在使用Gorilla的Go ReST服务中处理JSON

Question

I have a Go ReST service that receives JSON, and I need to edit the JSON so I may make two different structs.

My structs:

type Interaction struct{

 DrugName string `json:"drugName"`
 SeverityLevel string `json:"severityLevel"`
 Summary string `json:"summary"`
}

type Drug struct {
 Name string `json:"drugName"`
 Dosages []string `json:"dosages"`
 Interactions []Interaction `json:"interactions"`
}

Example JSON being sent:

{"drugName":"foo","dosages":["dos1"],"interactions":[["advil","high","summaryForAdvil"]]}

The ReST service:

func CreateDrug(w http.ResponseWriter, r *http.Request) {

  //I verified the received JSON by printing out the bytes:
  bytes, _ := ioutil.ReadAll(r.Body)
}

My goal is the make two different JSONs in the CreateDrug function so I may make the two different structs, Drug and Interaction:

{"drugName":"foo","dosages":["dos1"]}
{"drugName":"advil", "severityLevel":"high", "summary":"summaryForAdvil"}

In Go, in this function, how do I use the received JSON to make two new JSONs?

Answer 1

Unmarshal the request to a struct matching the structure of the request, copy values to the structs you have defined, and marshal to create the result.

func CreateDrug(w http.ResponseWriter, r *http.Request) {

  // Unmarshal request to value matching the structure of the incoming JSON

  var v struct {
    DrugName     string
    Dosages      []string
    Interactions [][3]string
  }
  if err := json.NewDecoder(r.Body).Decode(&v); err != nil {
    // handle error
  }

  // Copy to new struct values.

  var interactions []Interaction
  for _, i := range v.Interactions {
    interactions = append(interactions, Interaction{DrugName: i[0], SeverityLevel: i[1], Summary: i[2]})
  }

  drug := &Drug{Name: v.DrugName, Dosages: v.Dosages, Interactions: interactions}

  // Marshal back to JSON.

  data, err := json.Marshal(drug)
  if err != nil {
      // handle error
  }

  // Do something with data.
}

<kbd>Playground link</kbd>

(I am assuming that you want a single JSON value for Drug with the Interactions field filled in. If that's not what you want, marshal the Drug and Interactions values separately.)