Line data    Source code

       1              : import 'dart:async';
       2              : import 'dart:convert';
       3              : 
       4              : import 'package:http/http.dart';
       5              : 
       6              : // ignore: one_member_abstracts
       7              : 
       8              : /// RPC Service base class.
       9              : abstract class RpcService {
      10              :   /// Constructor.
      11            4 :   RpcService(this.url);
      12              : 
      13              :   /// Url.
      14              :   final String url;
      15              : 
      16              :   /// Performs an RPC request, asking the server to execute the function with
      17              :   /// the given name and the associated parameters, which need to be encodable
      18              :   /// with the [json] class of dart:convert.
      19              :   ///
      20              :   /// When the request is successful, an [RPCResponse] with the request id and
      21              :   /// the data from the server will be returned. If not, an RPCError will be
      22              :   /// thrown. Other errors might be thrown if an IO-Error occurs.
      23              :   Future<RPCResponse> call(String function, [List<dynamic>? params]);
      24              : }
      25              : 
      26              : /// Json RPC Service.
      27              : class JsonRPC extends RpcService {
      28              :   /// Constructor.
      29            8 :   JsonRPC(String url, this.client) : super(url);
      30              : 
      31              :   /// Http client.
      32              :   final Client client;
      33              : 
      34              :   int _currentRequestId = 1;
      35              : 
      36              :   /// Performs an RPC request, asking the server to execute the function with
      37              :   /// the given name and the associated parameters, which need to be encodable
      38              :   /// with the [json] class of dart:convert.
      39              :   ///
      40              :   /// When the request is successful, an [RPCResponse] with the request id and
      41              :   /// the data from the server will be returned. If not, an RPCError will be
      42              :   /// thrown. Other errors might be thrown if an IO-Error occurs.
      43            4 :   @override
      44              :   Future<RPCResponse> call(String function, [List<dynamic>? params]) async {
      45            4 :     params ??= [];
      46              : 
      47            4 :     final requestPayload = {
      48              :       'jsonrpc': '2.0',
      49              :       'method': function,
      50              :       'params': params,
      51            8 :       'id': _currentRequestId++,
      52              :     };
      53              : 
      54            8 :     final response = await client.post(
      55            8 :       Uri.parse(url),
      56            4 :       headers: {'Content-Type': 'application/json'},
      57            4 :       body: json.encode(requestPayload),
      58              :     );
      59              : 
      60            8 :     if (response.statusCode != 200) {
      61            6 :       throw HttpError(response.statusCode, response.body);
      62              :     }
      63              : 
      64            8 :     final data = json.decode(response.body) as Map<String, dynamic>;
      65              : 
      66            4 :     if (data.containsKey('error')) {
      67            1 :       final error = data['error'];
      68              : 
      69            1 :       final code = error['code'] as int;
      70            1 :       final message = error['message'] as String;
      71            1 :       final errorData = error['data'];
      72              : 
      73            1 :       throw RPCError(code, message, errorData);
      74              :     }
      75              : 
      76            4 :     final id_d = data['id'];
      77            4 :     final id = id_d is int ? id_d : int.tryParse(id_d as String);
      78            4 :     final result = data['result'];
      79            4 :     return RPCResponse(id ?? -1, result);
      80              :   }
      81              : }
      82              : 
      83              : /// Response from the server to an rpc request. Contains the id of the request
      84              : /// and the corresponding result as sent by the server.
      85              : class RPCResponse {
      86              :   /// Constructor.
      87            5 :   const RPCResponse(this.id, this.result);
      88              : 
      89              :   /// Id.
      90              :   final int id;
      91              : 
      92              :   /// Result.
      93              :   final dynamic result;
      94              : }
      95              : 
      96              : /// Exception thrown when an the server returns an error code to an rpc request.
      97              : class RPCError implements Exception {
      98              :   /// Constructor.
      99            1 :   const RPCError(this.errorCode, this.message, this.data);
     100              : 
     101              :   /// Error code.
     102              :   final int errorCode;
     103              : 
     104              :   /// Message.
     105              :   final String message;
     106              : 
     107              :   /// Data.
     108              :   final dynamic data;
     109              : 
     110            1 :   @override
     111              :   String toString() {
     112            3 :     return 'RPCError: got code $errorCode with msg "$message".';
     113              :   }
     114              : }
     115              : 
     116              : class HttpError implements Exception {
     117              :   /// Constructor.
     118            2 :   const HttpError(this.statusCode, this.message);
     119              : 
     120              :   /// Status code.
     121              :   final int statusCode;
     122              : 
     123              :   /// Message.
     124              :   final String message;
     125              : 
     126            2 :   @override
     127              :   String toString() {
     128            6 :     return 'HttpError: got code $statusCode with msg "$message".';
     129              :   }
     130              : }