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nodejs callback: doesn't detect any errors, just like if there were no error at all

Node js/Javascript doesn't catch the error while querying mysql server
The nodejs server queries the submittedName from form, checks the database along with submittedName. If submittedName matches with the submittedName, renders success. If it doesn't match, it should render notfound.
But indeed, it does not. Instead, it renders success. Even on wrong input.
app.post("/whatisyourname", (req, res) => {
var submittedName = req.body.details;
console.log(details);
//query the mysql database
conn.query(
"SELECT * FROM giftapp where name= ?",
submittedName,
(err, rs) => {
//handle the error
if (err) {
console.log(err);
//while it should render the "notfound" file,
//it renders "success"
res.render("notfound");
} else {
//if no error, render success
res.render("success", { myR: rs[0] });
}
}
);
I expect to be forwarded to "notfound" in case of wrong input or just any error
And to be forwarded to "success" in case of correct input

The express server or sql connection or callback won't throw any error in this case. You will get an error if something goes wrong while querying the db, i.e Invalid query or connection error etc. In your case the query executes successfully and gives you the result which is an empty array. You need to manually check and return the result. Change your code like:
app.post("/whatisyourname", (req, res) => {
const submittedName = req.body.details;
console.log(details);
//query the mysql database
conn.query(
"SELECT * FROM giftapp where name= ?",
submittedName,
(err, results) => {
if (err) {
console.log(err);
res.render("notfound");
} else {
if (results && results.length > 0) {
res.render("success", { myR: results[0] });
} else {
res.render("notfound");
}
}
});
});
Hope this helps :)

var submittedName = req.body.details;
var sql = 'SELECT * FROM giftapp WHERE name = ?';
con.query(sql, [submittedName], function (err, result) {
if (err) res.render("notfound"); // if you view is called notfound.ejs remove the space between not and found.
console.log(result);
res.render("success", { myR: result[0] }); // need success.ejs
});

How can I fix set headers in node js?

I am trying to redirect from the condition of a mysql to a get method but it does not work. How could I solve it?
app.post('/responses/',(req,res)=>{
var {text, context ={} } = req.body;
var params = {
input: {text},
workspace_id: '07',
context
}`
`assistant.message(params,(err,response) => {
if(err){
res.status(500).json(err);
}
else {
res.json(response);
console.log(JSON.stringify(response, null, 2));
}
if(response.context.rfc){
var RFC = response.context.rfc;
connection.connect(function(err) {
if (err) throw err;
connection.query(`SELECT * FROM test where RFC = '${RFC}'`, function (err, result, fields) {
if(result.length){
console.log("login");
}
else {
console.log('no login');
res.redirect('/home'); //Her not redirect.
}
});
});
}
});
});
Because show this error: hrow err; // Rethrow non-MySQL errors ^Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client

The error message indicates you are trying to set headers after the response is already sent. From your sample code, looks like your API call (whatever assistant.message is) is returning RFC. You then attempt to redirect to another page, but you've already called res.json, which begins sending a response to the browser.
You need to refactor your controller a bit so that you only call res.redirect or res.json, not both.

Insert error in rethindb using node

I am new to rethinkdb.
When I try out the sample code in https://github.com/rethinkdb/rethinkdb-example-nodejs/tree/master/todo-angular-express
function create(req, res, next) {
var todo = req.body;
todo.createdAt = r.now(); // Set the field `createdAt` to the current time
r.table('todos').insert(todo, {returnVals: true}).run(req._rdbConn, function(error, result) {
if (error) {
handleError(res, error)
}
else if (result.inserted !== 1) {
handleError(res, new Error("Document was not inserted."))
}
else {
res.send(JSON.stringify(result.new_val));
}
next();
});
}
I got the following error:
500 Internal Server Error
{"error":"return_vals renamed to return_changes in:\nr.table(\"todos\").insert({title: r.json(\"\"abcde\"\"), completed: r.json(\"false\"), createdAt: r.now()}, {returnVals: true})\n
And then I tried out the sample code in http://rethinkdb.com/docs/examples/node-todo/
function create(req, res, next) {
var todo = req.body; // req.body was created by `bodyParser`
todo.createdAt = r.now(); // Set the field `createdAt` to the current time
r.table('todos').insert(todo, {returnChanges: true}).run(req._rdbConn, function(error, result) {
if (error) {
handleError(res, error)
}
else if (result.inserted !== 1) {
handleError(res, new Error("Document was not inserted."))
}
else {
res.send(JSON.stringify(result.changes[0].new_val));
}
next();
});
}
I got the following error:
500 Internal Server Error
{"error":"Unrecognized optional argument returnChanges. in:\nr.table(\"todos\").insert({title: r.json(\"\"abcde\"\"), completed: r.json(\"false\"), createdAt: r.now()}, {returnChanges: true})\n "}
It seems that rethinkdb have changed returnVals to return_changes / returnChanges, and the argument of insert().
And I have the problem fixed when I used return_changes.
What is the right way to work on insert in latest version?
Do rethinkdb always changes its syntax?

