I've tried using the following code in my measure.ts script:
Deno.DatagramConn.send(...)
When I run my script like this: deno run --unstable --allow-all measure.ts I get the following error:
Property 'DatagramConn' does not exist on type 'typeof Deno'. 'Deno.DatagramConn' is an
unstable API. Did you forget to run with the '--unstable' flag?
This error seems to simultaneously deny and confirm the existence of the Deno.DatagramConn API
Similarly I've tried
Deno.connect({transport : 'udp'})
but this gives me the follow error (which probably makes sense as UDP is 'connectionless'):
Type '"udp"' is not assignable to type '"tcp"
I seem to have figured it out. I actually need to first listen on a socket, and then send data on it.
const addr : Deno.NetAddr = {transport: "udp", port: 8125, hostname: "1.2.3.4"};
const socket = await Deno.listenDatagram({
port: 0,
transport: "udp",
hostname: "0.0.0.0"
});
socket.send(new Uint8Array(), addr);
It's easy when you know how ¯\_(ツ)_/¯
Related
Im running a function to ingest data to a Redis instance. However, I am encountering an issue where I can't seem to connect to the client.
Here is the part of the code where it connects to the server.
const redis = require('redis');
require('dotenv').config;
const REDISHOST = process.env.REDISHOST;
const REDISPORT = 6379;
const REDISAUTH = process.env.AUTHSTRING;
const client = redis.createClient({
port: REDISPORT,
host: REDISHOST,
password: REDISAUTH
});
await client.connect();
Here is the whole error message:
"Error: connect ECONNREFUSED 127.0.0.1:6379
at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1278:16)
at TCPConnectWrap.callbackTrampoline (node:internal/async_hooks:130:17)"
Any help would be appreciated. Thanks
I have tried using ioredis instead of redis but it shows a different error altogether.
It's trying to connect to localhost and Redis doesn't exist there. IF not given a hostname, this is the default behavior of Redis.
Looking at your code, this is probably because the REDISHOST environment variable isn't defined.
I am able to work with Truffle and Ganache-cli. Have deployed the contract and can play with that using truffle console
truffle(development)>
Voting.deployed().then(function(contractInstance)
{contractInstance.voteForCandidate('Rama').then(function(v)
{console.log(v)})})
undefined
truffle(development)> { tx:
'0xe4f8d00f7732c09df9e832bba0be9f37c3e2f594d3fbb8aba93fcb7faa0f441d',
receipt:
{ transactionHash:
'0xe4f8d00f7732c09df9e832bba0be9f37c3e2f594d3fbb8aba93fcb7faa0f441d',
transactionIndex: 0,
blockHash:
'0x639482c03dba071973c162668903ab98fb6ba4dbd8878e15ec7539b83f0e888f',
blockNumber: 10,
gasUsed: 28387,
cumulativeGasUsed: 28387,
contractAddress: null,
logs: [],
status: '0x01',
logsBloom: ... }
Now when i started a server using "npm run dev". Server started fine but is not connecting with the Blockchain
i am getting the error
Uncaught (in promise) Error: Contract has not been deployed to detected network (network/artifact mismatch)
This is my truffle.js
// Allows us to use ES6 in our migrations and tests.
require('babel-register')
module.exports = {
networks: {
development: {
host: '127.0.0.1',
port: 8545,
network_id: '*', // Match any network id
gas: 1470000
}
}
}
Can you please guide me how i can connect ?
Solve the issue.
issue was at currentProvider, i gave the url of ganache blockchain provider and it worked.
if (typeof web3 !== 'undefined') {
console.warn("Using web3 detected from external source like Metamask")
// Use Mist/MetaMask's provider
// window.web3 = new Web3(web3.currentProvider);
window.web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"));
} else {
console.warn("No web3 detected. Falling back to http://localhost:8545. You should remove this fallback when you deploy live, as it's inherently insecure. Consider switching to Metamask for development. More info here: http://truffleframework.com/tutorials/truffle-and-metamask");
// fallback - use your fallback strategy (local node / hosted node + in-dapp id mgmt / fail)
window.web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
}
In your truffle.js, change 8545 to 7545.
Or, in Ganache (GUI), click the gear in the upper right corner and change the port number from 7545 to 8545, then restart. With ganache-cli use -p 8545 option on startup to set 8545 as the port to listen on.
Either way, the mismatch seems to be the issue; these numbers should match. This is a common issue.
Also feel free to check out ethereum.stackexchange.com. If you want your question moved there, you can flag it and leave a message for a moderator to do that.
i try to run my first deepstream.io server from this link but i get this error :
error:
CONNECTION_ERROR | Error: listen EADDRINUSE 127.0.0.1:3003
PLUGIN_ERROR | connectionEndpoint wasn't initialised in time
f:\try\deep\node_modules\deepstream.io\src\utils\dependency-
initialiser.js:96
throw error
^
Error: connectionEndpoint wasn't initialised in time
at DependencyInitialiser._onTimeout
(f:\try\deep\node_modules\deepstream.io\src\utils\dependency-
initialiser.js:94:17)
at ontimeout (timers.js:386:14)
at tryOnTimeout (timers.js:250:5)
at Timer.listOnTimeout (timers.js:214:5)
and this is my code:
const DeepStreamServer = require("deepstream.io")
const C = DeepStreamServer.constants;
const server = new DeepStreamServer({
host:'localhost',
port:3003
})
server.start();
In deepstream 3.0 we released our HTTP endpoint, by default this runs alongside our websocket endpoint.
