feat(service): Adds HomeAssistant service

Author: iamajoe

service/homeassistant/README.md

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+# HomeAssistant service
+
+[HomeAssistant](https://www.home-assistant.io) is an application that handles home automation and integration
+
+## Usage
+
+[HomeAssistant webhook trigger](https://www.home-assistant.io/docs/automation/trigger/#webhook-trigger)
+
+```go
+// Create a HomeAssistant service
+haService := homeassistant.New()
+
+// Add webhook
+haService.AddWebhook("https://url-to-home-assistant", "<webhook_id>", "<http_method>")
+
+// Tell our notifier to use the service.
+notify.UseServices(haService)
+
+// Send a test message.
+_ = notify.Send(
+    context.Background(),
+    "Subject/Title",
+    "The actual message - Hello, you awesome gophers! :)",
+)
+```

service/homeassistant/homeassistant.go

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+package homeassistant
+
+import (
+	"context"
+	stdhttp "net/http"
+	"strings"
+
+	"github.com/nikoksr/notify/service/http"
+)
+
+// HomeAssistant struct holds necessary data to communicate with the HomeAssistant API.
+type HomeAssistant struct {
+	httpClient http.Service
+}
+
+// New returns a new instance of a HomeAssistant notification service.
+func New() (*HomeAssistant, error) {
+	h := HomeAssistant{
+		httpClient: *http.New(),
+	}
+	return &h, nil
+}
+
+// AddWebhook takes HomeAssistant automation webhooks and adds them. The Send method will send to all these
+// baseUrl should be the home assistant base url for example https://your-home-assistant:8123
+// hookId should be what was set at the trigger of the webhook
+// method should be the method selected at the trigger of the webhook
+// For more information read HomeAssistant documentation at:
+// - https://www.home-assistant.io/docs/automation/trigger/#webhook-trigger
+func (h *HomeAssistant) AddWebhook(baseUrl string, hookId string, method string) {
+	baseUrl = strings.TrimRight(baseUrl, "/")
+	u := baseUrl + "/api/webhook/" + hookId
+
+	// From example:
+	// curl -X POST -d 'key=value&key2=value2' https://your-home-assistant:8123/api/webhook/some_hook_id
+
+	hook := &http.Webhook{
+		URL:         u,
+		Header:      stdhttp.Header{},
+		ContentType: "application/json",
+		Method:      strings.ToUpper(method),
+		BuildPayload: func(subject, message string) (payload any) {
+			dataMap := make(map[string]string)
+			dataMap["subject"] = subject
+			dataMap["message"] = message
+
+			return dataMap
+		},
+	}
+
+	h.httpClient.AddReceivers(hook)
+}
+
+// Send takes a subject and a message and sends them to all previously set webhooks
+func (h HomeAssistant) Send(ctx context.Context, subject, message string) error {
+	// TODO: should setup mqtt automation integration as well
+	//       https://www.home-assistant.io/docs/automation/trigger/#mqtt-trigger
+
+	return h.httpClient.Send(ctx, subject, message)
+}

service/homeassistant/homeassistant_test.go

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+package homeassistant
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNew(t *testing.T) {
+	t.Parallel()
+
+	s1, err := New()
+	assert.NotNil(t, s1, "service should not be nil")
+	assert.Nil(t, err, "error should not exist")
+
+	s2, err := New()
+	assert.NotNil(t, s2, "service should not be nil")
+	assert.Equal(t, s1, s2, "services should be equal")
+	assert.Nil(t, err, "error should not exist")
+}
+
+func TestService_Send(t *testing.T) {
+	t.Parallel()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	hookId := "very_long_hook_id_to_test_out"
+	subject := "test subject"
+	message := "test message"
+
+	sent := false
+	svr := httptest.NewServer(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		if !strings.Contains(r.URL.Path, "/api/webhook/"+hookId) {
+			return
+		}
+
+		var m map[string]string
+		err := json.NewDecoder(r.Body).Decode(&m)
+		if err != nil || m == nil {
+			return
+		}
+
+		if s, ok := m["subject"]; !ok || s != subject {
+			return
+		}
+
+		if s, ok := m["message"]; !ok || s != message {
+			return
+		}
+
+		sent = true
+	}))
+	defer svr.Close()
+
+	// Create service with local server as receiver
+	service, _ := New()
+	service.AddWebhook(svr.URL, hookId, "POST")
+
+	// Sending this notification should work without any issues
+	err := service.Send(ctx, subject, message)
+	assert.NoError(t, err, "error should be nil")
+	assert.True(t, sent, "message was not received")
+}