How to render a json string from bson document [duplicate] - json

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Closed 3 years ago.
I am struggling to create a valid JSON string from a BSON document in Go for an API.
Let's say I have an object like this:
type MyObject struct {
Name string
}
I call my database which returns to me a cursor containing many documents as: [{"Name": "object_name"}, ...]
I am able to retrieve all the documents via a loop like
for cur.Next(ctx) {
var obj MyObject
err := cur.Decode(&obj)
//then display error if there's one
}
And now I would like to end up with a JSON string containing all the documents my database returned in order to send it via HTTP.
Because, if use I fmt.Println(obj)I end up with something like this: [{object1_name} {object2_name} ...] which is, according to me, not a valid format that I can use for an API.
I know json.Marshal(obj) can actually encode to valid JSON and I can decode it with os.Stdout.Write(obj) but I didn't manage to store this valid string in a variable. How can I manage to do this?

Answer 1

From Golang documentation for json package
package main
import (
"encoding/json"
"fmt"
)
func main() {
type ColorGroup struct {
ID int `json:"id"`
Name string `json:"name"`
Colors []string `json:"colors"`
}
group := ColorGroup{
ID: 1,
Name: "Reds",
Colors: []string{"Crimson", "Red", "Ruby", "Maroon"},
}
b, err := json.Marshal(group)
if err != nil {
fmt.Println("error:", err)
} else {
str := string(b)
fmt.Println("stringified json is:", str)
}
}
Output
stringified json is: {"id":1,"name":"Reds","colors":["Crimson","Red","Ruby","Maroon"]}
The json.Marshal return two values - a byte array and error
If error is nil then you can obtain the string by converting byte array to string using
str := string(b)