YAJL Framework
The YAJL framework is an Objective-C framework for the YAJL SAX-style JSON parser.
Features
- Stream parsing, comments in JSON, better error messages.
- Parse directly from NSString or NSData.
- Generate JSON from default or custom types.
- Properly handles large numeric types.
- Document style parser.
- Error by exception or out error.
Integration
CocoaPods
pod "YAJLO"
Swift Package Manager
You can use The Swift Package Manager to install yajl-objc by adding the proper description to your Package.swift file:
// swift-tools-version:5.5
import PackageDescription
let package = Package(
name: "YOUR_PROJECT_NAME",
dependencies: [
.package(url: "https://github.com/gabriel/yajl-objc.git", from: "0.3.4"),
]
)
Usage
#import <YAJLO/NSObject+YAJL.h>
#import <YAJLO/YAJLDocument.h>
#import <YAJLO/YAJLGen.h>
#import <YAJLO/YAJLParser.h>
To parse JSON from NSData
NSData *JSONData = [NSData dataWithContentsOfFile:@"example.json"];
NSArray *arrayFromData = [JSONData yajl_JSON];
To parse JSON from NSString
NSString *JSONString = @"[1, 2, 3]";
NSArray *arrayFromString = [JSONString yajl_JSON];
To parse JSON from NSString with error and comments
// With options and out error
NSString *JSONString = @"[1, 2, 3] // Allow comments";
NSError *error = nil;
NSArray *arrayFromString = [JSONString yajl_JSONWithOptions:YAJLParserOptionsAllowComments error:&error];
To generate JSON from an object, NSArray, NSDictionary, etc.
NSDictionary *dict = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"];
NSString *JSONString = [dict yajl_JSONString];
// ==> {"key":"value"}
To generate JSON from an object, beautified with custom indent
// Beautified with custon indent string
NSArray *array = [NSArray arrayWithObjects:@"value1", @"value2", nil];
NSString *JSONString = [dict yajl_JSONStringWithOptions:YAJLGenOptionsBeautify indentString:@" "];
To use the streaming (or SAX style) parser, use YAJLParser
NSData *data = [NSData dataWithContentsOfFile:@"example.json"];
YAJLParser *parser = [[YAJLParser alloc] initWithParserOptions:YAJLParserOptionsAllowComments];
parser.delegate = self;
[parser parse:data];
if (parser.parserError) {
NSLog(@"Error:\n%@", parser.parserError);
}
parser.delegate = nil;
// Include delegate methods from YAJLParserDelegate
- (void)parserDidStartDictionary:(YAJLParser *)parser { }
- (void)parserDidEndDictionary:(YAJLParser *)parser { }
- (void)parserDidStartArray:(YAJLParser *)parser { }
- (void)parserDidEndArray:(YAJLParser *)parser { }
- (void)parser:(YAJLParser *)parser didMapKey:(NSString *)key { }
- (void)parser:(YAJLParser *)parser didAdd:(id)value { }
Parser Options
There are options when parsing that can be specified with initWithParserOptions: (YAJLParser).
YAJLParserOptionsAllowComments
: Allows comments in JSONYAJLParserOptionsCheckUTF8
: Will verify UTF-8YAJLParserOptionsStrictPrecision
: Will force strict precision and return integer overflow error, if number is greater than long long.
Parsing as data becomes available
YAJLParser *parser = [[YAJLParser alloc] init];
parser.delegate = self;
// A chunk of data comes...
YAJLParserStatus status = [parser parse:chunk1];
// 'status' should be YAJLParserStatusInsufficientData, if its not finished
if (parser.parserError)
NSLog(@"Error:\n%@", parser.parserError);
// Another chunk of data comes...
YAJLParserStatus status = [parser parse:chunk2];
// 'status' should be YAJLParserStatusOK if its finished
if (parser.parserError)
NSLog(@"Error:\n%@", parser.parserError);
Document style parsing
To use the document style, use YAJLDocument. Usage should be very similar to NSXMLDocument.
NSData *data = [NSData dataWithContentsOfFile:@"example.json"];
NSError *error = nil;
YAJLDocument *document = [[YAJLDocument alloc] initWithData:data parserOptions:YAJLParserOptionsNone error:&error];
// Access root element at document.root
NSLog(@"Root: %@", document.root);
Document style parsing as data becomes available
YAJLDocument *document = [[YAJLDocument alloc] init];
document.delegate = self;
NSError *error = nil;
[document parse:chunk1 error:error];
[document parse:chunk2 error:error];
// You can access root element at document.root
NSLog(@"Root: %@", document.root);
// Or via the YAJLDocumentDelegate delegate methods
- (void)document:(YAJLDocument *)document didAddDictionary:(NSDictionary *)dict { }
- (void)document:(YAJLDocument *)document didAddArray:(NSArray *)array { }
- (void)document:(YAJLDocument *)document didAddObject:(id)object toArray:(NSArray *)array { }
- (void)document:(YAJLDocument *)document didSetObject:(id)object forKey:(id)key inDictionary:(NSDictionary *)dict { }
Load JSON from Bundle
id JSONValue = [[NSBundle mainBundle] yajl_JSONFromResource:@"kegs.json"];
Customized Encoding
To implement JSON encodable value for custom objects or override for existing objects, implement - (id)JSON;
For example:
@interface CustomObject : NSObject
@end
@implementation CustomObject
- (id)JSON {
return [NSArray arrayWithObject:[NSNumber numberWithInteger:1]];
}
@end