feat(integration): add Slack integration

internal/integration/integration.go

@@ -28,6 +28,7 @@ import (
 	"miniflux.app/v2/internal/integration/readwise"
 	"miniflux.app/v2/internal/integration/shaarli"
 	"miniflux.app/v2/internal/integration/shiori"
+	"miniflux.app/v2/internal/integration/slack"
 	"miniflux.app/v2/internal/integration/telegrambot"
 	"miniflux.app/v2/internal/integration/wallabag"
 	"miniflux.app/v2/internal/integration/webhook"
@@ -553,6 +554,22 @@ func PushEntries(feed *model.Feed, entries model.Entries, userIntegrations *mode
 		}
 	}
 
+	if userIntegrations.SlackEnabled {
+		slog.Debug("Sending new entries to Slack",
+			slog.Int64("user_id", userIntegrations.UserID),
+			slog.Int("nb_entries", len(entries)),
+			slog.Int64("feed_id", feed.ID),
+		)
+
+		client := slack.NewClient(
+			userIntegrations.SlackWebhookLink,
+		)
+
+		if err := client.SendSlackMsg(feed, entries); err != nil {
+			slog.Warn("Unable to send new entries to Slack", slog.Any("error", err))
+		}
+	}
+
 	// Integrations that only support sending individual entries
 	if userIntegrations.TelegramBotEnabled {
 		for _, entry := range entries {

internal/integration/slack/slack.go

@@ -0,0 +1,113 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Slack Webhooks documentation: https://api.slack.com/messaging/webhooks
+
+package slack // import "miniflux.app/v2/internal/integration/slack"
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"miniflux.app/v2/internal/model"
+	"miniflux.app/v2/internal/urllib"
+	"miniflux.app/v2/internal/version"
+)
+
+const defaultClientTimeout = 10 * time.Second
+const slackMsgColor = "#5865F2"
+
+type Client struct {
+	webhookURL string
+}
+
+func NewClient(webhookURL string) *Client {
+	return &Client{webhookURL: webhookURL}
+}
+
+func (c *Client) SendSlackMsg(feed *model.Feed, entries model.Entries) error {
+	for _, entry := range entries {
+		requestBody, err := json.Marshal(&slackMessage{
+			Attachments: []slackAttachments{
+				{
+					Title: "RSS feed update from Miniflux",
+					Color: slackMsgColor,
+					Fields: []slackFields{
+						{
+							Title: "Updated feed",
+							Value: feed.Title,
+						},
+						{
+							Title: "Article title",
+							Value: entry.Title,
+						},
+						{
+							Title: "Article link",
+							Value: entry.URL,
+						},
+						{
+							Title: "Author",
+							Value: entry.Author,
+							Short: true,
+						},
+						{
+							Title: "Source website",
+							Value: urllib.RootURL(feed.SiteURL),
+							Short: true,
+						},
+					},
+				},
+			},
+		})
+		if err != nil {
+			return fmt.Errorf("slack: unable to encode request body: %v", err)
+		}
+
+		request, err := http.NewRequest(http.MethodPost, c.webhookURL, bytes.NewReader(requestBody))
+		if err != nil {
+			return fmt.Errorf("slack: unable to create request: %v", err)
+		}
+
+		request.Header.Set("Content-Type", "application/json")
+		request.Header.Set("User-Agent", "Miniflux/"+version.Version)
+
+		slog.Debug("Sending Slack notification",
+			slog.String("webhookURL", c.webhookURL),
+			slog.String("title", feed.Title),
+			slog.String("entry_url", entry.URL),
+		)
+
+		httpClient := &http.Client{Timeout: defaultClientTimeout}
+		response, err := httpClient.Do(request)
+		if err != nil {
+			return fmt.Errorf("slack: unable to send request: %v", err)
+		}
+		response.Body.Close()
+
+		if response.StatusCode >= 400 {
+			return fmt.Errorf("slack: unable to send a notification: url=%s status=%d", c.webhookURL, response.StatusCode)
+		}
+	}
+
+	return nil
+}
+
+type slackFields struct {
+	Title string `json:"title"`
+	Value string `json:"value"`
+	Short bool   `json:"short,omitempty"`
+}
+
+type slackAttachments struct {
+	Title  string        `json:"title"`
+	Color  string        `json:"color"`
+	Fields []slackFields `json:"fields"`
+}
+
+type slackMessage struct {
+	Attachments []slackAttachments `json:"attachments"`
+}