I have been following a tutorial on setting up REST APIs in Node, using Express for an app that accesses an existing MariaDB database. My version only needs to read data and I have the DB co-located with the Node application (same host).
My goal for this entry-level example is to just access the data, using static SQL, so I can see it rendered in the web page by the JSON pritifier.
[Next, I want to present the data in a table (EJS?). Later, when I can get that to work, I'll add form controls (React?) to let a user specify start and end date bounds for the SQL query. Finally I'll aim to render the data as a line graph (D3js).]
The tutorial runs the web server successfully (it returns 'OK' on the base URL), but when I go to URL/solarData it tries an async function to getMultiple rows from the DB, it responds:
Bind parameters must not contain undefined. To pass SQL NULL specify JS null TypeError: Bind parameters must not contain undefined. To pass SQL NULL specify JS null
at /SunnyData/solarViz/node_modules/mysql2/lib/connection.js:628:17
at Array.forEach (<anonymous>)
at Connection.execute (/SunnyData/solarViz/node_modules/mysql2/lib/connection.js:620:22)
at /SunnyData/solarViz/node_modules/mysql2/promise.js:120:11
at new Promise (<anonymous>)
at PromiseConnection.execute (/SunnyData/solarViz/node_modules/mysql2/promise.js:117:12)
at Object.query (/SunnyData/solarViz/services/db.js:6:40)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
at async Object.getMultiple (/SunnyData/solarViz/services/solarData.js:7:16)
at async /SunnyData/solarViz/routes/solarData.js:8:14
app.js:61
./app.js
const express = require('express');
const app = express();
const port = process.env.PORT || 3800;
const solarDataRouter = require('./routes/solarData');
app.use(express.json());
app.use(
express.urlencoded({
extended: true,
})
);
app.get('/', (req, res) => {
res.json({'message': 'ok'});
})
app.use('/solarData', solarDataRouter);
/* Error handler middleware */
app.use((err, req, res, next) => {
const statusCode = err.statusCode || 500;
console.error(err.message, err.stack);
res.status(statusCode).json({'message': err.message});
return;
});
app.listen(port, () => {
console.log(`Example app listening at http://localhost:${port}`)
});
./routes/solarData.js
const express = require('express');
const router = express.Router();
const solarData = require('../services/solarData');
/* GET solar data. */
router.get('/', async function(req, res, next) {
try {
res.json(await solarData.getMultiple(req.query.page));
} catch (err) {
console.error(`Error while getting solar data `, err.message);
next(err);
}
});
module.exports = router;
./config.js
const env = process.env;
const config = {
db: {
host: env.SUNNY_HOST,
user: env.SUNNY_USER,
password: env.SUNNY_PW,
database: env.SUNNY_DB,
},
listPerPage: env.LIST_PER_PAGE,
};
module.exports = config;
./services/solarData.js
const db = require('./db');
const helper = require('../helper');
const config = require('../config');
async function getMultiple(page = 1){
const offset = helper.getOffset(page, config.listPerPage);
const rows = await db.query(
`SELECT * FROM DTP LIMIT ?,?`, [offset, config.listPerPage]
);
const data = helper.emptyOrRows(rows);
const meta = {page};
return {
data,
meta
}
}
module.exports.getMultiple = getMultiple;
./services/db.js
const mysql = require('mysql2/promise');
const config = require('../config');
async function query(sql, params) {
const connection = await mysql.createConnection(config.db);
const [results, ] = await connection.execute(sql, params);
return results;
}
module.exports = {
query
}
I've left out the ./helper.js
Everything runs fine until I direct the webpage to /solarData. At that point I get the Debug Console (vscode) mentioned up-front
Searching seems to point at a mysql2 shortcoming/bug but not at a practical solution
If you respond, please describe the 'bind' mechanism, as I'm not sure what's going on.
Hope I've put enough info in. Please ask if I need to add anything else.
The error says
Bind parameters must not contain undefined.
It means that in the file ./services/solarData.js on the line
const rows = await db.query(
`SELECT * FROM DTP LIMIT ?,?`, [offset, config.listPerPage]
);
Some of the 2 variables is undefined, you need to check offset and config.listPerPage to be defined.
Just use
console.log('offset: ' + offset)
console.log('listPerPage: ' + config.listPerPage)
and you will find out what is undefined in your case
Can we get the variables in the query string in Node.js just like we get them in $_GET in PHP?
I know that in Node.js we can get the URL in the request. Is there a method to get the query string parameters?