Because of this, passing the port option at the root level of the config no longer works (it overrides both the HTTP and websocket port options, as you can see in the screen capture provided, both endpoints are trying to start on the same port).
You can override each of these ports as follows:
const deepstream = require('deepstream.io')
const server = new deepstream({
connectionEndpoints: {
http: {
options: {
port: ...
}
},
websocket: {
options: {
port: ...
}
}
}
})
server.start()
Or you can define your config in a file and point to that while initialising deepstream[1].
[1] deepstream server configuration
One solution that i find is passing empty config object so inseted of :
const server = new DeepStreamServer({
host:'localhost',
port:3003
})
i'm just using this :
const server = new DeepStreamServer({})
and now everything work's well.
All the bellow is for Version 4.2.2 (last version by now)
I was having the same Port in use or config file not found errors. And i was using typescript and i didn't pay attention too to the output dir and build (which can be a problem when one use typescript and build). I was able to run the server in the end. And i had a lot of analysis.
I checked up the code source and i have seen how the config is loaded
const SUPPORTED_EXTENSIONS = ['.yml', '.yaml', '.json', '.js']
const DEFAULT_CONFIG_DIRS = [
path.join('.', 'conf', 'config'), path.join('..', 'conf', 'config'),
'/etc/deepstream/config', '/usr/local/etc/deepstream/config',
'/usr/local/etc/deepstream/conf/config',
]
DEFAULT_CONFIG_DIRS.push(path.join(process.argv[1], '..', 'conf', 'config'))
DEFAULT_CONFIG_DIRS.push(path.join(process.argv[1], '..', '..', 'conf', 'config'))
Also i tested different things and all. Here what i came up with:
First of all if we don't precise any parameter in the constructor. A config from the default directories will get to load. If there isn't then the server fail to run.
And one of the places where we can put a config is ./conf in the same folder as the server node script.
Secondly we can precise a config as a string path (parameter in the constructor). config.yml or one of the supported extensions. That will allow the server to load the server config + the permission.yml and users.yml configs. Which too are supposed to be in the same folder. If not in the same folder there load will fail, and therefor the permission plugin will not load. And so does the users config. And no fall back to default will happen.
Thirdly the supported extensions for the config files are: yml, yaml, json, js.
In nodejs context. If nothing precised. There is no fallback to some default config. The config need to be provided in one of the default folders, or by precising a path to it. Or by passing a config object. And all the optional options will default to some values if not provided ( a bit bellow there is an example that can show that ). Know however that precising an end point is very important and required.
To precise the path, we need to precise the path to the config.yml file (the server config) [example: path.join(__dirname, './conf/config.yml')]. Then from the same dir permission.yml and users.yml will be retrieved (the extension can be any of the supported one). We can not precise a path to a directory, it will fail.
We can precise the path to permission config or user config separatly within config.yaml as shown bellow:
# Permissioning example with default values for config-based permissioning
permission:
type: config
options:
path: ./permissions.yml
maxRuleIterations: 3
cacheEvacuationInterval: 60000
Finally we can pass an object to configure the server, or by passing null as a parameter and use .set methods (i didn't test the second method). For configuring the server we need to follow the same structure as the yml file. With sometimes a bit different naming. The typescript declaration files or types show us the way. With an editor like vscode. Even if we are not using typescript we can keep get the auto completion and type definitions.
And the simplest for equivalent to the previous version is :
const webSocketServer = new Deepstream({
connectionEndpoints: [
{
type: 'ws-websocket',
options: {
port: 6020,
host: '127.0.0.1',
urlPath: '/deepstream'
}
}
]
});
webSocketServer.start();
the above is the new syntax and way.
const server = new DeepStreamServer({
host:'localhost',
port:3003
})
^^^^^^^ is completely deprecated and not supported in version 4 (the doc is not updated).
So I've got this scenario where I have separate Web server and MySQL server, and I can only connect to the MySQL server from the web server.
So basically everytime I have to go like:
step 1: 'ssh -i ~/somecert.pem ubuntu#1.2.3.4'
step 2: 'mysqldump -u root -p'password' -h 6.7.8.9 database_name > output.sql'
I'm new to gulp and my aim was to create a task that could automate all this, so running one gulp task would automatically deliver me the SQL file.
This would make the developer life a lot easier since it would just take a command to download the latest db dump.
