Function CELMatcherImpl

modules/caddyhttp/celmatcher.go:391–434

CELMatcherImpl creates a new cel.Library based on the following pieces of data: - macroName: the function name to be used within CEL. This will be a macro and not a function proper. - funcName: the function overload name generated by the CEL macro used to represent the matcher. - matcherDataTypes:

(macroName, funcName string, matcherDataTypes []*cel.Type, fac any)

// to provide a custom macro which does a more detailed analysis of the CEL
// literal provided to the macro as an argument.
func CELMatcherImpl(macroName, funcName string, matcherDataTypes []*cel.Type, fac any) (cel.Library, error) {
	requestType := cel.ObjectType("http.Request")
	var macro parser.Macro
	switch len(matcherDataTypes) {
	case 1:
		matcherDataType := matcherDataTypes[0]
		switch matcherDataType.String() {
		case "list(string)":
			macro = parser.NewGlobalVarArgMacro(macroName, celMatcherStringListMacroExpander(funcName))
		case cel.StringType.String():
			macro = parser.NewGlobalMacro(macroName, 1, celMatcherStringMacroExpander(funcName))
		case CELTypeJSON.String():
			macro = parser.NewGlobalMacro(macroName, 1, celMatcherJSONMacroExpander(funcName))
		default:
			return nil, fmt.Errorf("unsupported matcher data type: %s", matcherDataType)
		}
	case 2:
		if matcherDataTypes[0] == cel.StringType && matcherDataTypes[1] == cel.StringType {
			macro = parser.NewGlobalMacro(macroName, 2, celMatcherStringListMacroExpander(funcName))
			matcherDataTypes = []*cel.Type{cel.ListType(cel.StringType)}
		} else {
			return nil, fmt.Errorf("unsupported matcher data type: %s, %s", matcherDataTypes[0], matcherDataTypes[1])
		}
	case 3:
		// nolint:gosec // false positive, impossible to be out of bounds; see: https://github.com/securego/gosec/issues/1525
		if matcherDataTypes[0] == cel.StringType && matcherDataTypes[1] == cel.StringType && matcherDataTypes[2] == cel.StringType {
			macro = parser.NewGlobalMacro(macroName, 3, celMatcherStringListMacroExpander(funcName))
			matcherDataTypes = []*cel.Type{cel.ListType(cel.StringType)}
		} else {
			// nolint:gosec // false positive, impossible to be out of bounds; see: https://github.com/securego/gosec/issues/1525
			return nil, fmt.Errorf("unsupported matcher data type: %s, %s, %s", matcherDataTypes[0], matcherDataTypes[1], matcherDataTypes[2])
		}
	}
	envOptions := []cel.EnvOption{
		cel.Macros(macro),
		cel.Function(funcName,
			cel.Overload(funcName, append([]*cel.Type{requestType}, matcherDataTypes...), cel.BoolType),
			cel.SingletonBinaryBinding(CELMatcherRuntimeFunction(funcName, fac))),
	}
	programOptions := []cel.ProgramOption{
		cel.CustomDecorator(CELMatcherDecorator(funcName, fac)),
	}
	return NewMatcherCELLibrary(envOptions, programOptions), nil
}

// CELMatcherFactory converts a constant CEL value into a RequestMatcher.
// Deprecated: Use CELMatcherWithErrorFactory instead.