a parser for questions that hashy supports

request.go

@@ -0,0 +1,51 @@
+package hashy
+
+import (
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+// Request represents a DNS request to hashy that hashy recognizes.
+type Request struct {
+	// ID is the value to hash. This is required.
+	ID string
+
+	// Nonce is an optional entropy value sent by the client.
+	Nonce string
+
+	// Group is the optional group name to restrict returned services.
+	Group string
+
+	// Qtype is the record type being requested.
+	Qtype uint16
+
+	// Origin is the domain that hashy recognized when it parsed this request.
+	Origin string
+}
+
+// QuestionParser provides the logic to parse a DNS question into a request
+// that hashy recognizes.
+type QuestionParser struct {
+	// Origin is the domain that is supported for hashy queries.
+	Origin string
+}
+
+// Parse examines a DNS question and produces a Request. If the question
+// is not supported, this method returns false.
+func (qp *QuestionParser) Parse(q dns.Question) (r Request, supported bool) {
+	if q.Qclass != dns.ClassINET && q.Qclass != dns.ClassANY {
+		return
+	}
+
+	prefix, found := strings.CutSuffix(q.Name, qp.Origin)
+	if !found {
+		return
+	}
+
+	r.Qtype = q.Qtype
+	r.Origin = qp.Origin
+	r.ID, r.Group, _ = strings.Cut(prefix, ".")
+	r.ID, r.Nonce, _ = strings.Cut(r.ID, "-")
+	return
+}