diff options
Diffstat (limited to 'crawler.go')
-rw-r--r-- | crawler.go | 28 |
1 files changed, 17 insertions, 11 deletions
@@ -112,21 +112,27 @@ func (f FetcherFunc) Fetch(u string) (*http.Response, error) { // unless the handler returns the special error ErrRetryRequest. type Handler interface { // Handle the response from a URL. - Handle(*Crawler, string, int, *http.Response, error) error + Handle(Publisher, string, int, *http.Response, error) error } // HandlerFunc wraps a function into the Handler interface. -type HandlerFunc func(*Crawler, string, int, *http.Response, error) error +type HandlerFunc func(Publisher, string, int, *http.Response, error) error // Handle the response from a URL. -func (f HandlerFunc) Handle(db *Crawler, u string, depth int, resp *http.Response, err error) error { - return f(db, u, depth, resp, err) +func (f HandlerFunc) Handle(p Publisher, u string, depth int, resp *http.Response, err error) error { + return f(p, u, depth, resp, err) } // ErrRetryRequest is returned by a Handler when the request should be // retried after some time. var ErrRetryRequest = errors.New("retry_request") +// Publisher is an interface to something with an Enqueue() method to +// add new potential URLs to crawl. +type Publisher interface { + Enqueue(Outlink, int) error +} + // The Crawler object contains the crawler state. type Crawler struct { db *gobDB @@ -341,8 +347,8 @@ func (c *Crawler) Close() { // and adds them to the queue for crawling. It will call the wrapped // handler on all requests regardless. func FollowRedirects(wrap Handler) Handler { - return HandlerFunc(func(c *Crawler, u string, depth int, resp *http.Response, err error) error { - if herr := wrap.Handle(c, u, depth, resp, err); herr != nil { + return HandlerFunc(func(p Publisher, u string, depth int, resp *http.Response, err error) error { + if herr := wrap.Handle(p, u, depth, resp, err); herr != nil { return herr } @@ -356,7 +362,7 @@ func FollowRedirects(wrap Handler) Handler { if uerr != nil { log.Printf("error parsing Location header: %v", uerr) } else { - return c.Enqueue(Outlink{URL: locationURL, Tag: TagPrimary}, depth+1) + return p.Enqueue(Outlink{URL: locationURL, Tag: TagPrimary}, depth+1) } } return nil @@ -367,14 +373,14 @@ func FollowRedirects(wrap Handler) Handler { // "successful" HTTP status code (anything < 400). When using this // wrapper, subsequent Handle calls will always have err set to nil. func FilterErrors(wrap Handler) Handler { - return HandlerFunc(func(c *Crawler, u string, depth int, resp *http.Response, err error) error { + return HandlerFunc(func(p Publisher, u string, depth int, resp *http.Response, err error) error { if err != nil { return nil } if resp.StatusCode >= 400 { return nil } - return wrap.Handle(c, u, depth, resp, nil) + return wrap.Handle(p, u, depth, resp, nil) }) } @@ -382,11 +388,11 @@ func FilterErrors(wrap Handler) Handler { // temporary errors (all transport-level errors are considered // temporary, as well as any HTTP status code >= 500). func HandleRetries(wrap Handler) Handler { - return HandlerFunc(func(c *Crawler, u string, depth int, resp *http.Response, err error) error { + return HandlerFunc(func(p Publisher, u string, depth int, resp *http.Response, err error) error { if err != nil || resp.StatusCode == http.StatusTooManyRequests || resp.StatusCode >= 500 { return ErrRetryRequest } - return wrap.Handle(c, u, depth, resp, nil) + return wrap.Handle(p, u, depth, resp, nil) }) } |