特定参与者的历史学家

您可以将自v0.20以来的REST
API调用的结果返回给调用的客户端应用程序，因此可以进行如下操作（未经测试，但是您知道了）。注意：您可以直接通过REST直接使用您的参数（或您为自己的业务网络创建的任何端点-
下面的示例是

trade-network

使用API​​的NODE JS Client：

    const BusinessNetworkConnection = require('composer-client').BusinessNetworkConnection;    const rp = require('request-promise');    this.bizNetworkConnection = new BusinessNetworkConnection();    this.cardName ='admin@mynet';    this.businessNetworkIdentifier = 'mynet';    this.bizNetworkConnection.connect(this.cardName)    .then((result) => {    //You can do ANYTHING HERE eg.    })    .catch((error) => {    throw error;    });    // set up my read only transaction object - find the history of a particular Participant - note it could equally be an Asset instead !    var obj = {        "$class": "org.example.trading.MyPartHistory",        "tradeId": "P1"    };    async function callPartHistory() {    var options = {        method: 'POST',        uri: 'http://localhost:3000/api/MyPartHistory',        body: obj,        json: true     };    let results = await rp(options);    //    console.log("Return value from REST API is " + results);    console.log(" ");    console.log(`PARTICIPANT HISTORY for Asset ID:  ${results[0].tradeId} is: `);     console.log("=============================================");    for (const part of results) {         console.log(`${part.tradeId}  ${part.name}` );    }   }   // Main   callPartHistory();

//模型文件

@commit(false)@returns(Trader[])transaction MyPartHistory {o String tradeId}

只读交易处理器代码（在“ logic.js”中）：

async function participantHistory(tx) {    const partId = tx.tradeid;    const nativeSupport = tx.nativeSupport;    // const partRegistry = await getParticipantRegistry('org.example.trading.Trader')    const nativeKey = getNativeAPI().createCompositeKey('Asset:org.example.trading.Trader', [partId]);    const iterator = await getNativeAPI().getHistoryForKey(nativeKey);    let results = [];    let res = {done : false};    while (!res.done) {        res = await iterator.next();        if (res && res.value && res.value.value) { let val = res.value.value.toString('utf8'); if (val.length > 0) {    console.log("@debug val is  " + val );    results.push(JSON.parse(val)); }        }        if (res && res.done) { try {     iterator.close(); } catch (err) { }        }    }    var newArray = [];    for (const item of results) { newArray.push(getSerializer().fromJSON(item));    }    console.log("@debug the results to be returned are as follows: ");    return newArray; // returns something to my NodeJS client (called via REST API)}