正文
Most often developer needs to consume JSON data from other service and query over them. Querying JSON document is little time-consuming. For the last few days, I was working on a package for Golang to query JSON data easily. The idea and inspiration
come from
PHP-JSONQ
by Nahid Bin Azhar.
Let's take a sample JSON data to start with:
{
"name":"computers",
"description":"List of computer products",
"vendor":{
"name":"Star Trek",
"email":"[email protected]",
"website":"www.example.com",
"items":[
{"id":1, "name":"MacBook Pro 13 inch retina","price":1350},
{"id":2, "name":"MacBook Pro 15 inch retina", "price":1700},
{"id":3, "name":"Sony VAIO", "price":1200},
{"id":4, "name":"Fujitsu", "price":850},
{"id":5, "name":"HP core i5", "price":850, "key": 2300},
{"id":6, "name":"HP core i7", "price":950},
{"id":null, "name":"HP core i3 SSD", "price":850}
],
"prices":[
2400,
2100,
1200,
400.87,
89.90,
150.10
]
}
}
Let's find a deeply nested property and handle error properly, in this case, we'll try to access
name
from the second element of
items
array, note:
items
is a property of
vendor
object. See the example
below:
package main
import (
"fmt"
"log"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.Find("vendor.items.[1].name")
if jq.Error() != nil {
log.Fatal(jq.Errors())
}
fmt.Println(res)
}
Yahooooo! Very simple right? It looks like working with
ORM
of JSON data. Let's see some more example to query over the sample data.
Example 1
Query:
select * from vendor.items where price > 1200 or id null
Using
gojsonq
we can do the query like:
package main
import (
"fmt"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).OrWhere("id", "=", nil).Get()
fmt.Println(res)
// output: [map[price:1350 id:1 name:MacBook Pro 13 inch retina] map[id:2 name:MacBook Pro 15 inch retina price:1700] map[id:<nil> name:HP core i3 SSD price:850]]
}
Example 2
Query:
select name, price from vendor.items where price > 1200 or id null
Using
gojsonq
we can do the query like:
package main
import (
"fmt"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).OrWhere("id", "=", nil).Only("name", "price")
fmt.Println(res)
// output: [map[name:MacBook Pro 13 inch retina price:1350] map[name:MacBook Pro 15 inch retina price:1700] map[name:HP core i3 SSD price:850]]
}
Example 3
Query:
select sum(price) from vendor.items where price > 1200 or id null
Using
gojsonq
we can do the query like:
package main
import (
"fmt"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).OrWhere("id", "=", nil).Sum("price")
fmt.Println(res)
// output: 3900
}
Example 4
Query:
select price from vendor.items where price > 1200
