I'm struggling with async await block. I have looked the multiple resources on the net but I just can't understand what I'm doing wrong here:
app.post('/api/my-api', async (req, res, next) => {
try {
filecontent = req.files.userFile.data.toString('utf8')
console.log("decoded file : ", filecontent);
let encoded_file = new Buffer(filecontent).toString('base64');
var apiClass = new RPC("http://localhost:1006", "my-api");
//the asynchronous function :
const answ = await apiMethod.call("api", [{"file" : encoded_file, "fileName":req.files.userFile.name}], res.json);
//the code I'd like to execute only after the previous function has finished :
console.log("answer : ", answ);
console.log("answering...");
res.json(answ);
} catch (err) {
console.log(err);
}
Apparently my console.log
are executed before the the await
line is done. I can tell because there's a console.log()
in the asynchronous function too, and my res.json
is sent before I receive answ
.
How do I make sure the asynchronous function finishes before the rest of the code?
Edit: here is the apiMethod.call function:
call(id, params) {
let options = {
url: this.url,
method: "post",
headers:
{
"content-type": "text/plain"
},
body: JSON.stringify( {"jsonrpc": "2.0", "id": id, "method": this.procedure, "params": params })
};
console.log(options);
request(options, (error, response, body) => {
if (error) {
console.error('An error has occurred: ', error);
} else {
console.log('Post successful: response: ', body);
}
});
}
Issue is in call
function. Since it has async code ( request
call), it should be wrapped in promise which should resolve from callback function of request
.
Updating call function to something like below should help:
function call(id, params) {
return new Promise((resolve, reject) => {
let options = {
url: this.url,
method: "post",
headers: {
"content-type": "text/plain",
},
body: JSON.stringify({
jsonrpc: "2.0",
id: id,
method: this.procedure,
params: params,
}),
};
console.log(options);
request(options, (error, response, body) => {
if (error) {
console.error("An error has occurred: ", error);
reject(error);
} else {
console.log("Post successful: response: ", body);
resolve(body);
}
});
})
}
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