1 files changed, 96 insertions, 0 deletions
diff --git a/spartan/response.go b/spartan/response.go
new file mode 100644
index 0000000..edc1db6
--- /dev/null
+++ b/spartan/response.go
@@ -0,0 +1,96 @@
+package spartan
+
+import (
+	"bytes"
+	"io"
+	"sync"
+
+	"tildegit.org/tjp/gus"
+)
+
+// The spartan response types.
+const (
+	StatusSuccess     gus.Status = 2
+	StatusRedirect    gus.Status = 3
+	StatusClientError gus.Status = 4
+	StatusServerError gus.Status = 5
+)
+
+// Success builds a successful spartan response.
+func Success(mediatype string, body io.Reader) *gus.Response {
+	return &gus.Response{
+		Status: StatusSuccess,
+		Meta:   mediatype,
+		Body:   body,
+	}
+}
+
+// Redirect builds a spartan redirect response.
+func Redirect(url string) *gus.Response {
+	return &gus.Response{
+		Status: StatusRedirect,
+		Meta:   url,
+	}
+}
+
+// ClientError builds a "client error" spartan response.
+func ClientError(err error) *gus.Response {
+	return &gus.Response{
+		Status: StatusClientError,
+		Meta: err.Error(),
+	}
+}
+
+// ServerError builds a "server error" spartan response.
+func ServerError(err error) *gus.Response {
+	return &gus.Response{
+		Status: StatusServerError,
+		Meta: err.Error(),
+	}
+}
+
+// NewResponseReader builds a reader for a response.
+func NewResponseReader(response *gus.Response) gus.ResponseReader {
+	return &responseReader{
+		Response: response,
+		once:     &sync.Once{},
+	}
+}
+
+type responseReader struct {
+	*gus.Response
+	reader io.Reader
+	once   *sync.Once
+}
+
+func (rdr *responseReader) Read(b []byte) (int, error) {
+	rdr.ensureReader()
+	return rdr.reader.Read(b)
+}
+
+func (rdr *responseReader) WriteTo(dst io.Writer) (int64, error) {
+	rdr.ensureReader()
+	return rdr.reader.(io.WriterTo).WriteTo(dst)
+}
+
+func (rdr *responseReader) ensureReader() {
+	rdr.once.Do(func() {
+		hdr := bytes.NewBuffer(rdr.headerLine())
+		if rdr.Body != nil {
+			rdr.reader = io.MultiReader(hdr, rdr.Body)
+		} else {
+			rdr.reader = hdr
+		}
+	})
+}
+
+func (rdr *responseReader) headerLine() []byte {
+	meta := rdr.Meta.(string)
+	buf := make([]byte, len(meta)+4)
+	buf[0] = byte(rdr.Status) + '0'
+	buf[1] = ' '
+	copy(buf[2:], meta)
+	buf[len(buf)-2] = '\r'
+	buf[len(buf)-1] = '\n'
+	return buf
+}