Adds a writeJSON helper

1 files changed, 36 insertions, 0 deletions

diff --git a/cmd/api/helpers.go b/cmd/api/helpers.go
new file mode 100644
index 0000000..77fbf0c
--- /dev/null
+++ b/cmd/api/helpers.go
@@ -0,0 +1,36 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+// writeJSON() helper for sending responses. This takes the destination http.ResponseWriter, the
+// HTTP status code to sned, 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, returing the error if there was one.
+	js, err := json.Marshal(data)
+	if err != nil {
+		return err
+	}
+
+	// Append a newline to make it easier tro view in terminal applications
+	js = append(js, '\n')
+
+	// We know now 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 okay if the provided header map is nil. Go doesn't throw an error
+	// if you wanmt to try to range over (or more generally reader from) a nil map.
+	for key, value := range headers {
+		w.Header()[key] = value
+	}
+	// Add 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
+}