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Convenience method for Facebook iOS SDK to page through all graph results
//
// FBSDKGraphRequest+Paging.h
// Facebook Paging Extension
//
// Created by Yonat Sharon on 04.04.2016.
// Copyright © 2016 Yonat Sharon. All rights reserved.
//
#import <FBSDKCoreKit/FBSDKCoreKit.h>
@interface FBSDKGraphRequest (Paging)
/// Page through results, executing the completion block for each page of results.
- (void)startPagingWithCompletionHandler:(void (^)(id result, NSError *error))completion;
@end
//
// FBSDKGraphRequest+Paging.m
// Facebook Paging Extension
//
// Created by Yonat Sharon on 04.04.2016.
// Copyright © 2016 Yonat Sharon. All rights reserved.
//
#import "FBSDKGraphRequest+Paging.h"
@interface FBSDKGraphRequest (PagingPrivate)
- (void)pageJSON:(id)json completionHandler:(void (^)(id result, NSError *error))completion;
- (id)decodeJSONResult:(NSData *)data response:(NSURLResponse *)response error:(NSError *)error;
@end
@implementation FBSDKGraphRequest (Paging)
- (void)startPagingWithCompletionHandler:(void (^)(id result, NSError *error))completion {
[self startWithCompletionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
if (error) {
NSLog(@"Error executing facebook request %@ info: %@", self.graphPath, error.localizedDescription);
completion(nil, error);
return;
};
completion(result, nil);
[self pageJSON:result completionHandler:completion];
}];
}
@end
@implementation FBSDKGraphRequest (PagingPrivate)
- (void)pageJSON:(id)json completionHandler:(void (^)(id result, NSError *error))completion {
NSString *nextPage = json[@"paging"][@"next"];
if (!nextPage) return;
[[[NSURLSession sharedSession] dataTaskWithURL:[NSURL URLWithString:nextPage] completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
id json = [self decodeJSONResult:data response:response error:error];
if (!json) {
completion(nil, error);
return;
}
completion(json, nil);
[self pageJSON:json completionHandler:completion];
}] resume];
}
- (id)decodeJSONResult:(NSData *)data response:(NSURLResponse *)response error:(NSError *)error {
if (error) {
NSLog(@"Error executing facebook paging: %@", error.localizedDescription);
return nil;
};
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
if (httpResponse.statusCode != 200) {
NSLog(@"facebook paging request returned status: %d", (int)httpResponse.statusCode);
return nil;
}
NSError *jsonDecodingError = nil;
id json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&jsonDecodingError];
if (jsonDecodingError) {
NSString *returnString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
if ([returnString isEqualToString:@"none"]) {
json = [NSDictionary dictionary];
}
else {
NSLog(@"facebook paging request returned malformed JSON: %@", returnString);
return nil;
}
}
return json;
}
@end
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