How do I make an http request using cookies on flutter?
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);
});
}
}
I've published a small flutter library called requests to assist with cookie-aware http requests.
dependencies:
requests: ^3.0.1
Usage:
import 'package:requests/requests.dart';
// ...
// this will persist cookies
var r1 = await Requests.post("https://example.com/api/v1/login", json: {"username":"...", "password":"..."} );
r1.raiseForStatus();
// this will re-use the persisted cookies
var r2 = await Requests.get("https://example.com/api/v1/stuff");
r2.raiseForStatus();
print(r2.json()['id'])
find out more about requests
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 GET
s and POST
s 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);
}
}
}