finger protocol client

finger/client.go

@@ -0,0 +1,59 @@
+package finger
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net"
+	"strings"
+
+	sr "tildegit.org/tjp/sliderule"
+)
+
+// Client is used for sending finger requests and reading responses.
+//
+// It carries no state and is reusable simultaneously by multiple goroutines.
+//
+// The zero value is immediately usable.
+type Client struct{}
+
+// RoundTrip sends a single finger request and returns its response.
+func (c Client) RoundTrip(request *sr.Request) (*sr.Response, error) {
+	if request.Scheme != "finger" && request.Scheme != "" {
+		return nil, errors.New("non-finger protocols not supported")
+	}
+
+	host := request.Host
+	if _, port, _ := net.SplitHostPort(host); port == "" {
+		host = net.JoinHostPort(host, "79")
+	}
+
+	conn, err := net.Dial("tcp", host)
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	request.RemoteAddr = conn.RemoteAddr()
+	request.TLSState = nil
+
+	if _, err := conn.Write([]byte(strings.TrimPrefix(request.Path, "/") + "\r\n")); err != nil {
+		return nil, err
+	}
+
+	response, err := io.ReadAll(conn)
+	if err != nil {
+		return nil, err
+	}
+
+	return &sr.Response{Body: bytes.NewBuffer(response)}, nil
+}
+
+// Fetch resolves a finger query.
+func (c Client) Fetch(query string) (*sr.Response, error) {
+	req, err := ParseRequest(bytes.NewBufferString(query + "\r\n"))
+	if err != nil {
+		return nil, err
+	}
+	return c.RoundTrip(req)
+}