如何获取访问令牌以通过代理发送 FCM？

Question

我是 FCM 新手，正在编写一个 java 程序来推送消息。我的应用程序服务器位于我们公司场所，通过代理服务器访问互联网。我的问题是如何通过代理获取访问令牌？下面是代码片段

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

  googleCredential.refreshToken();

  return googleCredential.getAccessToken();
}

Answer 1

我设法使用匿名 HttpTransportFactory 实现来做到这一点：

var proxyUrl = URI.create(YOUR_PROXY);
var googleCredentials = GoogleCredentials.fromStream(new FileInputStream("service-account.json"),
        () -> new NetHttpTransport.Builder()
        .setProxy(new Proxy(Type.HTTP, new InetSocketAddress(proxyUrl.getHost(), proxyUrl.getPort())))
        .build()
    )
    .createScoped(Arrays.asList(SCOPES))
    .refreshAccessToken();

googleCredentials.refresh();
return googleCredentials.getAccessToken();

请注意，它使用

GoogleCredentials

而不是

GoogleCredential

，因为在撰写此答案时，后者已被弃用。

编辑： 由于您需要为代理提供凭据，因此解决方案变得更加复杂，但这实际上是我最终使用的：

private HttpTransportFactory getHttpTransportFactory(FirebaseProperties properties) {
    if (properties.getHttpProxy() == null) {
      return ApacheHttpTransport::new;
    }

    var proxyUrl = URI.create(properties.getHttpProxy());
    HttpHost proxyHostDetails = new HttpHost(proxyUrl.getHost(), proxyUrl.getPort());
    HttpRoutePlanner httpRoutePlanner = new DefaultProxyRoutePlanner(proxyHostDetails);

    HttpClientBuilder httpClientBuilder = ApacheHttpTransport.newDefaultHttpClientBuilder()
        .setRoutePlanner(httpRoutePlanner);

    if (isNotBlank(properties.getHttpProxyUser())) {
      CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
      credentialsProvider.setCredentials(new AuthScope(proxyHostDetails.getHostName(), proxyHostDetails.getPort()),
          new UsernamePasswordCredentials(properties.getHttpProxyUser(), properties.getHttpProxyPassword()));

      httpClientBuilder.setProxyAuthenticationStrategy(ProxyAuthenticationStrategy.INSTANCE)
          .setDefaultCredentialsProvider(credentialsProvider);
    }

    return () -> new ApacheHttpTransport(httpClientBuilder.build());
}

其中

FirebaseProperties

只是自定义

@ConfigurationProperties

类，保存代理连接所需的数据。然后您可以使用

GoogleCredentials.getApplicationDefault(getHttpTransportFactory(properties)).createScoped(MESSAGING_SCOPE)

创建凭证对象