Add convience method for webhooks

Resolves slack-go#355

Author: ghostsquad

dialog_test.go

@@ -299,7 +299,7 @@ func TestOpenDialog(t *testing.T) {
 	}
 	err = api.OpenDialog("", *dialog)
 	if err == nil {
-		t.Errorf("Did not error with empty trigger: %s", err)
+		t.Errorf("Did not error with empty trigger, %s", err)
 		return
 	}
 }

webhooks.go

@@ -0,0 +1,33 @@
+package slack
+
+import (
+	"github.com/pkg/errors"
+	"net/http"
+	"bytes"
+	"encoding/json"
+)
+
+type WebhookMessage struct {
+	Text    		string 				`json:"text,omitempty"`
+	Attachments []Attachment	`json:"attachments,omitempty"`
+}
+
+func PostWebhook(url string, msg *WebhookMessage) error {
+	raw, err := json.Marshal(msg)
+
+	if err != nil {
+		return errors.Wrap(err, "marshal failed")
+	}
+
+	response, err := http.Post(url, "application/json", bytes.NewReader(raw));
+
+	if err != nil {
+		return errors.Wrap(err, "failed to post webhook")
+	}
+
+	if response.StatusCode != http.StatusOK {
+		return statusCodeError{Code: response.StatusCode, Status: response.Status}
+	}
+
+	return nil
+}

webhooks_test.go

@@ -0,0 +1,65 @@
+package slack
+
+import (
+	"testing"
+	"net/http"
+	"encoding/json"
+	"reflect"
+)
+
+func TestPostWebhook_OK(t *testing.T) {
+	once.Do(startServer)
+
+	var receivedPayload WebhookMessage
+
+	http.HandleFunc("/webhook", func(rw http.ResponseWriter, r *http.Request) {
+		rw.Header().Set("Content-Type", "application/json")
+
+		decoder := json.NewDecoder(r.Body)
+		err := decoder.Decode(&receivedPayload)
+		if err != nil {
+			t.Errorf("Request contained invalid JSON, %s", err)
+		}
+
+		response := []byte(`{}`)
+		rw.Write(response)
+	})
+
+	url := "http://" + serverAddr + "/webhook"
+
+	payload := &WebhookMessage{
+		Text: "Test Text",
+		Attachments: []Attachment{
+			{
+				Text: "Foo",
+			},
+		},
+	}
+
+	err := PostWebhook(url, payload)
+
+	if err != nil {
+		t.Errorf("Expected not to receive error: %s", err)
+	}
+
+	if !reflect.DeepEqual(payload, &receivedPayload) {
+		t.Errorf("Payload did not match\nwant: %#v\n got: %#v", payload, receivedPayload)
+	}
+}
+
+func TestPostWebhook_NotOK(t *testing.T) {
+	once.Do(startServer)
+
+	http.HandleFunc("/webhook2", func(rw http.ResponseWriter, r *http.Request) {
+		rw.WriteHeader(http.StatusInternalServerError)
+		rw.Write([]byte("500 - Something bad happened!"))
+	})
+
+	url := "http://" + serverAddr + "/webhook2"
+
+	err := PostWebhook(url, &WebhookMessage{})
+
+	if err == nil {
+		t.Errorf("Expected to receive error")
+	}
+}