisableCompression)
 
 	// now try backend with the options
 	sendGetRequest(t, ctx, client2, fmt.Sprintf("http://%s/foo", addr2), expectSuccess("got it"))
@@ -271,6 +275,7 @@ func TestNewClient_TransportConfig(t *testing.T) {
 	require.Equal(t, int64(10101), rtOpts.MaxResponseHeaderBytes)
 	require.Equal(t, time.Second, rtOpts.IdleConnTimeout)
 	require.True(t, rtOpts.KeepWarm)
+	require.True(t, rtOpts.DisableCompression)
 	// and check that settings were conveyed to round tripper as expected
 	val, ok = latestResults.Load(addr2)
 	require.True(t, ok)
@@ -282,6 +287,7 @@ func TestNewClient_TransportConfig(t *testing.T) {
 	require.Equal(t, 5*time.Second, transport.TLSHandshakeTimeout)
 	require.Equal(t, int64(10101), transport.MaxResponseHeaderBytes)
 	require.Equal(t, time.Second, transport.IdleConnTimeout)
+	require.True(t, transport.DisableCompression)
 
 	// This one allows redirects
 	sendGetRequest(t, ctx, client2, fmt.Sprintf("http://%s/redirect3", addr2), expectSuccess("got it"))

transport.go

@@ -105,6 +105,9 @@ type TransportConfig struct {
 	// KeepWarm indicates that the round-tripper should try to keep a ready
 	// network connection open to reduce any delays in processing a request.
 	KeepWarm bool
+	// DisableCompression is used by the round-tripper to disable automatically
+	// requesting compressed content and decompressing transparently.
+	DisableCompression bool
 }
 
 func transportConfigFromOptions(opts *clientOptions) TransportConfig {
@@ -116,6 +119,7 @@ func transportConfigFromOptions(opts *clientOptions) TransportConfig {
 		IdleConnTimeout:         opts.idleConnTimeout,
 		TLSClientConfig:         opts.tlsClientConfig,
 		TLSHandshakeTimeout:     opts.tlsHandshakeTimeout,
+		DisableCompression:      opts.disableCompression,
 	}
 }
 
@@ -134,6 +138,7 @@ func (s simpleTransport) NewRoundTripper(_, _ string, opts TransportConfig) Roun
 		TLSClientConfig:        opts.TLSClientConfig,
 		MaxResponseHeaderBytes: opts.MaxResponseHeaderBytes,
 		ExpectContinueTimeout:  1 * time.Second,
+		DisableCompression:     opts.DisableCompression,
 	}
 	// no way to populate pre-warm function since http.Transport doesn't provide
 	// any way to do that :(
@@ -151,7 +156,8 @@ func (s h2cTransport) NewRoundTripper(_, _ string, opts TransportConfig) RoundTr
 		},
 		// We don't bother setting the TLS config, because h2c is plain-text only
 		//TLSClientConfig:   opts.TLSClientConfig,
-		MaxHeaderListSize: uint32(opts.MaxResponseHeaderBytes),
+		MaxHeaderListSize:  uint32(opts.MaxResponseHeaderBytes),
+		DisableCompression: opts.DisableCompression,
 	}
 	return RoundTripperResult{RoundTripper: transport, Scheme: "http", Close: transport.CloseIdleConnections}
 }