Wake call mechanism

Applications wake the wallet service

Certain wallet applications that implement special adaptation layers support being called from within other applications on the phone.

In this section, we talk about how to wake the wallet from inside an application and implement features such as login and smart contract invocation (including payment method). For more details on the application wake mechanism, please refer to Android application demo.

Interaction Process

Transaction flow

dAPI protocol usage

With respect to the wake call, the development process involves implementing two functions - login and smart contract invocation.

The login process is simpler at it's core, so we won't go into any unnecessary details. The process is illustrated in the following section.

Smart contract invocation has a much broader scope of application. dApps can use smart contracts to implement various different kinds of logic. For example, in the case of a game, there are different operations and services that can be carried out using smart contracts, such as buying, selling, renting, etc.

The core sequence of the login operation is illustrated in the picture below:

The dApp communicates with the back end to fetch the callback URL and a message to be sent to the dedicated provider, along with other information (depending upon the implementation logic), and wakes the wallet.
The provider wallet carries out user authentication and signs the message.
The signed message is then returned to the dApp back end using the designated callback URL, along with the signed message, the signature and a public key for verification purposes.
The back end finally verifies the signature and sends a success/failure response to the dApp.

When the dApp needs to login, it fetches the relevant login data in order to send it to the provider wallet.

An example of the data structure:

{
    "action": "login",
    "id": "10ba038e-48da-487b-96e8-8d3b99b6d18a",
    "version": "v1.0.0",
    "params": {
        "type": "ontid or account",
        "dappName": "dapp Name",
        "dappIcon": "dapp Icon",
        "message": "helloworld",
        "expire": 1546415363,
        "callback": "http://127.0.0.1:80/login/callback"
    }
}

Specific usage procedure

Establish whether or not Cyano Wallet is installed on the system. An example verification method is provided below.

public static boolean checkInstallCynoApp(Context context) {
       final PackageManager packageManager = context.getPackageManager();// Fetch the package manager
       List<PackageInfo> pinfo = packageManager.getInstalledPackages(0);// Get a list of all the installed packaged on the system
       if (pinfo != null) {
           for (int i = 0; i < pinfo.size(); i++) {
               String pn = pinfo.get(i).packageName.toLowerCase(Locale.ENGLISH);
               if (pn.equals("com.github.ont.cyanowallet")) {
                   return true;
               }
           }
       }
       return false;
   }

dApp sends the data it received from the dApp server to the dedicated provider (wallet). This can be realized in the following manner:

   String data = "{\"action\":\"login\",\"id\":\"10ba038e-48da-487b-96e8-8d3b99b6d18a\",\"version\":\"v1.0.0\",\"params\":{\"type\":\"ontid or account\",\"dappName\":\"dapp Name\",\"dappIcon\":\"dapp Icon\",\"message\":\"helloworld\",\"expire\":1546415363,\"callback\":\"http://127.0.0.1:80/login/callback\"}}"; //此处就是将之前的登录数据拼接后的状态。

   String sendData = Base64.encodeToString(Uri.encode(data).getBytes(), Base64.NO_WRAP);
   Intent intent = new Intent("android.intent.action.VIEW");
   intent.setData(Uri.parse("ontprovider://ont.io?param=" + sendData ));
   intent.addCategory("android.intent.category.DEFAULT");
   startActivity(intent);

The provider verifies the submitted information and signs it, and transmits it back to the specified callback address. The developer need not execute this step manually.
The dApp back end verifies the signature to establish whether the login succeeded or failed and notifies the dApp.

2. Smart Contract Invocation

The core contract invocation process is illustrated in the figure below:

dApp side creates a contract invocation data set and sends it to the dedicated provider.
The provider carries out user authentication, signature process, and carries out the transaction by communicating with the blockchain.
The provider receives the transaction hash from the blockchain and transmits it to the dApp back end using the specified callback address.
The dApp server end queries the blockchain for the execution result using the transaction hash.
The final result is returned to the dApp, made accessible to the user.

