Partial-JSON-Paser-KMP

中文

Introduction

This library helps to parse and repair partial JSON (that is, incomplete JSON) in Kotlin. Perfect for handling streaming JSON from LLMs like ChatGPT. It is implemented in pure Kotlin so that can be used in KMP project.

Features

• Parse incomplete JSON strings into usable objects
• Complete/Repair partial JSON to valid JSON format
• Handle streaming JSON data in real-time
• Pure Kotlin implementation for KMP compatibility
• Robust error handling for malformed JSON

Usage

Parse Partial JSON

import com.funnysaltyfish.partialjsonparser.PartialJsonParser

val partialJson = "{\"key\":\"Hello, "
val map = PartialJsonParser.parse(partialJson) as? Map<*, *> // Map(key=Hello, )
println(map) // {key=Hello, }
println(map?.get("key")) // Hello,

Complete/Repair Partial JSON

import com.funnysaltyfish.partialjsonparser.PartialJsonParser

val partialJson = "{\"key\":\"Hello, "
val completedJson = PartialJsonParser.complete(partialJson)
println(completedJson) // {"key":"Hello, "}

// More examples
val incomplete = "{\"name\":\"John\", \"age\":"
val repaired = PartialJsonParser.complete(incomplete)
println(repaired) // {"name":"John"}

The parse method will throw JsonParseException if the JSON is invalid. The complete method repairs partial JSON into valid JSON format by removing incomplete elements.

(In some extreme cases, it might also throw IndexOutOfBoundsException, which should not occur although. If that did happen, feel free to open an issue with your sample.)

Actually, parse is just a combination of tokenize and parseTokens, you can use them separately if you want

fun parse(str: String): Any? {
    val tokens = Tokenizer.tokenize(str)
    return Parser.parseTokens(tokens)
}

Implementation

The library is published to Maven Central.

implementation("io.github.funnysaltyfish:partial-json-parser:1.0.3")

Examples

Parse Examples

Below are some examples: (originJsonString -> parsed map)

{"ke                      -> {}
{"key"                    -> {}
{"key":                   -> {}
{"key":"te                -> {key=te}
{"key":"text", "key2      -> {key=text}
{"key":"text", "key2":"t} -> {key=text, key2=t}}

{"k":[1,2,3               -> {k=[1.0, 2.0, 3.0]}
{"k":[[1,2                -> {k=[[1.0, 2.0]]}
{"k":[[1,2],["v"          -> {k=[[1.0, 2.0], [v]]}
{"k":{"k2":1              -> {k={k2=1.0}}
{"k":{"k2":1, "k3":2      -> {k={k2=1.0, k3=2.0}}
{"k":{"k2":1, "k3":       -> {k={k2=1.0}}
{"k":[{"k2":1, "k3":2     -> {k=[{k2=1.0, k3=2.0}]}

Complete/Repair Examples

Below are examples of JSON completion/repair: (partial JSON -> completed JSON)

{"key                                   -> {}
{"key":                                 -> {}
{"key":"te                              -> {"key":"te"}
{"key":"text", "key2                    -> {"key":"text"}
{"key":"text", "key2":"t                -> {"key":"text","key2":"t"}
{"key":123,                             -> {"key":123}
{"key":[1,2,3                           -> {"key":[1,2,3]}
{"key":[                                -> {"key":[]}
{"key":{"inner                          -> {"key":{}}
{"key":{"inner":"val",                  -> {"key":{"inner":"val"}}
[1,2,3                                  -> [1,2,3]
["a","b                                 -> ["a","b"]
[{"key":"val                            -> [{"key":"val"}]
[{"key":"val",                          -> [{"key":"val"}]
{"a":{"b":{"c":"val                     -> {"a":{"b":{"c":"val"}}}
{"a":{"b":[1,2,{"c":"val                -> {"a":{"b":[1,2,{"c":"val"}]}}
{"a":[{"b":{"c":"val                    -> {"a":[{"b":{"c":"val"}}]}
{"outer":{"inner":{"key":"value", "key2 -> {"outer":{"inner":{"key":"value"}}}
{"numbers":[1,2.5,3], "incomplete":     -> {"numbers":[1,2.5,3]}
{"a":1, "b":                            -> {"a":1}

To see more examples, please run ParseTest.kt and CompleteTest.kt.

Origin Source

Interestingly, the code is converted from the TypeScript library here by GitHub Copilot, I make it suitable for Kotlin style, modify some extreme cases, write some tests and publish it to Maven Central. Thanks for it.