refactor(httpx): improve and modernize (1/n) (#647)

This PR starts to implement the refactoring described at https://github.com/ooni/probe/issues/1951. I originally wrote more patches than the ones in this PR, but overall they were not readable. Since I want to squash and merge, here's a reasonable subset of the original patches that will still be readable and understandable in the future.

internal/engine/probeservices/bouncer.go

@@ -9,6 +9,6 @@ import (
 // GetTestHelpers is like GetCollectors but for test helpers.
 func (c Client) GetTestHelpers(
 	ctx context.Context) (output map[string][]model.OOAPIService, err error) {
-	err = c.Client.GetJSON(ctx, "/api/v1/test-helpers", &output)
+	err = c.APIClient.GetJSON(ctx, "/api/v1/test-helpers", &output)
 	return
 }

internal/engine/probeservices/checkin.go

@@ -16,7 +16,7 @@ type checkInResult struct {
 // Returns the list of tests to run and the URLs, on success, or an explanatory error, in case of failure.
 func (c Client) CheckIn(ctx context.Context, config model.OOAPICheckInConfig) (*model.OOAPICheckInInfo, error) {
 	var response checkInResult
-	if err := c.Client.PostJSON(ctx, "/api/v1/check-in", config, &response); err != nil {
+	if err := c.APIClient.PostJSON(ctx, "/api/v1/check-in", config, &response); err != nil {
 		return nil, err
 	}
 	return &response.Tests, nil

internal/engine/probeservices/checkreportid.go

@@ -16,7 +16,7 @@ func (c Client) CheckReportID(ctx context.Context, reportID string) (bool, error
 	query := url.Values{}
 	query.Add("report_id", reportID)
 	var response checkReportIDResponse
-	err := (httpx.Client{
+	err := (&httpx.APIClient{
 		BaseURL:    c.BaseURL,
 		HTTPClient: c.HTTPClient,
 		Logger:     c.Logger,

internal/engine/probeservices/checkreportid_test.go

@@ -15,7 +15,7 @@ import (
 
 func TestCheckReportIDWorkingAsIntended(t *testing.T) {
 	client := probeservices.Client{
-		Client: httpx.Client{
+		APIClient: httpx.APIClient{
 			BaseURL:    "https://ams-pg.ooni.org/",
 			HTTPClient: http.DefaultClient,
 			Logger:     log.Log,
@@ -38,7 +38,7 @@ func TestCheckReportIDWorkingAsIntended(t *testing.T) {
 
 func TestCheckReportIDWorkingWithCancelledContext(t *testing.T) {
 	client := probeservices.Client{
-		Client: httpx.Client{
+		APIClient: httpx.APIClient{
 			BaseURL:    "https://ams-pg.ooni.org/",
 			HTTPClient: http.DefaultClient,
 			Logger:     log.Log,

internal/engine/probeservices/collector.go

@@ -105,7 +105,7 @@ func (c Client) OpenReport(ctx context.Context, rt ReportTemplate) (ReportChanne
 		return nil, ErrUnsupportedFormat
 	}
 	var cor collectorOpenResponse
-	if err := c.Client.PostJSON(ctx, "/report", rt, &cor); err != nil {
+	if err := c.APIClient.PostJSON(ctx, "/report", rt, &cor); err != nil {
 		return nil, err
 	}
 	for _, format := range cor.SupportedFormats {
@@ -144,7 +144,7 @@ func (r reportChan) CanSubmit(m *model.Measurement) bool {
 func (r reportChan) SubmitMeasurement(ctx context.Context, m *model.Measurement) error {
 	var updateResponse collectorUpdateResponse
 	m.ReportID = r.ID
-	err := r.client.Client.PostJSON(
+	err := r.client.APIClient.PostJSON(
 		ctx, fmt.Sprintf("/report/%s", r.ID), collectorUpdateRequest{
 			Format:  "json",
 			Content: m,

internal/engine/probeservices/login.go

@@ -29,7 +29,7 @@ func (c Client) MaybeLogin(ctx context.Context) error {
 	}
 	c.LoginCalls.Add(1)
 	var auth LoginAuth
-	if err := c.Client.PostJSON(ctx, "/api/v1/login", *creds, &auth); err != nil {
+	if err := c.APIClient.PostJSON(ctx, "/api/v1/login", *creds, &auth); err != nil {
 		return err
 	}
 	state.Expire = auth.Expire

internal/engine/probeservices/measurementmeta.go

@@ -54,7 +54,7 @@ func (c Client) GetMeasurementMeta(
 		query.Add("full", "true")
 	}
 	var response MeasurementMeta
-	err := (httpx.Client{
+	err := (&httpx.APIClient{
 		BaseURL:    c.BaseURL,
 		HTTPClient: c.HTTPClient,
 		Logger:     c.Logger,

