[cheerios]

Ok, I have searched and searched, and I have been completely unsuccessful at finding some kind of instructions for using the XML-Parser I KNOW is part of OS X. I know it's part of CoreFoundation, but i can't figure out how to use it...

[juanpacolopez]

Originally posted by cheerios:
Ok, I have searched and searched, and I have been completely unsuccessful at finding some kind of instructions for using the XML-Parser I KNOW is part of OS X. I know it's part of CoreFoundation, but i can't figure out how to use it...

Here's an example that might help:

NSData *xmlData;
NSMutableDictionary *myDict;

//add some data to the dictionary

xmlData = [NSPropertyListSerialization dataFromPropertyList:myDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];

[xmlData writeToFile:[[NSBundle mainBundle] pathForResource:@"my" ofType:@"plist"] atomically:YES];

----

The above example would write the contents of myDict out to an xml file (named "my.plist"). To read back the data in said file, use something like:

NSMutableDictionary *myDict;

myDict = [[NSMutableDictionary alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"my" ofType:@"plist"]];

As long as your dictionary is properly formatted; this should work perfectly!

[cheerios]

That looks like it's close to what I'm searchin' for. What I'm doin' now is making a string w/ init with contents of file, and makingranges, and walking throguh the file character by character until I find the open and close tags. *eek*

Problem being: NSDictionary's are HashTables (to borrow terminology i'm more familiar with). so... what does it do when I have 2 tags w/ the same name? that's perfectly legal XML, but you're not allowed to have 2 identical keys in a HashTable...

edit: to clarify, I don't need to write XML files, just read em, and they'll look something like this:

Code:
<?xml version="1.0" encoding="ISO8859-1" ?> 
<dataroot>
<fsm>
    <description>finite state machine that only accepts strings that do not end with ab</description>
    <alphabet>ab</alphabet>
    <acceptstates>
        <state>0</state><state>1</state>
    </acceptstates>
    <nextstatetable>
        <tablerow>
            <state>1</state><state>0</state>
        </tablerow>
        <tablerow>
            <state>0</state><state>2</state>
        </tablerow>
        <tablerow>
            <state>1</state><state>0</state>
        </tablerow>
    </nextstatetable>
</fsm>
</dataroot>

so those state tags... are they gonna be a problem?

[Chuckit]

Are you looking for something like this?

[cheerios]

been there, seen that. problem is, they have 1 example, and no documentation about what CFURLCreateDataAndPropertiesFromResource() and CFXMLTreeCreateFromData() take as arguments. This is what pisses me off about apple's documentation! what KIND of URL does the function want? I tried giving it an NSString I tried giving it a c-string, I tried giving it an NSURL... it wants a URL. wtf????

[Chuckit]

Originally posted by cheerios:
been there, seen that. problem is, they have 1 example, and no documentation about what CFURLCreateDataAndPropertiesFromResource() and CFXMLTreeCreateFromData() take as arguments. This is what pisses me off about apple's documentation! what KIND of URL does the function want? I tried giving it an NSString I tried giving it a c-string, I tried giving it an NSURL... it wants a URL. wtf????

From a look at the API listing (available on your hard drive here if you've got the dev tools installed), it appears to want a CFURL.

[cheerios]

yeah, i finally came to that conclusion... *blush* so... current problem involves the fact I can't call CFTree functions on a CFXMLTree ( which Apple does in it's source code. I dunno if I'm doin' something stupid, or what, but it Signal 10 error's every time i call a CFTree function. code & output follow...

Code:
#import "xml.h"


@implementation xml
+(void)parseXML: (NSString *)path
{
    NSLog(@"I am here!");
    CFXMLTreeRef    cfXMLTree;
    CFDataRef       xmlData;
    CFURLRef pathURL = CFURLCreateFromFileSystemRepresentation (
                    kCFAllocatorDefault,
                    [path cString],
                    [path cStringLength],
                    NO);


    // Load the XML data using its URL.
    NSLog(@"about to load the XML file");
    CFURLCreateDataAndPropertiesFromResource(kCFAllocatorDefault, 
                pathURL, &xmlData, NULL, NULL, NULL);

// Parse the XML and get the CFXMLTree.
    NSLog(@"loaded XML, about to parse it!");
    cfXMLTree = CFXMLTreeCreateFromData(kCFAllocatorDefault,
                    xmlData, 
                    pathURL, 
                    kCFXMLParserSkipWhitespace,
                    kCFXMLNodeCurrentVersion);
    NSLog(@"finished parsing");
    
    //int childCount = CFTreeGetChildCount(cfXMLTree);
    NSLog(@"childcount");
    int index;
    CFXMLTreeRef    xmlTreeNode;
    CFXMLNodeRef    xmlNode;

    NSLog(@"about to for-loop");
    for (index = 0; index < 2; index++) 
    {
        NSLog(@"just about to call CFTree");
        xmlTreeNode = CFTreeGetChildAtIndex(cfXMLTree, index);
        NSLog(@"called CFTree, calling CFXML");
        xmlNode = CFXMLTreeGetNode(xmlTreeNode);
        CFShow(CFXMLNodeGetString(xmlNode));
        //NSLog("%s\n",CFXMLNodeGetString(xmlNode));
    }
}

@end

2003-10-14 17:28:24.790 experiment[13414] I am here!
2003-10-14 17:28:24.799 experiment[13414] about to load the XML file
2003-10-14 17:28:24.807 experiment[13414] loaded XML, about to parse it!
2003-10-14 17:28:24.816 experiment[13414] finished parsing
2003-10-14 17:28:24.824 experiment[13414] childcount
2003-10-14 17:28:24.832 experiment[13414] about to for-loop
2003-10-14 17:28:24.840 experiment[13414] just about to call CFTree

experiment has exited due to signal 10 (SIGBUS).

