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https://github.com/SBJson/SBJson

This framework implements a strict JSON parser and generator in Objective-C.
https://github.com/SBJson/SBJson

carthage chunk json objective-c parsing sbjson

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This framework implements a strict JSON parser and generator in Objective-C.

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# SBJson 5



Chunk-based JSON parsing and generation in Objective-C.



[![CircleCI](https://circleci.com/gh/SBJson/SBJson.svg?style=svg)](https://circleci.com/gh/SBJson/SBJson)

[![Project Status: Inactive - The project has reached a stable, usable state but is no longer being actively developed; support/maintenance will be provided as time allows.](http://www.repostatus.org/badges/0.1.0/inactive.svg)](http://www.repostatus.org/#inactive)

[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)



# Overview



SBJson's number one feature is stream/chunk-based operation. Feed the parser one or

more chunks of UTF8-encoded data and it will call a block you provide with each

root-level document or array. Or, optionally, for each top-level entry in each

root-level array.



With this you can reduce the apparent latency for each

download/parse cycle of documents over a slow connection. You can start

parsing *and return chunks of the parsed document* before the full document

has downloaded. You can also parse massive documents bit by bit so you

don't have to keep them all in memory.



SBJson maps JSON types to Objective-C types in the following way:



| JSON Type | Objective-C Type                |

|-----------|---------------------------------|

| null      | NSNull                          |

| string    | NSString                        |

| array     | NSMutableArray                  |

| object    | NSMutableDictionary             |

| true      | -[NSNumber numberWithBool: YES] |

| false     | -[NSNumber numberWithBool: NO]  |

| number    | NSNumber                        |



- Booleans roundtrip properly even though Objective-C doesn't have a

  dedicated class for boolean values.

- Integers use either `long long` or `unsigned long long` if they fit,

  to avoid rounding errors.  For all other numbers we use the `double`

  type, with all the potential rounding errors that entails.



## "Plain" Chunk Based Parsing



First define a simple block & an error handler. (These are just minimal

examples. You should strive to do something better that makes sense in your

application!)



```objc

SBJson5ValueBlock block = ^(id v, BOOL *stop) {

    BOOL isArray = [v isKindOfClass:[NSArray class]];

    NSLog(@"Found: %@", isArray ? @"Array" : @"Object");

};



SBJson5ErrorBlock eh = ^(NSError* err) {

    NSLog(@"OOPS: %@", err);

    exit(1);

};

```



Then create a parser and add data to it:



```objc

id parser = [SBJson5Parser parserWithBlock:block

                              errorHandler:eh];



id data = [@"[true," dataWithEncoding:NSUTF8StringEncoding];

[parser parse:data]; // returns SBJson5ParserWaitingForData



// block is not called yet...



// ok, now we add another value and close the array



data = [@"false]" dataWithEncoding:NSUTF8StringEncoding];

[parser parse:data]; // returns SBJson5ParserComplete



// the above -parse: method calls your block before returning.

```



Alright! Now let's look at something slightly more interesting.



## Handling multiple documents



This is useful for something like Twitter's feed, which gives you one JSON

document per line. Here is an example of parsing many consequtive JSON

documents, where your block will be called once for each document:



```objc

id parser = [SBJson5Parser multiRootParserWithBlock:block

                                       errorHandler:eh];



// Note that this input contains multiple top-level JSON documents

id data = [@"[]{}" dataWithEncoding:NSUTF8StringEncoding];

[parser parse:data];

[parser parse:data];

```



The above example will print:



```

Found: Array

Found: Object

Found: Array

Found: Object

```



## Unwrapping a gigantic top-level array



Often you won't have control over the input you're parsing, so can't use a

multiRootParser. But, all is not lost: if you are parsing a long array you can

get the same effect by using an unwrapRootArrayParser:



```objc

id parser = [SBJson5Parser unwrapRootArrayParserWithBlock:block

                                             errorHandler:eh];



// Note that this input contains A SINGLE top-level document

id data = [@"[[],{},[],{}]" dataWithEncoding:NSUTF8StringEncoding];

[parser parse:data];

```



## Other features



* For safety there is a max nesting level for all input. This defaults to 32,

  but is configurable.

* The writer can sort dictionary keys so output is consistent across writes.

* The writer can create human-readable output, with newlines and indents.

* You can install SBJson v3, v4 and v5 side-by-side in the same application.

  (This is possible because all classes & public symbols contains the major

  version number.)



