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// A restartable crawler that dumps everything to a WARC file.
package main
import (
"bytes"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/url"
"os"
"regexp"
"strconv"
"strings"
"git.autistici.org/ale/crawl"
"github.com/PuerkitoBio/goquery"
)
var (
dbPath = flag.String("state", "crawldb", "crawl state database path")
concurrency = flag.Int("c", 10, "concurrent workers")
depth = flag.Int("depth", 10, "maximum link depth")
validSchemes = flag.String("schemes", "http,https", "comma-separated list of allowed protocols")
outputFile = flag.String("output", "crawl.warc.gz", "output WARC file")
urlcssRx = regexp.MustCompile(`background.*:.*url\(["']?([^'"\)]+)["']?\)`)
)
var linkMatches = []struct {
tag string
attr string
}{
{"a", "href"},
{"link", "href"},
{"img", "src"},
{"script", "src"},
}
func extractLinks(c *crawl.Crawler, u string, depth int, resp *http.Response, err error) error {
var outlinks []string
ctype := resp.Header.Get("Content-Type")
if strings.HasPrefix(ctype, "text/html") {
doc, err := goquery.NewDocumentFromResponse(resp)
if err != nil {
return err
}
for _, lm := range linkMatches {
doc.Find(fmt.Sprintf("%s[%s]", lm.tag, lm.attr)).Each(func(i int, s *goquery.Selection) {
val, _ := s.Attr(lm.attr)
outlinks = append(outlinks, val)
})
}
} else if strings.HasPrefix(ctype, "text/css") {
if data, err := ioutil.ReadAll(resp.Body); err == nil {
for _, val := range urlcssRx.FindAllStringSubmatch(string(data), -1) {
outlinks = append(outlinks, val[1])
}
}
}
// Uniquify and parse outbound links.
links := make(map[string]*url.URL)
for _, val := range outlinks {
if linkurl, err := resp.Request.URL.Parse(val); err == nil {
links[linkurl.String()] = linkurl
}
}
for _, link := range links {
//log.Printf("%s -> %s", u, link.String())
c.Enqueue(link, depth+1)
}
return nil
}
type fakeCloser struct {
io.Reader
}
func (f *fakeCloser) Close() error {
return nil
}
func hdr2str(h http.Header) []byte {
var b bytes.Buffer
h.Write(&b)
return b.Bytes()
}
type warcSaveHandler struct {
warc *crawl.WarcWriter
warcInfoID string
}
func (h *warcSaveHandler) Handle(c *crawl.Crawler, u string, depth int, resp *http.Response, err error) error {
data, derr := ioutil.ReadAll(resp.Body)
if derr != nil {
return err
}
resp.Body = &fakeCloser{bytes.NewReader(data)}
// Dump the request.
var b bytes.Buffer
resp.Request.Write(&b)
hdr := crawl.NewWarcHeader()
hdr.Set("WARC-Type", "request")
hdr.Set("WARC-Target-URI", resp.Request.URL.String())
hdr.Set("WARC-Warcinfo-ID", h.warcInfoID)
hdr.Set("Content-Length", strconv.Itoa(b.Len()))
w := h.warc.NewRecord(hdr)
w.Write(b.Bytes())
w.Close()
// Dump the response.
statusLine := fmt.Sprintf("HTTP/1.1 %s", resp.Status)
respPayload := bytes.Join([][]byte{
[]byte(statusLine), hdr2str(resp.Header), data},
[]byte{'\r', '\n'})
hdr = crawl.NewWarcHeader()
hdr.Set("WARC-Type", "response")
hdr.Set("WARC-Target-URI", resp.Request.URL.String())
hdr.Set("WARC-Warcinfo-ID", h.warcInfoID)
hdr.Set("Content-Length", strconv.Itoa(len(respPayload)))
w = h.warc.NewRecord(hdr)
w.Write(respPayload)
w.Close()
return extractLinks(c, u, depth, resp, err)
}
func NewSaveHandler(w *crawl.WarcWriter) crawl.Handler {
info := strings.Join([]string{
"Software: crawl/1.0\r\n",
"Format: WARC File Format 1.0\r\n",
"Conformsto: http://bibnum.bnf.fr/WARC/WARC_ISO_28500_version1_latestdraft.pdf\r\n",
}, "")
hdr := crawl.NewWarcHeader()
hdr.Set("WARC-Type", "warcinfo")
hdr.Set("WARC-Warcinfo-ID", hdr.Get("WARC-Record-ID"))
hdr.Set("Content-Length", strconv.Itoa(len(info)))
hdrw := w.NewRecord(hdr)
io.WriteString(hdrw, info)
hdrw.Close()
return &warcSaveHandler{
warc: w,
warcInfoID: hdr.Get("WARC-Record-ID"),
}
}
func main() {
flag.Parse()
outf, err := os.Create(*outputFile)
if err != nil {
log.Fatal(err)
}
seeds := crawl.MustParseURLs(flag.Args())
scope := crawl.NewSeedScope(seeds, *depth, strings.Split(*validSchemes, ","))
w := crawl.NewWarcWriter(outf)
defer w.Close()
saver := NewSaveHandler(w)
crawler, err := crawl.NewCrawler("crawldb", seeds, scope, crawl.FetcherFunc(http.Get), saver)
if err != nil {
log.Fatal(err)
}
crawler.Run()
}
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