Saving and Loading Web Content

After the user edits the content of a WebView, you need some way to access the modified document. In a Cocoa document-based application, you typically allow the user to save and load the document.

For example, in the MiniBrowser application located in /Developer/Examples/WebKit, you would implement MyDocument’s dataRepresentationOfType: method to return an NSData representation of the HTML source. Then implement MyDocument’s loadDataRepresentation:ofType: method to transform an NSData representation to HTML source and load it into the WebView. Follow these steps to add saving and loading to the MiniBrowser application.

1. First add a variable and accessors to MyDocument to store the HTML source. Modify MyDocument.h as follows and implement the corresponding accessor methods in MyDocument.m:

   @interface MyDocument : NSDocument

   {

   ...

   // Editing Support

   NSString *_source;

   }

   ...

   // Editing Support

   - (NSString *)source;

   - (void)setSource:(NSString *)webContent;

   @end

2. Next, implement MyDocument’s dataRepresentationOfType: method to get the HTML source from the DOM, set the _source instance variable, and convert it to an NSData object as follows:

   - (NSData *)dataRepresentationOfType:(NSString *)aType

   {

   if (![aType isEqualToString:HTMLDocumentType])

   return nil;

   [self setSource:[(DOMHTMLElement *)[[[webView mainFrame] DOMDocument] documentElement] outerHTML]];

   return [[self source] dataUsingEncoding:NSISOLatin1StringEncoding];

   }

3. Then implement MyDocument’s loadDataRepresentation:ofType: method to transform the NSData object to HTML source as follows:

   - (BOOL)loadDataRepresentation:(NSData *)data ofType:(NSString *)aType

   {

   if (![aType isEqualToString:HTMLDocumentType])

   return NO;

   [self setSource:[[NSString alloc] initWithData:data encoding:NSISOLatin1StringEncoding]];

   [[webView mainFrame] loadHTMLString:[self source] baseURL:nil];

   return YES;

   }