从 Node.js 向 iOS 发送变音符号

Question

我不知道这是 Node.js 还是 iOS 问题，但是当我尝试发送包含变音符号（ä、ö 和 ü）的 JSON 对象时，设置的内容长度似乎是错误的。

这是我的设置：

我的 Node.js 服务器通过以下方式发送数据：

[..mongodb request..].toArray(function(err, result) {
    res.setHeader('Content-Type', 'application/json');
    var body = JSON.stringify(result);

    console.log(body);
    console.log(body.length);

    res.setHeader('charset', 'utf8');
    res.setHeader('Content-Length', body.length);
    res.end(body);
});

这会产生以下对象：

[
{
    "_id": "51da7eb5d5f9ad77302a26c6",
    "loc": [
        53.560994,
        9.929796
    ],
    "street": "Kühnehöfe 25",
    "time": 1373273781535
},
{
    "_id": "51da7eb9d5f9ad77302a26c7",
    "loc": [
        53.561899,
        9.930203
    ],
    "street": "Kühnehöfe 17",
    "time": 1373273785156
}
]

其中（解析为字符串）长度为 215。这也设置为内容长度。

在我的 iOS 项目中，我有以下设置：

-(void)serverRequest {

    // Initialize new mutable data
    NSMutableData *data = [[NSMutableData alloc] init];
    self.receivedData = data;

    // Initialize URL that is going to be fetched.
    NSURL *url = [NSURL URLWithString:@"http://localhost:8000/getSpots"];

    // Initialize a request from a URL
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[url standardizedURL]];

    // Set HTTP method
    [request setHTTPMethod:@"POST"];

    // Initialize post data
    NSDictionary* jsonDict = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:coordinate.latitude], @"lat", [NSNumber numberWithFloat:coordinate.longitude], @"lng", accessToken, @"accessToken", nil];//dictionaryWithObjectsAndKeys:coord.latitude, nil]
    NSError *error;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonDict
                                                   options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
                                                     error:&error];

    // Set request content type we MUST set this value.
    [request setValue:@"application/json; charset=utf-8" forHTTPHeaderField:@"content-type"];

    // Set post data of request
    [request setHTTPBody:jsonData];

    // Initialize a connection from request
    NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    self.connectionGetSpots = connection;

    // Start the connection
    [connection start];
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
    [self.receivedData appendData:data];

    NSLog(@"loading: %d, %lld", [self.receivedData length], dataSize);  // Both 215 (correct)
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
    dataSize = [response expectedContentLength];
    NSLog(@"dataSize: %lld", dataSize);  // is 215 (correct)
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
    NSString *responseData = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];
    NSLog(@"rD: %@, %d" ,responseData, [responseData length]);
}

connectionDidFinishLoading 函数记录以下内容：

[
{
    "_id": "51da7eb5d5f9ad77302a26c6",
    "loc": [
        53.560994,
        9.929796
    ],
    "street": "Kühnehöfe 25",
    "time": 1373273781535
},
{
    "_id": "51da7eb9d5f9ad77302a26c7",
    "loc": [
        53.561899,
        9.930203
    ],
    "street": "Kühnehöfe 17",
    "time": 13732737851
,211

如您所见，JSON 对象中有四个变音符号，并且缺少四个字符。如果我添加另一个带有两个变音符号的位置，则会丢失另外两个字符。

我猜某处内容类型设置错误，但我不确定我必须做什么。

Answer 1

将此用于正确的 UTF-8 长度：

new Buffer(body).length