RemoteCurrencyServer/RemoteCurrencyServerConnection.h

/*
    File:       RemoteCurrencyServerConnection.h
 
    Contains:   Manages the server side of a client-server connection.
 
    Written by: DTS
 
    Copyright:  Copyright (c) 2011 Apple Inc. All Rights Reserved.
 
    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.
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                non-exclusive license, under Apple's copyrights in this
                original Apple software (the "Apple Software"), to use,
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                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
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*/
 
#import "QCommandLineConnection.h"
 
/*
    Protocol Notes
    --------------
    The server implements a very simple command line protocol:
    
    o Each incoming request is just a command line with a CR LF terminator.
    
    o A response consists of one or more data lines followed by a status 
      line.  Each data line starts with two spaces and ends with a CR LF.
      The status line starts with either a plus or a minus character, 
      followed by a space, followed by a comment, where a plus indicates 
      success and a minus indicates failure.
    
    o An empty line is considered a valid command, which the server 
      acknowledges as success automatically.
 
    For example, a help command sequence starts by the client sending 
    the following:
    
    "help" CR LF
    
    to which the server replies:
    
    "  convert <name> <value> to <name>" CR LF
    "  goodbye" CR LF
    "  hello" CR LF
    "  help" CR LF
    "  stop" CR LF
    "+ OK" CR LF    
 
    The commands supported by this connection are all pretty boring, except 
    for the convert "command", which is the command used by the client to 
    actually converter currencies.
*/
 
@protocol RemoteCurrencyServerConnectionDelegate;
 
@interface RemoteCurrencyServerConnection : QCommandLineConnection
 
// Most of the heavy lifting is done by the QCommandLineConnection superclass.  The 
// following inherited methods are critical to all clients:
// 
// - (id)initWithInputStream:(NSInputStream *)inputStream outputStream:(NSOutputStream *)outputStream;
// - (void)open;
// - (void)close;
 
@property (nonatomic, assign, readwrite) id<RemoteCurrencyServerConnectionDelegate> serverDelegate;
 
- (void)sendResponse:(NSString *)response;
    // Sends a single line response to the client, prefixed by "+ ".
    
- (void)sendResponse:(NSString *)response lines:(NSArray *)lines;
    // Sends a multi-line response to the client, where each line 
    // from the lines array is sent prefixed by two spaces, followed 
    // by a positive response consisting of "+ " and the response 
    // string.
    // 
    // lines may be empty, in which case this is the same as calling 
    // -sendResponse:.
 
- (void)sendError:(NSString *)response;
    // Sends an error to the client, prefixed by "- ".
 
@end
 
@protocol RemoteCurrencyServerConnectionDelegate <NSObject>
 
@required
 
- (void)remoteCurrencyServerConnection:(RemoteCurrencyServerConnection *)connection willCloseWithError:(NSError *)error;
    // Called when the connection is closed from the network side of things (but not 
    // if you call -close on it).  You should implement this method to remove the connection 
    // from your table of active connections.
    //
    // error will be nil if the connection closed due to EOF; otherwise 
    // error will represent the reason for the close.
 
// The following are called when the connection parses the corresponding incoming command. 
// The supplied scanner object has already skipped over the command (and any trailing 
// whilespace) and the delegate can use it to extract command arguments.
//
// Note that the help command is implemented internally by the connection object itself.
 
- (void)remoteCurrencyServerConnection:(RemoteCurrencyServerConnection *)connection helloCommand:(NSScanner *)scanner;
- (void)remoteCurrencyServerConnection:(RemoteCurrencyServerConnection *)connection goodbyeCommand:(NSScanner *)scanner;
- (void)remoteCurrencyServerConnection:(RemoteCurrencyServerConnection *)connection stopCommand:(NSScanner *)scanner;
- (void)remoteCurrencyServerConnection:(RemoteCurrencyServerConnection *)connection convertCommand:(NSScanner *)scanner;
 
- (void)remoteCurrencyServerConnection:(RemoteCurrencyServerConnection *)connection logWithFormat:(NSString *)format arguments:(va_list)argList;
    // Called when the connection wants to log something.
 
@end