## A word of warning



Stream based parsing does mean that you lose some of the correctness

verification you would have with a parser that considered the entire input

before returning an answer. It is technically possible to have some parts of a

document returned *as if they were correct* but then encounter an error in a

later part of the document. You should keep this in mind when considering

whether it would suit your application.



# American Fuzzy Lop



I've run [AFL][] on the sbjson binary for over 24 hours, with no crashes

found. (I cannot reproduce the hangs reported when attempting to parse them

manually.)



[AFL]: http://lcamtuf.coredump.cx/afl/



```

                       american fuzzy lop 2.35b (sbjson)



┌─ process timing ─────────────────────────────────────┬─ overall results ─────┐

│        run time : 1 days, 0 hrs, 45 min, 26 sec      │  cycles done : 2      │

│   last new path : 0 days, 0 hrs, 5 min, 24 sec       │  total paths : 555    │

│ last uniq crash : none seen yet                      │ uniq crashes : 0      │

│  last uniq hang : 0 days, 2 hrs, 11 min, 43 sec      │   uniq hangs : 19     │

├─ cycle progress ────────────────────┬─ map coverage ─┴───────────────────────┤

│  now processing : 250* (45.05%)     │    map density : 0.70% / 1.77%         │

│ paths timed out : 0 (0.00%)         │ count coverage : 3.40 bits/tuple       │

├─ stage progress ────────────────────┼─ findings in depth ────────────────────┤

│  now trying : auto extras (over)    │ favored paths : 99 (17.84%)            │

│ stage execs : 603/35.6k (1.70%)     │  new edges on : 116 (20.90%)           │

│ total execs : 20.4M                 │ total crashes : 0 (0 unique)           │

│  exec speed : 481.9/sec             │   total hangs : 44 (19 unique)         │

├─ fuzzing strategy yields ───────────┴───────────────┬─ path geometry ────────┤

│   bit flips : 320/900k, 58/900k, 5/899k             │    levels : 8          │

│  byte flips : 0/112k, 4/112k, 3/112k                │   pending : 385        │

│ arithmetics : 66/6.24M, 0/412k, 0/35                │  pend fav : 1          │

│  known ints : 5/544k, 0/3.08M, 0/4.93M              │ own finds : 554        │

│  dictionary : 0/0, 0/0, 29/1.83M                    │  imported : n/a        │

│       havoc : 64/300k, 0/0                          │ stability : 100.00%    │

│        trim : 45.19%/56.5k, 0.00%                   ├────────────────────────┘

^C────────────────────────────────────────────────────┘             [cpu: 74%]



+++ Testing aborted by user +++

[+] We're done here. Have a nice day!

```



# API Documentation



Please see the [API Documentation](http://cocoadocs.org/docsets/SBJson) for

more details.



# Installation



## CocoaPods



The preferred way to use SBJson is by using

[CocoaPods](http://cocoapods.org/?q=sbjson). In your Podfile use:



    pod 'SBJson', '~> 5.0.0'



## Carthage



SBJson is compatible with _Carthage_. Follow the [Getting Started Guide for iOS](https://github.com/Carthage/Carthage#if-youre-building-for-ios-tvos-or-watchos).



	github "SBJson/SBJson" == 5.0.2



## Bundle the source files



An alternative that I no longer recommend is to copy all the source files (the

contents of the `Classes` folder) into your own Xcode project.



# Examples



* https://github.com/SBJson/ChunkedDelivery - a toy example showing how one can

  use `NSURLSessionDataDelegate` to do chunked delivery.

* https://github.com/SBJson/DisplayPretty - a very brief example using SBJson 4

  to reflow JSON on OS X.



# Support



* Review (or create) StackOverflow questions [tagged with

  `SBJson`](http://stackoverflow.com/questions/tagged/sbjson) if you

  have questions about how to use the library.

* Use the [issue tracker](http://github.com/SBJson/SBJson/issues) if you

  have found a bug.

* I regret I'm only able to support the current major release.



## Philosophy on backwards compatibility



SBJson practice [Semantic Versioning](https://semver.org/), which

means we do not break the API in major releases. If something requires

a backwards-incompatible change, we release a new major version.

(Hence why a library of less than 1k lines has more major versions

than Emacs.)



I also try support a gradual migration from one major version to the

other by allowing the last three major versions to co-exist in the

same app without conflicts. The way to do this is putting the major

version number in all the library's symbols and file names. So if v6

ever comes out, the `SBJson5Parser` class would become

`SBJson6Parser`, etc.



# License



BSD. See [LICENSE](LICENSE) for details.