Yandex Cloud function to get RSS feed built from Todoist tasks with "rss" label

todoist-to-rss.go

package main

import (
	"context"
	"encoding/json"
	"encoding/xml"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"slices"
	"time"
)

type Response struct {
	StatusCode int         `json:"statusCode"`
	Body       interface{} `json:"body"`
}

type TodoistTask struct {
	ID          string   `json:"id"`
	Content     string   `json:"content"`
	Description string   `json:"description"`
	CreatedAt   string   `json:"created_at"`
	URL         string   `json:"url"`
	Labels      []string `json:"labels"`
}

type RSS struct {
	XMLName xml.Name `xml:"rss"`
	Version string   `xml:"version,attr"`
	Channel Channel  `xml:"channel"`
}

type Channel struct {
	Title       string `xml:"title"`
	Link        string `xml:"link"`
	Description string `xml:"description"`
	Items       []Item `xml:"item"`
}

type Item struct {
	Title       string `xml:"title"`
	Link        string `xml:"link"`
	Description string `xml:"description"`
	PubDate     string `xml:"pubDate"`
	GUID        string `xml:"guid"`
}

func Handler(ctx context.Context) (*Response, error) {
	token := os.Getenv("TODOIST_TOKEN")
	if token == "" {
		return nil, fmt.Errorf("TODOIST_TOKEN environment variable is not set")
	}

	client := &http.Client{Timeout: 10 * time.Second}
	req, err := http.NewRequestWithContext(ctx, "GET", "https://api.todoist.com/rest/v2/tasks", nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Authorization", "Bearer "+token)

	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := ioutil.ReadAll(resp.Body)
		return nil, fmt.Errorf("failed to fetch tasks: %s", string(bodyBytes))
	}

	bodyBytes, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	var tasks []TodoistTask
	if err := json.Unmarshal(bodyBytes, &tasks); err != nil {
		return nil, err
	}

	var filtered []TodoistTask
	for _, task := range tasks {
		if slices.Contains(task.Labels, "rss") {
			filtered = append(filtered, task)
		}
	}

	rss := RSS{
		Version: "2.0",
		Channel: Channel{
			Title:       "Todoist Tasks",
			Link:        "https://todoist.com",
			Description: "RSS feed of Todoist tasks",
		},
	}

	for _, task := range filtered {
		t, err := time.Parse(time.RFC3339Nano, task.CreatedAt)
		if err != nil {
			t = time.Now()
		}
		item := Item{
			Title:       task.Content,
			Link:        task.URL,
			Description: task.Description,
			PubDate:     t.Format(time.RFC1123Z),
			GUID:        task.ID,
		}
		rss.Channel.Items = append(rss.Channel.Items, item)
	}

	output, err := xml.MarshalIndent(rss, "", "  ")
	if err != nil {
		return nil, err
	}
	rssFeed := xml.Header + string(output)

	return &Response{
		StatusCode: 200,
		Body:       rssFeed,
	}, nil
}