// 添加请求值或条目值到列表。
func appendDataList(dataList []base.Data, data base.Data, respDepth uint32) []base.Data {
if data == nil {
return dataList
}
req, ok := data.(*base.Request)
if !ok {
return append(dataList, data)
}
newDepth := respDepth + 1
if req.Depth() != newDepth {
req = base.NewRequest(req.HttpReq(), newDepth)
}
return append(dataList, req)
}
// 响应解析函数。只解析“A”标签。
func parseForATag(httpResp *http.Response, respDepth uint32) ([]base.Data, []error) {
// TODO 支持更多的HTTP响应状态
if httpResp.StatusCode != 200 {
err := errors.New(
fmt.Sprintf("Unsupported status code %d. (httpResponse=%v)", httpResp))
return nil, []error{err}
}
var reqUrl *url.URL = httpResp.Request.URL
var httpRespBody io.ReadCloser = httpResp.Body
defer func() {
if httpRespBody != nil {
httpRespBody.Close()
}
}()
dataList := make([]base.Data, 0)
errs := make([]error, 0)
// 开始解析
doc, err := goquery.NewDocumentFromReader(httpRespBody)
if err != nil {
errs = append(errs, err)
return dataList, errs
}
// 查找“A”标签并提取链接地址
doc.Find("a").Each(func(index int, sel *goquery.Selection) {
href, exists := sel.Attr("href")
// 前期过滤
if !exists || href == "" || href == "#" || href == "/" {
return
}
href = strings.TrimSpace(href)
lowerHref := strings.ToLower(href)
// 暂不支持对Javascript代码的解析。
if href != "" && !strings.HasPrefix(lowerHref, "javascript") {
aUrl, err := url.Parse(href)
if err != nil {
errs = append(errs, err)
return
}
if !aUrl.IsAbs() {
aUrl = reqUrl.ResolveReference(aUrl)
}
httpReq, err := http.NewRequest("GET", aUrl.String(), nil)
if err != nil {
errs = append(errs, err)
} else {
req := base.NewRequest(httpReq, respDepth)
dataList = append(dataList, req)
}
}
text := strings.TrimSpace(sel.Text())
if text != "" {
imap := make(map[string]interface{})
imap["parent_url"] = reqUrl
imap["a.text"] = text
imap["a.index"] = index
item := base.Item(imap)
dataList = append(dataList, &item)
}
})
return dataList, errs
}
func (sched *myScheduler) Start(
channelArgs base.ChannelArgs,
poolBaseArgs base.PoolBaseArgs,
crawlDepth uint32,
httpClientGenerator GenHttpClient,
respParsers []anlz.ParseResponse,
itemProcessors []ipl.ProcessItem,
firstHttpReq *http.Request) (err error) {
defer func() {
if p := recover(); p != nil {
errMsg := fmt.Sprintf("Fatal Scheduler Error: %s\n", p)
logger.Fatal(errMsg)
err = errors.New(errMsg)
}
}()
if atomic.LoadUint32(&sched.running) == 1 {
return errors.New("The scheduler has been started!\n")
}
atomic.StoreUint32(&sched.running, 1)
if err := channelArgs.Check(); err != nil {
return err
}
sched.channelArgs = channelArgs
if err := poolBaseArgs.Check(); err != nil {
return err
}
sched.poolBaseArgs = poolBaseArgs
sched.crawlDepth = crawlDepth
sched.chanman = generateChannelManager(sched.channelArgs)
if httpClientGenerator == nil {
return errors.New("The HTTP client generator list is invalid!")
}
dlpool, err :=
generatePageDownloaderPool(
sched.poolBaseArgs.PageDownloaderPoolSize(),
httpClientGenerator)
if err != nil {
errMsg :=
fmt.Sprintf("Occur error when get page downloader pool: %s\n", err)
return errors.New(errMsg)
}
sched.dlpool = dlpool
analyzerPool, err := generateAnalyzerPool(sched.poolBaseArgs.AnalyzerPoolSize())
if err != nil {
errMsg :=
fmt.Sprintf("Occur error when get analyzer pool: %s\n", err)
return errors.New(errMsg)
}
sched.analyzerPool = analyzerPool
if itemProcessors == nil {
return errors.New("The item processor list is invalid!")
}
for i, ip := range itemProcessors {
if ip == nil {
return errors.New(fmt.Sprintf("The %dth item processor is invalid!", i))
}
}
sched.itemPipeline = generateItemPipeline(itemProcessors)
if sched.stopSign == nil {
sched.stopSign = mdw.NewStopSign()
} else {
sched.stopSign.Reset()
}
sched.reqCache = newRequestCache()
sched.urlMap = make(map[string]bool)
sched.startDownloading()
sched.activateAnalyzers(respParsers)
sched.openItemPipeline()
sched.schedule(10 * time.Millisecond)
if firstHttpReq == nil {
return errors.New("The first HTTP request is invalid!")
}
pd, err := getPrimaryDomain(firstHttpReq.Host)
if err != nil {
return err
}
sched.primaryDomain = pd
firstReq := base.NewRequest(firstHttpReq, 0)
sched.reqCache.put(firstReq)
return nil
}