NSLog show strange character instead of the JSON

Question

I have this code below that handles the response send by my server with sockets:

uint8_t buffer[4096];
        int len;
        NSMutableString *total = [[NSMutableString alloc] init];
        while ([inputStream hasBytesAvailable]) {
            len = (int)[inputStream read:buffer maxLength:sizeof(buffer)];
            if (len > 0) {

                NSLog(@"Buffer: %s",buffer);
                [total appendString: [[NSString alloc] initWithBytes:buffer length:len encoding:NSASCIIStringEncoding]];
                NSLog(@"Receive: %@, len: %d",total,len);
                NSLog(@"len: %d, receive: %@",len,total);

}

}

My server send a text file like this:

[{"name_user":"stack overflow","user_key":"XXXXXXX","type":21}]

The problem with this code is, if I send that JSON, the console log shows the length of that JSON. But If I send this JSON below:

[[{"name_user":"stack overflow","user_key":"XXXXXXX","type":21}],[{"name_user":"lacrifilm","user_key":"XXXXXXX","type":21}]]

That represents two values in JSON the console log shows:

Buffer: ~
Receive: ~
len: 184, receive: ~

I believe the problem is not in my server, because if it was I would be getting: Receive: ~, len: 184, instead of Receive: ~ without len: 184 as we saw in the second call of NSLog in my command above.

How can I solve this problem?

Possible duplicate of [Why doesn't cast work from NSData to String? Swift](http://stackoverflow.com/questions/36894972/why-doesnt-cast-work-from-nsdata-to-string-swift) — Larme, May 14 '16 at 10:13

score 2 · Accepted Answer · answered May 14 '16 at 02:49

2

You are building up your string incorrectly. You are reading a series of bytes, not pieces of a string. So build up an NSMutableData, and then create an NSString once you have all of the data. More like this:

uint8_t buffer[4096];
NSMutableData *data = [[NSMutableData alloc] init];
while ([inputStream hasBytesAvailable]) {
    NSInteger len = [inputStream read:buffer maxLength:sizeof(buffer)];
    if (len > 0) {
        //NSLog(@"Buffer: %s",buffer); // can't do this - buffer isn't a null-terminated C-string
        [data appendBytes:buffer length:len];
        NSLog(@"Receive: %@, len: %d", data, (int)len);
    }
}

NSString *total = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"Total: %@", total);

answered May 14 '16 at 02:49

rmaddy

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It works, I can see the hash of NSData but the NSString total is returning `null`, I believe that when I convert it to an NSArray I can see the values right? – Lacrifilm May 14 '16 at 03:00
2

If `total` is `nil` but `data` seems to have the right amount of data, then the string may not be in UTF-8 encoding. Do you know what string encoding your server is using? – rmaddy May 14 '16 at 03:01
2

And if you actually are using NSJSONSerialization, then there is no need to create a string. Just pass `data` in directly. Though that only works if `NSData` is a string encoded in one of 5 specific encodings (see the docs). – rmaddy May 14 '16 at 03:04

NSLog show strange character instead of the JSON

1 Answers1