通过JavaScript访问FCM令牌密钥

Question

是否有任何选项可以通过客户端的Java脚本获得FCM访问令牌密钥？我正在为一个简单的android应用程序使用Firebase，我想让一些用户可以选择发送推送通知消息。

​

function getAccessToken(){  }

var xhr = new XMLHttpRequest();
xhr.responseType = "json";
xhr.open('POST', "https://fcm.googleapis.com/v1/projects/**********/messages:send", true);
xhr.setRequestHeader('Authorization', "Bearer " + getAccessToken());

​

我用下面的代码片段尝试了@Ali的建议，但是现在我从refreshAccessToken(.)获得了一个异常带有"Scopes未配置为服务帐户“的消息。我想澄清的是，Ali的答案的第一个注释中的DotNet代码仍然在处理同一个JSON文件。

​

@JavascriptInterface
private static String readToken() throws IOException, InterruptedException {
    String str = new String("{\n" +
            "  \"type\": \"service_account\",\n" +
            "  \"project_id\": \"*****\",\n" +
            "  \"private_key_id\": \"*****\",\n" +
            "  \"private_key\": \"-----BEGIN PRIVATE KEY-----\\n*****\\n-----END PRIVATE KEY-----\\n\",\n" +
            "  \"client_email\": \"*****\",\n" +
            "  \"client_id\": \"*****\",\n" +
            "  \"auth_uri\": \"*****",\n" +
            "  \"token_uri\": \"*****",\n" +
            "  \"auth_provider_x509_cert_url\": \"*****",\n" +
            "  \"client_x509_cert_url\": \"*****\"\n" + "}\n");

    InputStream stream = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8));
    GoogleCredentials googleCredential = GoogleCredentials.fromStream(stream);
    googleCredential.createScoped(Arrays.asList("https://www.googleapis.com/auth/firebase.messaging"));

    AccessToken token = googleCredential.refreshAccessToken();
    String x = token.getTokenValue();
    return x;
}

​

Answer 1

在创建webview之后，启用JavaScript并附加一个JavaScript接口并命名为：

WebSettings webSettings = webview.getSettings();
webSettings.setJavaScriptEnabled(true);
webview.addJavascriptInterface(this, "InterfaceName");

现在，您可以将任何Java函数分配到JavaScript接口，并通过网页访问它。

获取用户FCM令牌的示例：

@JavascriptInterface
public String readToken(){
    String token = FirebaseInstanceId.getInstance().getToken();
    return token;
}

获取FCM访问令牌密钥(参考文献)的示例：

@JavascriptInterface
private static String readToken() throws IOException {
  GoogleCredential googleCredential = GoogleCredential
      .fromStream(new FileInputStream("service-account.json"))
      .createScoped(Arrays.asList(SCOPES));
  googleCredential.refreshToken();
  return googleCredential.getAccessToken();
}

若要将访问令牌添加到HTTP请求头，请执行以下操作：

URL url = new URL(BASE_URL + FCM_SEND_ENDPOINT);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestProperty("Authorization", "Bearer " + getAccessToken());
httpURLConnection.setRequestProperty("Content-Type", "application/json; UTF-8");
return httpURLConnection;

这就是如何在定义了接口的JavaScript中使用WebView调用该函数：

<script>
   var token=InterfaceName.readToken();
</scritp>