Add hooks support for WebSub (formerly PubSubHubbub) protocol (#2397)

Fixes: #1265.

github/github.go

@@ -426,6 +426,33 @@ func (c *Client) NewRequest(method, urlStr string, body interface{}) (*http.Requ
 	return req, nil
 }
 
+// NewFormRequest creates an API request. A relative URL can be provided in urlStr,
+// in which case it is resolved relative to the BaseURL of the Client.
+// Relative URLs should always be specified without a preceding slash.
+// Body is sent with Content-Type: application/x-www-form-urlencoded.
+func (c *Client) NewFormRequest(urlStr string, body io.Reader) (*http.Request, error) {
+	if !strings.HasSuffix(c.BaseURL.Path, "/") {
+		return nil, fmt.Errorf("BaseURL must have a trailing slash, but %q does not", c.BaseURL)
+	}
+
+	u, err := c.BaseURL.Parse(urlStr)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, u.String(), body)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("Accept", mediaTypeV3)
+	if c.UserAgent != "" {
+		req.Header.Set("User-Agent", c.UserAgent)
+	}
+	return req, nil
+}
+
 // NewUploadRequest creates an upload request. A relative URL can be provided in
 // urlStr, in which case it is resolved relative to the UploadURL of the Client.
 // Relative URLs should always be specified without a preceding slash.

github/github_test.go

@@ -602,6 +602,84 @@ func TestNewRequest_errorForNoTrailingSlash(t *testing.T) {
 	}
 }
 
+func TestNewFormRequest(t *testing.T) {
+	c := NewClient(nil)
+
+	inURL, outURL := "/foo", defaultBaseURL+"foo"
+	form := url.Values{}
+	form.Add("login", "l")
+	inBody, outBody := strings.NewReader(form.Encode()), "login=l"
+	req, _ := c.NewFormRequest(inURL, inBody)
+
+	// test that relative URL was expanded
+	if got, want := req.URL.String(), outURL; got != want {
+		t.Errorf("NewFormRequest(%q) URL is %v, want %v", inURL, got, want)
+	}
+
+	// test that body was form encoded
+	body, _ := ioutil.ReadAll(req.Body)
+	if got, want := string(body), outBody; got != want {
+		t.Errorf("NewFormRequest(%q) Body is %v, want %v", inBody, got, want)
+	}
+
+	// test that default user-agent is attached to the request
+	if got, want := req.Header.Get("User-Agent"), c.UserAgent; got != want {
+		t.Errorf("NewFormRequest() User-Agent is %v, want %v", got, want)
+	}
+}
+
+func TestNewFormRequest_badURL(t *testing.T) {
+	c := NewClient(nil)
+	_, err := c.NewFormRequest(":", nil)
+	testURLParseError(t, err)
+}
+
+func TestNewFormRequest_emptyUserAgent(t *testing.T) {
+	c := NewClient(nil)
+	c.UserAgent = ""
+	req, err := c.NewFormRequest(".", nil)
+	if err != nil {
+		t.Fatalf("NewFormRequest returned unexpected error: %v", err)
+	}
+	if _, ok := req.Header["User-Agent"]; ok {
+		t.Fatal("constructed request contains unexpected User-Agent header")
+	}
+}
+
+func TestNewFormRequest_emptyBody(t *testing.T) {
+	c := NewClient(nil)
+	req, err := c.NewFormRequest(".", nil)
+	if err != nil {
+		t.Fatalf("NewFormRequest returned unexpected error: %v", err)
+	}
+	if req.Body != nil {
+		t.Fatalf("constructed request contains a non-nil Body")
+	}
+}
+
+func TestNewFormRequest_errorForNoTrailingSlash(t *testing.T) {
+	tests := []struct {
+		rawURL    string
+		wantError bool
+	}{
+		{rawURL: "https://example.com/api/v3", wantError: true},
+		{rawURL: "https://example.com/api/v3/", wantError: false},
+	}
+	c := NewClient(nil)
+	for _, test := range tests {
+		u, err := url.Parse(test.rawURL)
+		if err != nil {
+			t.Fatalf("url.Parse returned unexpected error: %v.", err)
+		}
+		c.BaseURL = u
+		if _, err := c.NewFormRequest("test", nil); test.wantError && err == nil {
+			t.Fatalf("Expected error to be returned.")
+		} else if !test.wantError && err != nil {
+			t.Fatalf("NewFormRequest returned unexpected error: %v.", err)
+		}
+	}
+}
+
 func TestNewUploadRequest_badURL(t *testing.T) {
 	c := NewClient(nil)
 	_, err := c.NewUploadRequest(":", nil, 0, "")

github/repos_hooks.go

@@ -8,6 +8,9 @@ package github
 import (
 	"context"
 	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
 	"time"
 )
 
