A simple sync with the iPhone DropBox API - iphone

Question

I am getting slightly frustrated with the DropBox API. It is supposed to be all simple and straight forward, but I have yet to come a across a simple and plain explanation of how to do a simple sync.
I followed all the instruction you can find in the readme which comes withe DropBox API. To test the whole thing, I have created two buttons to download and upload a file from or to my DropBox. The files are found in my app documents folder.
This works splendidly:
-(void) DBupload:(id)sender
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents directory
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:#"MyExample.txt"];
// NSError *error;
[self.restClient uploadFile:#"MyExample.txt" toPath:#"/MyExamplePath" fromPath:filePath];
}
-(void) DBdownload:(id)sender
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents directory
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:#"MyExample.txt"];
NSError *error;
[self.restClient loadFile:#"/myExamplePath/MyExample.txt" intoPath:filePath];
}
However, I am now wondering how to achieve a simply sync. Right now, I can manually upload and download. But what I need in order to sync is to:
find out if the MyExample.txt in my App's folder or in my DropBox folder is more recent
if the txt in the App's folder is more recent: drop it into dropbox (overriding the old), i.e. call my DBupload method
if the txt in the drop box is more recent: download it into the apps folder, i.e. call my DBdownload method
Perhaps I am just too dumb, but does dropBox detail somewhere how to achieve this rather simple and straight forward task?
I know that there is this but it doesn't really give any code samples.
Thanks for any suggestions.
EDIT
OK, so I figured that my first step is to find out the last modified date of MyExample.txt which is found in the dropBox.
I wrote a wonderful method called DBsync in which I simply put this command:
-(void) DBsync
{
[self.restClient loadMetadata:#"/myExamplePath"];
}
This calls the following method which gets the metadata. This was a suggested answer to this post, and I commented it a bit out so as to make it plain what is happening (if there are more dumb people like myself:
- (void)restClient:(DBRestClient*)client loadedMetadata:(DBMetadata*)metadata {
NSLog(#"restClient:loadedMetadata function called");
NSEnumerator *e= [metadata.contents objectEnumerator]; // indexes files in dropbox?
DBMetadata *dbObject; // loads metadate we need, e.g. lastModifiedDated
int numberOfFiles = [metadata.contents count]; // counts files in DropBox - I guess we don't really need this
NSLog(#"numberOfFiles %i", numberOfFiles);
while ((dbObject = [e nextObject])) { // this goes through every single file in the DropBox
if (!dbObject.isDirectory) { // this determines whether we are talking about a file or a folder
NSString *fileName = [dbObject.path lastPathComponent]; // this puts the name of the last component, e.g. in /MyExamplePath/MyExample.txt = MyExample.txt into fileName
NSLog(#"File which is currently being checked: %#", fileName);
if ([fileName isEqualToString:#"MyExample.txt"]) {
NSLog(#"Found it: %#", fileName);
NSLog(#"Date last modified: %#", dbObject.lastModifiedDate);
/* to do: call dbupload if dbObject.lastModifiedDate > than your local file*/
}
}
}
}
I will post the next step once I managed to do so...

Answer 1

I think what you are looking for is the loadmetadata method. Here is an untested example:
- (void)restClient:(DBRestClient*)client loadedMetadata:(DBMetadata*)metadata {
NSEnumerator *e= [metadata.contents objectEnumerator];
DBMetadata *dbObject;
numberOfFiles = [metadata.contents count];
while ((dbObject = [e nextObject])) {
if (!dbObject.isDirectory) {
NSString *fileName = [dbObject.path lastPathComponent];
if (![fileName isEqualToString:#"MyExample.txt"]) {
/* call dbupload if dbObject.lastModifiedDate > than your local file*/
}
}
}

Answer 2

You don't need an enumerator, just use the good old for... loop ;)
- (void)restClient:(DBRestClient *)client loadedMetadata:(DBMetadata *)metadata {
for (DBMetadata * child in metadata.contents) {
if (!child.isDirectory) {
NSString *fileName = [dbObject.path lastPathComponent];
if (![fileName isEqualToString:#"MyExample.txt"]) {
/* call dbupload if dbObject.lastModifiedDate > than your local file*/
}
}
}
}