Store multiple json object in to a text file iOS - ios

Question

When there is no internet connection on device, i am storing the json in to a text file. But the problem is, if i do again it is getting replaced. Here is what i am doing for store into a text file. How to store multiple json object in a text file.When i get connection i need to post json to server.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [paths objectAtIndex:0];
NSString *filePath = [docDir stringByAppendingPathComponent:#"File.json"];
[jsonString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error];
Please advice.

Answer 1

That's not so straight forward as concatenating multiple JSON files does not result in a valid JSON file. To do this properly requires you to read and parse the existing JSON file, which will give you an NSArray or NSDictionary top-level object, then append the data from the new JSON file and write the whole thing out.
That is inefficient as you are processing old data.
Therefore I would suggest you write new data to a new file, using the current date/time for the filename, and when it's time to upload, read each of the files and upload them individually, one-at-a-time. Then delete each file as it's uploaded.

Answer 2

Use below method to append text to file
-(void) writeToLogFile:(NSString*)content{
content = [NSString stringWithFormat:#"%#\n",content];
//get the documents directory:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [paths objectAtIndex:0];
NSString *filePath = [docDir stringByAppendingPathComponent:#"File.json"];
NSFileHandle *fileHandle = [NSFileHandle fileHandleForWritingAtPath:fileName];
if (fileHandle){
[fileHandle seekToEndOfFile];
[fileHandle writeData:[content dataUsingEncoding:NSUTF8StringEncoding]];
[fileHandle closeFile];
}
else{
[content writeToFile:fileName
atomically:NO
encoding:NSStringEncodingConversionAllowLossy
error:nil];
}
}