postman 在接口调用中使用动态变量

在接口调用中经常会遇到使用sign签名，需要动态生成，并且有加密，排序等需求

// Replace with your app secret  
var secret = "7bf9fa93cd06a160c03f5789be285ac36df8701f"    
    
function objKeySort(obj) {    
    var newKey = Object.keys(obj).sort()    
    var newObj = {}    
    for (var i = 0; i < newKey.length; i++) {    
        newObj[newKey[i]] = obj[newKey[i]]    
    }    
    return newObj    
}    
    
function getEnvVar(k) {    
    var v = pm.variables.get(k)    
    if (v != null) {    
        return v    
    }    
    v = pm.environment.get(k)    
    if (v != null) {    
        return v    
    }    
    v = pm.globals.get(k)    
    if (v != null) {    
        return v    
    }    
    return null    
}    
    
var ts = Date.parse(new Date()) / 1000    
pm.variables.set("timestamp", ts)    
    
calSign = function(secret) {    
    var ts = getEnvVar("timestamp")    
    var queryParam = pm.request.url.query.members    
    var param = {}    
    for (var item in queryParam) {    
        if (queryParam[item].key == "timestamp") {    
            v = ts    
        } else {    
            var v = queryParam[item].value    
            if (v == null || v == "{{" + queryParam[item].key + "}}") {    
                v = getEnvVar(queryParam[item].key)    
            }    
        }    
        param[queryParam[item].key] = interpolateVar(v)    
    }    
    
    delete param["sign"]    
    delete param["access_token"]    
    var sortedObj = objKeySort(param)    
    var signstring = secret + pm.request.url.getPath()    
    for (var key in sortedObj) {    
        signstring = signstring + key + sortedObj[key]    
    }    
    signstring = signstring + interpolateVar(pm.request.body.toString()) +  secret    
    console.log(signstring)    
    sign = CryptoJS.HmacSHA256(signstring, secret).toString()    
    return sign    
}    
    
function interpolateVar (value) {    
    const {Property} = require('postman-collection')    
    return Property.replaceSubstitutions(value, pm.variables.toObject())    
}    
    
var sign = calSign(secret)    
pm.variables.set("sign", sign)