Inventors quantify new functionality: Easily create HTTP services using the _Serve function

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In the development of quantitative transactions and automation strategies, HTTP services are sometimes used._Serve()Functions that provide users with the ability to create flexible HTTP, HTTPS, and TCP services. Through this feature, developers can simplify the service configuration process and implement more customized services in a quantified environment, making policy design more seamless and convenient._Serve()Use scenarios and basic functions to help you quickly quantify this all-new feature.

About the_Serve()This is the latest update to the platform's API documentation:

https://www.fmz.com/syntax-guide/fun/global/__serve

The need

Platform upgraded_Serve()Functions (as previously, JavaScript did not have the ability to create services, which only supported JavaScript policies) are simply the ability to create web services. We can develop many functions based on this functionality to solve many needs. For example, the ability to have external interfaces, data forwarding, supporting platforms with universal protocols, seamlessly encapsulating FMZ platforms not supported by exchanges, etc.

In this article, we're going to illustrate the need to "seamlessly wrap up exchanges that do not support the FMZ platform with the support of the general protocol functionality of the platform".This is a guide to the General Protocol.In Python, we use the Python language for OKX transactions, so the on-the-spot mode encapsulates the API ((since FMZ itself supports OKX, using OKX here is just an example, and applies to all exchanges that do not have access to other FMZ platforms).); In Python, the general protocol program needs to run separately when JavaScript language is supported._Serve()After the functions, the JavaScript language's tactics for accessing the general protocols are simpler.

We're going to wrap the general protocols of the exchange interface that we're going to wrap as a "template library" directly into the policy, so that the policy has seamless access to the exchanges that are not supported on FMZ.

https://www.fmz.com/digest-topic/10518

• The general protocol exchange on the platform is configured as follows:

  

  You can use this to create templates./OKXIdentify the exchange to which the object of the General Protocol Exchange belongs.

Implementation of the common protocol template

The first step is to create a new strategy in the inventor's quantitative trading platform, with the policy type set to template libraries and the strategy language set to JavaScript.

Design of template parameters

Add 3 parameters to create a good policy template:

Then you can start designing and writing the code for the universal protocol template.

Code Implemented

The code is written in TS style.$.startService()A function is an interface function in a template that is used to start a universal protocol service.

// @ts-check

$.startService = function (address, port, proxyConfig) {
    __Serve(`http://${address}:${port}`, function (ctx, proxyConfig) {
        // interface
        interface IData {
            data: object
            raw: object
        }
        
        interface IError {
            error: any
        }
        
        // custom protocol for OKX
        class CustomProtocolOKX {
            apiBase: string = "https://www.okx.com"
            accessKey: string
            secretKey: string
            passphrase: string
            proxyConfig: string = ""
            simulate: boolean = false
            
            constructor(accessKey: string, secretKey: string, passphrase: string, simulate?: boolean, proxyConfig?: string) {
                this.accessKey = accessKey
                this.secretKey = secretKey
                this.passphrase = passphrase
                if (typeof(simulate) == "boolean") {
                    this.simulate = simulate
                }
                this.proxyConfig = proxyConfig
            }
            
            httpReq(method: string, path: string, query: string = "", params: {[key: string]: any} = {}, headers: {key: string, value: string | ArrayBuffer}[] = []): {[key: string]: any} {
                let ret = null
                let options = {
                    method: method,                    
                    headers: {
                        'User-Agent': 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6', 
                        'Content-Type': 'application/json; charset=UTF-8',
                        'x-simulated-trading': this.simulate ? "1" : "0"
                    },
                }
                
                // headers
                if (Array.isArray(headers) && headers.length > 0) {
                    for (var pair of headers) {
                        options.headers[pair.key] = pair.value
                    }
                }
                
                let url = ""
                if (method == "GET") {
                    if (typeof(query) == "string" && query.length > 0) {
                        url = `${this.apiBase}${path}?${query}`
                    } else {
                        url = `${this.apiBase}${path}`
                    }
                } else {
                    url = `${this.apiBase}${path}`
                    options.body = JSON.stringify(params)
                }

