我正在尝试使用AFNetworking 2.0从Parse.com后端获取记录。我希望在某个日期之后更新记录。 Parse.com文档声明针对日期字段的比较查询需要以以下格式进行URL编码：
'where={"createdAt":{"$gte":{"__type":"Date","iso":"2011-08-21T18:02:52.249Z"}}}'
这完全适用于卷曲。
在我的应用中，我使用AFNetworking 2.0来运行查询，如下所示。我在初始化共享客户端时首先设置请求和响应序列化程序：
+ (CSC_ParseClient *)sharedClient {
static CSC_ParseClient *_sharedClient = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
NSURL *baseURL = [NSURL URLWithString:@"https://api.parse.com"];
NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
[config setHTTPAdditionalHeaders:@{ @"Accept":@"application/json",
@"Content-type":@"application/json",
@"X-Parse-Application-Id":@"my app ID",
@"X-Parse-REST-API-Key":@"my api key"}];
NSURLCache *cache = [[NSURLCache alloc] initWithMemoryCapacity:10 * 1024 * 1024
diskCapacity:50 * 1024 * 1024
diskPath:nil];
[config setURLCache:cache];
_sharedClient = [[CSC_ParseClient alloc] initWithBaseURL:baseURL
sessionConfiguration:config];
_sharedClient.responseSerializer = [AFJSONResponseSerializer serializer];
_sharedClient.requestSerializer = [AFJSONRequestSerializer serializer];
});
return _sharedClient;
}
- (NSURLSessionDataTask *)eventsForSalesMeetingID:(NSString *)meetingID sinceDate:(NSDate *)lastUpdate completion:( void (^)(NSArray *results, NSError *error) )completion {
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
[dateFormatter setTimeZone:gmt];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
NSString *dateString = [dateFormatter stringFromDate:lastUpdate];
NSLog(@"date = %@", dateString);
NSDictionary *params = @{@"where": @{@"updatedAt": @{@"$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;
}
但这会从服务器产生400错误。解码后返回的url编码查询字符串如下所示：
where[updatedAt][$gte][__type]=Date&where[updatedAt][$gte][iso]=2014-01-07T23:56:29.274Z
我尝试对查询字符串的后端进行硬编码，如下所示：
NSString *dateQueryString = [NSString stringWithFormat:@"{\"$gte\":{\"__type\":\"Date\",\"iso\":\"%@\"}}", dateString];
NSDictionary *params = @{@"where":@{@"updatedAt":dateQueryString}};
这让我更接近，但仍然是400错误;来自服务器的返回查询字符串如下所示：
where[updatedAt]={"$gte":{"__type":"Date","iso":"2014-01-07T23:56:29.274Z"}}
如何从AFNetworking获取正确的查询字符串？我开始使用ParseSDK，这使得这个查询变得非常容易，但是他们的SDK很重（30+ MB）。
答案 0 :(得分：2)
来自parse.com REST文档here：
where参数的值应该编码为JSON。因此，如果您查看请求的实际URL，它将是JSON编码的，然后是URL编码的
您与硬编码字符串非常接近，您只需对整个查询进行URL编码即可。我在以下方面取得了成功：
NSString *dateQueryString = [NSString stringWithFormat:@"{\"updatedAt\":{\"$gte\":{\"__type\":\"Date\",\"iso\":\"%@\"}}}", dateString];
NSDictionary *parameters = @{@"where": dateQueryString};
以下使用NSDictionary构造dateQueryString：
NSString *dateQueryString;
NSDictionary *query = @{ @"updatedAt": @{ @"$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};
为了完整性 - 我正在使用AFHTTPSessionManager子类的共享实例：
@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;
}
并且这样称呼它：
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);
}];
很抱歉这篇长篇文章，希望有所帮助