Syncing sqlite database with iCloud

Question

I have my sqlite database. now i want syncing with icloud. I read blogs saying sqlite syncing with icloud is not supported. Either go for core data OR "Do what exactly core data does".

Now it is not posible for me to go for core data.So like second option "Do something similar to how CoreData syncs sqlite DBs: send "transaction logs" to iCloud instead and build each local sqlite file off of those."

please can anyone share any sample code for "transaction log" of sqlite OR can expalin in detail stepwise what i need to do?

Answer 1

1) I followed this link to create xml. You can download respective api from its github.Link is - http://arashpayan.com/blog/2009/01/14/apxml-nsxmldocument-substitute-for-iphoneipod-touch/

2) on button click:

-(IBAction) btniCloudPressed:(id)sender
{
    // create the document with it’s root element
    APDocument *doc = [[APDocument alloc] initWithRootElement:[APElement elementWithName:@"Properties"]];
    APElement *rootElement = [doc rootElement]; // retrieves same element we created the line above

    NSMutableArray *addrList = [[NSMutableArray alloc] init];
    NSString *select_query;
    const char *select_stmt;
    sqlite3_stmt *compiled_stmt;
    if (sqlite3_open([[app getDBPath] UTF8String], &dbconn) == SQLITE_OK)
    {
        select_query = [NSString stringWithFormat:@"SELECT * FROM Properties"];
        select_stmt = [select_query UTF8String];
        if(sqlite3_prepare_v2(dbconn, select_stmt, -1, &compiled_stmt, NULL) == SQLITE_OK) 
        {
            while(sqlite3_step(compiled_stmt) == SQLITE_ROW) 
            {
                NSString *addr = [NSString stringWithFormat:@"%@",[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,0)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,1)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,2)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,3)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,4)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,5)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,6)]];
                addr = [NSString stringWithFormat:@"%@#%@",addr,[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,7)]];

                //NSLog(@"%@",addr);
                [addrList addObject:addr];
            }
            sqlite3_finalize(compiled_stmt);
        }
        else 
        {
            NSLog(@"Error while creating detail view statement. '%s'", sqlite3_errmsg(dbconn));
        }

    }

    for(int i =0 ; i < [addrList count]; i++)
    {
        NSArray *addr = [[NSArray alloc] initWithArray:[[addrList objectAtIndex:i] componentsSeparatedByString:@"#"]];

        APElement *property = [APElement elementWithName:@"Property"];
        [property addAttributeNamed:@"id" withValue:[addr objectAtIndex:0]];
        [property addAttributeNamed:@"street" withValue:[addr objectAtIndex:1]];
        [property addAttributeNamed:@"city" withValue:[addr objectAtIndex:2]];
        [property addAttributeNamed:@"state" withValue:[addr objectAtIndex:3]];
        [property addAttributeNamed:@"zip" withValue:[addr objectAtIndex:4]];
        [property addAttributeNamed:@"status" withValue:[addr objectAtIndex:5]];
        [property addAttributeNamed:@"lastupdated" withValue:[addr objectAtIndex:6]];
        [property addAttributeNamed:@"deleted" withValue:[addr objectAtIndex:7]];
        [rootElement addChild:property];
        [property release];

        APElement *fullscore = [APElement elementWithName:@"FullScoreReport"];
        [property addChild:fullscore];
        [fullscore release];
        select_query = [NSString stringWithFormat:@"SELECT AnsNo,Answer,AnswerScore,MaxScore,AnsIndex FROM FullScoreReport WHERE Addr_ID = %@",[addr objectAtIndex:0]];
        select_stmt = [select_query UTF8String];
        if(sqlite3_prepare_v2(dbconn, select_stmt, -1, &compiled_stmt, NULL) == SQLITE_OK) 
        {
            while(sqlite3_step(compiled_stmt) == SQLITE_ROW) 
            {
                APElement *answer = [APElement elementWithName:@"Answer"];
                [answer addAttributeNamed:@"AnsNo" withValue:[NSString stringWithFormat:@"%@",[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,0)]]];
                [answer addAttributeNamed:@"Answer" withValue:[NSString stringWithFormat:@"%@",[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,1)]]];
                [answer addAttributeNamed:@"AnswerScore" withValue:[NSString stringWithFormat:@"%@",[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,2)]]];
                [answer addAttributeNamed:@"MaxScore" withValue:[NSString stringWithFormat:@"%@",[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,3)]]];
                [answer addAttributeNamed:@"AnsIndex" withValue:[NSString stringWithFormat:@"%@",[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiled_stmt,4)]]];
                [fullscore addChild:answer];
                [answer release];
            }
            sqlite3_finalize(compiled_stmt);
        }
    }
    sqlite3_close(dbconn);


