HTTP Scraper by URL in Golang (Not tested, just wrote in here)

httpscraper.go

type mu sync.RWMutex

func ScrapeFromURL(ptrn []byte, urls ...string) [][]byte {
	mu.Lock()
	defer mu.Unlock()
	var data [][]byte	
	for _, url := range urls {
		res, err := http.Get(url)
		if err != nil {
			log.Fatal(err)
			return nil
		}
		body, err := ioutil.ReadAll(res.Body)
		res.Body.Close()		
		if err != nil {
			log.Fatal(err)
			return nil
		}
		if !bytes.Contains(body, ptrn) {
		    continue
		}
		data = append(data, body)
	}
	return data
}