Sockets in Cocoa
After brushes with network programming in .NET
(the System.Net.Sockets namespace) and Java (the java.net package), I assumed
that Apple's Cocoa framework would also have nice abstractions for working with
raw sockets. So far this does not appear to be the case...
Cocoa's NSSocketPort seemed like a good place to
start, but apparently the name of this class is misleading. Rather than an
Objective-C wrapper for BSD sockets, it turns out that NSSocketPort is used for
Cocoa's distributed objects. These are something I haven't played with yet; they
have no relevance to my current project because the server side of things isn't
Cocoa.
While there are several third-party solutions available (see this nice summary from Stepwise), I decided to take the time to learn a bit about BSD socket programming from the ground up and try to apply that knowledge to my little Cocoa project. If nothing else, I figured that the knowledge gained would help me choose one of the third party frameworks.
The best web-based resource I found for aspiring network programmers is Beej's Guide to Network Programming, which not only covers the basics, but proves that technical writing needn't bore one to tears. Most any programmer familiar with the C language should have no trouble reading through this guide.
A reinforcement and review of topics from Beej's Guide can be found in Micheal Beam's Networking and the BSD Sockets API article on O'Reilly's MacDevCenter, which is part 2 of a 3 part article (part 1 deals with using Rendezvous for service discovery). In the followup article titled Networking in Cocoa, Mike begins to put an Objective-C spin on the topic using the NSFileHandle class of Cocoa's Foundation framework. According to Apple's overview of NSFileHandle, "It provides the only Foundation object that can read and write to communications channels such as those implemented by sockets, pipes, and devices."
For my current need to create a TCP client, NSFileHandle will get me there, but it's worth mentioning that NSFileHandle has its limitations. From that same page of Apple's documentation, we find that "NSFileHandle currently handles only communication through stream-type sockets. If you want to use datagrams or other types of sockets, you must create and manage the connection using native system routines."
Time to drop a note in Apple's suggestion box, I guess...
While there are several third-party solutions available (see this nice summary from Stepwise), I decided to take the time to learn a bit about BSD socket programming from the ground up and try to apply that knowledge to my little Cocoa project. If nothing else, I figured that the knowledge gained would help me choose one of the third party frameworks.
The best web-based resource I found for aspiring network programmers is Beej's Guide to Network Programming, which not only covers the basics, but proves that technical writing needn't bore one to tears. Most any programmer familiar with the C language should have no trouble reading through this guide.
A reinforcement and review of topics from Beej's Guide can be found in Micheal Beam's Networking and the BSD Sockets API article on O'Reilly's MacDevCenter, which is part 2 of a 3 part article (part 1 deals with using Rendezvous for service discovery). In the followup article titled Networking in Cocoa, Mike begins to put an Objective-C spin on the topic using the NSFileHandle class of Cocoa's Foundation framework. According to Apple's overview of NSFileHandle, "It provides the only Foundation object that can read and write to communications channels such as those implemented by sockets, pipes, and devices."
For my current need to create a TCP client, NSFileHandle will get me there, but it's worth mentioning that NSFileHandle has its limitations. From that same page of Apple's documentation, we find that "NSFileHandle currently handles only communication through stream-type sockets. If you want to use datagrams or other types of sockets, you must create and manage the connection using native system routines."
Time to drop a note in Apple's suggestion box, I guess...
Posted: Tue - December 28, 2004 at 05:07 PM
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