I am trying to connect to a Cassandra cluster in NodeJs but when I execute a query, prepared or not, it just gets stuck. The callback isn't called at all and the process is just hanging. What could cause this? I am able to connect using devcenter using the same host/keyspace.
var Cassandra = require('cassandra-driver');
var cassandraClient = new Cassandra.Client({ contactPoints:['*.*.*.*'], keyspace: '*'});
cassandraClient.on('log', function(level, className, message, furtherInfo) {
console.log('log event: %s -- %s', level, message);
});
cassandraClient.connect(function (err) {
console.log(err)
});
console.log("Starting C* getting data");
cassandraClient.execute(query, params, {prepare: true}, function(err, result) {
if(err) console.log(err);
res = result;
console.log("Done C*");
console.log('result: ' + result.rows[0]);
notDone = false;
});
Output:
Init Get IP Info
log event: info -- Adding host *.*.*.*:9042
Starting C* getting data
And it gets stuck there. Any idea what is causing this?
Related
I have a SQLite database I am trying to add data to with the sqlite3 package. My query is as follows, and works in the SQLite command line.
'INSERT INTO `EVENTS`(`ID`,`EventName`,`EventSociety`,`BookerName`,`BookerEmail`,`BookerStudentID`,`BookerPhone`,`TimeStart`,`TimeEnd`,`EquipmentList`,`EventSearchYear`,`EventSearchMonth`,`EventSearchDay`) VALUES (NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);';
And I'm using this code to insert to the database in node.
db.run("begin transaction");
let sql = 'INSERT INTO `EVENTS`(`ID`,`EventName`,`EventSociety`,`BookerName`,`BookerEmail`,`BookerStudentID`,`BookerPhone`,`TimeStart`,`TimeEnd`,`EquipmentList`,`EventSearchYear`,`EventSearchMonth`,`EventSearchDay`) VALUES (NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);';
console.log(sql);
db.run(sql,(err) => {
res.send('ok');
});
db.run("commit");
Trying this in node hard crashes, with a Illegal instruction: 4. However, it is only happening on two tables, both with over 5 fields, in my database, and not any other smaller ones. Is there a character limit I'm unaware of?
To avoid crash, we need to handle error as below:
Example
The line db.run(sql, params, function (err) { in below example:
let sql = `INSERT INTO Users(id,firstName,lastName,email,password,permissionLevel) VALUES (?,?,?, ?,?,?)`;
let params = [uuid4(), "fn1", "ln1", "a#a2.com", "pwd1", 0];
db.run(sql, params, function (err) {
if (err) {
console.error("Error: Insert failed: ", err.message);
console.error("Error: Full error: ", err);
return;
}
console.log("insert success");
});
I've searched on how to create a sqlite3 database with a callback in Node.js and have not been able to find any links. Can someone point me towards documentation or provide a 2-3 line code sample to achieve the following:
Create a sqlite3 database and catch an error if the creation fails for any reason.
Here is what I've tried:
let dbCreate = new sqlite3.Database("./user1.db", sqlite3.OPEN_CREATE, function(err){
if(!err){
logger.infoLog("Successfully created DB file: " + dbFileForUser + " for user: " + username );
} else {
logger.infoLog("Failed to create DB file: " + dbFileForUser + ". Error: " + err );
}
});
dbHandler[username] = dbCreate;
When I execute this, I get the following error:
"Failed to create DB file: ./database/user1.db. Error: Error: SQLITE_MISUSE: bad parameter or other API misuse"
This call without callback works just fine.
var customDB = new sqlite3.Database("./custom.db", sqlite3.OPEN_READWRITE | sqlite3.OPEN_CREATE);
But in this, I will not know if I run into any errors while creating the Database.
Try this:
let userDB = new sqlite3.Database("./user1.db",
sqlite3.OPEN_READWRITE | sqlite3.OPEN_CREATE,
(err) => {
// do your thing
});
Example.
#Irvin is correct, we can have a look at http://www.sqlitetutorial.net/sqlite-nodejs/connect/ and
check it says if you skip the 2nd parameter, it takes default value as sqlite3.OPEN_READWRITE | sqlite3.OPEN_CREATE
and in this case if database does not exist new database will be created with connection.
sqlite3.OPEN_READWRITE: It is to open database connection and perform read and write operation.
sqlite3.OPEN_CREATE : It is to create database (if it does not exist) and open connection.
So here is the first way where you have to skip the 2nd parameter and close the problem without an extra effort.
const sqlite3 = require("sqlite3").verbose();
let db = new sqlite3.Database('./user1.db', (err) => {
if (err) {
console.error(err.message);
} else {
console.log('Connected to the chinook database.|');
}
});
db.close((err) => {
if (err) {
return console.error(err.message);
}
console.log('Close the database connection.');
});
And this is the 2nd way to connect with database (already answered by #Irvin).
const sqlite3 = require("sqlite3").verbose();
let db = new sqlite3.Database('./user1.db', sqlite3.OPEN_READWRITE | sqlite3.OPEN_CREATE
, (err) => {
if (err) {
console.error(err.message);
} else {
console.log('Connected to the chinook database.');
}
});
db.close((err) => {
if (err) {
return console.error(err.message);
}
console.log('Close the database connection.');
});
Right now, I'm writing a small web application using node.js with my partner. In the application, we need to query some data from database using mongoose, then, send the data to the client.Trying to do this, I'm using the code below:
io.sockets.on('connection', function (socket) {
var id = socket.id;
socket.on('request', function (data) {
mongoose.createConnection(dbConfig.url);
var ClassX = require("./models/" + data.request);
var class_query = ClassX.findOne({}, function (err, result) {
if (err) {
console.log("There is an error: "+ err);
return handleError(err);
}
if (!result) {
console.log("No result!");
}
io.sockets.to(id).emit("response", result);
});
});
});
But it doesn't work.
