Google Android应用内购买“内容交付”如何正确交付内容？

Question

我目前正在尝试编写应用内购买代码。我一直在寻找有关Google无法解决的某些问题的最佳做法的文档，信息和教程。

到目前为止，我所做的是：

我正在运行一个结算服务，可以处理与Google Play的通话。该服务可以完成“示例”交易，我的应用程序会收到该消息。

我现在想将内容传送到设备。我认为接下来需要发生的事情：

1. 我的应用程序需要与我的服务器联系，并显示成功交易的证明。做一些Cert的手摇晃或者说些废话。

2. 然后，我将下载内容并将其放入数据库中。我可能应该使用某种设备唯一的加密来加密数据库。

我正在寻找学习如何做上述2件事以及需要做的其他事情。我想要合理数量的安全性/加密。任何文档/教程/示例项目都很棒，我试图搜索这些东西，但是没有找到我想要的东西。

Answer 1

您必须对示例中的计费服务客户端代码进行一些更改。

首先，您应该调用服务器以获取将被用于RestoreTransactions或进行购买的随机数，以使事情尽可能安全。

让我们跟随发生的事情。这是Google Play调用的BillingReceiver：

/**
 * This is called when Android Market sends information about a purchase state
 * change. The signedData parameter is a plaintext JSON string that is
 * signed by the server with the developer's private key. The signature
 * for the signed data is passed in the signature parameter.
 * @param context the context
 * @param signedData the (unencrypted) JSON string
 * @param signature the signature for the signedData
 */
private void purchaseStateChanged(Context context, String signedData, String signature) {
    Intent intent = new Intent(Consts.ACTION_PURCHASE_STATE_CHANGED);
    intent.setClass(context, BillingService.class);
    intent.putExtra(Consts.INAPP_SIGNED_DATA, signedData);
    intent.putExtra(Consts.INAPP_SIGNATURE, signature);
    context.startService(intent);
}

如果查看BillingService.java中的handleCommand，它将处理此意图：

/**
 * The {@link BillingReceiver} sends messages to this service using intents.
 * Each intent has an action and some extra arguments specific to that action.
 * @param intent the intent containing one of the supported actions
 * @param startId an identifier for the invocation instance of this service
 */
public void handleCommand(Intent intent, int startId) {
    String action = intent.getAction();
    if (Consts.DEBUG) {
        Log.i(TAG, "handleCommand() action: " + action);
    }
    if (Consts.ACTION_CONFIRM_NOTIFICATION.equals(action)) {
        String[] notifyIds = intent.getStringArrayExtra(Consts.NOTIFICATION_ID);
        confirmNotifications(startId, notifyIds);
    } else if (Consts.ACTION_GET_PURCHASE_INFORMATION.equals(action)) {
        String notifyId = intent.getStringExtra(Consts.NOTIFICATION_ID);
        getPurchaseInformation(startId, new String[] { notifyId });
    } else if (Consts.ACTION_PURCHASE_STATE_CHANGED.equals(action)) {
        String signedData = intent.getStringExtra(Consts.INAPP_SIGNED_DATA);
        String signature = intent.getStringExtra(Consts.INAPP_SIGNATURE);
        purchaseStateChanged(startId, signedData, signature);
    } else if (Consts.ACTION_RESPONSE_CODE.equals(action)) {
        long requestId = intent.getLongExtra(Consts.INAPP_REQUEST_ID, -1);
        int responseCodeIndex = intent.getIntExtra(Consts.INAPP_RESPONSE_CODE,
                ResponseCode.RESULT_ERROR.ordinal());
        ResponseCode responseCode = ResponseCode.valueOf(responseCodeIndex);
        checkResponseCode(requestId, responseCode);
    }
}

然后调用PurchaseStateChanged函数。该功能应由对服务器的调用代替，以创建用于内容传递的会话。应该将Security.java中的代码移植到服务器端，以验证云中的事务。

/**
 * Verifies that the data was signed with the given signature, and calls
 * {@link ResponseHandler#purchaseResponse(Context, PurchaseState, String, String, long)}
 * for each verified purchase.
 * @param startId an identifier for the invocation instance of this service
 * @param signedData the signed JSON string (signed, not encrypted)
 * @param signature the signature for the data, signed with the private key
 */
private void purchaseStateChanged(int startId, String signedData, String signature) {
    ArrayList<Security.VerifiedPurchase> purchases;
    purchases = Security.verifyPurchase(signedData, signature);
    if (purchases == null) {
        return;
    }

    ArrayList<String> notifyList = new ArrayList<String>();
    for (VerifiedPurchase vp : purchases) {
        if (vp.notificationId != null) {
            notifyList.add(vp.notificationId);
        }
        ResponseHandler.purchaseResponse(this, vp.purchaseState, vp.productId,
                vp.orderId, vp.purchaseTime, vp.developerPayload);
    }
    if (!notifyList.isEmpty()) {
        String[] notifyIds = notifyList.toArray(new String[notifyList.size()]);
        confirmNotifications(startId, notifyIds);
    }
}

确保将公共密钥放在已移植的Security.java文件中的服务器端。