How do I make an http request using cookies on flutter?

Question

I'd like to make an http request to a remote server while properly handling cookies (eg. storing cookies sent by the server, and sending those cookies when I make subsequent requests). It'd be nice to preserve any and all cookies

for http request I am using

static Future<Map> postData(Map data) async {   http.Response res = await http.post(url, body: data); // post api call   Map data = JSON.decode(res.body);   return data; } 

Answer 1

Here's an example of how to grab a session cookie and return it on subsequent requests. You could easily adapt it to return multiple cookies. Make a Session class and route all your GETs and POSTs through it.

class Session {   Map<String, String> headers = {};    Future<Map> get(String url) async {     http.Response response = await http.get(url, headers: headers);     updateCookie(response);     return json.decode(response.body);   }    Future<Map> post(String url, dynamic data) async {     http.Response response = await http.post(url, body: data, headers: headers);     updateCookie(response);     return json.decode(response.body);   }    void updateCookie(http.Response response) {     String rawCookie = response.headers['set-cookie'];     if (rawCookie != null) {       int index = rawCookie.indexOf(';');       headers['cookie'] =           (index == -1) ? rawCookie : rawCookie.substring(0, index);     }   } } 

Answer 2

I have improved the Richard Heap's solution to be capable to process multiple 'Set-cookies' and multiple cookies.

In my case, the server returns multiples 'Set-cookies'. The http package concatenate all the set-cookies headers in one header and separate it by comma (',').

class NetworkService {    final JsonDecoder _decoder = new JsonDecoder();   final JsonEncoder _encoder = new JsonEncoder();    Map<String, String> headers = {"content-type": "text/json"};   Map<String, String> cookies = {};    void _updateCookie(http.Response response) {     String allSetCookie = response.headers['set-cookie'];      if (allSetCookie != null) {        var setCookies = allSetCookie.split(',');        for (var setCookie in setCookies) {         var cookies = setCookie.split(';');          for (var cookie in cookies) {           _setCookie(cookie);         }       }        headers['cookie'] = _generateCookieHeader();     }   }    void _setCookie(String rawCookie) {     if (rawCookie.length > 0) {       var keyValue = rawCookie.split('=');       if (keyValue.length == 2) {         var key = keyValue[0].trim();         var value = keyValue[1];          // ignore keys that aren't cookies         if (key == 'path' || key == 'expires')           return;          this.cookies[key] = value;       }     }   }    String _generateCookieHeader() {     String cookie = "";      for (var key in cookies.keys) {       if (cookie.length > 0)         cookie += ";";       cookie += key + "=" + cookies[key];     }      return cookie;   }    Future<dynamic> get(String url) {     return http.get(url, headers: headers).then((http.Response response) {       final String res = response.body;       final int statusCode = response.statusCode;        _updateCookie(response);        if (statusCode < 200 || statusCode > 400 || json == null) {         throw new Exception("Error while fetching data");       }       return _decoder.convert(res);     });   }    Future<dynamic> post(String url, {body, encoding}) {     return http         .post(url, body: _encoder.convert(body), headers: headers, encoding: encoding)         .then((http.Response response) {       final String res = response.body;       final int statusCode = response.statusCode;        _updateCookie(response);        if (statusCode < 200 || statusCode > 400 || json == null) {         throw new Exception("Error while fetching data");       }       return _decoder.convert(res);     });   } }