Parse.com and AFNetworking 2.0 Date Queries - ios

Question

I'm trying to use AFNetworking 2.0 to get records from a Parse.com backend. I want to get records updated after a certain date. Parse.com documentation states that comparison queries against a date field need to be url encoded in the format:
'where={"createdAt":{"$gte":{"__type":"Date","iso":"2011-08-21T18:02:52.249Z"}}}'
This works perfectly using curl.
In my app, I am using AFNetworking 2.0 to run the query as below. I first set the request and response serializer when initializing the shared client:
+ (CSC_ParseClient *)sharedClient {
static CSC_ParseClient *_sharedClient = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
NSURL *baseURL = [NSURL URLWithString:#"https://api.parse.com"];
NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
[config setHTTPAdditionalHeaders:#{ #"Accept":#"application/json",
#"Content-type":#"application/json",
#"X-Parse-Application-Id":#"my app ID",
#"X-Parse-REST-API-Key":#"my api key"}];
NSURLCache *cache = [[NSURLCache alloc] initWithMemoryCapacity:10 * 1024 * 1024
diskCapacity:50 * 1024 * 1024
diskPath:nil];
[config setURLCache:cache];
_sharedClient = [[CSC_ParseClient alloc] initWithBaseURL:baseURL
sessionConfiguration:config];
_sharedClient.responseSerializer = [AFJSONResponseSerializer serializer];
_sharedClient.requestSerializer = [AFJSONRequestSerializer serializer];
});
return _sharedClient;
}
- (NSURLSessionDataTask *)eventsForSalesMeetingID:(NSString *)meetingID sinceDate:(NSDate *)lastUpdate completion:( void (^)(NSArray *results, NSError *error) )completion {
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:#"GMT"];
[dateFormatter setTimeZone:gmt];
[dateFormatter setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
NSString *dateString = [dateFormatter stringFromDate:lastUpdate];
NSLog(#"date = %#", dateString);
NSDictionary *params = #{#"where": #{#"updatedAt": #{#"$gte": #{#"__type":#"Date", #"iso": dateString}}}};
NSURLSessionDataTask *task = [self GET:#"/1/classes/SalesMeetingEvents"
parameters:params
success:^(NSURLSessionDataTask *task, id responseObject) {
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)task.response;
NSLog(#"Response = %#", httpResponse);
if (httpResponse.statusCode == 200) {
dispatch_async(dispatch_get_main_queue(), ^{
completion(responseObject[#"results"], nil);
});
} else {
dispatch_async(dispatch_get_main_queue(), ^{
completion(nil, nil);
});
NSLog(#"Received: %#", responseObject);
NSLog(#"Received HTTP %d", httpResponse.statusCode);
}
} failure:^(NSURLSessionDataTask *task, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
completion(nil, error);
});
}];
return task;
}
But this yields a 400 error from the server. The url encoded query string returned looks like this after decoding:
where[updatedAt][$gte][__type]=Date&where[updatedAt][$gte][iso]=2014-01-07T23:56:29.274Z
I tried hard-coding the back end of the querystring like this:
NSString *dateQueryString = [NSString stringWithFormat:#"{\"$gte\":{\"__type\":\"Date\",\"iso\":\"%#\"}}", dateString];
NSDictionary *params = #{#"where":#{#"updatedAt":dateQueryString}};
This gets me closer, but still a 400 error; the returned query string from the server looks like this:
where[updatedAt]={"$gte":{"__type":"Date","iso":"2014-01-07T23:56:29.274Z"}}
How do I get the proper query string from AFNetworking? I started out using the ParseSDK, which made this query super easy, but their SDK is way to heavy (30+ MB).

Answer 1

From the parse.com REST documentation here:
The value of the where parameter should be encoded JSON. Thus, if you look at the actual URL requested, it would be JSON-encoded, then URL-encoded
You are so close with your hardcoded string, you just need to URL-encode the whole query. I have had success with the following:
NSString *dateQueryString = [NSString stringWithFormat:#"{\"updatedAt\":{\"$gte\":{\"__type\":\"Date\",\"iso\":\"%#\"}}}", dateString];
NSDictionary *parameters = #{#"where": dateQueryString};
The following uses an NSDictionary to construct the dateQueryString:
NSString *dateQueryString;
NSDictionary *query = #{ #"updatedAt": #{ #"$gte": #{#"__type":#"Date",#"iso":dateString}}};
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:query
options:nil
error:&error];
if (!jsonData) {
NSLog(#"Error: %#", [error localizedDescription]);
}
NSString *dateQueryString = [[NSString alloc] initWithData:jsonData
encoding:NSUTF8StringEncoding];
NSDictionary *parameters = #{#"where": dateQueryString};
For completeness - I am using a shared instance of an AFHTTPSessionManager subclass:
#implementation ParseAPISessionManager
+ (instancetype)sharedSession {
static ParseAPISessionManager *_sharedClient = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_sharedClient = [[ParseAPISessionManager alloc] initWithBaseURL:[NSURL URLWithString:parseAPIBaseURLString]];
});
return _sharedClient;
}
- (id)initWithBaseURL:(NSURL *)url {
self = [super initWithBaseURL:url];
if (self) {
self.requestSerializer = [AFJSONRequestSerializer serializer];
[self.requestSerializer setValue:parseAPIApplicationId forHTTPHeaderField:#"X-Parse-Application-Id"];
[self.requestSerializer setValue:parseRESTAPIKey forHTTPHeaderField:#"X-Parse-REST-API-Key"];
}
return self;
}
And calling it like this:
ParseAPISessionManager *manager = [ParseAPISessionManager sharedSession];
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:13];
[comps setMonth:2];
[comps setYear:2014];
[comps setHour:16];
[comps setMinute:0];
NSDate *feb13 = [[NSCalendar currentCalendar] dateFromComponents:comps];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss.'999Z'"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:#"GMT"]];
NSString *feb13str = [dateFormatter stringFromDate: feb13];
NSString *queryStr = [NSString stringWithFormat:#"{\"updatedAt\":{\"$gte\":{\"__type\":\"Date\",\"iso\":\"%#\"}}}", feb13str];
NSDictionary *parameters = #{#"where": queryStr};
[manager GET:#"classes/TestClass" parameters:parameters success:^(NSURLSessionDataTask *operation, id responseObject) {
NSLog(#"%#", responseObject);
} failure:^(NSURLSessionDataTask *operation, NSError *error) {
NSLog(#"Error: %#", error);
}];
Sorry for the long post, hope it helps