NSJSONSerialization error - objective-c

Question

I'm trying to send json object to server. But I received an error and I can't fix it.
-(void) connectToHost{
CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)#"localhost", 9123, &readStream, &writeStream);
inputStream = (__bridge NSInputStream *)readStream;
outputStream = (__bridge NSOutputStream *)writeStream;
[inputStream setDelegate:self];
[outputStream setDelegate:self];
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[inputStream open];
[outputStream open]; }
This is my connection to host.
NSDictionary *setUser = [NSDictionary
dictionaryWithObjectsAndKeys:[#"u" stringByAppendingString:my.id],#"id",
#"GET_USER_INFO",#"command",
#"",#"value",
nil];
NSArray *array = [NSArray arrayWithObject:setUser];
jsonDataToSendTheServer = [array JSONRepresentation];
NSLog(#" %# ", jsonDataToSendTheServer);
// array = [NSArray arrayWithObject:jsonDataToSendTheServer];
NSLog(#" %# ", array);
NSLog(#"true or false %c",[NSJSONSerialization
isValidJSONObject: array]);
bytesWritten = [NSJSONSerialization writeJSONObject:array toStream:outputStream options:NSJSONWritingPrettyPrinted error:nil];
and this part is NSJSONSerialization part.
However I got an error.
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '***+[NSJSONSerialization writeJSONObject:toStream:options:error:]: stream is not open for writing'
I'm new at objective-c. I can't fix the problem for 3 hours.
=======================================
edit:
- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {
NSLog(#"stream event %i", streamEvent); //this doesn't post in the log when stream opened...
NSLog(#"bytes %i",bytesWritten);
switch (streamEvent) {
case NSStreamEventOpenCompleted:
NSLog(#"Stream opened");
break;
case NSStreamEventHasBytesAvailable:
if (theStream == inputStream) {
uint8_t buffer[1024];
int len;
while ([inputStream hasBytesAvailable]) {
len = [inputStream read:buffer maxLength:sizeof(buffer)];
if (len > 0) {
NSString *output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSUTF8StringEncoding];
if (nil != output) {
NSLog(#"server said: %#", output);
//[self messageReceived:output];
}
}
}
}
break;
case NSStreamEventEndEncountered:
[theStream close];
[theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
//[theStream release];
theStream = nil;
break;
case NSStreamEventHasSpaceAvailable:
{
uint8_t *readBytes = (uint8_t *)[_data mutableBytes];
readBytes += bytesWritten; // instance variable to move pointer
int data_len = [_data length];
unsigned int len = ((data_len - bytesWritten >= 1024) ?
1024 : (data_len-bytesWritten));
uint8_t buf[len];
(void)memcpy(buf, readBytes, len);
//len = [theStream write:(const uint8_t *)buf maxLength:len];
NSLog(#"written %s", buf );
bytesWritten += len;
}
break;
case NSStreamEventErrorOccurred:
{
NSLog(#"no connection");
}
case NSStreamEventNone:
{
//printf("EVENT: None.\n");
break;
}
default:
NSLog(#"Unknown event");
}}
this is my stream: handleEvent: function.
Now after I did add the connectionToHost to delegate I get this kind of error.
012-08-10 16:14:27.302 TaraftarlikOyunu[2274:c07] written P∏◊P‡ˇø
2012-08-10 16:14:28.399 TaraftarlikOyunu[2274:c07] benim bu id 587127341
2012-08-10 16:14:28.399 TaraftarlikOyunu[2274:c07] benim ad Ahmet
2012-08-10 16:14:28.400 TaraftarlikOyunu[2274:c07]
[{"id":"u581277341","command":"GET_USER_INFO","value":""}]
2012-08-10 16:14:28.404 TaraftarlikOyunu[2274:c07] stream event 4
2012-08-10 16:14:28.404 TaraftarlikOyunu[2274:c07] bytes 86
(lldb)
now I don't have an idea that if it buffered or not
=======================EDIT2===============
sorry about this.
the problem probably appears because of this
(void)memcpy(buf, readBytes, len);
I just copy and paste this part of code.
what may be the problem!

Answer 1

The connection method you are using is a little much.
You need to make sure the connection has happened in the delegate
- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {
switch (streamEvent) {
case NSStreamEventHasSpaceAvailable:
NSLog(#\"None!\");
break;
case NSStreamEventOpenCompleted:
NSLog(#\"Stream opened\");
//NOW you can write to the stream