Add json helper functions

broker-service/cmd/api/handlers.go

@@ -1,24 +1,14 @@
 package main
 
 import (
-	"encoding/json"
 	"net/http"
 )
 
-type jsonResponse struct {
-	Error   bool   `json:"error"`
-	Message string `json:"message"`
-	Data    any    `json:"data,omitempty"`
-}
-
 func (app *Config) Broker(w http.ResponseWriter, r *http.Request) {
 	payload := jsonResponse{
 		Error:   false,
 		Message: "Hit the broker",
 	}
 
-	out, _ := json.MarshalIndent(payload, "", "\t")
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(http.StatusAccepted)
-	w.Write(out)
+	app.writeJSON(w, http.StatusOK, payload)
 }

broker-service/cmd/api/helpers.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+)
+
+type jsonResponse struct {
+	Error   bool   `json:"error"`
+	Message string `json:"message"`
+	Data    any    `json:"data,omitempty"`
+}
+
+func (app *Config) readJSON(w http.ResponseWriter, r *http.Request, data any) error {
+	maxBytes := 1048576 // one megabyte
+
+	r.Body = http.MaxBytesReader(w, r.Body, int64(maxBytes))
+
+	dec := json.NewDecoder(r.Body)
+
+	err := dec.Decode(data)
+	if err != nil {
+		return err
+	}
+
+	err = dec.Decode(&struct{}{})
+	if err != io.EOF {
+		return errors.New("body must have only a single JSON value")
+	}
+
+	return nil
+}
+
+func (app *Config) writeJSON(
+	w http.ResponseWriter,
+	status int,
+	data any,
+	headers ...http.Header,
+) error {
+	out, err := json.Marshal(data)
+	if err != nil {
+		return err
+	}
+
+	if len(headers) > 0 {
+		for key, value := range headers[0] {
+			w.Header()[key] = value
+		}
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_, err = w.Write(out)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (app *Config) errorJSON(w http.ResponseWriter, err error, status ...int) error {
+	statusCode := http.StatusBadRequest
+
+	if len(status) > 0 {
+		statusCode = status[0]
+	}
+
+	var payload jsonResponse
+	payload.Error = true
+	payload.Message = err.Error()
+
+	return app.writeJSON(w, statusCode, payload)
+}