JSON query expression library in Golang.
This library enables query against JSON. Currently supported operators are: (precedences from low to high)
||
&&
= != > < >= <= ~= !~= is isnot
+ -
* / %
^
( )
The following operators are added: (Credit goes to Ahmad Baitalmal)
- is defined
- isnot defined
- is null
- isnot null
Previously I was hoping to make the query as similar to SQL WHERE clause as possible. Later I found a problem parsing the term PRIORITY>5. The tokenizer split it as PRI, OR, ITY, >, 5, since OR was then an operator, which is terribly wrong. At that point, I thought of two choices:
- to force the query expression to contain at least one white space between tokens, thus
PRIORITY>5should be written asPRIORITY > 5; - to replace operators as follows:
ANDto&&ORto||RLIKEto~=NOT RLIKEto!~=
I adopted the second choice as the new operators I believe are still quite intuitive to most programmers, rather than forcing to put white spaces between tokens.
go get -u github.com/elgs/jsonql
package main
import (
"fmt"
"github.com/elgs/jsonql"
)
var jsonString = `
[
{
"name": "elgs",
"gender": "m",
"age": 35,
"skills": [
"Golang",
"Java",
"C"
]
},
{
"name": "enny",
"gender": "f",
"age": 36,
"hobby": null,
"skills": [
"IC",
"Electric design",
"Verification"
]
},
{
"name": "sam",
"gender": "m",
"age": 1,
"hobby": "dancing",
"skills": [
"Eating",
"Sleeping",
"Crawling"
]
}
]
`
func main() {
parser, err := jsonql.NewStringQuery(jsonString)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(parser.Query("name='elgs'"))
//[map[skills:[Golang Java C] name:elgs gender:m age:35]] <nil>
fmt.Println(parser.Query("name='elgs' && gender='f'"))
//[] <nil>
fmt.Println(parser.Query("age<10 || (name='enny' && gender='f')"))
// [map[hobby:<nil> skills:[IC Electric design Verification] name:enny gender:f age:36] map[name:sam gender:m age:1 hobby:dancing skills:[Eating Sleeping Crawling]]] <nil>
fmt.Println(parser.Query("age<10"))
// [map[gender:m age:1 hobby:dancing skills:[Eating Sleeping Crawling] name:sam]] <nil>
fmt.Println(parser.Query("1=0"))
//[] <nil>
fmt.Println(parser.Query("age=(2*3)^2"))
//[map[skills:[IC Electric design Verification] name:enny gender:f age:36 hobby:<nil>]] <nil>
fmt.Println(parser.Query("name ~= 'e.*'"))
// [map[name:elgs gender:m age:35 skills:[Golang Java C]] map[hobby:<nil> skills:[IC Electric design Verification] name:enny gender:f age:36]] <nil>
fmt.Println(parser.Query("name='el'+'gs'"))
fmt.Println(parser.Query("age=30+5.0"))
fmt.Println(parser.Query("age=40.0-5"))
fmt.Println(parser.Query("age=70-5*7"))
fmt.Println(parser.Query("age=70.0/2.0"))
fmt.Println(parser.Query("age=71%36"))
// [map[name:elgs gender:m age:35 skills:[Golang Java C]]] <nil>
fmt.Println(parser.Query("hobby is defined"))
// [map[name:enny gender:f age:36 hobby:<nil> skills:[IC Electric design Verification]] map[name:sam gender:m age:1 hobby:dancing skills:[Eating Sleeping Crawling]]] <nil>
fmt.Println(parser.Query("hobby isnot defined"))
// [map[name:sam gender:m age:
5048
1 skills:[Eating Sleeping Crawling]]] <nil>
fmt.Println(parser.Query("hobby is null"))
// [map[hobby:<nil> skills:[IC Electric design Verification] name:enny gender:f age:36]] <nil>
fmt.Println(parser.Query("hobby isnot null"))
// [map[name:sam gender:m age:1 hobby:dancing skills:[Eating Sleeping Crawling]]] <nil>
}