http response tooling written

internal/site/response/write.go

@@ -0,0 +1,56 @@
+package response
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+)
+
+func Write(w http.ResponseWriter, r *http.Request, res Response) {
+	// w.Header() must be set before ResponseWriter.WriteHeader is called
+	// or redirect is attempted
+	hdrs := w.Header()
+	for _, ck := range res.getCookies() {
+		hdrs.Add("Set-Cookie", ck.String())
+	}
+
+	if code, to, ok := res.getRedirect(); ok {
+		http.Redirect(w, r, to, code.Int())
+		return
+	}
+
+	// the body is written after the status header, but it's read here
+	// first, because if an error is incurred, an error status header will
+	// need to be written.
+	body, bodySet, err := res.getBody()
+	if err != nil {
+		http.Error(
+			w,
+			fmt.Sprintf("Failed to construct response body: %v", err.Error()),
+			http.StatusInternalServerError,
+		)
+		return
+	}
+
+	if status, ok := res.getStatus(); ok {
+		w.WriteHeader(status)
+	}
+	if bodySet {
+		// will automatically set the status header,
+		// if w.WriteHeader wasn't already called
+		io.Copy(w, body)
+	}
+
+}
+
+func WriteError(w http.ResponseWriter, err error) {
+	var status int
+
+	if e, ok := getError(err); ok {
+		if status, ok = e.getStatus(); !ok {
+			status = http.StatusInternalServerError
+		}
+	}
+
+	http.Error(w, err.Error(), status)
+}