Function applyHeaderOp

modules/caddyhttp/headers/caddyfile.go:225–289

(ops *HeaderOps, respHeaderOps *RespHeaderOps, field, value string, replacement *string)

}

func applyHeaderOp(ops *HeaderOps, respHeaderOps *RespHeaderOps, field, value string, replacement *string) error {
	switch {
	case strings.HasPrefix(field, "+"): // append
		if ops.Add == nil {
			ops.Add = make(http.Header)
		}
		ops.Add.Add(field[1:], value)

	case strings.HasPrefix(field, "-"): // delete
		ops.Delete = append(ops.Delete, field[1:])
		if respHeaderOps != nil {
			respHeaderOps.Deferred = true
		}

	case strings.HasPrefix(field, "?"): // default (conditional on not existing) - response headers only
		if respHeaderOps == nil {
			return fmt.Errorf("%v: the default header modifier ('?') can only be used on response headers; for conditional manipulation of request headers, use matchers", field)
		}
		if respHeaderOps.Require == nil {
			respHeaderOps.Require = &caddyhttp.ResponseMatcher{
				Headers: make(http.Header),
			}
		}
		field = strings.TrimPrefix(field, "?")
		respHeaderOps.Require.Headers[field] = nil
		if respHeaderOps.Set == nil {
			respHeaderOps.Set = make(http.Header)
		}
		respHeaderOps.Set.Set(field, value)

	case replacement != nil: // replace
		// allow defer shortcut for replace syntax
		if strings.HasPrefix(field, ">") && respHeaderOps != nil {
			respHeaderOps.Deferred = true
		}
		if ops.Replace == nil {
			ops.Replace = make(map[string][]Replacement)
		}
		field = strings.TrimLeft(field, "+-?>")
		ops.Replace[field] = append(
			ops.Replace[field],
			Replacement{
				SearchRegexp: value,
				Replace:      *replacement,
			},
		)

	case strings.HasPrefix(field, ">"): // set (overwrite) with defer
		if ops.Set == nil {
			ops.Set = make(http.Header)
		}
		ops.Set.Set(field[1:], value)
		if respHeaderOps != nil {
			respHeaderOps.Deferred = true
		}

	default: // set (overwrite)
		if ops.Set == nil {