How do I convert class objects to JSON for request?

Question

I have some sort of data lets say Passengers and inside passenger I have children's array and infant's array, I am just bamboozled and just didn't get any clue to convert list of passengers to JSON.

In objective-c so far I have seen that we convert class object to NSDictionary by it toDictionary method.

My question is what if we have list of class object.. what's the catch here? how we gonna convert that list?

I have NSMutableArray of passengers and inside a passenger object I have NSMutableArray of children and infants.

How can I convert that list of passengers to Dictionary for request?

I am new to objective-c, in java we used to serialise and deserialize.

I have already tried converting NSMutableArray to NSDictionary and so on but it seems like it doesn't work at all.

{
   "airline_code":"AA",
   "inbound_trip_id":122222,
   "outbound_trip_id":111111,
   "passengers":[
      {
         "address_line1":"fdsdsf",
         "address_line2":"",
         "children":[
            {
               "city":"abx",
               "country":"abcd",
               "country_access_code":"11",
               "country_code":"AK",
               "date_of_birth":"4#8#2017",
               "email_address":"[email protected]",
               "first_name":"munna",
               "gender":"Male",
               "inbound_ssr_id":[
                  40420
               ],
               "last_name":"khna",
               "middle_name":"",
               "nationality":"aaaa",
               "outbound_ssr_id":[
                  40417
               ],
               "passport_expiry_date":"4#29#2019",
               "passport_issue_date":"4#8#2019",
               "passport_number":"PPA2345",
               "phone_number":"111111111",
               "state":"aaa",
               "title":"Mr",
               "titleIndex":0,
               "zip_code":"123213"
            }
         ],
         "city":"Dadu",
         "country":"aa",
         "country_access_code":"11",
         "country_code":"aa",
         "date_of_birth":"4#8#1973",
         "email_address":"[email protected]",
         "firstAdult":0,
         "first_name":"aaa",
         "gender":"Male",
         "inbound_ssr_id":[
            40421
         ],
         "billing_info":false,
         "last_name":"ccc",
         "middle_name":"",
         "nationality":"PK",
         "outbound_ssr_id":[
            40416
         ],
         "passport_expiry_date":"4#29#2019",
         "passport_issue_date":"4#8#2019",
         "passport_number":"PPA12345",
         "phone_number":"111111111",
         "state":"OOA",
         "title":"Mr",
         "zip_code":"324546"
      },
      {
         "address_line1":"dfdsfdsf",
         "address_line2":"",
         "city":"Beletwene",
         "country":"Somalia",
         "country_access_code":"252",
         "country_code":"SO",
         "date_of_birth":"4#8#1989",
         "email_address":"[email protected]",
         "firstAdult":0,
         "first_name":"vv",
         "gender":"Male",
         "genederIndex":0,
         "inbound_ssr_id":[
            40419
         ],
         "billing_info":false,
         "last_name":"fdf",
         "middle_name":"",
         "nationality":"PP",
         "outbound_ssr_id":[
            40418
         ],
         "passport_expiry_date":"4#29#2019",
         "passport_issue_date":"4#8#2019",
         "passport_number":"PPA123435",
         "phone_number":"615100002",
         "state":"PPA",
         "title":"Mr",
         "titleIndex":0,
         "zip_code":"23454"
      }
   ],
   "search_id":"0000000000000000000000000000000000000",
   "token_id":"0000000000000000000000000000000000000"
}

Answer 1

I do both the toDictionary and fromDictionary inside of a class object. If an object has nested class objects, they, likewise, need to implement a toDictionary and fromDictionary methods. Here is an example of a Claim class that contains an array of Trip classes:

Claim.h

#import <Foundation/Foundation.h>

@interface Claim : NSObject <NSCopying>
{

}

-(id) copy;
-(id) copyWithZone: (NSZone *) zone;

@property (nonatomic, strong) NSNumber *claimID;
@property (nonatomic, strong) NSString *claimantName;
@property (nonatomic, strong) NSNumber *totalAmount;
@property (nonatomic, strong) NSMutableArray *trips;
@property (nonatomic, assign) BOOL isDirty;


-(void) fromDictionary:(NSDictionary *)dict;
-(NSMutableDictionary *) toDictionary;

-(void) getClaim:(NSInteger)claim_id;
-(void) getTrips;

-(BOOL) saveClaim;
-(BOOL) addClaim;
-(BOOL) updateClaim;
-(BOOL) deleteClaim;

