How can I transfer and instance of a class through SOAP?

Question

I have an app that communicates with a web service VIA SOAP. So far the communications have been strictly string values and the like. Some of these values in classes, some not.

My question is: Is it possible to pass an instance of a class through SOAP?

Something with the syntax like..

//class declaration in .h
 Myclass class

in the .m

 class.string = @"stuff";
 class.integer = 5;

then create the SOAP string

[NSString stringWithFormat:@"<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<stuff xmlns="http://website.com/">
  <class>%@</class>
</stuff>
</soap:Body>
</soap:Envelope>,class];

Is something like this possible as long as the web service knows how to handle it?

Are you looking to transfer an _instance_ of a class, or are you looking to define a new class entirely? — Ben S, Jan 10 '12 at 20:57
transfer an instance of the class. Complete with all the stored values and everything. — Jesse Durham, Jan 10 '12 at 21:07

score 1 · Accepted Answer · answered Jan 10 '12 at 21:17

1

To transfer an instance of a class, look into the NSCoding protocol.

The Archiving and Serializations Programming Guide has some examples on how to do what you're asking, specifically the Encoding and Decoding Objects chapter.

answered Jan 10 '12 at 21:17

Ben S

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I have no control over what is done on the webservice side. Its written in VB I believe. Will it be able to handle this information if I pass it? Or will they have to go through a process to decode the object? – Jesse Durham Jan 10 '12 at 21:32
VB doesn't understand Objective-C binaries (ehm, obviously). Serializing the object is only good if you intend to store it and then get it back to the objective-c side. It is a bad idea if you intend to pass values to the server. In this case just write some XML from Objective-C. – Jano Jan 10 '12 at 21:47
There was no requirement that VB was involved in the question. I assumed the instance was being stored by the web service. I would go with JSON or XML in that case. Simply encode the object's state in one of those formats and decode it in VB. – Ben S Jan 10 '12 at 21:57
Ok, yeah my mistake. This object is being passed to the server and will not be used again by my app. I was going to mention that just now but you guys found out already. I'll use the XML option in that case. Thanks. – Jesse Durham Jan 10 '12 at 22:04

score 0 · Answer 2 · edited May 23 '17 at 12:12

Use NSKeyedArchiver.

// serialize object to data with the given key
+ (NSData*) archive:(id<NSCoding>)object key:(NSString*const)key {
    NSMutableData *data = [[NSMutableData alloc] init];
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    [archiver encodeObject:object forKey:key];
    [archiver finishEncoding];
    [archiver release];
    return [data autorelease];
}

+ (id<NSCoding>) unarchiveKey:(NSString*const)key data:(NSData*)codedData{
    // unarchive
    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:codedData];
    id<NSCoding,NSObject> object = [unarchiver decodeObjectForKey:key];
    [unarchiver finishDecoding];
    [unarchiver release];
    return object;
}

and you need to edit the object to serialize to implement NSCoding for its ivars:

#pragma mark - NSCoding

- (void)encodeWithCoder:(NSCoder*)coder {
    [super encodeWithCoder:coder];
    [coder encodeObject:self.myVar forKey:@"someArbitraryKey"];
    // ... other ivars
}

- (id)initWithCoder:(NSCoder*)coder {
    self = [super initWithCoder:coder];
    if(self) {
        self.myVar = [coder decodeObjectForKey:@"someArbitraryKey"];
        // ...other ivars
    }
    return self;
}

So create two methods for archive and unarchive, and implement NSCoding in the object to serialize. Then take the NSData and make it Base64 to add it to SOAP. Basically that. I didn'tn compile anything, good luck. Read Ben's link.

How can I transfer and instance of a class through SOAP?

2 Answers2