errors.go.tmpl

{{define "errors"}}
{{- /* Generates the classes for both base Webrpc errors and custom errors defined in the schema */ -}}

{{- $rpcErrors := .WebrpcErrors -}}
{{- $schemaErrors := .Errors -}}

/// Unrecoverable errors representing an invalid use of the API, bad schema, or
/// failure in the core of Webrpc (i.e. a bug).
class WebrpcError extends Error {
    WebrpcError._({
        required this.id, 
        required this.message, 
        required this.httpStatus,
    });
    
    factory WebrpcError.fromCode(int code) {
        switch (code) {
            {{- range $_, $_ := $rpcErrors}}
            {{- $isError := (lt .HTTPStatus 500)}}
            {{- if $isError}}
            case {{.Code}}:
                return WebrpcError._(
                    id: ErrorId.{{firstLetterToLower .Name}}, 
                    message: '{{.Message}}',
                    httpStatus: {{.HTTPStatus}},
                );
            {{end -}}
            {{end -}}

            {{- range $_, $_ := $schemaErrors}}
            {{- $isError := (lt .HTTPStatus 500)}}
            {{- if $isError}}
            case {{.Code}}:
                return WebrpcError._(
                    id: ErrorId.{{firstLetterToLower .Name}}, 
                    message: '{{.Message}}',
                    httpStatus: {{.HTTPStatus}},
                );
            {{end -}}
            {{end}}
            default:
                throw ArgumentError.value(code, "code", "Unrecognized");
        }
    }

    final ErrorId id;
    final String message;
    final int httpStatus;
}

/// Recoverable errors that should generally be caught, representing a
/// bad state or temporary failure.
class WebrpcException implements Exception {
    WebrpcException._({
        required this.id, 
        required this.message, 
        required this.httpStatus,
    });
    
    factory WebrpcException.fromCode(int code) {
        switch (code) {
            {{- range $_, $_ := $rpcErrors}}
            {{- $isError := (lt .HTTPStatus 500)}}
            {{- if (not $isError)}}
            case {{.Code}}:
                return WebrpcException._(
                    id: ErrorId.{{firstLetterToLower .Name}}, 
                    message: '{{.Message}}',
                    httpStatus: {{.HTTPStatus}},
                );
            {{end -}}
            {{end -}}

            {{- range $_, $_ := $schemaErrors}}
            {{- $isError := (lt .HTTPStatus 500)}}
            {{- if (not $isError)}}
            case {{.Code}}:
                return WebrpcException._(
                    id: ErrorId.{{firstLetterToLower .Name}}, 
                    message: '{{.Message}}',
                    httpStatus: {{.HTTPStatus}},
                );
            {{end -}}
            {{end}}
            default:
                throw ArgumentError.value(code, "code", "Unrecognized code $code");
        }
    }

    final ErrorId id;
    final String message;
    final int httpStatus;
}

/// Unique ID of a custom schema error or base Webrpc error.
enum ErrorId {
    {{- range $i, $_ := $rpcErrors}}
    {{firstLetterToLower .Name}}(code: {{.Code}}, name: '{{.Name}}')
    {{- if (lt $i (lastIndex $rpcErrors))}},{{else if $schemaErrors}},{{else}};{{end}}
    {{- end}}

    {{- range $i, $_ := $schemaErrors}}
    {{firstLetterToLower .Name}}(code: {{.Code}}, name: '{{.Name}}')
    {{- ternary (lt $i (lastIndex $schemaErrors)) "," ";"}}
    {{- end}}

    const ErrorId({
        required this.code,
        required this.name,
    });

    final int code;
    final String name;
}

{{end}}