And when the code is running, the log file of the database show some information like below:
2017-02-23T15:40:48.426+0800 I NETWORK [thread1] connection accepted from 127.0.0.1:5015 #3 (3 connections now open)
2017-02-23T15:40:48.428+0800 I NETWORK [conn3] received client metadata from 127.0.0.1:5015 conn3: { driver: { name: "n
odejs", version: "2.2.24" }, os: { type: "Windows_NT", name: "win32", architecture: "x64", version: "10.0.14393" }, plat
form: "Node.js v6.9.5, LE, mongodb-core: 2.1.8" }
The information "[conn3] received client metadata ..." seems weird. And, from the experience of many attempts, I think the callback function of ClassX.finOne() has not been executed. And I totally don't know why.
I've got this error when trying to POST
> process.nextTick(function() { throw err; });
> ^
>
> TypeError: first argument must be a string or Buffer
> at ServerResponse.OutgoingMessage.end (_http_outgoing.js:524:11)
Errors shows that something's wrong with utils and cursor both from mongodb module, but what are they?
Everything works nice on GET but brakes on POST (postman and passing as text {"name":"Computer","price":2500}) - i cannot trace which module or instance is braking the code.
This is my conn with db:
// Our primary interface for the MongoDB instance
var MongoClient = require('mongodb').MongoClient;
// Used in order verify correct return values
var assert = require('assert');
var connect = function (databaseName, callBack) {
var url = 'mongodb://localhost:27017/' + databaseName;
MongoClient.connect(url,
function (error, database) {
assert.equal(null, error);
console.log("Succesfully connected to MongoDB instance!");
callBack(database);
});
};
exports.find = function (databaseName, collectionName, query, callback) {
connect(databaseName, function (database) {
var collection = database.collection(collectionName);
collection.find(query).toArray(
// Callback method
function (err, documents) {
// Make sure nothing went wrong
assert.equal(err, null);
// Print all the documents which we found, if any
console.log("MongoDB returned the following documents:");
console.dir(documents)
callback(err, documents);
// Close the database connection to free resources
database.close();
})
})
};
exports.insert = function (databaseName, collectionName, object, callback) {
connect(databaseName, function (database) {
var collection = database.collection(collectionName);
collection.insert(document, {w: 1}, function (err, documents) {
console.log("Added a new document");
console.log(documents[0]);
callback(err, documents[0]);
});
})
};
exports.remove = function (databaseName, collectionName, object, callback) {
connect(databaseName, function (database) {
var collection = database.collection(collectionName);
collection.remove(object, function (err, result) {
callback(err, result);
database.close();
});
})
};
The issue is actually pretty straightforward, so I'm surprised that you're not getting a better error message.
In your code:
collection.insert(document, {w: 1}, function (err, documents) {
console.log("Added a new document");
console.log(documents[0]); // I expect this to log undefined
callback(err, documents[0]);
});
The second argument passed into the collection.insert callback is actually a results object, not the documents that were inserted. So, documents[0] ends up being undefined because it's not an array of documents. Thus, when you trying to send undefined as a response, it's failing.
If you intention is to pass the newly created documents, you're going to have to use the result object to get the _id and attach it to the document you inserted.
As a side note, I would consider keeping a connection open to your database rather than creating a new connection every time you want to talk with Mongo.
I'm working on my Capstone project and it requires to store some telemetry data on a database. I'm using PostgreSQL 9.5 for the database and node for the server.
My problem is that when I try to send a query from the server I'm getting a query error [Error: Connection Terminated]. If I use JSON.stringify(err) I only see empty brackets as the result {}. What is interesting is that if I use pgAdmin client and execute the same query, the record is added successfully without any kind on error.
Here is the code I'm using in the server to send the query:
client.connect(function(err) {
if(err){
return console.error('could not connect to postgres', err);
}
//Checks if there is survey data to process
if(surveyFlag){
//Query to insert survey record
//Returns survey record's auto-generated id to use it when creating or updating the //telemetry record in the database
var query = 'INSERT INTO survey_response (perceived_risk, actual_risk) '+
'VALUES (' + telemetryRecord.survey.perceivedRisk +', ' +
telemetryRecord.survey.actualRisk +') ' +
'RETURNING survey_id';
client.query(query, function(err, result) {
console.log("Query: " + query);
if(err) {
console.log(err);
return console.error('error running survey query', err);
}
surveyID = result.rows[0].survey_id;
//Testing
console.log ("Survey response added with ID: " + surveyID);
});
//Close the connection
client.end();
});
The code client.end() is put at the same level of the code client.query(). Since client.query() is asynchronous, the client.end() gets called immediately after you start the query. By the time the query comes back the client has already ended which is causing the problem.
Try placing the client.end() code within the callback function of client.query().
client.query(query, function(err, result) {
console.log("Query: " + query);
if(err) {
console.log(err);
return console.error('error running survey query', err);
}
surveyID = result.rows[0].survey_id;
//Testing
console.log ("Survey response added with ID: " + surveyID);
//Close the connection
client.end();
});