Flutter中http請求抓包的完美解決方案

Future<HttpClientRequest> getUrl(Uri url) => _openUrl("get", url);

Future<_HttpClientRequest> _openUrl(String method, Uri uri) {
 .
 .
 .
 // Check to see if a proxy server should be used for this connection.
 var proxyConf = const _ProxyConfiguration.direct();
 if (_findProxy != null) {
 // TODO(sgjesse): Keep a map of these as normally only a few
 // configuration strings will be used.
 try {
 proxyConf = new _ProxyConfiguration(_findProxy(uri));
 } catch (error, stackTrace) {
 return new Future.error(error, stackTrace);
 }
 }
 return _getConnection(uri.host, port, proxyConf, isSecure)
 .then((_ConnectionInfo info) {
 .
 .
 .
 });
}

Future<_ConnectionInfo> _getConnection(String uriHost, int uriPort,
 _ProxyConfiguration proxyConf, bool isSecure) {
 Iterator<_Proxy> proxies = proxyConf.proxies.iterator;

 Future<_ConnectionInfo> connect(error) {
 if (!proxies.moveNext()) return new Future.error(error);
 _Proxy proxy = proxies.current;
 String host = proxy.isDirect ? uriHost : proxy.host;
 int port = proxy.isDirect ? uriPort : proxy.port;
 return _getConnectionTarget(host, port, isSecure)
 .connect(uriHost, uriPort, proxy, this)
 // On error, continue with next proxy.
 .catchError(connect);
 }

 return connect(new HttpException("No proxies given"));
}

Function _findProxy = HttpClient.findProxyFromEnvironment;

static String findProxyFromEnvironment(Uri url,
 {Map<String, String> environment}) {
 HttpOverrides overrides = HttpOverrides.current;
 if (overrides == null) {
 return _HttpClient._findProxyFromEnvironment(url, environment);
 }
 return overrides.findProxyFromEnvironment(url, environment);
}

static String _findProxyFromEnvironment(
 Uri url, Map<String, String> environment) {
 checkNoProxy(String option) {
 if (option == null) return null;
 Iterator<String> names = option.split(",").map((s) => s.trim()).iterator;
 while (names.moveNext()) {
 var name = names.current;
 if ((name.startsWith("[") &&
 name.endsWith("]") &&
 "[${url.host}]" == name) ||
 (name.isNotEmpty && url.host.endsWith(name))) {
 return "DIRECT";
 }
 }
 return null;
 }

 checkProxy(String option) {
 if (option == null) return null;
 option = option.trim();
 if (option.isEmpty) return null;
 int pos = option.indexOf("://");
 if (pos >= 0) {
 option = option.substring(pos + 3);
 }
 pos = option.indexOf("/");
 if (pos >= 0) {
 option = option.substring(0, pos);
 }
 // Add default port if no port configured.
 if (option.indexOf("[") == 0) {
 var pos = option.lastIndexOf(":");
 if (option.indexOf("]") > pos) option = "$option:1080";
 } else {
 if (option.indexOf(":") == -1) option = "$option:1080";
 }
 return "PROXY $option";
 }

 // Default to using the process current environment.
 if (environment == null) environment = _platformEnvironmentCache;

 String proxyCfg;

 String noProxy = environment["no_proxy"];
 if (noProxy == null) noProxy = environment["NO_PROXY"];
 if ((proxyCfg = checkNoProxy(noProxy)) != null) {
 return proxyCfg;
 }

 if (url.scheme == "http") {
 String proxy = environment["http_proxy"];
 if (proxy == null) proxy = environment["HTTP_PROXY"];
 if ((proxyCfg = checkProxy(proxy)) != null) {
 return proxyCfg;
 }
 } else if (url.scheme == "https") {
 String proxy = environment["https_proxy"];
 if (proxy == null) proxy = environment["HTTPS_PROXY"];
 if ((proxyCfg = checkProxy(proxy)) != null) {
 return proxyCfg;
 }
 }
 return "DIRECT";
}

_getHttpData() async {
 var httpClient = new HttpClient();
 httpClient.findProxy = (url) {
 return HttpClient.findProxyFromEnvironment(url, environment: {"http_proxy": 'http://192.168.124.7:8888',});
 };
 var uri =
 new Uri.http('t.weather.sojson.com', '/api/weather/city/101210101');
 var request = await httpClient.getUrl(uri);
 var response = await request.close();
 if (response.statusCode == 200) {
 print('請求成功');
 var responseBody = await response.transform(Utf8Decoder()).join();
 print('responseBody = $responseBody');
 } else {
 print('請求失敗');
 }
}

$ ping t.weather.sojson.com
PING nm.ctn.aicdn.com (58.222.18.24): 56 data bytes
64 bytes from 58.222.18.24: icmp_seq=0 ttl=54 time=16.792 ms
64 bytes from 58.222.18.24: icmp_seq=1 ttl=54 time=16.926 ms
64 bytes from 58.222.18.24: icmp_seq=2 ttl=54 time=15.804 ms