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":"info@example.com",
"website":"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
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).Pluck("price")
fmt.Println(res)
// output: [1350 1700]
}
Example 5
Query: select * from vendor.items order by price
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").SortBy("price").Get()
fmt.Println(res)
// output: [map[id:<nil> name:HP core i3 SSD price:850] map[id:4 name:Fujitsu price:850] map[id:5 name:HP core i5 price:850 key:2300] map[id:6 name:HP core i7 price:950] map[id:3 name:Sony VAIO price:1200] map[id:1 name:MacBook Pro 13 inch retina price:1350] map[id:2 name:MacBook Pro 15 inch retina price:1700]]
}
Example 6
Using gojsonq You can handle errors properly, see the code snippet below:
package main
import (
"log"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./invalid-file.xjsn")
err := jq.Error()
if err != nil {
log.Fatal(err)
// 2018/06/25 00:48:58 gojsonq: open ./invalid-file.xjsn: no such file or directory
// exit status 1
}
}
Example 7
Let's assume we have a JSON document like this one
{
"users":[
{
"id":1,
"name":{
"first":"John",
"last":"Ramboo"
}
},
{
"id":2,
"name":{
"first":"Ethan",
"last":"Hunt"
}
},
{
"id":3,
"name":{
"first":"John",
"last":"Doe"
}
}
]
}
We want to run a query like this:
Query: select * from users where name.first=John
Using the package you can do the query easily, see the code snippet below:
package main
import (
"fmt"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./data.json")
res := jq.From("users").WhereEqual("name.first", "John").Get()
fmt.Println(res) //output: [map[id:1 name:map[first:John last:Ramboo]] map[id:3 name:map[first:John last:Doe]]]
}
You can access nested level property using DOT (.) for methods like Where/GroupBy/SortBy etc
Note: There are some other useful methods to make life easier! If you like the package do not forget to share with your community and star the repository
Repo link: gojsonq
Thank you very much for reading this article and don't forget to give your feedback on comment :)