Creating writeJSON method inside helpers.go file. Using writeJSON helper inside healthcheckHandler.

cmd/api/healthcheck.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"encoding/json"
 	"net/http"
 )
 
@@ -20,25 +19,9 @@ func (app *application) healthcheckHandler(w http.ResponseWriter, r *http.Reques
 		"version":     version,
 	}
 
-	/*
-		Pass the map to the json.Marshal() function. This returns a []byte slice
-		containing the encoded JSON. If there was an error, we log it and send the client
-		a generic error message.
-	*/
-	js, err := json.Marshal(data)
+	err := app.writeJSON(w, http.StatusOK, data, nil)
 	if err != nil {
 		app.logger.Error(err.Error())
-		http.Error(w, "The server encountered a problem and could not process your request.", http.StatusInternalServerError)
+		http.Error(w, "The server encountered a problem and could not process your request", http.StatusInternalServerError)
 	}
-
-	// Append a newline to the JSON. This is just a small nicety to make it easier to
-	// view in terminal applications.
-	js = append(js, '\n')
-
-	// At this point, we know that encoding the data worked without any problem, so we
-	// can safely set any necessary HTTP headers for a successful response.
-	w.Header().Set("Content-Type", "application/json")
-
-	// Use w.Write() to send the []byte slice containing the JSON as the response body.
-	w.Write(js)
 }

cmd/api/helpers.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"errors"
 	"github.com/julienschmidt/httprouter"
 	"net/http"
@@ -41,3 +42,38 @@ func (app *application) readIDParam(r *http.Request) (int64, error) {
 
 	return id, nil
 }
+
+/*
+Define a writeJSON() helper for sending responses. This takes the destination
+http.ResponseWriter, the HTTP status code to send, the data to encode to JSON, and a
+header map containing any additional HTTP headers we want to include in the response.
+*/
+func (app *application) writeJSON(w http.ResponseWriter, status int, data any, headers http.Header) error {
+	// Encode the data to JSON, returning the error if there was one.
+	js, err := json.Marshal(data)
+	if err != nil {
+		return err
+	}
+
+	// Append a newline to make it easier to view in terminal applications.
+	js = append(js, '\n')
+
+	/*
+		At this point, we know that we won't encounter any more errors before writing the
+		response, so it's safe to add any headers that we want to include. We loop
+		through the header map and add each header to the http.ResponseWriter header map.
+		Note that it's OK if the provided header map is nil. Go doesn't throw an error
+		if you try to range over (or generally, read from) a nil map.
+	*/
+	for key, value := range headers {
+		w.Header()[key] = value
+	}
+
+	// And the "Content-Type: application/json" header, then write the status code and
+	// JSON response.
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	w.Write(js)
+
+	return nil
+}