This is where I got so far (gulpfile.js):
////////////////////////////////////////////////////////////////////
// Run: 'gulp download-db' to get latest SQL dump from production //
// File will be put under the 'dumps' folder //
////////////////////////////////////////////////////////////////////
// Load stuff
'use strict'
var gulp = require('gulp')
var GulpSSH = require('gulp-ssh')
var fs = require('fs');
// Function to get home path
function getUserHome() {
return process.env.HOME || process.env.USERPROFILE;
}
var homepath = getUserHome();
///////////////////////////////////////
// SETTINGS (change if needed) //
///////////////////////////////////////
var config = {
// SSH connection
host: '1.2.3.4',
port: 22,
username: 'ubuntu',
//password: '1337p4ssw0rd', // Uncomment if needed
privateKey: fs.readFileSync( homepath + '/certs/somecert.pem'), // Uncomment if needed
// MySQL connection
db_host: 'localhost',
db_name: 'clients_db',
db_username: 'root',
db_password: 'dbp4ssw0rd',
}
////////////////////////////////////////////////
// Core script, don't need to touch from here //
////////////////////////////////////////////////
// Set up SSH connector
var gulpSSH = new GulpSSH({
ignoreErrors: true,
sshConfig: config
})
// Run the mysqldump
gulp.task('download-db', function(){
return gulpSSH
// runs the mysql dump
.exec(['mysqldump -u '+config.db_username+' -p\''+config.db_password+'\' -h '+config.db_host+' '+config.db_name+''], {filePath: 'dump.sql'})
// pipes output into local folder
.pipe(gulp.dest('dumps'))
})
// Run search/replace "optional"
SSH into the web server runs fine, but I have an issue when trying to get the mysqldump, I'm getting this message:
events.js:85
throw er; // Unhandled 'error' event
^
Error: Warning:
If I try the same mysqldump command manually from the server SSH, I get:
Warning: mysqldump: unknown variable 'loose-local-infile=1'
Followed by the correct mylsql dump info.
So I think this warning message is messing up my script, I would like to ignore warnings in cases like this, but don't know how to do it or if it's possible.
Also I read that using the password directly in the command line is not really good practice.
Ideally, I would like to have all the config vars loaded from another file, but this is my first gulp task and not really familiar with how I would do that.
Can someone with experience in Gulp orient me towards a good way of getting this thing done? Or do you think I shouldn't be using Gulp for this at all?
Thanks!
As I suspected, that warning message was preventing the gulp task from finalizing, I got rid of it by commenting the: loose-local-infile=1 From /etc/mysql/my.cnf
When using https.request with node.js v04.7, I get the following error:
Error: socket hang up
at CleartextStream.<anonymous> (http.js:1272:45)
at CleartextStream.emit (events.js:61:17)
at Array.<anonymous> (tls.js:617:22)
at EventEmitter._tickCallback (node.js:126:26)
Simplified code that will generate the error:
var https = require('https')
, fs = require('fs')
var options = {
host: 'localhost'
, port: 8000
, key: fs.readFileSync('../../test-key.pem')
, cert: fs.readFileSync('../../test-cert.pem')
}
// Set up server and start listening
https.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'})
res.end('success')
}).listen(options.port, options.host)
// Wait a second to let the server start up
setTimeout(function() {
var clientRequest = https.request(options, function(res) {
res.on('data', function (chunk) {
console.log('Called')
})
})
clientRequest.write('')
clientRequest.end()
}, 1000)
I get the error even with the server and client running on different node instances and have tested with port 8000, 3000, and 443 and with and without the SSL certificates. I do have libssl and libssl-dev on my Ubuntu machine.
Any ideas on what could be the cause?
In
https.createServer(function (req, res) {
you are missing options when you create the server, should be:
https.createServer(options, function (req, res) {
with your key and cert inside
I had a very similar problem where the response's end event never fired.
Adding this line fixed the problem:
// Hack to emit end on close because of a core bug that never fires end
response.on('close', function () {response.emit('end')});
I found an example of this in the request library mentioned in the previous answer.
Short answer: Use the the latest source code instead of the one you have. Store it where you will and then require it, you are good to go.
In the request 1.2.0 source code, main.js line 76, I see
http.createClient(options.uri.port, options.uri.hostname, options.uri.protocol === 'https:');
Looking at the http.js source code, I see
exports.createClient = function(port, host) {
var c = new Client();
c.port = port;
c.host = host;
return c;
};
It is requesting with 3 params but the actual function only has 2. The functionality is replaced with a separate module for https.
Looking at the latest main.js source code, I see dramatic changes. The most important is the addition of require('https').
It appears that request has been fixed but never re-released. Fortunately, the fix seems to work if you just copy manually from the raw view of the latest main.js source code and use it instead.
I had a similar problem and i think i got a fix. but then I have another socket problem.
See my solution here: http://groups.google.com/group/nodejs/browse_thread/thread/9189df2597aa199e/b83b16c08a051706?lnk=gst&q=hang+up#b83b16c08a051706
key point: use 0.4.8, http.request instead of http.createClient.
However, the new problem is, if I let the program running for long time, (I actually left the program running but no activity during weekend), then I will get socket hang up error when I send a request to http Server. (not even reach the http.request). I don't know if it is because of my code, or it is different problem with http Server