@@ -197,3 +200,55 @@ func (s *RepositoriesService) TestHook(ctx context.Context, owner, repo string,
 	}
 	return s.client.Do(ctx, req, nil)
 }
+
+// Subscribe lets servers register to receive updates when a topic is updated.
+//
+// GitHub API docs: https://docs.github.com/en/rest/webhooks#pubsubhubbub
+func (s *RepositoriesService) Subscribe(ctx context.Context, owner, repo, event, callback string, secret []byte) (*Response, error) {
+	req, err := s.createWebSubRequest("subscribe", owner, repo, event, callback, secret)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.client.Do(ctx, req, nil)
+}
+
+// Unsubscribe lets servers unregister to no longer receive updates when a topic is updated.
+//
+// GitHub API docs: https://docs.github.com/en/rest/webhooks#pubsubhubbub
+func (s *RepositoriesService) Unsubscribe(ctx context.Context, owner, repo, event, callback string, secret []byte) (*Response, error) {
+	req, err := s.createWebSubRequest("unsubscribe", owner, repo, event, callback, secret)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.client.Do(ctx, req, nil)
+}
+
+// createWebSubRequest returns a subscribe/unsubscribe request that implements
+// the WebSub (formerly PubSubHubbub) protocol.
+//
+// See: https://www.w3.org/TR/websub/#subscriber-sends-subscription-request
+func (s *RepositoriesService) createWebSubRequest(hubMode, owner, repo, event, callback string, secret []byte) (*http.Request, error) {
+	topic := fmt.Sprintf(
+		"https://github.com/%s/%s/events/%s",
+		owner,
+		repo,
+		event,
+	)
+	form := url.Values{}
+	form.Add("hub.mode", hubMode)
+	form.Add("hub.topic", topic)
+	form.Add("hub.callback", callback)
+	if secret != nil {
+		form.Add("hub.secret", string(secret))
+	}
+	body := strings.NewReader(form.Encode())
+
+	req, err := s.client.NewFormRequest("hub", body)
+	if err != nil {
+		return nil, err
+	}
+
+	return req, nil
+}

github/repos_hooks_test.go

@@ -564,3 +564,69 @@ func TestBranchHook_Marshal(t *testing.T) {
 
 	testJSONMarshal(t, v, want)
 }
+
+func TestRepositoriesService_Subscribe(t *testing.T) {
+	client, mux, _, teardown := setup()
+	defer teardown()
+
+	mux.HandleFunc("/hub", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, http.MethodPost)
+		testHeader(t, r, "Content-Type", "application/x-www-form-urlencoded")
+		testFormValues(t, r, values{
+			"hub.mode":     "subscribe",
+			"hub.topic":    "https://github.com/o/r/events/push",
+			"hub.callback": "http://postbin.org/123",
+			"hub.secret":   "test secret",
+		})
+	})
+
+	ctx := context.Background()
+	_, err := client.Repositories.Subscribe(
+		ctx,
+		"o",
+		"r",
+		"push",
+		"http://postbin.org/123",
+		[]byte("test secret"),
+	)
+	if err != nil {
+		t.Errorf("Repositories.Subscribe returned error: %v", err)
+	}
+
+	testNewRequestAndDoFailure(t, "Subscribe", client, func() (*Response, error) {
+		return client.Repositories.Subscribe(ctx, "o", "r", "push", "http://postbin.org/123", nil)
+	})
+}
+
+func TestRepositoriesService_Unsubscribe(t *testing.T) {
+	client, mux, _, teardown := setup()
+	defer teardown()
+
+	mux.HandleFunc("/hub", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, http.MethodPost)
+		testHeader(t, r, "Content-Type", "application/x-www-form-urlencoded")
+		testFormValues(t, r, values{
+			"hub.mode":     "unsubscribe",
+			"hub.topic":    "https://github.com/o/r/events/push",
+			"hub.callback": "http://postbin.org/123",
+			"hub.secret":   "test secret",
+		})
+	})
+
+	ctx := context.Background()
+	_, err := client.Repositories.Unsubscribe(
+		ctx,
+		"o",
+		"r",
+		"push",
+		"http://postbin.org/123",
+		[]byte("test secret"),
+	)
+	if err != nil {
+		t.Errorf("Repositories.Unsubscribe returned error: %v", err)
+	}
+
+	testNewRequestAndDoFailure(t, "Unsubscribe", client, func() (*Response, error) {
+		return client.Repositories.Unsubscribe(ctx, "o", "r", "push", "http://postbin.org/123", nil)
+	})
+}