需求
由于最近要获取阿里系网站的信息，网站在登录模块做了大量的保护工作，我的需求是拿到登录之后的cookie以获得session字段的值，用来保持登录状态。所以想通过webview来获取登录的信息。
在flutter上面比较流行的一个webview插件为：flutter_webview_plugin
flutter_webview_plugin 使用
1.在app的路由上面添加登录的页面
routes: {
"/web_login":(_) => new WebviewScaffold(url: Config.login,
withLocalStorage: true,
hidden: true,
userAgent: "Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Mobile Safari/537.36",
appBar: new AppBar(
centerTitle: true ,
title: new Text("登录"),
),
initialChild: Container(
child: new Center(
child: new CupertinoActivityIndicator(animating: true,),
),
),),
注意：userAgent字段一定要加上，不然在ios下打开WKwebview会白屏
2.初始化flutterWebviewPlugin，作为全局变量；并且在启动app时如果没登录就跳转到登录界面
final flutterWebviewPlugin = new FlutterWebviewPlugin();
if(_event.data.length == 0){
print("nologin ");
Navigator.of(context).pushNamed("/web_login");
_webViewLogin();
}else{
print("get events data successfully");
}
3.监听url的变化，监测到跳转到成功之后的界面后获取cookies然后保存到sp中
flutterWebviewPlugin.onUrlChanged.listen((String url){
var _uri = Uri.parse(url);
if(_uri.path == "/dashboard"){
Navigator.of(context).pop();
flutterWebviewPlugin.close();
print("登陆成功");
flutterWebviewPlugin.getCookies().then((Map<String,String> _cookies){
print(_cookies);
_saveCookie();
});
}
});
以为这样就大功告成，但是打印出来的cookie其实是不包含session字段的。
看一下getCookies()方法的源码：
Future<Map<String, String>> getCookies() async {
final cookiesString = await evalJavascript('document.cookie');
final cookies = <String, String>{};
if (cookiesString?.isNotEmpty == true) {
cookiesString.split(';').forEach((String cookie) {
final split = cookie.split('=');
cookies[split[0]] = split[1];
});
}
return cookies;
}
通过js来获得cookie，大多数网站都会做跨域安全处理，这样基本上不可能会获得session的值，那就毫无意义。
改轮子
目前flutter 插件中并没有可以直接获取webview cookie插件，因此只能自己改轮子
flutter_webview_plugin 使用的是 webview和wkwebview;
修改插件的方式为：
Android Studio左侧projet窗口——External Libraries——Flutter Plugins——flutter_webview_plugin
Android获取cookie实现：
1.修改flutter_webview_plugin/android文件夹下的WebviewManager.java
新加一个方法：
void getAllCookies(MethodCall call, final MethodChannel.Result result){
String url = call.argument("url");
CookieManager cookieManager = CookieManager.getInstance();
String cookieStr = cookieManager.getCookie(url);
result.success(cookieStr);
}
2.修改flutter_webview_plugin/android文件夹下的FlutterWebviewPlugin.java
@Override
public void onMethodCall(MethodCall call, MethodChannel.Result result) {
switch (call.method) {
case "launch":
openUrl(call, result);
break;
case "close":
close(call, result);
break;
case "eval":
eval(call, result);
break;
case "resize":
resize(call, result);
break;
case "reload":
reload(call, result);
break;
case "back":
back(call, result);
break;
case "forward":
forward(call, result);
break;
case "hide":
hide(call, result);
break;
case "show":
show(call, result);
break;
case "reloadUrl":
reloadUrl(call, result);
break;
case "stopLoading":
stopLoading(call, result);
break;
case "cleanCookies":
cleanCookies(call, result);
break;
case "getAllCookies":
getAllCookies(call,result);
break;
default:
result.notImplemented();
break;
}
}
在onMethodCall方法上新增case的分支，用于判断使用的方法是getAllCookies
3.新增一个getAllCookies的方法
private void getAllCookies(MethodCall call, final MethodChannel.Result result){
if (webViewManager != null){
webViewManager.getAllCookies(call,result);
}
}
IOS获取Cookie的实现
1.修改flutter_webview_plugin/ios/Classes文件夹下的FlutterWebviewPlugin.m
- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
if ([@"launch" isEqualToString:call.method]) {
if (!self.webview)
[self initWebview:call];
else
[self navigate:call];
result(nil);
} else if ([@"close" isEqualToString:call.method]) {
[self closeWebView];
result(nil);
} else if ([@"eval" isEqualToString:call.method]) {
[self evalJavascript:call completionHandler:^(NSString * response) {
result(response);
}];
} else if ([@"resize" isEqualToString:call.method]) {
[self resize:call];
result(nil);
} else if ([@"reloadUrl" isEqualToString:call.method]) {
[self reloadUrl:call];
result(nil);
} else if ([@"show" isEqualToString:call.method]) {
[self show];
result(nil);
} else if ([@"hide" isEqualToString:call.method]) {
[self hide];
result(nil);
} else if ([@"stopLoading" isEqualToString:call.method]) {
[self stopLoading];
result(nil);
} else if ([@"cleanCookies" isEqualToString:call.method]) {
[self cleanCookies];
} else if ([@"back" isEqualToString:call.method]) {
[self back];
result(nil);
} else if ([@"forward" isEqualToString:call.method]) {
[self forward];
result(nil);
} else if ([@"reload" isEqualToString:call.method]) {
[self reload];
result(nil);
}else if ([@"getAllCookies" isEqualToString:call.method]){
[self getAllCookies:call completionHandler:^(NSString *cookies) {
result(cookies);
}];
}else {
result(FlutterMethodNotImplemented);
}
}
添加一个getAllCookies的分支判断
2.添加一个方法
仅支持ios11以上
- (void)getAllCookies:(FlutterMethodCall*)call
completionHandler:(void (^_Nullable)(NSString * cookies))completionHandler {
if (self.webview != nil) {
NSString *url = call.arguments[@"url"];
WKHTTPCookieStore *cookieStore = self.webview.configuration.websiteDataStore.httpCookieStore;
[cookieStore getAllCookies:^(NSArray<NSHTTPCookie *> * _Nonnull cookies) {
NSString *allCookies = @"";
NSEnumerator *cookie_enum = [cookies objectEnumerator];
NSHTTPCookie *temp_cookie;
while (temp_cookie = [cookie_enum nextObject]) {
NSString *temp = [NSString stringWithFormat:@"%@=%@;",[temp_cookie name],[temp_cookie value]];
allCookies = [allCookies stringByAppendingString:temp];
}
completionHandler([NSString stringWithFormat:@"%@", allCookies]);
}];
} else {
completionHandler(nil);
}
}
Dart修改
修改flutter_webview_plugin/lib/src文件夹下的base.dart
添加getAllCookies的方法
/// Get AllCookies
Future<String> getAllCookies(String url) async {
final res = await _channel.invokeMethod('getAllCookies', {'url': url});
return res;
}
使用
Future<Null> _getAllCookies() async {
try {
final String result = await flutterWebviewPlugin.getAllCookies("https://www.yuque.com/dashboard");
print(result);
cookie = result;
_saveCookie();
_getHttpData();
} on PlatformException catch (e) {
cookie = "";
}
}
注意：getAllCookies必须在浏览器未关闭之前获取，否则会获取空值
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