Begin implementing HTTP replacer and static responder

1 files changed, 75 insertions, 0 deletions

diff --git a/modules/caddyhttp/replacer.go b/modules/caddyhttp/replacer.go
new file mode 100644
index 0000000..6a2ecd1
--- /dev/null
+++ b/modules/caddyhttp/replacer.go
@@ -0,0 +1,75 @@
+package caddyhttp
+
+import (
+	"net/http"
+	"strings"
+)
+
+type Replacer struct {
+	req    *http.Request
+	resp   http.ResponseWriter
+	custom map[string]string
+}
+
+// Map sets a custom variable mapping to a value.
+func (r *Replacer) Map(variable, value string) {
+	r.custom[variable] = value
+}
+
+// Replace replaces placeholders in input with the value. If
+// the value is empty string, the placeholder is substituted
+// with the value empty.
+func (r *Replacer) Replace(input, empty string) string {
+	if !strings.Contains(input, phOpen) {
+		return input
+	}
+
+	input = r.replaceAll(input, empty, r.defaults())
+	input = r.replaceAll(input, empty, r.custom)
+
+	return input
+}
+
+func (r *Replacer) replaceAll(input, empty string, mapping map[string]string) string {
+	for key, val := range mapping {
+		if val == "" {
+			val = empty
+		}
+		input = strings.ReplaceAll(input, phOpen+key+phClose, val)
+	}
+	return input
+}
+
+func (r *Replacer) defaults() map[string]string {
+	m := map[string]string{
+		"host":   r.req.Host,
+		"method": r.req.Method,
+		"scheme": func() string {
+			if r.req.TLS != nil {
+				return "https"
+			}
+			return "http"
+		}(),
+		"uri": r.req.URL.RequestURI(),
+	}
+
+	for field, vals := range r.req.Header {
+		m[">"+strings.ToLower(field)] = strings.Join(vals, ",")
+	}
+
+	for field, vals := range r.resp.Header() {
+		m["<"+strings.ToLower(field)] = strings.Join(vals, ",")
+	}
+
+	for _, cookie := range r.req.Cookies() {
+		m["~"+cookie.Name] = cookie.Value
+	}
+
+	for param, vals := range r.req.URL.Query() {
+		m["?"+param] = strings.Join(vals, ",")
+	}
+
+	return m
+}
+
+const phOpen, phClose = "{", "}"