I have function calling anther function to return string, but I get undefined. because of the read file implement first

Question

I'm not that expert, but I can handle it: this calling the function checkTLS

// params={ibmdev_tls: 'not imp',ibmqa_tls: 'not imp',ibmqa_ssl: 'not imp'}  

Object.keys(params).forEach( key => {
    console.log(key);
    if(key.includes("tls")){ 
        //splitting parms to get cluster id
        clusterId=key.substring(0, key.indexOf("_"));
        console.log("cluster ID=="+clusterId);
        tlsresualt= checkTLS(clusterId);
        console.log("tls resualt is="+ tlsresualt);
        req.body[`${clusterId}_tls`]=tlsresualt;
        console.log(req.body.ibmdev_tls);
        console.log("==================================");
    }
});

The checktlsStatus is what I need to pass:

function checkTLS(clusterID){
    fs.readFile("clusterinfo/clusterinfo.json",(err, clusters) => {
        TlsVerion="TLS12";
        if(TlsVerion.includes("TLS12")){ 
            console.log(`TLs check status ------------------------ for ${clusterID}`);
            console.log(` TLs match the Secuity Baseline requirment for ${clusterID}`);
            checktlsStatus="implemented";
            //req.body.ibmdevtls=tlsStatus;
            //return console.log(checktlsStatur+ "check for tls successed");
            // req.body.(`${clusterID}`+`tls`)=tlsStatus;
            return checktlsStatus;
        }
    )};
}

I have tried await and asycn , also execSync(sleep 20);

nothing in your code is asyncrhonous, so, no need for await or async — Jaromanda X, Mar 06 '23 at 05:54
And where and how do you define the TlsVersion variable that you use in the checkTLS() function? — Alexandr Kamenev, Mar 06 '23 at 05:56
your variable name you assign to is `tlsResualt` but you then subsequently "use" `tlsresualt` ... — Jaromanda X, Mar 06 '23 at 05:57
I figure it out, if I make return outside the `fs.read`, will take it, but inside the `fs.read` not returned. — Hermione Granger, Mar 06 '23 at 06:41

Rajesh Ramesh · Answer 1 · 2023-03-06T09:44:26.317

I have modified your code with same functionality using async and await. Contents variable has the read file's contents.

    const fs = require('fs')
    const util = require('util')`enter code here`
    const readFileContent = util.promisify(fs.readFile)
    const fetchFile = async (path,clusterID) => {
    const buff = await readFileContent(path)

    const contents = buff.toString()
    TlsVerion="TLS12";
    if(TlsVerion.includes("TLS12")){ 
          console.log(`TLs check status ------------------------ for ${clusterID}`);
          console.log(` TLs match the Secuity Baseline requirment for ${clusterID}`);
          checktlsStatus="implemented";
          return checktlsStatus;
      }
      console.log(`\nContents of the file :`)
    }
       

    async function neo(){
        params={ibmdev_tls: 'not imp',ibmqa_tls: 'not imp',ibmqa_ssl: 'not imp'}  

        for (const property in params) {
            console.log(property);
            if(property.includes("tls")){ 
                //splitting parms to get cluster id
                clusterId=property.substring(0, property.indexOf("_"));
                console.log("cluster ID=="+clusterId);
                tlsresualt = await fetchFile('file.json',clusterId);
                console.log("tls resualt is="+ tlsresualt);
                console.log("==================================");
        }
        }
    }


    neo()

Reference from Here. You may refer the same for detailed explanation

the file content in JSON format and I need it that way, but you have converted to string. — Hermione Granger, Mar 06 '23 at 10:06

LiHS · Accepted Answer · 2023-03-06T10:39:53.480

Callback doesn't work that way!

Think about this:

function foo(name, callback) {
  callback(name.length);
}

function bar() {
  const abc = foo("something", (n) => {
    return n + 10;
  });
  console.log(abc);
}

bar();

The abc will always undifined because foo has no return value!

The callback return value is omitted by foo.

This is how you think fs.readFile works. But it not work like that way!

There is someways to solve it:

Add a callback to checkTLS function.
Use fs.readFileSync.
(Recommand)Use Promise(async/await) API.

Let's do it:

const fs = require("fs");
params={ibmdev_tls: 'not imp',ibmqa_tls: 'not imp',ibmqa_ssl: 'not imp'}  

Object.keys(params).forEach(async (key) => {
    console.log(key);
    if(key.includes("tls")){ 
        //splitting parms to get cluster id
        clusterId=key.substring(0, key.indexOf("_"));
        console.log("cluster ID=="+clusterId);
        // this changed
        const tlsresualt = await checkTLS(clusterId);
        console.log("tls resualt is="+ tlsresualt);
        // req.body[`${clusterId}_tls`]=tlsresualt;
        // console.log(req.body.ibmdev_tls);
        console.log("==================================");
    }
});

async function checkTLS(clusterID){
    const clusters = await fs.promises.readFile("clusterinfo/clusterinfo.json");
    TlsVerion="TLS12";
    if(TlsVerion.includes("TLS12")){ 
        console.log(`TLs check status ------------------------ for ${clusterID}`);
        console.log(` TLs match the Secuity Baseline requirment for ${clusterID}`);
        checktlsStatus="implemented";
        //req.body.ibmdevtls=tlsStatus;
        //return console.log(checktlsStatur+ "check for tls successed");
        // req.body.(`${clusterID}`+`tls`)=tlsStatus;
        return checktlsStatus;
    }
}

I'm not sure what you want to do. So just remake checkTLS to an async function.

I recommand use fs.promises and async/await, if you don't want it. Try this:

const fs = require("fs");

params={ibmdev_tls: 'not imp',ibmqa_tls: 'not imp',ibmqa_ssl: 'not imp'}  

Object.keys(params).forEach( key => {
    console.log(key);
    if(key.includes("tls")){ 
        //splitting parms to get cluster id
        clusterId=key.substring(0, key.indexOf("_"));
        console.log("cluster ID=="+clusterId);
        // this changed
        checkTLS(clusterId)
            .then(tlsresualt => {
                console.log("tls resualt is="+ tlsresualt);
                // req.body[`${clusterId}_tls`]=tlsresualt;
                // console.log(req.body.ibmdev_tls);
                console.log("==================================");
            });
    }
});

function checkTLS(clusterID){
    return new Promise(resolve => {
        fs.readFile("clusterinfo/clusterinfo.json",(err, clusters) => {
            TlsVerion="TLS12";
            if(TlsVerion.includes("TLS12")){ 
                console.log(`TLs check status ------------------------ for ${clusterID}`);
                console.log(` TLs match the Secuity Baseline requirment for ${clusterID}`);
                checktlsStatus="implemented";
                //req.body.ibmdevtls=tlsStatus;
                //return console.log(checktlsStatur+ "check for tls successed");
                // req.body.(`${clusterID}`+`tls`)=tlsStatus;
                resolve(checktlsStatus);
            }
        });
    });
}

References:

what I want is to check TLS version in node, then return if implemented to reflecte it to req.body. — Hermione Granger, Mar 06 '23 at 10:27
the read file to take clusterID and cluster token to login then check for tls — Hermione Granger, Mar 06 '23 at 10:29
Ok. Sorry for not test locally. I edited it, and comment req variable. It should run just node it. — LiHS, Mar 06 '23 at 10:41

I have function calling anther function to return string, but I get undefined. because of the read file implement first

2 Answers2