scraper.go

package main

import (
	"context"
	"database/sql"
	"log"
	"strings"
	"sync"
	"time"

	"github.com/aadityadike/RSS-Aggregator/internal/database"
	"github.com/google/uuid"
)

func scraper(db *database.Queries, concurrency int, timeBetweenRequest time.Duration) {

	log.Printf("Scraping on %v Go Routine every %s duration", concurrency, timeBetweenRequest)
	ticker := time.NewTicker(timeBetweenRequest)
	for ; ; <-ticker.C {
		feeds, err := db.GetNextFeedsToFetch(
			context.Background(), int32(concurrency),
		)
		if err != nil {
			log.Printf("Error in Fetching Feeds: %s", err)
			continue
		}

		wg := &sync.WaitGroup{}
		for _, feed := range feeds {
			wg.Add(1)
			go scrapeFeed(db, wg, feed)
		}
		wg.Wait()
	}
}

func scrapeFeed(db *database.Queries, wg *sync.WaitGroup, feed database.Feed) {
	defer wg.Done()
	_, err := db.MarkFeedAsFetched(context.Background(), feed.ID)

	if err != nil {
		log.Println("Error in Marking Feed: ", err)
		return
	}

	rssFeed, err := getAllFeeds(feed.Url)

	if err != nil {
		log.Println("Error in getting Feed: ", err)
		return
	}

	for _, item := range rssFeed.Channel.Items {

		description := sql.NullString{}
		if item.Description != "" {
			description.String = item.Description
			description.Valid = true
		}

		pubAt, err := time.Parse(time.RFC1123, item.PubDate)

		if err != nil {
			log.Println("Error in Parsing Time: ", err)
		}

		_, err = db.CreatePost(context.Background(), database.CreatePostParams{
			ID:          uuid.New(),
			CreatedAt:   time.Now(),
			UpdatedAt:   time.Now(),
			Title:       item.Title,
			Description: description,
			PublishedAt: pubAt,
			Url:         item.Link,
			FeedID:      feed.ID,
		})

		if err != nil {
			if strings.Contains(err.Error(), "duplicate key value violates unique constraint") {
				continue
			}
			log.Println("Error in Creating Post: ", err)
		}
	}

	log.Printf("Feeds %v collected, %v posts found", feed.Name, len(rssFeed.Channel.Items))
}