@end

And here is the implementation of the Claim class:

#import "Claim.h"
#import "AppDelegate.h"
#import "Trip.h"

@implementation Claim

@synthesize claimID;
@synthesize claimantName;
@synthesize totalAmount;
@synthesize trips;
@synthesize isDirty;

- (id)init {
    if (self = [super init]) {

        self.claimID = [NSNumber numberWithInteger:0];
        self.claimantName = @"";
        self.totalAmount = [NSNumber numberWithInteger:0];
        self.trips = [[NSMutableArray alloc] init];

        self.isDirty = NO;

    }
    return self;
}

-(id) copy
{

    Claim *newClaim = [[Claim alloc] init];
    newClaim.claimID = [self.claimID copy];
    newClaim.claimantName = [self.claimantName copy];
    newClaim.totalAmount = [self.totalAmount copy];
    newClaim.trips = [[NSMutableArray alloc] initWithArray:self.trips copyItems:YES];

    newClaim.isDirty = self.isDirty;

    return newClaim;
}

-(id) copyWithZone: (NSZone *) zone
{

    Claim *newClaim = [[Claim alloc] init];
    newClaim.claimID = [self.claimID copy];
    newClaim.claimantName = [self.claimantName copy];
    newClaim.totalAmount = [self.totalAmount copy];
    newClaim.adjMiles = [self.adjMiles copy];
    newClaim.trips = [[NSMutableArray alloc] initWithArray:self.trips copyItems:YES];

    newClaim.isDirty = self.isDirty;

    return newClaim;
}


-(NSMutableDictionary *)toDictionary
{

    NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
    [dict setObject:self.claimID forKey:@"claim_id"];
    [dict setObject:self.claimantName forKey:@"claimant_name"];
    [dict setObject:self.totalAmount forKey:@"total_amount"];

    NSMutableArray *tripArray = [[NSMutableArray alloc] init];

    for (Trip * item in self.trips) {
        NSDictionary *theDict = [item toDictionary];
        [tripArray addObject:theDict];

    }

    [dict setObject:tripArray forKey:@"trips"];

    if (self.isDirty== YES) {
        [dict setValue:@YES forKey:@"is_dirty"];
    } else {
        [dict setValue:@NO forKey:@"is_dirty"];
    }

    return dict;
}

-(void)fromDictionary:(NSDictionary *)dict
{

    self.claimID = [dict objectForKey:@"claim_id"];
    if ([self.claimID isEqual:[NSNull null]]) {
        self.claimID = [NSNumber numberWithInt:0];
    }

    self.claimantName  = [dict objectForKey:@"claimant_name"];
    if ([self.claimantName isEqual:[NSNull null]]) {
        self.claimantName = @"";
    }

    self.totalAmount  = [dict objectForKey:@"total_amount"];
    if ([self.totalAmount isEqual:[NSNull null]]) {
        self.totalAmount = [NSNumber numberWithDouble:0.00];
    }

    self.trips  = [[NSMutableArray alloc] init];

for (NSDictionary *dict in arrayTrips) {
    Trip *item = [[Trip alloc] init];
    [item fromDictionary:dict];
    [self.trips addObject:item];
}

long ruDirty = [[dict valueForKey:@"is_dirty"] integerValue];

if (ruDirty == 1) {
    self.isDirty = YES;
} else {
    self.isDirty = NO;
}

}

- (NSString *)clearNulls:(const char *)value {

    NSString *result;

    if (value == NULL) {
        result = @"";
    } else if (value == nil) {
        result = @"";
    } else {
        result = [[NSString alloc] initWithUTF8String:value];
    }

    return result;
}

-(void)getClaim:(NSInteger)claim_id
{
}


-(void)getTrips
{
}


-(BOOL) saveClaim {

    if ([self.claimID integerValue] == 0) {
        return [self addClaim];
    } else {
        return [self updateClaim];
    }

}

-(BOOL) addClaim {

    return dataSaved;

}

-(BOOL) updateClaim {

    return dataSaved;
}

-(BOOL) deleteClaim {

    return didDelete;

}

@end

Answer 2

The NSJSONSerialization class can convert NSDictionary to JSON. See https://developer.apple.com/documentation/foundation/nsjsonserialization

Answer 3

You can use codable to serialize a Class to JSON string and do the reverse. Thought the example in Swift JSONEncoder can be accessed from Objective-C.

How to use Codable protocol in objective c data model class?