public async validateToken(req, res): Promise<any> {
const token = req.headers.authorization.split(" ")[1] || req.params.token;
await this.redisClient.SISMEMBER("tokenBlackListSet", token, function(
err,
data
) {
if (data) { // here i get data=1 as token is present in tokenBlackListSet
return { // so this should be returned as json
status: 400,
error: "Invalid Token"
};
}
});
}
// in other async function
const response = await validateToken(req,res);
console.log(response) // returned value is always undefined
4 Answers
Since the SISMEMBER method return a boolean, and not the value returned by the callback, you can return a new Promise that you resolve in the callback :
public async validateToken(req, res): Promise<any> {
const token = req.headers.authorization.split(" ")[1] || req.params.token;
return new Promise(function (resolve, reject) { // Here I create a new Promise that will resolve (or reject) when your callback is called
this.redisClient.SISMEMBER("tokenBlackListSet", token, function(
err,
data
) {
if (err) { // If there is an error, we reject the promise
reject(err);
}
else if (data) { // If you have some data, the promise will resolve with the object
resolve({
status: 400,
error: "Invalid Token"
});
}
});
}
}
Notice I removed the await since it is now redundant with the fact that we return a promise already.
Comments
Hope this will work
public async validateToken(req, res): Promise<any> {
const token = req.headers.authorization.split(" ")[1] || req.params.token;
return await this.redisClient.SISMEMBER("tokenBlackListSet", token, (err,data)=> {
if (err) { throw new Error(err) }
else return { status: 400,error: "Invalid Token"};
}
});
}
3 Comments
Seblor
Same as Radu's answer : Are you sure SISMEMBER will resolve with the returned value from the callback ?
Andrei Piatrou
looks like
await here is redundant.Andrei Piatrou
this.redisClient.SISMEMBER returns a promise that can be resolved by a caller of validateToken function.Create a Promise object, and resolve that from inside the callback
public async validateToken(req, res): Promise<any> {
let resCallback, rejCallback
const returnPromise = new Promise((resolve, reject) => {
resCallback = resolve
refCallback = reject
})
const token = req.headers.authorization.split(" ")[1] || req.params.token;
await this.redisClient.SISMEMBER("tokenBlackListSet", token, function(
err,
data
) {
if (data) { // here i get data=1 as token is present in tokenBlackListSet
resCallback({ // so this should be returned as json
status: 400,
error: "Invalid Token"
});
}
});
return retPromise
}
2 Comments
Seblor
Are you sure
SISMEMBER will resolve with the returned value from the callback ?
pradeep desai
i need to return json based on 'data' variable's value in callback function
I do not think that the this.redisClient.SISMEMBER will wrap your callback result as a promise. If it would be case, you wouldn't be one here to ask the question.
Your result is lost in the void at the moment as the callback result is not passed as a return value.
Wrap the function into a promise and resolve or reject it when the callback is invoked by your library:
async function getSISMember() {
return new Promise((resolve, reject) => {
this.redisClient.SISMEMBER("tokenBlackListSet", token, function(
err,
data
) {
if (err) return reject(err); // Throw an error if an error is passed to callback
if (data) { // Return the object you want to return by resolving the promise
resolve({
status: 400,
error: "Invalid Token"
});
}
});
})
}
await getSISMember() should now either error or give you the JSON response
1 Comment
Jeffrey Devloo
Checkout @Seblor's answer as he implemented the function as a whole. I just ensured the result of your function would be resolved into a promise, which he did too.
validateTokenhas noreturnstatement