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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"
"os"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"git.autistici.org/ale/crawl"
"git.autistici.org/ale/crawl/analysis"
"git.autistici.org/ale/crawl/warc"
)
var (
dbPath = flag.String("state", "crawldb", "crawl state database path")
keepDb = flag.Bool("keep", false, "keep the state database when done")
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")
)
func extractLinks(c *crawl.Crawler, u string, depth int, resp *http.Response, err error) error {
links, err := analysis.GetLinks(resp)
if err != nil {
return err
}
for _, link := range links {
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 *warc.Writer
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 := warc.NewHeader()
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 = warc.NewHeader()
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 *warc.Writer) 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 := warc.NewHeader()
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"),
}
}
type crawlStats struct {
bytes int64
start time.Time
lock sync.Mutex
states map[int]int
}
func (c *crawlStats) Update(resp *http.Response) {
c.lock.Lock()
defer c.lock.Unlock()
c.states[resp.StatusCode]++
resp.Body = &byteCounter{resp.Body}
}
func (c *crawlStats) UpdateBytes(n int64) {
atomic.AddInt64(&c.bytes, n)
}
func (c *crawlStats) Dump() {
c.lock.Lock()
defer c.lock.Unlock()
rate := float64(c.bytes) / time.Since(c.start).Seconds() / 1000
fmt.Fprintf(os.Stderr, "stats: downloaded %d bytes (%.4g KB/s), status: %v\n", c.bytes, rate, c.states)
}
var (
stats *crawlStats
client *http.Client
)
func fetch(urlstr string) (*http.Response, error) {
resp, err := client.Get(urlstr)
if err == nil {
stats.Update(resp)
}
return resp, err
}
func init() {
client = &http.Client{}
stats = &crawlStats{
states: make(map[int]int),
start: time.Now(),
}
go func() {
for range time.Tick(10 * time.Second) {
stats.Dump()
}
}()
}
type byteCounter struct {
io.ReadCloser
}
func (b *byteCounter) Read(buf []byte) (int, error) {
n, err := b.ReadCloser.Read(buf)
if n > 0 {
stats.UpdateBytes(int64(n))
}
return n, err
}
func main() {
flag.Parse()
outf, err := os.Create(*outputFile)
if err != nil {
log.Fatal(err)
}
seeds := crawl.MustParseURLs(flag.Args())
scope := []crawl.Scope{
crawl.NewSchemeScope(strings.Split(*validSchemes, ",")),
crawl.NewDepthScope(*depth),
crawl.NewSeedScope(seeds),
crawl.NewRegexpIgnoreScope(nil),
}
w := warc.NewWriter(outf)
defer w.Close()
saver := NewSaveHandler(w)
crawler, err := crawl.NewCrawler(*dbPath, seeds, scope, crawl.FetcherFunc(fetch), crawl.NewRedirectHandler(saver))
if err != nil {
log.Fatal(err)
}
crawler.Run(*concurrency)
crawler.Close()
if !*keepDb {
os.RemoveAll(*dbPath)
}
}
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