Retrieving JSON from a Request Body in Go
When working with POST requests that contain JSON content, it becomes necessary to extract the JSON data from the request's body. However, this can be a puzzling task for Go beginners who are migrating code from languages like Node.js.
To address this issue, several approaches have been attempted:
var v interface{}<br>err := json.NewDecoder(context.Request().Body).Decode(&v)<br>if err != nil {</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">return result, err}
fmt.Println(v)
In this example, the result will often be empty, indicating that the body is empty. This is because http.Request.Body is a buffer, and once data is read from it, it cannot be read again.
Another approach is:
m := echo.Map{}<br>if err := context.Bind(&m); err != nil {</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">return result, err}
fmt.Println(m)
Here, the code results in an error message of "EOF." This error occurs because there is no content-type header in the request, so Echo cannot determine the type of data being sent.
Finally, an attempt to read the body directly:
body, error := ioutil.ReadAll(context.Request().Body)<br>if error != nil {</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">return result, error}
fmt.Println(body)
Results in an empty array of bytes, as ioutil.ReadAll() consumes the request body.
The solution lies in understanding the nature of http.Request.Body as a buffer and finding a way to restore it after reading. The following code snippet provides a workaround:
// Read the Body content<br>var bodyBytes []byte<br>if context.Request().Body != nil {</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">bodyBytes, _ = ioutil.ReadAll(context.Request().Body)}
// Restore the io.ReadCloser to its original state
context.Request().Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))
// Continue to use the Body, like Binding it to a struct:
order := new(models.GeaOrder)
error := context.Bind(order)
With this workaround, it is now possible to read the body, preserve its contents for later use, and bind its data to a struct successfully.
The above is the detailed content of How to Retrieve JSON Data from a Request Body in Go?. For more information, please follow other related articles on the PHP Chinese website!
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
