如何向 Dart http 请求添加查询参数？

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¶m2=two”附加到我的 url 时，我无法获得正确响应的请求，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} 只是一个传递的整数值（请参阅 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

您需要构建一个 Uri 并将其用于请求。像

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

有一个 dart 包为 http 请求提供了一些帮助程序 classes。

基本工具：https://github.com/Ephenodrom/Dart-Basic-Utils

安装：

dependencies:
  basic_utils: ^1.4.0

用法

您可以为每个请求添加一个 headers 的映射和查询参数。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);

补充信息：

这些都是来自 HttpUtils 的方法 class。

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 3

已接受的答案对我不起作用，但在 URL 末尾添加一个不带引号的“&”解决了我的问题。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";

为此：（注意末尾的“&”）。

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

Answer 4

遇到了同样的问题。如果我的 url 是端口类似于 https://localhost:5001 的本地主机，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);

希望对您有所帮助。

Answer 5

使用 Uri 构造函数构建您的查询，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 6

如果您不想覆盖基本端点 url 的方案，请使用以下技术将地图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 7

我制作了一个小实用程序函数，用于解析 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 8

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,
);

Answer 9

这个更简单

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

Answer 10

从 flutter 代码复制的以下函数只能用于创建查询字符串部分：

String queryString(Map<String, dynamic> queryParameters) {
  var result = StringBuffer();
  var separator = "";

  void writeParameter(String key, String? value) {
    result.write(separator);
    separator = "&";
    result.write(Uri.encodeQueryComponent(key));
    if (value != null && value.isNotEmpty) {
      result.write("=");
      result.write(Uri.encodeQueryComponent(value));
    }
  }

  queryParameters.forEach((key, value) {
    if (value == null || value is String) {
      writeParameter(key, value);
    } else {
      Iterable values = value;
      for (String value in values) {
        writeParameter(key, value);
      }
    }
  });
  return result.toString();
}

用法：

var q = queryString({"a":"b&", "c":["1","xyz"]});
// a=b%26&c=1&c=xyz

Answer 11

你可以用这个：

String _getParamsFromBody( Map<String, dynamic>? body) {
String params = '?';
for (var i = 0; i < body!.keys.length; i++) {
  params += '${List.from(body!.keys)[i]}=${List.from(body!.values)[i]}';
  if (i != body!.keys.length - 1) {
    params += '&';
  }
}
log(params);
return params;

}

Uri.parse("https://www.myurl.com/api/v1/test"+ _getParamsFromBody({'param1':'value1','param2':'value2}))

如何向 Dart http 请求添加查询参数？

How do you add query parameters to a Dart http request?

http

get

dart

flutter

url-parameters