    NSString *prettyXML = [doc prettyXML];
    NSLog(@"\n\n%@",prettyXML);


    //***** PARSE XML FILE *****
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Properties.xml" ];
    NSData *file = [NSData dataWithBytes:[prettyXML UTF8String] length:strlen([prettyXML UTF8String])];
    [file writeToFile:path atomically:YES];


    NSString *fileName = [NSString stringWithFormat:@"Properties.xml"];
    NSURL *ubiq = [[NSFileManager defaultManager]URLForUbiquityContainerIdentifier:nil];
    NSURL *ubiquitousPackage = [[ubiq URLByAppendingPathComponent:@"Documents"]  URLByAppendingPathComponent:fileName];


    MyDocument *mydoc = [[MyDocument alloc] initWithFileURL:ubiquitousPackage];
    mydoc.xmlContent = prettyXML;
    [mydoc saveToURL:[mydoc fileURL]forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) 
     {

         if (success) 
         {
             NSLog(@"XML: Synced with icloud");
             UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"iCloud Syncing" message:@"Successfully synced with iCloud." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
             [alert show];
             [alert release];



         }
         else
             NSLog(@"XML: Syncing FAILED with icloud");


     }];

}

3)MyDocument.h file

#import <UIKit/UIKit.h>

@interface MyDocument : UIDocument
    @property (strong) NSString *xmlContent;
@end

4)MyDocument.m file

#import "MyDocument.h"

@implementation MyDocument
@synthesize xmlContent,zipDataContent;

// Called whenever the application reads data from the file system
- (BOOL)loadFromContents:(id)contents ofType:(NSString *)typeName error:(NSError **)outError
{
    // NSLog(@"* ---> typename: %@",typeName);
                self.xmlContent = [[NSString alloc] 
                               initWithBytes:[contents bytes] 
                               length:[contents length] 
                               encoding:NSUTF8StringEncoding]; 

    [[NSNotificationCenter defaultCenter] postNotificationName:@"noteModified" object:self];
    return YES;     
}

// Called whenever the application (auto)saves the content of a note
- (id)contentsForType:(NSString *)typeName error:(NSError **)outError 
{

        return [NSData dataWithBytes:[self.xmlContent UTF8String] length:[self.xmlContent length]];

}

@end

5) now in ur appdelegate

- (void)loadData:(NSMetadataQuery *)queryData
 {


    for (NSMetadataItem *item in [queryData results]) 
    {    
        NSString *filename = [item valueForAttribute:NSMetadataItemDisplayNameKey];
        NSNumber *filesize = [item valueForAttribute:NSMetadataItemFSSizeKey]; 
        NSDate *updated = [item valueForAttribute:NSMetadataItemFSContentChangeDateKey];
        NSLog(@"%@ (%@ bytes, updated %@) ", filename, filesize, updated);

        NSURL *url = [item valueForAttribute:NSMetadataItemURLKey];
        MyDocument *doc = [[MyDocument alloc] initWithFileURL:url];
        if([filename isEqualToString:@"Properties"])
        {
            [doc openWithCompletionHandler:^(BOOL success) {
                if (success) {
                    NSLog(@"XML: Success to open from iCloud");
                    NSData *file = [NSData dataWithContentsOfURL:url];
                    //NSString *xmlFile = [[NSString alloc] initWithData:file encoding:NSASCIIStringEncoding];
                    //NSLog(@"%@",xmlFile);

                    NSXMLParser *parser = [[NSXMLParser alloc] initWithData:file];
                    [parser setDelegate:self];
                    [parser parse];
                    //We hold here until the parser finishes execution
                    [parser release];
                }
                else 
                {
                    NSLog(@"XML: failed to open from iCloud");
                 }
            }]; 
        }
}
}

6) now in parser method fetch data and insert/update as needed in database.

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)nameSpaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
if ([elementName isEqual:@"Property"])
    {
        NSLog(@"Property attributes : %@|%@|%@|%@|%@|%@|%@|%@", [attributeDict objectForKey:@"id"],[attributeDict objectForKey:@"street"], [attributeDict objectForKey:@"city"], [attributeDict objectForKey:@"state"],[attributeDict objectForKey:@"zip"],[attributeDict objectForKey:@"status"],[attributeDict objectForKey:@"lastupdated"],[attributeDict objectForKey:@"deleted"]);
}
//like this way fetch all data and insert in db
}