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golang to crawler the url in html
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package main | |
import ( | |
"html" | |
"io/ioutil" | |
"log" | |
"net/http" | |
"net/url" | |
"regexp" | |
) | |
type JobResult_t struct { | |
Results []UrlResult_t | |
Urls map[string]bool | |
} | |
type UrlResult_t struct { | |
Url string | |
Images []string | |
} | |
func main() { | |
crawlUrl("http://www.sohu.com") | |
} | |
func crawlUrl(urlToCrawl string) { | |
var ( | |
err error | |
content string | |
imgs []string | |
urlToGet *url.URL | |
links []string | |
) | |
// Parse URL | |
if urlToGet, err = url.Parse(urlToCrawl); err != nil { | |
log.Println(err) | |
return | |
} | |
// Retrieve content of URL | |
if content, err = getUrlContent(urlToGet.String()); err != nil { | |
log.Println(err) | |
return | |
} | |
// Clean up HTML entities | |
content = html.UnescapeString(content) | |
if links, err = parseLinks(urlToGet, content); err != nil { | |
log.Println(err) | |
return | |
} | |
// Retrieve image URLs | |
if imgs, err = parseImages(urlToGet, content); err != nil { | |
log.Println(err) | |
return | |
} | |
for _, link := range links { | |
defer crawlUrl(link) | |
} | |
for _, img := range imgs { | |
log.Println(img) | |
} | |
} //crawlUrl | |
func getUrlContent(urlToGet string) (string, error) { | |
var ( | |
err error | |
content []byte | |
resp *http.Response | |
) | |
// GET content of URL | |
if resp, err = http.Get(urlToGet); err != nil { | |
return "", err | |
} | |
defer resp.Body.Close() | |
// Check if request was successful | |
if resp.StatusCode != 200 { | |
return "", err | |
} | |
// Read the body of the HTTP response | |
if content, err = ioutil.ReadAll(resp.Body); err != nil { | |
return "", err | |
} | |
return string(content), err | |
} | |
func parseImages(urlToGet *url.URL, content string) ([]string, error) { | |
var ( | |
err error | |
imgs []string | |
matches [][]string | |
findImages = regexp.MustCompile("<img.*?src=\"(.*?)\"") | |
) | |
// Retrieve all image URLs from string | |
matches = findImages.FindAllStringSubmatch(content, -1) | |
for _, val := range matches { | |
var imgUrl *url.URL | |
// Parse the image URL | |
if imgUrl, err = url.Parse(val[1]); err != nil { | |
return imgs, err | |
} | |
// If the URL is absolute, add it to the slice | |
// If the URL is relative, build an absolute URL | |
if imgUrl.IsAbs() { | |
imgs = append(imgs, imgUrl.String()) | |
} else { | |
imgs = append(imgs, urlToGet.Scheme+"://"+urlToGet.Host+imgUrl.String()) | |
} | |
} | |
return imgs, err | |
} | |
func parseLinks(urlToGet *url.URL, content string) ([]string, error) { | |
var ( | |
err error | |
links []string = make([]string, 0) | |
matches [][]string | |
findLinks = regexp.MustCompile("<a.*?href=\"(.*?)\"") | |
) | |
// Retrieve all anchor tag URLs from string | |
matches = findLinks.FindAllStringSubmatch(content, -1) | |
for _, val := range matches { | |
var linkUrl *url.URL | |
// Parse the anchr tag URL | |
if linkUrl, err = url.Parse(val[1]); err != nil { | |
return links, err | |
} | |
// If the URL is absolute, add it to the slice | |
// If the URL is relative, build an absolute URL | |
if linkUrl.IsAbs() { | |
links = append(links, linkUrl.String()) | |
} else { | |
links = append(links, urlToGet.Scheme+"://"+urlToGet.Host+linkUrl.String()) | |
} | |
} | |
return links, err | |
} |
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