146 lines
3.5 KiB
Go
146 lines
3.5 KiB
Go
/*
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* Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
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* Author: Alex Yatskov <alex@foosoft.net>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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package main
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import (
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"log"
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"net/url"
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"sync"
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"github.com/PuerkitoBio/goquery"
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)
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type review struct {
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name string
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address string
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url string
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features map[string]float64
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latitude float64
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longitude float64
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}
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type profiler interface {
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index(doc *goquery.Document) (string, []string)
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review(doc *goquery.Document) *review
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}
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func makeAbsUrl(ref, base string) (string, error) {
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b, err := url.Parse(base)
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if err != nil {
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return "", err
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}
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r, err := url.Parse(ref)
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if err != nil {
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return "", err
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}
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return b.ResolveReference(r).String(), nil
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}
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func decodeReviews(in chan review, out chan review, cache *geoCache) {
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for {
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if r, ok := <-in; ok {
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pos, err := cache.decode(r.address)
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if err == nil {
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r.latitude = pos.Latitude
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r.longitude = pos.Longitude
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out <- r
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} else {
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log.Printf("failed to decode address for %s (%v)", r.url, err)
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}
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} else {
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close(out)
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return
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}
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}
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}
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func scrapeReview(url string, out chan review, cache *webCache, group *sync.WaitGroup, prof profiler) {
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defer group.Done()
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doc, err := cache.load(url)
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if err != nil {
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log.Printf("failed to scrape review at %s (%v)", url, err)
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} else if r := prof.review(doc); r != nil {
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r.url = url
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out <- *r
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}
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}
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func scrapeIndex(indexUrl string, out chan review, cache *webCache, prof profiler) {
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doc, err := cache.load(indexUrl)
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if err != nil {
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log.Printf("failed to scrape index at %s (%v)", indexUrl, err)
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return
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}
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nextIndexUrl, reviewUrls := prof.index(doc)
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if err != nil {
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log.Fatal(err)
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}
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var group sync.WaitGroup
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for _, reviewUrl := range reviewUrls {
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absUrl, err := makeAbsUrl(reviewUrl, indexUrl)
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if err != nil {
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log.Fatal(err)
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}
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group.Add(1)
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go scrapeReview(absUrl, out, cache, &group, prof)
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}
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group.Wait()
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if nextIndexUrl == "" {
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close(out)
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} else {
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absUrl, err := makeAbsUrl(nextIndexUrl, indexUrl)
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if err != nil {
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log.Fatal(err)
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}
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scrapeIndex(absUrl, out, cache, prof)
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}
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}
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func scrape(url string, wc *webCache, gc *geoCache, prof profiler) []review {
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scrapeChan := make(chan review)
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decodeChan := make(chan review)
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go scrapeIndex(url, scrapeChan, wc, prof)
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go decodeReviews(scrapeChan, decodeChan, gc)
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var reviews []review
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for {
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if r, ok := <-decodeChan; ok {
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log.Print(r.name)
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reviews = append(reviews, r)
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} else {
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return reviews
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}
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}
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}
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