我可以从JSON文件中检索数据，但我无法添加它

Question

I read that question( click ). I read in similar articles. But it's not sending the data.

The program I want to do:

• I'm trying to make a login program.
• I have a JSON file that stores username and password data in it.
• From the outside, I can capture the data in the JSON file. (not problem)
• But I want to send the data. (this problem)
• The system does not issue an " error " warning. But it does not send the data in the JSON file.

---

Example JSON file:

{
    "jack":"jack123",
    "rick":"rick123",
    "maria":"maria123"
}

---

HTML CODE:

<input type="text" id="username" placeholder="username">
<input type="text" id="password" placeholder="password">
<button onclick=run()>CLICK RUN</button>
<button onclick=run1()>CLICK RUN1</button>

---

JAVASCRIPT CODE:

  function run1(){
    var username = $("#username").val();
    var password = $("#password").val();
    let xmlRequest,obj;
    xmlRequest = new XMLHttpRequest();
    xmlRequest.onreadystatechange = function(){
      if(this.readyState === 4 && this.status === 200){
        obj = JSON.parse(this.responseText);
        var res = obj[username];
        if(res == password){
          alert(`Welcome ${username}`);
        }
      }
    } 
    xmlRequest.open("GET","http://localhost/deneme/info.json",true);
    xmlRequest.send();
  }


  function run(){
    var username = $("#username").val();
    var password = $("#password").val();
    let xmlRequest,obj;
    xmlRequest = new XMLHttpRequest();
    var url = "http://localhost/deneme/info.json";
    xmlRequest.open("POST", url, true);
    xmlRequest.onreadystatechange = function(){
      if(this.readyState === 4 && this.status === 200){
        obj = JSON.parse(this.responseText);
      }
    } 

    var data = JSON.stringify({username:password});
    xmlRequest.send(data);
  }

---

NOTE: I don't know PHP.

Answer 1

There are plenty of problems in what you are trying to do. Even if you are front-end, you need to know how back-end works. Go with node.js, it uses javascript to build simple servers.

What you are doing is sending request, but it cannot be processed because you don't have access to file system of your computer from client-side javascript.

How it works: You send post request with some data. Your back-end gets this data and does smth with it. Writes to file or to database or performs any other action. What you are missing is server-side. Again, watch some tutorial about how to install node.js, npm, how to make simple server.

Besides that, you mustn't store logins and passwords in text files, and especially without encryption. This is a no-no.