获取API。 我从我自己的快递服务器得到一个空字符串

Question

I've set up an express.js server on 4000 port. getting a request and sending a plain text string.

let express = require("express");
const app = express();
const port = 4000;

app.listen(port, () => { console.log(`SERVER is running on port ${port}`)});

app.use(express.text());

app.get("/", (req,res) =>{
   console.log("Get from /");
   res.send("Hello world");
});

and i'am trying to fetch a string "Hello world"using fetchApi.

window.onload = ()=>{
  fetch("http://127.0.0.1:4000/", {
      method: "GET",
      mode: "no-cors"
  }).then(res=>{
      return res.text();
  }).then( text => {
      console.log(text);
  });
};

i am getting an empty string in console but when i open network sent requests i see the message in network response.

Answer 1

You said:

 mode: "no-cors"

Which means "I am not going to do anything that requires the server to grant permission with CORS so don't fill the console with errors if I don't have that permission".

Since reading a response cross-origin requires permission from CORS and you said you didn't want permission, you get an empty string back when you try to read the response.

If you want to read the response, you need CORS, so take the mode config out.

Answer 2

If you are using the last version of Express so try this code and you don't need express.text():

 const express = require("express");
 const app = express();
 const port = 4000;
 app.listen(port, () => { console.log(`SERVER is running on port ${port}`)}); 
 app.get("/", (req,res) =>{ console.log("Get from /"); res.send("Hello world") });

Then :

window.onload = ()=>{ fetch("http://127.0.0.1:4000/", { method: "GET"}).then(res=>{ return res }).then( text => { console.log(text); }); };