Re: TCP/IP Sockets from RPG

There is no such thing as a "fixed length" record in TCP. Just a guess but since you are not accounting for variable length data transmission size every receive your program will only work by chance. You have to check the length of the received data every read, then only read the amount (remainder) you need in each subsequent read. For example, if the total sender size is 4096 bytes per "record"(your terminology) and you read using a buffer and request size of 4096 bytes, that doesn't mean you will "get" 4096 bytes. Therefore, you have to check the total bytes sent, and keep reading until the total is equivalent to the amount you want being careful to only read the amount of bytes in remainder. If you request more than the amount available from the sender the program will hang on the socket until more data is available or time-out is received. Most good socket programs have a set of commands embedded in the socket stream which indicate states such as begin, end, length of transmission, etc.
I don't know about the tutorial you mentioned but there is a whole encyclopedia of network programming information. In order to trust your program to handle the variety of conditions when not controlling the whole process you will have to spend a good amount of time studying and practicing socket programming. If you want to learn socket programming then get a good book, learn C or Java and then just do it. If you do not have the time and it's an important product to your company then I suggest purchasing a vendors TCP toolkit or using Java libraries of which there are plenty. That way you can safely ignore all the networking details.
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