postFormData static method Null safety

Future<HttpRequest> postFormData(
  1. String url,
  2. Map<String, String> data,
  3. {bool? withCredentials,
  4. String? responseType,
  5. Map<String, String>? requestHeaders,
  6. void onProgress(
    1. ProgressEvent e
    )?}
)

Makes a server POST request with the specified data encoded as form data.

This is roughly the POST equivalent of getString. This method is similar to sending a FormData object with broader browser support but limited to String values.

If data is supplied, the key/value pairs are URI encoded with Uri.encodeQueryComponent and converted into an HTTP query string.

Unless otherwise specified, this method appends the following header:

Content-Type: application/x-www-form-urlencoded; charset=UTF-8

Here's an example of using this method:

var data = { 'firstName' : 'John', 'lastName' : 'Doe' };
HttpRequest.postFormData('/send', data).then((HttpRequest resp) {
  // Do something with the response.
});

See also:

Implementation

static Future<HttpRequest> postFormData(String url, Map<String, String> data,
    {bool? withCredentials,
    String? responseType,
    Map<String, String>? requestHeaders,
    void onProgress(ProgressEvent e)?}) {
  var parts = [];
  data.forEach((key, value) {
    parts.add('${Uri.encodeQueryComponent(key)}='
        '${Uri.encodeQueryComponent(value)}');
  });
  var formData = parts.join('&');

  if (requestHeaders == null) {
    requestHeaders = <String, String>{};
  }
  requestHeaders.putIfAbsent('Content-Type',
      () => 'application/x-www-form-urlencoded; charset=UTF-8');

  return request(url,
      method: 'POST',
      withCredentials: withCredentials,
      responseType: responseType,
      requestHeaders: requestHeaders,
      sendData: formData,
      onProgress: onProgress);
}