如何将查询参数添加到 Dart http 请求中？

Question

如何正确地将查询参数添加到 Dart http get 请求中？尝试将 '?param1=one&param2=two' 附加到我的网址时，我无法让我的请求正确响应，但它在 Postman 中正常工作。这是我的代码的要点：

    final String url = "https://www.myurl.com/api/v1/test/";
    String workingStringInPostman = "https://www.myurl.com/api/v1/test/123/?param1=one&param2=two";

    Map<String, String> qParams = {
     'param1': 'one',
     'param2': 'two',
    };


   var res = await http
      .get(Uri.encodeFull("$url${widget.pk}/"),
      headers: {HttpHeaders.authorizationHeader: "Token $token", 
        HttpHeaders.contentTypeHeader: "application/json"},
);

${widget.pk} 只是一个被传递的整数值（参见 workingStringInPostman 变量中的值 123。

qParams 是为了方便，以防需要 Uri 参数。

欢迎提供代码示例。

Answer 1

您需要构造一个Uri 并将其用于请求。类似的东西

final queryParameters = {
  'param1': 'one',
  'param2': 'two',
};
final uri =
    Uri.https('www.myurl.com', '/api/v1/test/${widget.pk}', queryParameters);
final response = await http.get(uri, headers: {
  HttpHeaders.authorizationHeader: 'Token $token',
  HttpHeaders.contentTypeHeader: 'application/json',
});

见https://api.dartlang.org/stable/2.0.0/dart-core/Uri/Uri.https.html

Answer 2

如果您不想覆盖基本端点 url 的方案，请使用以下技术将映射转换为查询字符串并将其附加到基本端点 url

var endpointUrl = 'https://www.myurl.com/api/v1/user';
Map<String, String> queryParams = {
  'param1': '1',
  'param2': '2'
};

var headers = {
  HttpHeaders.authorizationHeader: 'Token $token',
  HttpHeaders.contentTypeHeader: 'application/json',
}

String queryString = Uri.parse(queryParameters: queryParams).query;

var requestUrl = endpointUrl + '?' + queryString; // result - https://www.myurl.com/api/v1/user?param1=1&param2=2
var response = await http.get(requestUrl, headers: headers);

Answer 3

有同样的问题。如果我的 url 是带有 https://localhost:5001 之类的端口的 localhost，则接受的答案将不起作用。在花了 1 天时间寻找解决方案后，我想出了Dio library。以下是我使用Dio 的解决方案：

var _dio = new Dio();
var options = new Options;
options.headers['Authorization'] = 'bearer $token';
options.contentType = 'application/json';
String url = "https://www.myurl.com";
Map<String, String> qParams = {
  'param1': 'one',
  'param2': 'two',
};

var res = await _dio.get(url, options: options, queryParameters: qParams);

希望这会有所帮助。

Answer 4

这样更简单

final uri = Uri.parse('$baseUrl/v1/endpoint').replace(queryParameters: {
      'page': page,
      'itemsPerPage': itemsPerPage,
    });
final response = await client.get(uri);

Answer 5

有一个 dart 包为 http 请求提供了一些帮助类。

BasicUtils：https://github.com/Ephenodrom/Dart-Basic-Utils

安装它：

dependencies:
  basic_utils: ^1.4.0

用法

您可以为每个请求添加标头和查询参数的映射。看例子：

// Define some headers and query parameters
Map<String, String> headers = {
  "Accept": "application/json"
};
Map<String, String> queryParameters = {
  "foo": "bar"
};

// Body
String body = "{ 'some':'json'}";

// Send request
Map<String, dynamic> responseData = await HttpUtils.postForJson("api.com/dosomething", body,
      headers: headers, queryParameters: queryParameters);

附加信息：

这些都是来自 HttpUtils 类的方法。

Future<Map<Response> getForFullResponse(String url,{Map<String, dynamic> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> getForJson(String url,{Map<String, dynamic> queryParameters,Map<String, String> headers});
Future<String> getForString(String url,{Map<String, dynamic> queryParameters,Map<String, String> headers});
Future<Map<Response> postForFullResponse(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> postForJson(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<String> postForString(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Response> putForFullResponse(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> putForJson(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<String> putForString(String url, String body,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Response deleteForFullResponse(String url,{Map<String, String> queryParameters,Map<String, String> headers});
Future<Map<String, dynamic>> deleteForJson(String url,{Map<String, String> queryParameters,Map<String, String> headers});
Future<String> deleteForString(String url,{Map<String, String> queryParameters,Map<String, String> headers});
Map<String, dynamic> getQueryParameterFromUrl(String url);
String addQueryParameterToUrl(String url, Map<String, dynamic> queryParameters);

Answer 6

接受的答案对我不起作用，但在 URL 末尾添加不带引号的“&”可以解决我的问题。在这种情况下，更改以下行：

String workingStringInPostman = "https://www.myurl.com/api/v1/test/123/?param1=one&param2=two";

对此：（注意末尾的“&”）。

String workingStringInPostman = "https://www.myurl.com/api/v1/test/123/?param1=one&param2=two&";

Answer 7

使用Uri 构造函数来构建您的查询，它有一个queryParameter 属性。

var uri = Uri(
  scheme: 'https',
  host: 'example.com',
  path: '/foo/bar',
  fragment: 'baz',
  queryParameters: _yourQueryParameters,
);

var response = await http.get(uri);
if (response.statusCode == 200) {
  var json = jsonDecode(response.body);
  // Do whatever you want to do with json. 
}

Answer 8

我制作了一个小 util 函数来解析 authority / unencodedPath 参数以创建 Uri。

Uri createUri(String url, [Map<String, String> queryParameters]) {
  var isHttp = false;
  if (url.startsWith('https://') || (isHttp = url.startsWith('http://'))) {
    var authority = url.substring((isHttp ? 'http://' : 'https://').length);
    String path;
    final index = authority.indexOf('/');

    if (-1 == index) {
      path = '';
    } else {
      path = authority.substring(index);
      authority = authority.substring(0, authority.length - path.length);
    }

    if (isHttp) {
      return Uri.http(authority, path, queryParameters);
    } else {
      return Uri.https(authority, path, queryParameters);
    }
  } else if (url.startsWith('localhost')) {
    return createUri('http://' + url, queryParameters);
  }

  throw Exception('Unsupported scheme');
}

这是使用它的示例代码：

final String url = 'https://www.myurl.com/api/v1/test/${widget.pk}';
Map<String, String> qParams = {
  'param1': 'one',
  'param2': 'two',
};

var res = await http.get(
  createUri(url, qParams),
  headers: {
    HttpHeaders.authorizationHeader: "Token $token",
    HttpHeaders.contentTypeHeader: "application/json"
  },
);

Answer 9

使用Uri 传递查询参数，如。

final String url = "https://www.myurl.com/api/v1/test/${widget.pk}/";

Map<String, String> qParams = {
 'param1': 'one',
 'param2': 'two',
};
Map<String, String> header = {
HttpHeaders.authorizationHeader: "Token $token", 
    HttpHeaders.contentTypeHeader: "application/json"
};

Uri uri = Uri.parse(url);
final finalUri = uri.replace(queryParameters: qParams); //USE THIS

final response = await http.get(
  finalUri,
  headers: header,
);