cpolis/cmd/backend/rss.go

package backend

import (
	"fmt"
	"io"
	"os"
	"time"

	"git.streifling.com/jason/rss"
)

func GetChannel(db *DB, title, link, description string) (*rss.Channel, error) {
	channel := &rss.Channel{
		Title:       title,
		Link:        link,
		Description: description,
		Items:       make([]*rss.Item, 0),
	}

	articles, err := db.GetCertainArticles(true, false)
	if err != nil {
		return nil, fmt.Errorf("error fetching published articles: %v", err)
	}

	for _, article := range articles {
		tags, err := db.GetArticleTags(article.ID)
		if err != nil {
			return nil, fmt.Errorf("error fetching tags for article %v: %v", article.Title, err)
		}
		tagNames := make([]string, 0)
		for _, tag := range tags {
			tagNames = append(tagNames, tag.Name)
		}

		user, err := db.GetUser(article.AuthorID)
		if err != nil {
			return nil, fmt.Errorf("error finding user %v: %v", article.AuthorID, err)
		}

		channel.Items = append(channel.Items, &rss.Item{
			Title:       article.Title,
			Author:      user.FirstName + user.LastName,
			PubDate:     article.Created.Format(time.RFC1123Z),
			Description: article.Description,
			Content:     &rss.Content{Value: article.Content},
			Categories:  tagNames,
		})
	}

	return channel, nil
}

func GenerateRSS(db *DB, title, link, desc string) (*string, error) {
	channel := &rss.Channel{
		Title:       title,
		Link:        link,
		Description: desc,
		Items:       make([]*rss.Item, 0),
	}

	articles, err := db.GetCertainArticles(true, false)
	if err != nil {
		return nil, fmt.Errorf("error getting published articles for RSS feed: %v", err)
	}

	for _, article := range articles {
		tags, err := db.GetArticleTags(article.ID)
		if err != nil {
			return nil, fmt.Errorf("error getting tags for articles for RSS feed: %v", err)
		}
		tagNames := make([]string, 0)
		for _, tag := range tags {
			tagNames = append(tagNames, tag.Name)
		}
		tagNames = append(tagNames, fmt.Sprint("Orient Express ", article.IssueID))

		user, err := db.GetUser(article.AuthorID)
		if err != nil {
			return nil, fmt.Errorf("error getting user user info for RSS feed: %v", err)
		}

		articleTitle, err := ConvertToPlain(article.Title)
		if err != nil {
			return nil, fmt.Errorf("error converting title to plain text for RSS feed: %v", err)
		}

		articleDescription, err := ConvertToPlain(article.Description)
		if err != nil {
			return nil, fmt.Errorf("error converting description to plain text for RSS feed: %v", err)
		}

		articleContent, err := ConvertToHTML(article.Content)
		if err != nil {
			return nil, fmt.Errorf("error converting content to HTML for RSS feed: %v", err)
		}

		channel.Items = append(channel.Items, &rss.Item{
			Title:       articleTitle,
			Author:      user.FirstName + " " + user.LastName,
			PubDate:     article.Created.Format(time.RFC1123Z),
			Description: articleDescription,
			Content:     &rss.Content{Value: articleContent},
			Categories:  tagNames,
		})
	}

	feed := rss.NewFeed()
	feed.Channels = append(feed.Channels, channel)
	rss, err := feed.ToXML("UTF-8")
	if err != nil {
		return nil, fmt.Errorf("error converting RSS feed to XML: %v", err)
	}

	return &rss, nil
}

func SaveRSS(filename string, feed *string) error {
	file, err := os.Create(filename)
	if err != nil {
		return fmt.Errorf("error creating file for RSS feed: %v", err)
	}
	defer file.Close()
	if err = file.Chmod(0644); err != nil {
		return fmt.Errorf("error setting permissions for RSS file: %v", err)
	}

	if _, err = io.WriteString(file, *feed); err != nil {
		return fmt.Errorf("error writing to RSS file: %v", err)
	}

	return nil
}