此解析器仅从结果中返回一组值。我已经将endText方法识别为实际提取值的方法。 任何帮助理解此代码将不胜感激。谢谢。需要说明的是，此代码正在查询Microsoft的Bing Translate API，并来自此github项目：gpolak / FGTranslator
@interface XMLDictionaryParser () <NSXMLParserDelegate>
@property (nonatomic, strong) NSMutableDictionary *root;
@property (nonatomic, strong) NSMutableArray *stack;
@property (nonatomic, strong) NSMutableString *text;
@end
@implementation XMLDictionaryParser
+ (XMLDictionaryParser *)sharedInstance
{
static dispatch_once_t once;
static XMLDictionaryParser *sharedInstance;
dispatch_once(&once, ^{
sharedInstance = [[XMLDictionaryParser alloc] init];
});
return sharedInstance;
}
- (id)init
{
if ((self = [super init]))
{
_collapseTextNodes = YES;
_stripEmptyNodes = YES;
_trimWhiteSpace = YES;
_alwaysUseArrays = NO;
_preserveComments = NO;
_wrapRootNode = NO;
}
return self;
}
- (id)copyWithZone:(NSZone *)zone
{
XMLDictionaryParser *copy = [[[self class] allocWithZone:zone] init];
copy.collapseTextNodes = _collapseTextNodes;
copy.stripEmptyNodes = _stripEmptyNodes;
copy.trimWhiteSpace = _trimWhiteSpace;
copy.alwaysUseArrays = _alwaysUseArrays;
copy.preserveComments = _preserveComments;
copy.attributesMode = _attributesMode;
copy.nodeNameMode = _nodeNameMode;
copy.wrapRootNode = _wrapRootNode;
return copy;
}
- (NSDictionary *)dictionaryWithParser:(NSXMLParser *)parser
{
[parser setDelegate:self];
[parser parse];
id result = _root;
_root = nil;
_stack = nil;
_text = nil;
return result;
}
- (NSDictionary *)dictionaryWithData:(NSData *)data
{
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
return [self dictionaryWithParser:parser];
}
- (NSDictionary *)dictionaryWithString:(NSString *)string
{
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
return [self dictionaryWithData:data];
}
- (NSDictionary *)dictionaryWithFile:(NSString *)path
{
NSData *data = [NSData dataWithContentsOfFile:path];
return [self dictionaryWithData:data];
}
+ (NSString *)XMLStringForNode:(id)node withNodeName:(NSString *)nodeName
{
if ([node isKindOfClass:[NSArray class]])
{
NSMutableArray *nodes = [NSMutableArray arrayWithCapacity:[node count]];
for (id individualNode in node)
{
[nodes addObject:[self XMLStringForNode:individualNode withNodeName:nodeName]];
}
return [nodes componentsJoinedByString:@"\n"];
}
else if ([node isKindOfClass:[NSDictionary class]])
{
NSDictionary *attributes = [(NSDictionary *)node attributes];
NSMutableString *attributeString = [NSMutableString string];
for (NSString *key in [attributes allKeys])
{
[attributeString appendFormat:@" %@=\"%@\"", [[key description] XMLEncodedString], [[attributes[key] description] XMLEncodedString]];
}
NSString *innerXML = [node innerXML];
if ([innerXML length])
{
return [NSString stringWithFormat:@"<%1$@%2$@>%3$@</%1$@>", nodeName, attributeString, innerXML];
}
else
{
return [NSString stringWithFormat:@"<%@%@/>", nodeName, attributeString];
}
}
else
{
return [NSString stringWithFormat:@"<%1$@>%2$@</%1$@>", nodeName, [[node description] XMLEncodedString]];
}
}
- (void)endText
{
if (_trimWhiteSpace)
{
_text = [[_text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] mutableCopy];
}
if ([_text length])
{
NSMutableDictionary *top = [_stack lastObject];
id existing = top[XMLDictionaryTextKey];
if ([existing isKindOfClass:[NSArray class]])
{
[existing addObject:_text];
}
else if (existing)
{
top[XMLDictionaryTextKey] = [@[existing, _text] mutableCopy];
}
else
{
top[XMLDictionaryTextKey] = _text;
}
}
_text = nil;
}
- (void)addText:(NSString *)text
{
if (!_text)
{
_text = [NSMutableString stringWithString:text];
}
else
{
[_text appendString:text];
}
}
- (void)parser:(__unused NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(__unused NSString *)namespaceURI qualifiedName:(__unused NSString *)qName attributes:(NSDictionary *)attributeDict
