在OC代码中使用JSON访问web service的例子

/* Copyright (c) 2010, Stig Brautaset. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of the the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #import <Foundation/Foundation.h> /// Enable JSON writing for non-native objects @interface NSObject (SBProxyForJson) /** @brief Allows generation of JSON for otherwise unsupported classes. If you have a custom class that you want to create a JSON representation for you can implement this method in your class. It should return a representation of your object defined in terms of objects that can be translated into JSON. For example, a Person object might implement it like this: @code - (id)proxyForJson { return [NSDictionary dictionaryWithObjectsAndKeys: name, @"name", phone, @"phone", email, @"email", nil]; } @endcode */ - (id)proxyForJson; @end @class SBJsonStreamWriter; @protocol SBJsonStreamWriterDelegate - (void)writer:(SBJsonStreamWriter*)writer appendBytes:(const void *)bytes length:(NSUInteger)length; @end @class SBJsonStreamWriterState; /** @brief The Stream Writer class. Accepts a stream of messages and writes JSON of these to its delegate object. This class provides a range of high-, mid- and low-level methods. You can mix and match calls to these. For example, you may want to call -writeArrayOpen to start an array and then repeatedly call -writeObject: with various objects before finishing off with a -writeArrayClose call. @see @ref json2objc */ @interface SBJsonStreamWriter : NSObject { @private NSString *error; NSMutableArray *stateStack; __weak SBJsonStreamWriterState *state; id<SBJsonStreamWriterDelegate> delegate; NSUInteger maxDepth; BOOL sortKeys, humanReadable; } @property (nonatomic, assign) __weak SBJsonStreamWriterState *state; // Internal @property (nonatomic, readonly, retain) NSMutableArray *stateStack; // Internal /** @brief delegate to receive JSON output Delegate that will receive messages with output. */ @property (assign) id<SBJsonStreamWriterDelegate> delegate; /** @brief The maximum recursing depth. Defaults to 512. If the input is nested deeper than this the input will be deemed to be malicious and the parser returns nil, signalling an error. ("Nested too deep".) You can turn off this security feature by setting the maxDepth value to 0. */ @property NSUInteger maxDepth; /** @brief Whether we are generating human-readable (multiline) JSON. Set whether or not to generate human-readable JSON. The default is NO, which produces JSON without any whitespace between tokens. If set to YES, generates human-readable JSON with linebreaks after each array value and dictionary key/value pair, indented two spaces per nesting level. */ @property BOOL humanReadable; /** @brief Whether or not to sort the dictionary keys in the output. If this is set to YES, the dictionary keys in the JSON output will be in sorted order. (This is useful if you need to compare two structures, for example.) The default is NO. */ @property BOOL sortKeys; /// Contains the error description after an error has occured. @property (copy) NSString *error; /** Write an NSDictionary to the JSON stream. @return YES if successful, or NO on failure */ - (BOOL)writeObject:(NSDictionary*)dict; /** Write an NSArray to the JSON stream. @return YES if successful, or NO on failure */ - (BOOL)writeArray:(NSArray *)array; /** Start writing an Object to the stream @return YES if successful, or NO on failure */ - (BOOL)writeObjectOpen; /** Close the current object being written @return YES if successful, or NO on failure */ - (BOOL)writeObjectClose; /** Start writing an Array to the stream @return YES if successful, or NO on failure */ - (BOOL)writeArrayOpen; /** Close the current Array being written @return YES if successful, or NO on failure */ - (BOOL)writeArrayClose; /** Write a null to the stream @return YES if successful, or NO on failure */ - (BOOL)writeNull; /** Write a boolean to the stream @return YES if successful, or NO on failure */ - (BOOL)writeBool:(BOOL)x; /** Write a Number to the stream @return YES if successful, or NO on failure */ - (BOOL)writeNumber:(NSNumber*)n; /** Write a String to the stream @return YES if successful, or NO on failure */ - (BOOL)writeString:(NSString*)s; @end @interface SBJsonStreamWriter (Private) - (BOOL)writeValue:(id)v; - (void)appendBytes:(const void *)bytes length:(NSUInteger)length; @end