Add DShield example for fetching and parsing blocklist data

examples/dshield.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+
+	"git.kor-elf.net/kor-elf-shield/blocklist"
+	"git.kor-elf.net/kor-elf-shield/blocklist/parser"
+)
+
+/**
+ * An example of how to get a list of bad IP addresses from the service https://dshield.org/
+ */
+
+func main() {
+	url := "https://www.dshield.org/block.txt"
+	extract := parser.NewCIDRTextExtract(0, 2, "\t")
+	pars, err := parser.NewText(extract)
+	if err != nil {
+		panic(err)
+	}
+	config := blocklist.NewConfig(0)
+	ips, err := blocklist.Get(url, pars, config)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println(ips)
+
+	/*
+		// You can also get a range of IP addresses from this service (from to)
+		url := "https://www.dshield.org/block.txt"
+		extract := parser.NewIntervalTextExtract(0, 1, "\t")
+		pars, err := parser.NewText(extract)
+		if err != nil {
+			panic(err)
+		}
+		config := blocklist.NewConfigWithValidator(0, &parser.IPRangeValidator{})
+		ips, err := blocklist.Get(url, pars, config)
+		if err != nil {
+			panic(err)
+		}
+		fmt.Println(ips)
+	*/
+}