{
[self endText];
NSMutableDictionary *node = [NSMutableDictionary dictionary];
switch (_nodeNameMode)
{
case XMLDictionaryNodeNameModeRootOnly:
{
if (!_root)
{
node[XMLDictionaryNodeNameKey] = elementName;
}
break;
}
case XMLDictionaryNodeNameModeAlways:
{
node[XMLDictionaryNodeNameKey] = elementName;
break;
}
case XMLDictionaryNodeNameModeNever:
{
break;
}
}
if ([attributeDict count])
{
switch (_attributesMode)
{
case XMLDictionaryAttributesModePrefixed:
{
for (NSString *key in [attributeDict allKeys])
{
node[[XMLDictionaryAttributePrefix stringByAppendingString:key]] = attributeDict[key];
}
break;
}
case XMLDictionaryAttributesModeDictionary:
{
node[XMLDictionaryAttributesKey] = attributeDict;
break;
}
case XMLDictionaryAttributesModeUnprefixed:
{
[node addEntriesFromDictionary:attributeDict];
break;
}
case XMLDictionaryAttributesModeDiscard:
{
break;
}
}
}
if (!_root)
{
_root = node;
_stack = [NSMutableArray arrayWithObject:node];
if (_wrapRootNode)
{
_root = [NSMutableDictionary dictionaryWithObject:_root forKey:elementName];
[_stack insertObject:_root atIndex:0];
}
}
else
{
NSMutableDictionary *top = [_stack lastObject];
id existing = top[elementName];
if ([existing isKindOfClass:[NSArray class]])
{
[existing addObject:node];
}
else if (existing)
{
top[elementName] = [@[existing, node] mutableCopy];
}
else if (_alwaysUseArrays)
{
top[elementName] = [NSMutableArray arrayWithObject:node];
}
else
{
top[elementName] = node;
}
[_stack addObject:node];
}
}
- (NSString *)nameForNode:(NSDictionary *)node inDictionary:(NSDictionary *)dict
{
if (node.nodeName)
{
return node.nodeName;
}
else
{
for (NSString *name in dict)
{
id object = dict[name];
if (object == node)
{
return name;
}
else if ([object isKindOfClass:[NSArray class]] && [object containsObject:node])
{
return name;
}
}
}
return nil;
}
- (void)parser:(__unused NSXMLParser *)parser didEndElement:(__unused NSString *)elementName namespaceURI:(__unused NSString *)namespaceURI qualifiedName:(__unused NSString *)qName
{
[self endText];
NSMutableDictionary *top = [_stack lastObject];
[_stack removeLastObject];
if (!top.attributes && !top.childNodes && !top.comments)
{
NSMutableDictionary *newTop = [_stack lastObject];
NSString *nodeName = [self nameForNode:top inDictionary:newTop];
if (nodeName)
{
id parentNode = newTop[nodeName];
if (top.innerText && _collapseTextNodes)
{
if ([parentNode isKindOfClass:[NSArray class]])
{
parentNode[[parentNode count] - 1] = top.innerText;
}
else
{
newTop[nodeName] = top.innerText;
}
}
else if (!top.innerText && _stripEmptyNodes)
{
if ([parentNode isKindOfClass:[NSArray class]])
{
[parentNode removeLastObject];
}
else
{
[newTop removeObjectForKey:nodeName];
}
}
else if (!top.innerText && !_collapseTextNodes && !_stripEmptyNodes)
{
top[XMLDictionaryTextKey] = @"";
}
}
}
}
- (void)parser:(__unused NSXMLParser *)parser foundCharacters:(NSString *)string
{
[self addText:string];
}
- (void)parser:(__unused NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock
{
[self addText:[[NSString alloc] initWithData:CDATABlock encoding:NSUTF8StringEncoding]];
}
- (void)parser:(__unused NSXMLParser *)parser foundComment:(NSString *)comment
{
if (_preserveComments)
{
NSMutableDictionary *top = [_stack lastObject];
NSMutableArray *comments = top[XMLDictionaryCommentsKey];
if (!comments)
{
comments = [@[comment] mutableCopy];
top[XMLDictionaryCommentsKey] = comments;
}
else
{
[comments addObject:comment];
}
}
}
@end
@implementation NSDictionary(XMLDictionary)
+ (NSDictionary *)dictionaryWithXMLParser:(NSXMLParser *)parser
{
return [[[XMLDictionaryParser sharedInstance] copy] dictionaryWithParser:parser];
}
