Initial commit

pipe/dsl/context.go

@@ -0,0 +1,59 @@
+package dsl
+
+import (
+	"github.com/BytemarkHosting/go-pdns/pipe/backend"
+	"strconv"
+)
+
+// Callbacks are run with a context instance, which allows them to accumulate
+// answers while maintaining a short type signature. It will also make
+// concurrent callbacks easier, when we handle that, but for now one context
+// is maintained across all callbacks for a particular query
+type Context struct {
+	// Replies that don't specify a TTL will be given this instead.
+	DefaultTTL int
+
+	// The query that triggered this callback run. Note that its QType
+	// member may be "ANY"
+	Query *backend.Query
+
+	// QType this callback is being run as. Matches the qtype field given
+	// with the callback at the time DSL.Register was called
+	QType string
+
+	// The callback is registered with a regexp; if that regexp contains
+	// any match groups, then the matched text is placed here.
+	Matches []string
+
+	// Set this if an error has been encountered; no more callbacks will be
+	// run, and the error text (only) will be reported to the backend.
+	Error error
+
+	// Answers to be sent to the backend are stored here. Context.Reply()
+	// calls, etc, generate answers and put them here, for instance.
+	// If multiple callbacks are being run, then later callbacks will be
+	// able to see the answers earlier ones generated (for now)
+	Answers []*backend.Response
+}
+
+// Add an answer, using default QName and TTL for the query
+func (c *Context) Reply(content string) {
+	c.ReplyExtra(c.Query.QName, content, c.DefaultTTL)
+}
+
+// Add an answer, using the default QName but specifying a particular TTL
+func (c *Context) ReplyTTL(content string, ttl int) {
+	c.ReplyExtra(c.Query.QName, content, ttl)
+}
+
+// Add an answer, specifying both QName and TTL.
+func (c *Context) ReplyExtra(qname, content string, ttl int) {
+	c.Answers = append(c.Answers, &backend.Response{
+		QName:   qname,
+		QClass:  c.Query.QClass,
+		QType:   c.QType, // q.Query.QType may == "ANY"
+		Id:      c.Query.Id,
+		Content: content,
+		TTL:     strconv.Itoa(ttl),
+	})
+}