Golang YAML to JSON with Gin

2 min readNov 20, 2016

You have a YAML file and you want to display these informations in a HTTP API with a JSON result. So you need to read the file then binding YAML datas (keys and values) and display to JSON.

What do we need ?

We need a micro framework and to bind YAML, Gin and YAML.

go get gopkg.in/gin-gonic/gin.v1 && go get gopkg.in/yaml.v2

The YAML file

Create the YAML file named “config.yml”.

'title': 'My first article'
'email': 'go@email.com'
'tags': [go, golang, yaml, json]

So, keys are “title”, “email” and “tags” (the last is a string array).

The script

Create a “main.go” file.

package mainimport (
 "log"
 "io/ioutil" "gopkg.in/gin-gonic/gin.v1"
 "gopkg.in/yaml.v2"
)type Config struct {
 Title string `json:"title"`
 Email string `json:"email"`
 Tags []string `json:"tags"`
}func main() {
 r := gin.Default() r.GET("", func(c *gin.Context) {
  // The next
 }) r.Run(":3000")
}

As you can see, we load libraries then we declare a struct named “Config” with our 3 keys present in the YAML file.

Load the YAML file

For loading the file, we use the native function “ReadFile” from “ioutil”.

data, err := ioutil.ReadFile("config.yml")
if err != nil {
 log.Fatalf("error: %v", err)
}

Binding YAML datas

We gonna use the “Unmarshal” function from “Yaml” library.

var config Config
err = yaml.Unmarshal([]byte(data), &config)
if err != nil {
 log.Fatalf("error: %v", err)
}

And we put these datas in a new var “result”.

result := Config{
 Title: config.Title,
 Email: config.Email,
 Tags: config.Tags,
}

Display JSON result

With Gin it’s very simple, we just need to use the “c.JSON” function.

c.JSON(200, result)

Result & final code

After starting the server, you will get a JSON result.

{"title":"This is my go blog","email":"go@email.com","tags":["go","golang","yaml","json"]}

Sources

- Gin : https://github.com/gin-gonic/gin
- YAML : https://github.com/go-yaml/yaml
- YAML Lint : http://www.yamllint.com