NSXMLParser and initWithStream
NSXMLParser and initWithStream
- Subject: NSXMLParser and initWithStream
- From: John Drake <email@hidden>
- Date: Sun, 27 May 2012 20:14:16 -0400
I'm trying to use the NSStream classes to parse incoming incremental XML data. The data is never a complete XML Document, but I want to receive and process it in incremental chunks based off how much ever the socket can read.
Looking at the documentation for NSXMLParser, it seems like the initWithStream: method to initialize a NSXMLParser would be the perfect solution to my problem. I can initialize the parser with a NSInputStream and then call the parse method on NSXMLParser whenever I receive data over my socket which should in turn call the NSXMLParser delegates.
However, I'm not seeing any of the delegates being called, the only method I see being called is the stream delegate stream:handleEvent:. There seems to be little to no examples of this API from Apple or other developers. I could use libxml2 directly to accomplish what I want, but I am hoping I am just using NSXMLParser incorrectly.
Here is the source for what I am trying:
ContentParser.h:
@interface ContentParser : NSObject <NSStreamDelegate,
NSXMLParserDelegate>
{
NSInputStream *inputStream;
NSOutputStream *outputStream;
NSMutableData *receivedData;
NSXMLParser *xmlParser;
}
- (void)initStream;
ContentParser.m:
@implementation ContentParser
- (void)initStream
{
CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault,
(CFStringRef)@"<hostname>",
<port>,
&readStream,
&writeStream);
inputStream = (__bridge NSInputStream *)readStream;
outputStream = (__bridge NSOutputStream *)writeStream;
inputStream.delegate = self;
outputStream.delegate = self;
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]
forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]
forMode:NSDefaultRunLoopMode];
[inputStream open];
[outputStream open];
xmlParser = [[NSXMLParser alloc] initWithStream:inputStream];
[xmlParser setDelegate:self];
}
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName
attributes:(NSDictionary *)attributeDict
{
NSLog(@"didStartElement: %@, attributeDict: %@", elementName, attributeDict);
}
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
NSLog(@"foundCharacters: %@", string);
}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName
{
NSLog(@"didEndElement: %@", elementName);
}
- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
NSLog(@"Error %ld, Description: %@, Line: %ld, Column: %ld",
[parseError code], [[parser parserError] localizedDescription],
[parser lineNumber], [parser columnNumber]);
}
- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode
{
switch (eventCode) {
case NSStreamEventHasBytesAvailable:
{
if (stream == inputStream) {
NSInputStream *is = (NSInputStream *)stream;
if (receivedData == nil) {
receivedData = [[NSMutableData alloc] init];
}
uint8_t buf[1024];
NSInteger bytesRead = [is read:buf maxLength:1024];
if (bytesRead == -1) {
NSLog(@"Network read error");
} else if (bytesRead == 0) {
NSLog(@"No buffer received");
} else {
[receivedData appendBytes:buf length:bytesRead];
BOOL parserResult = [xmlParser parse];
if (parserResult == NO) {
NSLog(@"Unable to parse XML");
}
}
}
break;
}
default:
break;
}
}
@end
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