Query Azure from iOS - ios

Question

I am not figuring out how to perform a query in Azure. I did finally figure out inserts, but now I am trying to query from Azure. Two parts here, how do I return the result from Azure and how do I read the results in objective-C?
Thus far, I have this
-(double)GetValidAppVersion
{
// Create a proxy client for sending requests to the Azure platform.
MSClient *client = [MSClient clientWithApplicationURLString : #""
withApplicationKey : #"];
MSTable *appSettingsTable = [client getTable:#"AppSettings"];
NSPredicate * predicate = [NSPredicate predicateWithFormat:#"Key == AppVersion"];
NSArray *queryResults = [[NSArray alloc] init];
[appSettingsTable readWhere:predicate completion:^(NSArray *results, NSInteger totalCount, NSError *error)
{
self.items = [results mutableCopy];
}];
return 1.0;
}
I have not figured out the Azure side either. How can I query and return a result based on the input parameter?
My table is simple with
ID int
Key varchar
Value varchar
Any help with getting this going is greatly appreciated.
Edit:
I added this to my controller
-(bool) IsAppVersionValid
{
AppDelegate *delegate = [[UIApplication sharedApplication] delegate];
double validAppVersion = [delegate.appVersion doubleValue];
double serverAppVersion;
NSDictionary *item = #{ #"complete" : #(NO) };
[self.Service SelectAppVersion:item completion:^(NSUInteger index)
{
}];
return true;//clientVersion >= validAppVersion;
}
And this to my service (this is sloppy as it should be a simple completion block -- I would like to pass NSString * with the AppSettings key value and use that in the predicate as well. Any thoughts on the syntax for that?
typedef void (^CompletionWithAppVersionBlock)(NSUInteger index);
- (void) SelectAppVersion:(NSDictionary *) item
completion:() completion;

Answer 1

All of the read table read methods that are part of the iOS SDK for Mobile Services are asynchronous which means that you have to pass a completion block into them (as you're doing above where you're setting self.items = [results mutableCopy];) in order to then do something with the results they are fetching.
This means that in order to get the value you're looking for, you'll want to pass in a completion block into your GetValidAppVersion method. You can then pass the app version you're getting back to that block. So something like this:
-(void) GetValidAppVersion:(NSDictionary *)item completion:(CompletionWithVersion)completion
{
MSTable *appSettingsTable = [client getTable:#"AppSettings"];
NSPredicate * predicate = [NSPredicate predicateWithFormat:#"Key == AppVersion"];
NSArray *queryResults = [[NSArray alloc] init];
[appSettingsTable readWhere:predicate completion:^(NSArray *results, NSInteger totalCount, NSError *error)
{
completion([results objectAtIndex:0]);
}];
}
You would need to define the CompletionWithVersion as being a block with a parameter returned (the AppVersion). Take a look at the iOS quickstart application to see how the completion blocks are defined.