JSON 中的无效类型写入 (RTCIceCandidate)

Question

我正在使用 websocket 来调用 received、accept 等等。我在接受呼叫时收到 websocket 事件。

websocket 接受事件输出：-

{
    action = signal;
    "call_id" = 60a4d5b4850b3875f95dbc6e;
    event = CALL;
    from = 5b30ec0fa4cef4609038470b;
    id = "330A1A48-A6BA-4B29-A4A2-9D9FDB85144D";
    signal =     {
        offer = "RTC_OBJC_TYPE(RTCIceCandidate):\naudio\n0\ncandidate:1211696075 1 udp 41885439 3.8.66.208 62545 typ relay raddr 0.0.0.0 rport 0 generation 0 ufrag DT/j network-id 1 network-cost 10\nturn:3.8.66.208:3478?transport=udp";
    };
    to = 5b4854724f82e91934c1c475;
}

我正在使用下面的代码将上面的字典对象转换为 json 字符串。

-(NSString *)convertDictionaryToJsonString:(NSMutableDictionary *)dict {
    NSError *error;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:&error];
    NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    return jsonString;
}

问题：- 应用程序崩溃，原因是 - 'Invalid type in JSON write (RTCIceCandidate)'

谁能知道如何避免崩溃并解决这个问题？

谢谢。

Answer 1

以下是 JSON 的有效类型：

A Foundation object that may be converted to JSON must have the following properties:

The top level object is an NSArray or NSDictionary.

All objects are instances of NSString, NSNumber, NSArray, NSDictionary, or NSNull.

All dictionary keys are instances of NSString.

Numbers are not NaN or infinity.

你的错误是说在某些时候，有一个对象不是允许的类型，它是 RTCIceCandidate。

看到 "RTC_OBJC_TYPE(RTCIceCandidate):\naudio\n0\ncandidate:1211696075 1 udp 41885439 3.8.66.208 62545 typ relay raddr 0.0.0.0 rport 0 generation 0 ufrag DT/j network-id 1 network-cost 10\nturn:3.8.66.208:3478?transport=udp" 让你认为它确实是一个 NSString 但是，如果我们看到 RTCIceCandidate 的代码（因为它是罪魁祸首 class），我们就会看到覆盖 description:

- (NSString *)description {
  return [NSString stringWithFormat:@"RTCIceCandidate:\n%@\n%d\n%@\n%@",
                                    _sdpMid,
                                    _sdpMLineIndex,
                                    _sdp,
                                    _serverUrl];
}

有一个 RTCIceCandidate+JSON extension 提供了一些有趣的方法将 RTCIceCandidate 转换为 JSONString/JSONData。

您需要将罪魁祸首对象替换为允许的对象 class。

RTCIceCandidate *candidate = dict["signal"]["offer"];
NSString/NSDictionary *candidateValid = //Whatever the method you want with a method from RTCIceCandidate+JSON, custom one ?

dict[@"signal"] = @{@"offer": candidateValid}; //Because I guess that dict[@"signal"] is in a fact a `NSDictionary` and not a `NSMutableDictionary`

//Current code

JSON 中的无效类型写入 (RTCIceCandidate)

Invalid type in JSON write (RTCIceCandidate)

json

dictionary

objective-c

websocket

ios