internal/engine/probeservices/measurementmeta_test.go

@@ -16,7 +16,7 @@ import (
 
 func TestGetMeasurementMetaWorkingAsIntended(t *testing.T) {
 	client := probeservices.Client{
-		Client: httpx.Client{
+		APIClient: httpx.APIClient{
 			BaseURL:    "https://ams-pg.ooni.org/",
 			HTTPClient: http.DefaultClient,
 			Logger:     log.Log,
@@ -84,7 +84,7 @@ func TestGetMeasurementMetaWorkingAsIntended(t *testing.T) {
 
 func TestGetMeasurementMetaWorkingWithCancelledContext(t *testing.T) {
 	client := probeservices.Client{
-		Client: httpx.Client{
+		APIClient: httpx.APIClient{
 			BaseURL:    "https://ams-pg.ooni.org/",
 			HTTPClient: http.DefaultClient,
 			Logger:     log.Log,

internal/engine/probeservices/probeservices.go

@@ -65,7 +65,7 @@ type Session interface {
 
 // Client is a client for the OONI probe services API.
 type Client struct {
-	httpx.Client
+	httpx.APIClient
 	LoginCalls    *atomicx.Int64
 	RegisterCalls *atomicx.Int64
 	StateFile     StateFile
@@ -91,7 +91,7 @@ func (c Client) GetCredsAndAuth() (*LoginCredentials, *LoginAuth, error) {
 // function fails, e.g., we don't support the specified endpoint.
 func NewClient(sess Session, endpoint model.OOAPIService) (*Client, error) {
 	client := &Client{
-		Client: httpx.Client{
+		APIClient: httpx.APIClient{
 			BaseURL:    endpoint.Address,
 			HTTPClient: sess.DefaultHTTPClient(),
 			Logger:     sess.Logger(),
@@ -115,7 +115,7 @@ func NewClient(sess Session, endpoint model.OOAPIService) (*Client, error) {
 		if URL.Scheme != "https" || URL.Host != URL.Hostname() {
 			return nil, ErrUnsupportedCloudFrontAddress
 		}
-		client.Client.Host = URL.Hostname()
+		client.APIClient.Host = URL.Hostname()
 		URL.Host = endpoint.Front
 		client.BaseURL = URL.String()
 		if _, err := url.Parse(client.BaseURL); err != nil {

internal/engine/probeservices/psiphon.go

@@ -11,7 +11,9 @@ func (c Client) FetchPsiphonConfig(ctx context.Context) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	client := c.Client
+	// Note: the following code is very bad: it copies the original
+	// API client and then overrides one of its fields. Bleah...
+	client := c.APIClient
 	client.Authorization = fmt.Sprintf("Bearer %s", auth.Token)
 	return client.FetchResource(ctx, "/api/v1/test-list/psiphon-config")
 }

internal/engine/probeservices/register.go

@@ -33,7 +33,7 @@ func (c Client) MaybeRegister(ctx context.Context, metadata Metadata) error {
 		Password: pwd,
 	}
 	var resp registerResult
-	if err := c.Client.PostJSON(ctx, "/api/v1/register", req, &resp); err != nil {
+	if err := c.APIClient.PostJSON(ctx, "/api/v1/register", req, &resp); err != nil {
 		return err
 	}
 	state.ClientID = resp.ClientID

internal/engine/probeservices/tor.go

@@ -14,7 +14,9 @@ func (c Client) FetchTorTargets(ctx context.Context, cc string) (result map[stri
 	if err != nil {
 		return nil, err
 	}
-	client := c.Client
+	// Note: the following code is very bad: it copies the original
+	// API client and then overrides one of its fields. Bleah...
+	client := c.APIClient
 	client.Authorization = fmt.Sprintf("Bearer %s", auth.Token)
 	query := url.Values{}
 	query.Add("country_code", cc)

internal/engine/probeservices/tor_test.go

@@ -61,7 +61,7 @@ func (clnt *FetchTorTargetsHTTPTransport) RoundTrip(req *http.Request) (*http.Re
 func TestFetchTorTargetsSetsQueryString(t *testing.T) {
 	clnt := newclient()
 	txp := new(FetchTorTargetsHTTPTransport)
-	clnt.HTTPClient.Transport = txp
+	clnt.HTTPClient = &http.Client{Transport: txp}
 	if err := clnt.MaybeRegister(context.Background(), testorchestra.MetadataFixture()); err != nil {
 		t.Fatal(err)
 	}

internal/engine/probeservices/urls.go

@@ -28,7 +28,7 @@ func (c Client) FetchURLList(ctx context.Context, config model.OOAPIURLListConfi
 		query.Set("category_codes", strings.Join(config.Categories, ","))
 	}
 	var response urlListResult
-	err := c.Client.GetJSONWithQuery(ctx, "/api/v1/test-list/urls", query, &response)
+	err := c.APIClient.GetJSONWithQuery(ctx, "/api/v1/test-list/urls", query, &response)
 	if err != nil {
 		return nil, err
 	}