this is indeed a bug in the example code. I've opened https://github.com/rethinkdb/rethinkdb-example-nodejs/issues/3 so we can fix it.
Your second problem with returnChanges not being recognized might come from using an old RethinkDB node driver. Have you tried updating the driver? http://rethinkdb.com/docs/install-drivers/javascript/

How to assure you are closing your functions properly with Javascript?

Can anyone explain to me why I am processing the 50 records but I never get console.log("all records processed"); to the console.
It is like I am closing a function too soon or too late. What is the best approach when working with call backs because I am sure that is why I do not get "all records processed". I am using node v0.10.26 with the NPM oracle plugin.
var oracle = require('oracle');
var connectData = {
hostname: "127.0.0.1",
port: 1521,
database: "xe", // System ID (SID)
user: "user",
password: "password"
};
oracle.connect(connectData, function(err, connection) {
if (err) {
console.log("Error connecting to db:", err);
return;
}
connection.setPrefetchRowCount(50);
var reader = connection.reader("SELECT * FROM CARS", []);
function doRead(cb) {
reader.nextRow(function(err, row) {
if (err) return cb(err);
if (row) {
// do something with row
console.log("got " + JSON.stringify(row));
// recurse to read next record
return doRead(cb)
} else {
// we are done
return cb();
}
});
}
doRead(function(err) {
if (err) throw err; // or log it
console.log("all records processed");
});
});

Does it make a difference that you don't have a semicolon after the closing brace of connectData? Personally, I just set more and more console logs until I figure out the line that's messing everything up. That, or use breakpoints if you can.

For these step by step callbacks, I suggest you use async to manage the callback pyramid.

Undefined error in MEAN CRUD

{ text: undefined,
done: false,
_id: 529e16025f5222dc36000002,
__v: 0 }
PUT /api/todos/529e16025f5222dc36000002 200 142ms - 68b
I keep getting this error when trying to do an update for my simple CRUD todo list. When I submit the update, the change doesn't appear on screen, although the put says it's a 200. Not sure what steps to take so that I don't get this "undefined" error and so I can have the update show up on screen.
EDIT: Included more code
This is the back-end node code:
app.put('/api/todos/:_id', function(req, res) {
Todo.findById(req.params._id, function(err, todos){
todos.text = req.body.text;
console.log(todos);
todos.save(function() {
if (!err) {
res.send(todos);
} else if (err) {
res.send(err);
}
Todo.find(function(err, todos) {
if (err)
res.send(err);
res.json(todos);
});
});
});
});
This is the Angular front-end code:
$scope.updateTodo = function(id) {
$scope.newItem = prompt("Please enter your new item:", "");
$http.put('/api/todos/' + id, {formData: $scope.newItem}).success(function(data) {
$scope.todos = data;
});
$http.get('/api/todos').success(function(data) {
$scope.todos = data;
});
};

I think it's because of this:
$http.put('/api/todos/' + id, { formData: $scope.newItem} )
^^^^^^^^
You're passing a single formData parameter with the request, yet in your Express code, you use this:
req.body.text
Either try this:
req.body.formData.text
Or don't use the formData parameter at all and pass $scope.newItem directly.
Besides that, your Express code is a bit messy: it might send back multiple responses and it doesn't check for errors on the save (as #PaulGray also pointed out).