                // request
                try {
                    if (this.proxyConfig != "") {
                        url = `${this.proxyConfig}${url}`
                    }
                    ret = JSON.parse(HttpQuery(url, options))
                } catch(e) {
                    return null
                }
    
                return ret
            }

            callSignedAPI(method: string, path: string, query: string = "", params: {[key: string]: any} = {}): {[key: string]: any} {
                const strTime = new Date().toISOString().slice(0, -5) + 'Z'
                let jsonStr = ""
                if (method == "GET") {
                    jsonStr = Object.keys(params).length > 0 ? JSON.stringify(params) : ""
                } else {
                    jsonStr = Object.keys(params).length > 0 ? JSON.stringify(params) : "{}"
                }                
                let message = `${strTime}${method}${path}${jsonStr}`
                if (method === "GET" && query !== "") {
                    message = `${strTime}${method}${path}?${query}${jsonStr}`
                }

                const signature = Encode("sha256", "string", "base64", message, "string", this.secretKey)
                let headers = []
                headers.push({key: "OK-ACCESS-KEY", value: this.accessKey})
                headers.push({key: "OK-ACCESS-PASSPHRASE", value: this.passphrase})
                headers.push({key: "OK-ACCESS-TIMESTAMP", value: strTime})
                headers.push({key: "OK-ACCESS-SIGN", value: signature})                

                return this.httpReq(method, path, query, params, headers)
            }
            
            urlEncode(params: {[key: string]: string | number}): string {
                let encodeParams: string[] = []
                for (const [key, value] of Object.entries(params)) {
                    encodeParams.push(`${encodeURIComponent(key)}=${encodeURIComponent(value)}`)
                }

                return encodeParams.join("&")
            }

            symbol2Inst(symbol: string): string {
                let arr = symbol.split("_")
                if (arr.length >= 2) {
                    return `${arr[0]}-${arr[1]}`.toUpperCase()
                } else {
                    return `${arr[0]}-USDT`.toUpperCase()
                }
            }

            getSymbol(inst: string): string {
                let arr = inst.split("-")
                if (arr.length >= 2) {
                    return `${arr[0]}_${arr[1]}`.toUpperCase()
                } else {
                    return `${arr[0]}-USDT`.toUpperCase()
                }
            }
            
            // The following code encapsulates OKX's interface
            GetTicker(symbol: string): IData | IError {
                // GET /api/v5/market/ticker , param: instId 

                let inst = this.symbol2Inst(symbol)
                let ret = this.httpReq("GET", "/api/v5/market/ticker", `instId=${inst}`)

                let retData = {}
                for (var ele of ret["data"]) {
                    retData["symbol"] = this.getSymbol(ele["instId"])
                    retData["buy"] = ele["bidPx"]
                    retData["sell"] = ele["askPx"]
                    retData["high"] = ele["high24h"]
                    retData["low"] = ele["low24h"]
                    retData["open"] = ele["open24h"]
                    retData["last"] = ele["last"]
                    retData["vol"] = ele["vol24h"]
                    retData["time"] = ele["ts"]
                }

                return {data: retData, raw: ret}
            }
            
            GetAccount(): IData | IError {
                // GET /api/v5/account/balance
                
                let ret = this.callSignedAPI("GET", "/api/v5/account/balance")

                let retData = []
                for (var ele of ret["data"]) {
                    for (var detail of ele["details"]) {
                        let asset = {"currency": detail["ccy"], "free": detail["availEq"], "frozen": detail["ordFrozen"]}
                        if (detail["availEq"] == "") {
                            asset["free"] = detail["availBal"]
                        }
                        retData.push(asset)
                    }
                }
                
                return {data: retData, raw: ret}
            }

            IO(method: string, path: string, params: {[key: string]: any}): {[key: string]: any} {
                let ret = null 
                if (method == "GET") {
                    ret = this.callSignedAPI(method, path, this.urlEncode(params))
                } else {
                    ret = this.callSignedAPI(method, path, "", params)
                }

                return {data: ret}
            }
        }
        
        // protocol factory
        class ProtocolFactory {
            static createExWrapper(accessKey: string, secretKey: string, exName: string): any {
                let protocol = null
                if (exName == "/OKX") {
                    try {
                        let passphrase = ""
                        let simulate = false
                        let arrSecretKey = secretKey.split(",")