+ (NSDictionary *)dictionaryWithXMLData:(NSData *)data
{
return [[[XMLDictionaryParser sharedInstance] copy] dictionaryWithData:data];
}
+ (NSDictionary *)dictionaryWithXMLString:(NSString *)string
{
return [[[XMLDictionaryParser sharedInstance] copy] dictionaryWithString:string];
}
+ (NSDictionary *)dictionaryWithXMLFile:(NSString *)path
{
return [[[XMLDictionaryParser sharedInstance] copy] dictionaryWithFile:path];
}
- (NSDictionary *)attributes
{
NSDictionary *attributes = self[XMLDictionaryAttributesKey];
if (attributes)
{
return [attributes count]? attributes: nil;
}
else
{
NSMutableDictionary *filteredDict = [NSMutableDictionary dictionaryWithDictionary:self];
[filteredDict removeObjectsForKeys:@[XMLDictionaryCommentsKey, XMLDictionaryTextKey, XMLDictionaryNodeNameKey]];
for (NSString *key in [filteredDict allKeys])
{
[filteredDict removeObjectForKey:key];
if ([key hasPrefix:XMLDictionaryAttributePrefix])
{
filteredDict[[key substringFromIndex:[XMLDictionaryAttributePrefix length]]] = self[key];
}
}
return [filteredDict count]? filteredDict: nil;
}
return nil;
}
- (NSDictionary *)childNodes
{
NSMutableDictionary *filteredDict = [self mutableCopy];
[filteredDict removeObjectsForKeys:@[XMLDictionaryAttributesKey, XMLDictionaryCommentsKey, XMLDictionaryTextKey, XMLDictionaryNodeNameKey]];
for (NSString *key in [filteredDict allKeys])
{
if ([key hasPrefix:XMLDictionaryAttributePrefix])
{
[filteredDict removeObjectForKey:key];
}
}
return [filteredDict count]? filteredDict: nil;
}
- (NSArray *)comments
{
return self[XMLDictionaryCommentsKey];
}
- (NSString *)nodeName
{
return self[XMLDictionaryNodeNameKey];
}
- (id)innerText
{
id text = self[XMLDictionaryTextKey];
if ([text isKindOfClass:[NSArray class]])
{
return [text componentsJoinedByString:@"\n"];
}
else
{
return text;
}
}
- (NSString *)innerXML
{
NSMutableArray *nodes = [NSMutableArray array];
for (NSString *comment in [self comments])
{
[nodes addObject:[NSString stringWithFormat:@"<!--%@-->", [comment XMLEncodedString]]];
}
NSDictionary *childNodes = [self childNodes];
for (NSString *key in childNodes)
{
[nodes addObject:[XMLDictionaryParser XMLStringForNode:childNodes[key] withNodeName:key]];
}
NSString *text = [self innerText];
if (text)
{
[nodes addObject:[text XMLEncodedString]];
}
return [nodes componentsJoinedByString:@"\n"];
}
- (NSString *)XMLString
{
if ([self count] == 1 && ![self nodeName])
{
//ignore outermost dictionary
return [self innerXML];
}
else
{
return [XMLDictionaryParser XMLStringForNode:self withNodeName:[self nodeName] ?: @"root"];
}
}
- (NSArray *)arrayValueForKeyPath:(NSString *)keyPath
{
id value = [self valueForKeyPath:keyPath];
if (value && ![value isKindOfClass:[NSArray class]])
{
return @[value];
}
return value;
}
- (NSString *)stringValueForKeyPath:(NSString *)keyPath
{
id value = [self valueForKeyPath:keyPath];
if ([value isKindOfClass:[NSArray class]])
{
value = [value count]? value[0]: nil;
}
if ([value isKindOfClass:[NSDictionary class]])
{
return [(NSDictionary *)value innerText];
}
return value;
}
- (NSDictionary *)dictionaryValueForKeyPath:(NSString *)keyPath
{
id value = [self valueForKeyPath:keyPath];
if ([value isKindOfClass:[NSArray class]])
{
value = [value count]? value[0]: nil;
}
if ([value isKindOfClass:[NSString class]])
{
return @{XMLDictionaryTextKey: value};
}
return value;
}
@end
@implementation NSString (XMLDictionary)
- (NSString *)XMLEncodedString
{
return [[[[[self stringByReplacingOccurrencesOfString:@"&" withString:@"&"]
stringByReplacingOccurrencesOfString:@"<" withString:@"<"]
stringByReplacingOccurrencesOfString:@">" withString:@">"]
stringByReplacingOccurrencesOfString:@"\"" withString:@"""]
stringByReplacingOccurrencesOfString:@"\'" withString:@"'"];
}
@end