Read some json data without using struct [SOLVED]

[leogazio (Leonardo Gazio)]

Hey there, I got a json response from an API which my service integrates, I need only 1 data from all stuff from this json, searching on Google I found the solution below, e.g;

This code;

    // replace this by fetching actual response body
    responseBody := `{"textfield":"I'm a text.","num":1234,"list":[1,2,3]}`
    var data map[string]interface{}
    err := json.Unmarshal([]byte(responseBody), &data)
    if err != nil {
        panic(err)
    }
    fmt.Println(data["list"])
    fmt.Println(data["textfield"])

Reads the following json;

{"textfield":"I'm a text.","num":1234,"list":[1,2,3]}

In my situation I have the following json structure;

{"status":"sucesso","coderro":0,"erro":"","dados":[{"idboleto":"38106","datavencimento":"2017-11-10","datapagamento":"0000-00-00","codigodebarras":"...........................","urlfatura":".............","urlboleto":"THIS IS THE ONLY DATA THAT I NEED","dataemissao":"2017-09-12","valor":"70.00","valorpago":"0.00","meucodigo":"","cpfcnpj":"xxx.xxx.xxx-xx","nome":"...............................................","email":"","celular":"","fixo":"","status":"0"}]}

I need to get the “urlboleto” value, this data is inside an array, but the filter that I use always return only one array item, the structure is always the same as shown here.

How could I implement that code above to read this first item in “dados” array and the “urlboleto” attribute?

Tnx.

[christophberger]

Is “without using struct” a strict requirement?

Using JSON to Go, I get a valid struct back:

type AutoGenerated struct {
	Status  string `json:"status"`
	Coderro int    `json:"coderro"`
	Erro    string `json:"erro"`
	Dados   []struct {
		Idboleto       string `json:"idboleto"`
		Datavencimento string `json:"datavencimento"`
		Datapagamento  string `json:"datapagamento"`
		Codigodebarras string `json:"codigodebarras"`
		Urlfatura      string `json:"urlfatura"`
		Urlboleto      string `json:"urlboleto"`
		Dataemissao    string `json:"dataemissao"`
		Valor          string `json:"valor"`
		Valorpago      string `json:"valorpago"`
		Meucodigo      string `json:"meucodigo"`
		Cpfcnpj        string `json:"cpfcnpj"`
		Nome           string `json:"nome"`
		Email          string `json:"email"`
		Celular        string `json:"celular"`
		Fixo           string `json:"fixo"`
		Status         string `json:"status"`
	} `json:"dados"`
}

If you cannot use a struct, you would need to work with a couple of type assertions - see this playground code

If even this does not match all of your use cases, consider using a decoder instead of unmarshalling.

[nathankerr]

Another option is github.com/tidwall/gjson. It has a dot notation path for quickly extracting specific or sets of values from JSON.

If that doesn’t float your boat, there are other packages that might.

[leogazio (Leonardo Gazio)]

Hey there I already solved the problem months ago, I just forgot to mark the title as solved. Really appreciate your help. Thank you guys.