Cache scraping

.gitignore

@@ -1 +1,2 @@
 search-scrape
+web_cache

scrape.go

@@ -22,13 +22,6 @@
 
 package main
 
-import "log"
-
 func main() {
-	urlFormat := "http://tabelog.com/en/kanagawa/rstLst/{{.Page}}/"
-	tabelogReviews := "tabelog.json"
-
-	if err := scrapeTabelog(tabelogReviews, urlFormat); err != nil {
-		log.Fatal(err)
-	}
+	scrapeTabelog("http://tabelog.com/en/kanagawa/rstLst/1/", "tabelog.json", "web_cache")
 }

tabelog.go

@@ -23,14 +23,13 @@
 package main
 
 import (
-	"bytes"
 	"encoding/json"
 	"io/ioutil"
 	"log"
+	"net/url"
 	"strconv"
 	"strings"
 	"sync"
-	"text/template"
 
 	"github.com/PuerkitoBio/goquery"
 )
@@ -50,15 +49,31 @@ type tabelogReview struct {
 	Cost       float64
 	Drinks     float64
 	Url        string
+	Raw        string
 }
 
-func dumpReviews(filename string, in chan tabelogReview, out chan error) {
-	count := 1
+func makeAbsUrl(base, ref string) string {
+	b, err := url.Parse(base)
+	if err != nil {
+		log.Fatal(err)
+	}
 
+	r, err := url.Parse(ref)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return b.ResolveReference(r).String()
+}
+
+func dumpReviews(filename string, rc chan tabelogReview, cond *sync.Cond) {
+	defer cond.Signal()
+
+	count := 1
 	var reviews []tabelogReview
 	for {
-		if review, ok := <-in; ok {
-			log.Printf("%d\t%s", count, review.Name)
+		if review, ok := <-rc; ok {
+			log.Printf("%s (%d)", review.Name, count)
 			reviews = append(reviews, review)
 			count++
 		} else {
@@ -68,19 +83,20 @@ func dumpReviews(filename string, in chan tabelogReview, out chan error) {
 
 	js, err := json.MarshalIndent(reviews, "", "    ")
 	if err != nil {
-		out <- err
-		return
+		log.Fatal(err)
 	}
 
-	out <- ioutil.WriteFile(filename, js, 0644)
+	if err := ioutil.WriteFile(filename, js, 0644); err != nil {
+		log.Fatal(err)
+	}
 }
 
-func scrapeReview(url string, out chan tabelogReview, wg *sync.WaitGroup) {
+func scrapeReview(url string, rc chan tabelogReview, wg *sync.WaitGroup, wc *webCache) {
 	defer wg.Done()
 
-	doc, err := goquery.NewDocument(url)
+	doc, err := wc.fetchUrl(url)
 	if err != nil {
-		return
+		log.Fatal(err)
 	}
 
 	addresses := doc.Find("p.rd-detail-info__rst-address")
@@ -91,7 +107,7 @@ func scrapeReview(url string, out chan tabelogReview, wg *sync.WaitGroup) {
 	var review tabelogReview
 
 	review.Url = url
-	review.Name = doc.Find("div.rd-header__headline > h2 > a").Text()
+	review.Name = doc.Find("a.rd-header__rst-name-main").Text()
 	review.Address = strings.TrimSpace(addresses.First().Text())
 
 	if review.Dishes, err = strconv.ParseFloat(doc.Find("#js-rating-detail > dd:nth-child(2)").Text(), 8); err != nil {
@@ -110,46 +126,41 @@ func scrapeReview(url string, out chan tabelogReview, wg *sync.WaitGroup) {
 		return
 	}
 
-	out <- review
+	rc <- review
 }
 
-func scrapeIndex(url string, out chan tabelogReview) error {
-	doc, err := goquery.NewDocument(url)
+func scrapeIndex(url string, out chan tabelogReview, wc *webCache) {
+	doc, err := wc.fetchUrl(url)
 	if err != nil {
-		return err
+		log.Fatal(err)
 	}
 
 	var wg sync.WaitGroup
 	doc.Find("div.list-rst__header > p > a").Each(func(index int, sel *goquery.Selection) {
 		if href, ok := sel.Attr("href"); ok {
 			wg.Add(1)
-			go scrapeReview(href, out, &wg)
+			go scrapeReview(makeAbsUrl(url, href), out, &wg, wc)
 		}
 	})
-
 	wg.Wait()
-	return nil
+
+	if href, ok := doc.Find("a.c-pagination__target--next").Attr("href"); ok {
+		scrapeIndex(makeAbsUrl(url, href), out, wc)
+	}
 }
 
-func scrapeTabelog(filename, url string) error {
-	out := make(chan tabelogReview)
-	in := make(chan error)
-	go dumpReviews(filename, out, in)
-
-	t := template.New("tabelog")
-	t.Parse(url)
-
-	for i := 1; i <= 2; i++ {
-		var url bytes.Buffer
-		if err := t.Execute(&url, tabelogParams{i}); err != nil {
-			return err
+func scrapeTabelog(url, jsonFile, cacheDir string) {
+	wc, err := newWebCache(cacheDir)
+	if err != nil {
+		log.Fatal(err)
 	}
 
-		if err := scrapeIndex(string(url.Bytes()), out); err != nil {
-			return err
-		}
-	}
+	var cond sync.Cond
+	rc := make(chan tabelogReview)
+	go dumpReviews(jsonFile, rc, &cond)
 
-	close(out)
-	return <-in
+	scrapeIndex(url, rc, wc)
+
+	close(rc)
+	cond.Wait()
 }

webcache.go

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package main
+
+import (
+	"bytes"
+	"crypto/md5"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path"
+
+	"github.com/PuerkitoBio/goquery"
+)
+
+type webCache struct {
+	baseDir string
+}
+
+func newWebCache(baseDir string) (*webCache, error) {
+	if err := os.MkdirAll(baseDir, 0755); err != nil {
+		return nil, err
+	}
+
+	return &webCache{baseDir: baseDir}, nil
+}
+
+func (c *webCache) urlToLocal(url string) string {
+	hash := md5.New()
+	hash.Write([]byte(url))
+	return path.Join(c.baseDir, fmt.Sprintf("%x", hash.Sum(nil)))
+}
+
+func (c *webCache) fetchUrl(url string) (*goquery.Document, error) {
+	localPath := c.urlToLocal(url)
+
+	if file, err := os.Open(localPath); err == nil {
+		defer file.Close()
+		return goquery.NewDocumentFromReader(file)
+	} else {
+		res, err := http.Get(url)
+		if err != nil {
+			return nil, err
+		}
+		defer res.Body.Close()
+
+		var buff bytes.Buffer
+		if _, err := buff.ReadFrom(res.Body); err != nil {
+			return nil, err
+		}
+
+		if err := ioutil.WriteFile(localPath, buff.Bytes(), 0644); err != nil {
+			return nil, err
+		}
+
+		return goquery.NewDocumentFromReader(&buff)
+	}
+}