json-eval's Introduction

JSON EVAL

JSON EVAL is simple json evaluator that may be simplify business rule.

Operator

Operator supported

No.	Operator	Precedence
1	<	1 (left to right)
2	<=	1 (left to right)
3	>	1 (left to right)
4	>=	1 (left to right)
5	!=	2 (left to right)
6.	==	2 (left to right)
6	&&	3 (left to right)
7	\|\|	4 (left to right)
8	()

Evaluate

json-eval can evaluate json value with logical expression.

We have below json:

{
    "glossary": {
        "title": "example glossary",
        "GlossDiv": {
            "total": 1000
            "title": "S",
            "GlossList": {
                "GlossEntry": {
                    "ID": "SGML",
                    "SortAs": "SGML",
                    "GlossTerm": "Standard Generalized Markup Language",
                    "Acronym": "SGML",
                    "Abbrev": "ISO 8879:1986",
                    "GlossDef": {
                        "para": "A meta-markup language, used to create markup languages such as DocBook.",
                        "GlossSeeAlso": [
                            "GML",
                            "XML"
                        ]
                    },
                    "GlossSee": "markup"
                }
            }
        }
    }
}

expression:

glossary.title == "example glossary" && glossary.total > 100

Array of Index

json eval also has capability to extract array value from json. for example,

glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso[0]

Result:

"GML"

Example

Code snippets

jsonStr := `
    {
        "glossary": {
            "title": "example",
            "GlossDiv": {
                "total": 1000
            }
        }
    }    
`
expression := `glossary.title == "example" && (glossary.GlossDiv.total > 100)`
jsonEval := jsoneval.NewJsonEvaluator()
result, err := jsonEval.EvaluateJson(expression, jsonStr)
if err != nil {
    fmt.Println(err)
} else {
    fmt.Println(result)
}