Data is added from server

Question

I am working on an app that is using NSOutputStream and NSInputStream to try it out and see what I can make happen. I have modified This tutorial to allow me to use a old computer as a server! What I am having an issue with is i am trying to send a dictionary through a NSOutputStream and then receive it. unfortinily the server seems to be adding a byte of data so I can not successfully unarchive the data. Here is my code....

    //sending the data
     NSMutableDictionary *dic = [[NSMutableDictionary alloc] init];
        [dic setObject:@"hi" forKey:@"hello"];
        [dic setObject:@"whats up" forKey:@"huh"]; 
        NSData *data = [NSKeyedArchiver archivedDataWithRootObject:dic];//data is 365 bytes
        NSLog(@"%@",data);
        [self.outputStream write:data.bytes maxLength:data.length];



    //receiving data from NSInputStream
    case NSStreamEventHasBytesAvailable:
        NSLog(@"has bytes available");
        //_mutData = [NSMutableData new];
        _mutData = [[NSMutableData alloc] init];
        if (theStream == inputStream) {

            uint8_t buffer[1024];
            int len;

            while ([inputStream hasBytesAvailable]) {
                len = [inputStream read:buffer maxLength:sizeof(buffer)];
                if (len > 0) {



                    [_mutData appendBytes:buffer length:len];
                    NSLog(@"Data:  %@",_mutData);
                    NSLog(@"appended bytes");



                }
            }
        }
        break;

    // trying to make the data into the dictionary
    NSDictionary *dic = [NSKeyedUnarchiver unarchiveObjectWithData:_mutData];
        NSLog(@"%@",dic);

Upon trying to unarchiveOjectWithData I get an error message of "* -[NSKeyedUnarchiver initForReadingWithData:]: incomprehensible archive (0x62, 0x70, 0x6c, 0x69, 0x73, 0x74, 0x30, 0x30)".

Upon looking at the data it appears that it is all the same except for the last two values of the data that comes in from the server it adds "0a" to the end of the data.

My question is what is going wrong why is this data being added somewhere in the server? Thanks for any help!

Answer 1

While I have no idea what was actually going wrong and how make this work as just sending the data and receiving the data. You need some sort of termination part to make this work so I used two methods of converint NSData to a NSString and then converting a NSString to NSData.

    -(NSData *)interprateHexStringToData:(NSString *)hexString { 

    char const *chars = hexString.UTF8String; 
    NSUInteger charCount = strlen(chars); 
    NSUInteger byteCount = charCount / 2; 
    uint8_t *bytes = malloc(byteCount); 
    for (int i = 0; i < byteCount; ++i) { 
    unsigned int value; 
    sscanf(chars + i * 2, "%2x", &value); 
    bytes[i] = value; 
    } 
    return [NSData dataWithBytesNoCopy:bytes length:byteCount freeWhenDone:YES]; 
    } 

    -(NSString *)makeDataIntoString:(NSData *)data { 

    NSUInteger dataLength = [data length]; 
    NSMutableString *string = [NSMutableString stringWithCapacity:dataLength*2]; 
    const unsigned char *dataBytes = [data bytes]; 
    for (NSInteger idx = 0; idx < dataLength; ++idx) { 
    [string appendFormat:@"%02x", dataBytes[idx]]; 
    } 

    return string; 

    } 

to send my data I switched it up to this.

    NSMutableDictionary *dic = [[NSMutableDictionary alloc] init]; 

    [dic setObject:@"hi" forKey:@"hello"]; 
    [dic setObject:@"whats up" forKey:@"huh"]; 

    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:dic]; 

    NSLog(@"%@",data); 


    NSString *setUpString = [NSString stringWithFormat:@"||||%@",[self                 makeDataIntoString:data]]; 
    NSData *stringData = [setUpString dataUsingEncoding:NSUTF8StringEncoding]; 



    [self.outputStream write:stringData.bytes maxLength:stringData.length]; 

To sort out my data once i got it back from the server i did this.

    NSString *stringData = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; 

    NSLog(@"%@",stringData); 

    NSString *changed = [stringData stringByReplacingOccurrencesOfString:@"||||" withString:@""]; 
    NSLog(@"%@",changed); 
    NSData *dataFromTheString = [self interprateHexStringToData:changed]; 
    NSLog(@"%@",dataFromTheString); 
    @try { 
    NSDictionary *dictonary = [NSKeyedUnarchiver unarchiveObjectWithData:dataFromTheString]; 
    NSLog(@"%@",dictonary); 
    } 
    @catch (NSException *exception) { 
    NSLog(@"%@",exception); 
    }

I could not have reached this conclusion without sangony link to this other post GCDAsyncSocket alters data while transporting it Thanks!