Question

I’ve created a Mail.app plugin with Python to set a custom signature pulled from a remote server by swizzling the setSignature: method in ComposeBackEnd. As per the class dump below, I can set a plain text signature by using setSignatureContents: and this is functional.

@interface Signature : NSObject <NSCopying>
{
    NSString *_uniqueId;
    NSString *_name;
    NSData *_webArchiveData;
    BOOL _isRich;
    BOOL _isSavedAsRich;
    BOOL _isDirty;
    MFSyncedFile *_syncedFile;
}

- (id)syncedFile;
- (id)signaturePath;
- (unsigned long long)hash;
- (BOOL)isEqual:(id)arg1;
- (BOOL)isRich;
- (void)setIsRich:(BOOL)arg1;
- (void)setWebArchive:(id)arg1;
- (id)webArchive;
- (id)webArchiveData;
.....
- (void)setSignatureContents:(id)arg1;
- (id)signatureContents;
- (void)setSignatureName:(id)arg1;
- (id)signatureName;

@end

However when I attempt to set an HTML signature using setWebArchive: (which should take an NSData object):

signature.setWebArchive_(NSData.dataWithContentsOfURL_(NSURL.URLWithString_('http://...')))

I get the following error:

11/7/12 11:07:38.858 AM Mail[8820]: -[NSConcreteData data]: unrecognized selector sent to instance 0x7ffc2386bc00

(The remote file is already in the correct format)

Is there any way to make this work? Thanks in advance.

---

EDIT – tried this (returns WebArchive object which should respond to -[data]):

wds = WebDataSource.alloc().initWithRequest_(NSURLRequest.requestWithURL_(NSURL.URLWithString_('http://...')))
        webarchive = wds.webArchive
        signature.setWebArchive_(webarchive)

result:

11/7/12 3:26:59.173 PM Mail[16814]: An uncaught exception was raised
11/7/12 3:26:59.173 PM Mail[16814]: Class OC_PythonObject: no such selector: data

Answer 1

However when I attempt to set an HTML signature using setWebArchive: (which should take an NSData object)… I get the following error:

11/7/12 11:07:38.858 AM Mail[8820]: -[NSConcreteData data]: unrecognized selector

This error is telling you that -[setWebArchive:] is trying to call -[data] on your NSData object. Since -[NSData data] doesn’t exist, you get an unrecognized selector exception.

Clearly it doesn’t take an NSData, it takes something that responds to -[data] by returning an NSData.

EDIT – tried this (returns WebArchive object which should respond to -[data]):

wds = WebDataSource.alloc().initWithRequest_(NSURLRequest.requestWithURL_(NSURL.URLWithString_('http://...')))
webarchive = wds.webArchive
signature.setWebArchive_(webarchive)

Hold on… you haven’t shown the class dump for this one, but the other class has a method -[webArchive], not a properly webArchive. So, if they’re at all consistent, this one is also likely to have a method, not a property.

If so, this means wds.webArchive is not going to be a a WebArchive object, it’s going to be a wrapper object that represents roughly the ObjC equivalent of a Python bound method. And calling -[data] on that thing will almost certainly fail.

11/7/12 3:26:59.173 PM Mail[16814]: Class OC_PythonObject: no such selector: data

If you just change that to wds.webArchive(), that should fix the problem.

Finally, it’s worth doing a bit of debugging prints here. If you think you’ve got a WebArchive and -[WebArchive data] returns an NSData, you can test that really easily:

print webArchive
print webArchive.data()