refactor scraper into modules

1 files changed, 85 insertions, 0 deletions

diff --git a/modules/urlfilter/urlfilter.go b/modules/urlfilter/urlfilter.go
new file mode 100644
index 0000000..14576f0
--- /dev/null
+++ b/modules/urlfilter/urlfilter.go
@@ -0,0 +1,85 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package urlfilter
+
+import (
+	"regexp"
+
+	"github.com/philippta/flyscrape"
+)
+
+func init() {
+	flyscrape.RegisterModule(new(Module))
+}
+
+type Module struct {
+	URL         string   `json:"url"`
+	AllowedURLs []string `json:"allowedURLs"`
+	BlockedURLs []string `json:"blockedURLs"`
+
+	allowedURLsRE []*regexp.Regexp
+	blockedURLsRE []*regexp.Regexp
+}
+
+func (m *Module) ID() string {
+	return "urlfilter"
+}
+
+func (m *Module) OnLoad(v flyscrape.Visitor) {
+	for _, pat := range m.AllowedURLs {
+		re, err := regexp.Compile(pat)
+		if err != nil {
+			continue
+		}
+		m.allowedURLsRE = append(m.allowedURLsRE, re)
+	}
+
+	for _, pat := range m.BlockedURLs {
+		re, err := regexp.Compile(pat)
+		if err != nil {
+			continue
+		}
+		m.blockedURLsRE = append(m.blockedURLsRE, re)
+	}
+}
+
+func (m *Module) CanRequest(rawurl string, depth int) bool {
+	// allow root url
+	if rawurl == m.URL {
+		return true
+	}
+
+	// allow if no filter is set
+	if len(m.allowedURLsRE) == 0 && len(m.blockedURLsRE) == 0 {
+		return true
+	}
+
+	ok := false
+	if len(m.allowedURLsRE) == 0 {
+		ok = true
+	}
+
+	for _, re := range m.allowedURLsRE {
+		if re.MatchString(rawurl) {
+			ok = true
+			break
+		}
+	}
+
+	for _, re := range m.blockedURLsRE {
+		if re.MatchString(rawurl) {
+			ok = false
+			break
+		}
+	}
+
+	return ok
+}
+
+var (
+	_ flyscrape.Module     = (*Module)(nil)
+	_ flyscrape.CanRequest = (*Module)(nil)
+	_ flyscrape.OnLoad     = (*Module)(nil)
+)