From 79cbe7bfd06565d0e7ab0717119f78960ed54c08 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Tue, 22 Mar 2022 10:47:21 -0600
Subject: httpcaddyfile: Add 'vars' directive

See discussion in #4650
---
 modules/caddyhttp/vars.go | 66 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 59 insertions(+), 7 deletions(-)

(limited to 'modules/caddyhttp/vars.go')

diff --git a/modules/caddyhttp/vars.go b/modules/caddyhttp/vars.go
index b0f10a7..28d0ddf 100644
--- a/modules/caddyhttp/vars.go
+++ b/modules/caddyhttp/vars.go
@@ -37,7 +37,7 @@ func init() {
 //
 // The key is the variable name, and the value is the value of the
 // variable. Both the name and value may use or contain placeholders.
-type VarsMiddleware map[string]string
+type VarsMiddleware map[string]interface{}
 
 // CaddyModule returns the Caddy module information.
 func (VarsMiddleware) CaddyModule() caddy.ModuleInfo {
@@ -47,17 +47,67 @@ func (VarsMiddleware) CaddyModule() caddy.ModuleInfo {
 	}
 }
 
-func (t VarsMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
+func (m VarsMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
 	vars := r.Context().Value(VarsCtxKey).(map[string]interface{})
 	repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
-	for k, v := range t {
+	for k, v := range m {
 		keyExpanded := repl.ReplaceAll(k, "")
-		valExpanded := repl.ReplaceAll(v, "")
-		vars[keyExpanded] = valExpanded
+		if valStr, ok := v.(string); ok {
+			v = repl.ReplaceAll(valStr, "")
+		}
+		vars[keyExpanded] = v
 	}
 	return next.ServeHTTP(w, r)
 }
 
+// UnmarshalCaddyfile implements caddyfile.Unmarshaler. Syntax:
+//
+//     vars [<name> <val>] {
+//         <name> <val>
+//         ...
+//     }
+//
+func (m *VarsMiddleware) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	if *m == nil {
+		*m = make(VarsMiddleware)
+	}
+
+	nextVar := func(headerLine bool) error {
+		if headerLine {
+			// header line is optional
+			if !d.NextArg() {
+				return nil
+			}
+		}
+		varName := d.Val()
+
+		if !d.NextArg() {
+			return d.ArgErr()
+		}
+		varValue := d.ScalarVal()
+
+		(*m)[varName] = varValue
+
+		if d.NextArg() {
+			return d.ArgErr()
+		}
+		return nil
+	}
+
+	for d.Next() {
+		if err := nextVar(true); err != nil {
+			return err
+		}
+		for nesting := d.Nesting(); d.NextBlock(nesting); {
+			if err := nextVar(false); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
 // VarsMatcher is an HTTP request matcher which can match
 // requests based on variables in the context. The key is
 // the name of the variable, and the values are possible
@@ -261,6 +311,8 @@ func SetVar(ctx context.Context, key string, value interface{}) {
 
 // Interface guards
 var (
-	_ MiddlewareHandler = (*VarsMiddleware)(nil)
-	_ RequestMatcher    = (*VarsMatcher)(nil)
+	_ MiddlewareHandler     = (*VarsMiddleware)(nil)
+	_ caddyfile.Unmarshaler = (*VarsMiddleware)(nil)
+	_ RequestMatcher        = (*VarsMatcher)(nil)
+	_ caddyfile.Unmarshaler = (*VarsMatcher)(nil)
 )
-- 
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