[johnt519]

Try this article http://www.macedition.com/bolts/bolts_20030610.php

[Chuckit]

Originally posted by cheerios:
yeah, i finally came to that conclusion... *blush* so... current problem involves the fact I can't call CFTree functions on a CFXMLTree ( which Apple does in it's source code.

I have a very strong feeling you're getting a NULL somewhere in there -- quite possibly right at the beginning with the CFURL. Try putting tests for NULL after your creation functions and you'll probably find the culprit.

[lfrog2]

Also, an free marshaller:

http://homepage.mac.com/jimbokun/Excelsior.html

[cheerios]

thanks all... finally got it worked out a couple hours ago (writing a parser in another language for another class took precidence for awhile!). problem: had an un-closed tag that was crashing the parsing function. KaBoom, that's all she wrote. BAD APPLE! NO ERROR MESSAGES! (done complaining now). that article posted by johnt519 was especially helpful <does a happy dance of joy>

[macaroni]

Is the NSPropertyListSerialization all I need to save my custom objects as readable XML?

Here is a sample of my custom object:

@interface Markets : NSObject {
NSString *marketName;
NSString *marketOverview;
NSMutableArray *positionersArray;
}

and the positionersArray contain another custom object

@interface Positioners : NSObject {

NSString *position;
NSMutableArray *chartersArray;

}

I have been searching for a simple way of
storing my custom objects as readable XML.

Key-Coding stores it in a XML but the file
that it creates is not readable.

Any help would be appreciated....

Originally posted by cheerios:
thanks all... finally got it worked out a couple hours ago (writing a parser in another language for another class took precidence for awhile!). problem: had an un-closed tag that was crashing the parsing function. KaBoom, that's all she wrote. BAD APPLE! NO ERROR MESSAGES! (done complaining now). that article posted by johnt519 was especially helpful <does a happy dance of joy>

[cheerios]

by readable, do you mean by a human? or by code?

[macaroni]

by human...

The reason being is that the XML file will also be placed in a database, FileMaker I think and the XML will undergo an XSLT to fit the FileMaker ER.

thanks.

Originally posted by cheerios:
by readable, do you mean by a human? or by code?

[kido]

i think the easiest thing is to convert your custom objects to a representation made up of only NSDictionary, NSString, NSArray, etc. objects in order for NSPropertyListSerialization to work correctly. you would create a dictionary to represent your Markets object with keys to represent the instance variables marketName, marketOverview, and positionersArray. You would do the same for the Positioners object. The Markets dictionaries would be put into an NSArray and you would serialize that array with - (BOOL) writeToFile: (NSString *) path atomically: (BOOL) flag to get something like the following:

Code:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
	<dict>
		<key>marketName</key>
		<string></string>
		<key>marketOverview</key>
		<string></string>
		<key>positionersArray</key>
		<array>
			<dict>
				<key>chartersArray</key>
				<array>
					<string></string>
				</array>
				<key>position</key>
				<string></string>
			</dict>
		</array>
	</dict>
</array>
</plist>

that file could then be entered into your database and processed.

kido

[macaroni]

Thanks kido,

I guess I'll have to do some rework on my custom class objects.

Originally posted by kido:
i think the easiest thing is to convert your custom objects to a representation made up of only NSDictionary, NSString, NSArray, etc. objects in order for NSPropertyListSerialization to work correctly. you would create a dictionary to represent your Markets object with keys to represent the instance variables marketName, marketOverview, and positionersArray. You would do the same for the Positioners object. The Markets dictionaries would be put into an NSArray and you would serialize that array with - (BOOL) writeToFile: (NSString *) path atomically: (BOOL) flag to get something like the following:

Code:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
	<dict>
		<key>marketName</key>
		<string></string>
		<key>marketOverview</key>
		<string></string>
		<key>positionersArray</key>
		<array>
			<dict>
				<key>chartersArray</key>
				<array>
					<string></string>
				</array>
				<key>position</key>
				<string></string>
			</dict>
		</array>
	</dict>
</array>
</plist>

that file could then be entered into your database and processed.

kido

[macaroni]

If I rework my classes as simply instances of
NSArrays and NSDictionaries, I then would have to rework the code where the controller adds the instances to the appropriate container correct as opposed to the classes themselves adding their related objects.

I guess I'm not clearly bridging how to create object representations from that shown in the tutorial books to representing them as NSArrays and NSDictionaries that add/delete/modify their related objects.

I would appreciate any clarification...

Do I make my classes as subclasses of NSArray, NSDictionary in order to write their data as human readable XML?

Thanks in advance...