                        if (arrSecretKey.length == 2) {
                            secretKey = arrSecretKey[0]
                            passphrase = arrSecretKey[1]
                        } else if (arrSecretKey.length == 3) {
                            secretKey = arrSecretKey[0]
                            passphrase = arrSecretKey[1]
                            simulate = arrSecretKey[2] == "simulate" ? true : false 
                        } else {
                            return null
                        }
                        protocol = new CustomProtocolOKX(accessKey, secretKey, passphrase, simulate, proxyConfig)
                    } catch(e) {
                        Log("e.name:", e.name, "e.stack:", e.stack, "e.message:", e.message)
                        return null
                    }
                }
                return protocol
            }
        }
        
        // http service
        let resp = {}
        let reqMethod = ctx.method()
        let reqPath = ctx.path()
        let httpMethod = ctx.header("Http-Method")
        let reqBody = null

        try {
            reqBody = JSON.parse(ctx.body())
        } catch(e) {
            resp = {error: {name: e.name, stack: e.stack, message: e.message, errDesc: "JSON parse error."}}
        }

        // onPost
        if (reqMethod == "POST") {
            if (!["access_key", "secret_key", "method", "params"].every(key=> key in reqBody)) {
                resp = {error: {reqBody: reqBody, errDesc: "reqBody error."}}
            }

            if ("error" in resp) {
                ctx.write(JSON.stringify(resp))
                return 
            }

            let accessKey = reqBody["access_key"]
            let secretKey = reqBody["secret_key"]
            let method = reqBody["method"]
            let params = reqBody["params"]

            let protocol = ProtocolFactory.createExWrapper(accessKey, secretKey, reqPath)
            if (!protocol) {
                ctx.write(JSON.stringify({error: {errDesc: "createExWrapper error."}}))
                return 
            }

            // process GetTicker / GetAccount ...
            if (method == "ticker") {
                if (!["symbol"].every(key=> key in params)) {
                    resp = {error: {params: params, errDesc: "params error."}}
                } else {
                    let symbol = params["symbol"]
                    resp = protocol.GetTicker(symbol)
                }
            } else if (method == "accounts") {
                resp = protocol.GetAccount()
            } else if (method.slice(0, 6) == "__api_") {
                resp = protocol.IO(httpMethod, method.slice(6), params)
            } else {
                ctx.write(JSON.stringify({error: {method: method, errDesc: "method not support."}}))
                return 
            }

            ctx.write(JSON.stringify(resp))
        }
    }, proxyConfig)
}

function init() {
    $.startService(address, port, proxyConfig)
    Log("启动通用协议服务，address:", address, "，port:", port, "#FF0000")
    if (proxyConfig != "") {
        Log("设置代理：", proxyConfig, "#FF0000")
    }
}

This is a very limited section, so we don't implement all the interfaces here, we just implement the interface.Inquiry into the case、Inquiry into assets、IO callStudents who are interested can implement all interfaces; design completed, save template code, template name saved as: TypeScript version general protocol instance .

Testing strategies

Once OKX exchanges are configured with apkeys, secret keys, passphrases, etc., we can write a test policy to test it.

The strategy is to select a template library that we have designed:

The test strategy code is:

function main() {
    // 测试GetTicker
    Log(`exchange.GetTicker():`, exchange.GetTicker())

    // 测试GetAccount
    Log(`exchange.GetAccount():`, exchange.GetAccount())

    // 测试exchange.IO
    Log(`exchange.IO("api", "POST", "/api/v5/trade/cancel-all-after", "timeOut=0"):`, exchange.IO("api", "POST", "/api/v5/trade/cancel-all-after", "timeOut=0"))

    // 输出通用协议添加的交易所名称
    Log(`exchange.GetName():`, exchange.GetName())

    // 输出通用协议添加的交易所标签
    Log(`exchange.GetLabel():`, exchange.GetLabel())
}

Running tests

As you can see, the strategy is simply to select a template and achieve seamless access to the OKX exchange (although OKX exchanges already support, for example here OKX replaces an FMZ exchange that is not yet connected).