Smart Contract invocation data

A sample contract invocation data set:

{
    "action": "invoke",
    "version": "v1.0.0",
    "id": "10ba038e-48da-487b-96e8-8d3b99b6d18a",
    "params": {
        "login": true,
        "message": "will pay 1 ONT in this transaction",
        "callback": "http://101.132.193.149:4027/invoke/callback",
        "invokeConfig": {
            "contractHash": "16edbe366d1337eb510c2ff61099424c94aeef02",  //contract address
            "functions": [{
                "operation": "method name", //name of the method in the invoked smart contract
                "args": [{   //contract invocation arguments
                    "name": "arg0-list",//argument index 1's value is an array
                    "value": [true, 100, "Long:100000000000", "Address:AUr5QUfeBADq6BMY6Tp5yuMsUNGpsD7nLZ", "ByteArray:aabb", "String:hello", [true, 100], {
                        "key": 6
                    }]
                }, {
                    "name": "arg1-map",//argument index 2's value is a map
                    "value": {
                        "key": "String:hello",
                        "key1": "ByteArray:aabb",
                        "key2": "Long:100000000000",
                        "key3": true,
                        "key4": 100,
                        "key5": [100],
                        "key6": {
                            "key": 6
                        }
                    }
                },{
                       "name": "arg2-ByteArray", //argument index 3's value is a ByteArray
                       "value": "ByteArray:aabbcc"
                },{
                    "name": "arg3-int", //arguement index 4's value is int/long
                    "value": 100
                },{
                    "name": "arg4-str", //argument index 5's value is string
                    "value": "String:test"
                }]
            }],
            "payer": "AUr5QUfeBADq6BMY6Tp5yuMsUNGpsD7nLZ",
            "gasLimit": 20000,
            "gasPrice": 500
        }
    }
}

A Base58 address, for e.g., AUr5QUfeBADq6BMY6Tp5yuMsUNGpsD7nLZ __can be used to fill the %address parameter. The wallet converts the %address to the wallet's asset address. If the argument contains the %ontid, the wallet converts it to the wallet's ontid address.

Implementation Sequence

Ensuring the Provider-sdk wallet application is installed and deployed on the phone.
Composing the contract invocation JSON data set, making the wake call to the wallet.

Sample code:

String data="{\"action\":\"invoke\",\"version\":\"v1.0.0\",\"id\":\"10ba038e-48da-487b-96e8-8d3b99b6d18a\",\"params\":{\"login\":true,\"qrcodeUrl\":\"http://101.132.193.149:4027/qrcode/AUr5QUfeBADq6BMY6Tp5yuMsUNGpsD7nLZ\",\"message\":\"will pay 1 ONT in this transaction\",\"callback\":\"http://101.132.193.149:4027/invoke/callback\"}}";


String sendData = Base64.encodeToString(Uri.encode(data).getBytes(), Base64.NO_WRAP);
Intent intent = new Intent("android.intent.action.VIEW");
intent.setData(Uri.parse("ontprovider://ont.io?param=" + sendData ));
intent.addCategory("android.intent.category.DEFAULT");
startActivity(intent);

The provider authenticates, signs, pre-executes, and finally transmits the transaction to the chain. (This step does not require manual implementation)
The provider sends the transaction hash retrieved from the blockchain to the dApp back end. (This step is carried out depending on the dApp's event sequence)
dApp queries the result from the blockchain.

Query methods reference:

The dApp back end returns the result to the dApp, from where the user can access it. (Depends on the logic of the dApp)

dApp Server Callback Interface

The provider initiates transactions, carries out user authentication and signature, pre-executes the contract, and finally passes the transaction has to the callback URL via POST method.

If the transaction succeeds, the wallet returns the following to callback:

{
  "action": "invoke",
  "id": "10ba038e-48da-487b-96e8-8d3b99b6d18a",
  "error": 0,
  "desc": "SUCCESS",
  "result": "tx hash"
}

If the transaction fails, the wallet returns:

{
  "action": "invoke",
  "id": "10ba038e-48da-487b-96e8-8d3b99b6d18a",
  "error": 80001,
  "desc": "SEND TX ERROR",
  "result": 1
}

Demonstration

The two example applications demonstrate the wake call for specially designated wallets. The code can be used for reference.

Code base for Reference

Signature verification methods

Transaction event query methods

Cyano Wallet

dAPI - Mobile provider SDK

dAPI - Mobile client SDK

PreviousQR code mechanism NextCocos 2D-x

Last updated 5 years ago

Was this helpful?