console.debug("--------------------start--------------------");

try{
    //Secret key 
    var secretKey = "8YfPw4s6YLcYyLc8";
    console.debug("secretKey：" + secretKey);
    
         / / Set the request timestamp
    var signed_at = Math.round(new Date().getTime()/1000);
    pm.globals.set("signed_at", signed_at);
    console.debug("signed_at：" + signed_at);
    
         / / Request parameters
    var data = {};
    //GET
    if(pm.request.url.query instanceof Object){
        pm.request.url.query.each(function(obj){
            if(obj.disabled === undefined) data[obj.key] = obj.value;
        });
    }
    //POST
    if(pm.request.body.formdata instanceof Object){
        pm.request.body.formdata.each(function(obj){
            if(obj.disabled === undefined) data[obj.key] = obj.value;
        });
    }
    console.debug("data：" + JSON.stringify(data));
    
         / / Parameter ordering
    var params = [];
    for(var key in data){
        if(key != "sign") params.push(key);
    }
    params.sort();
    console.debug("params：" + params);
    
         / / Assemble the string
    var str = '';
    params.forEach(function(value){
        str += value;
        data[value] = data[value] ? data[value] : "";
        if(data[value].indexOf("{{")!= -1){
            str += pm.globals.get(data[value].replace(new RegExp('(\{|\})', "g"),""));
        }
        else{
            str += data[value];
        }
    });
    str = secretKey + str + secretKey;
    console.debug("str：" + str);
    
         / / Generate signature
    var sign = CryptoJS.MD5(str).toString();
    pm.globals.set("sign", sign);
    console.debug("sign：" + sign);
    
}catch(err){
    console.error("Pre-Request Script " + err.name + ":" + err.message);
}

console.debug("--------------------done--------------------");

Recently, I am getting lazy. I can take screenshots and take screenshots. Anyway, I have a lot of tutorials on the Internet. I just recorded them as my own records, and I have a joint learning.