Since you've mentioned Express.js in your tags, here is an Express-specific answer: use req.query. E.g.
var express = require('express');
var app = express();
app.get('/', function(req, res){
res.send('id: ' + req.query.id);
});
app.listen(3000);
In Express it's already done for you and you can simply use req.query for that:
var id = req.query.id; // $_GET["id"]
Otherwise, in NodeJS, you can access req.url and the builtin url module to url.parse it manually:
var url = require('url');
var url_parts = url.parse(request.url, true);
var query = url_parts.query;
In Express, use req.query.
req.params only gets the route parameters, not the query string parameters. See the express or sails documentation:
(req.params) Checks route params, ex: /user/:id
(req.query) Checks query string params, ex: ?id=12 Checks urlencoded body params
(req.body), ex: id=12 To utilize urlencoded request bodies, req.body should be an object. This can be done by using the _express.bodyParser middleware.
That said, most of the time, you want to get the value of a parameter irrespective of its source. In that case, use req.param('foo'). Note that this has been deprecated as of Express 4: http://expressjs.com/en/4x/api.html#req.param
The value of the parameter will be returned whether the variable was in the route parameters, query string, or the encoded request body.
Side note- if you're aiming to get the intersection of all three types of request parameters (similar to PHP's $_REQUEST), you just need to merge the parameters together-- here's how I set it up in Sails. Keep in mind that the path/route parameters object (req.params) has array properties, so order matters (although this may change in Express 4)
For Express.js you want to do req.params:
app.get('/user/:id', function(req, res) {
res.send('user' + req.params.id);
});
I learned from the other answers and decided to use this code throughout my site:
var query = require('url').parse(req.url,true).query;
Then you can just call
var id = query.id;
var option = query.option;
where the URL for get should be
/path/filename?id=123&option=456
//get query¶ms in express
//etc. example.com/user/000000?sex=female
app.get('/user/:id', function(req, res) {
const query = req.query;// query = {sex:"female"}
const params = req.params; //params = {id:"000000"}
})
If you are using ES6 and Express, try this destructuring approach:
const {id, since, fields, anotherField} = request.query;
In context:
const express = require('express');
const app = express();
app.get('/', function(req, res){
const {id, since, fields, anotherField} = req.query;
});
app.listen(3000);
You can use default values with destructuring too:
// sample request for testing
const req = {
query: {
id: '123',
fields: ['a', 'b', 'c']
}
}
const {
id,
since = new Date().toString(),
fields = ['x'],
anotherField = 'default'
} = req.query;
console.log(id, since, fields, anotherField)
There are 2 ways to pass parameters via GET method
Method 1 :
The MVC approach where you pass the parameters like /routename/:paramname
In this case you can use req.params.paramname to get the parameter value For Example refer below code where I am expecting Id as a param
link could be like : http://myhost.com/items/23
var express = require('express');
var app = express();
app.get("items/:id", function(req, res) {
var id = req.params.id;
//further operations to perform
});
app.listen(3000);
Method 2 :
General Approach : Passing variables as query string using '?' operator
For Example refer below code where I am expecting Id as a query parameter
link could be like : http://myhost.com/items?id=23
var express = require('express');
var app = express();
app.get("/items", function(req, res) {
var id = req.query.id;
//further operations to perform
});
app.listen(3000);
You should be able to do something like this:
var http = require('http');
var url = require('url');
http.createServer(function(req,res){
var url_parts = url.parse(req.url, true);
var query = url_parts.query;
console.log(query); //{Object}
res.end("End")
})
UPDATE 4 May 2014
Old answer preserved here: https://gist.github.com/stefek99/b10ed037d2a4a323d638
1) Install express: npm install express
app.js
var express = require('express');
var app = express();
app.get('/endpoint', function(request, response) {
var id = request.query.id;
response.end("I have received the ID: " + id);
});
app.listen(3000);
console.log("node express app started at http://localhost:3000");
2) Run the app: node app.js
3) Visit in the browser: http://localhost:3000/endpoint?id=something
I have received the ID: something
(many things have changed since my answer and I believe it is worth keeping things up to date)
Express specific simple ways to fetch
query strings(after ?) such as https://...?user=abc&id=123
var express = require('express');
var app = express();
app.get('/', function(req, res){
res.send('id: ' + req.query.id);
});
app.listen(3000);
query params such as https://.../get/users/:id
var express = require('express');
var app = express();
app.get('/get/users/:id', function(req, res){
res.send('id: ' + req.params.id);
});
app.listen(3000);
A small Node.js HTTP server listening on port 9080, parsing GET or POST data and sending it back to the client as part of the response is:
var sys = require('sys'),
url = require('url'),
http = require('http'),
qs = require('querystring');
var server = http.createServer(
function (request, response) {
if (request.method == 'POST') {
var body = '';
request.on('data', function (data) {
body += data;
});
request.on('end',function() {
var POST = qs.parse(body);
//console.log(POST);
response.writeHead( 200 );
response.write( JSON.stringify( POST ) );
response.end();
});
}
else if(request.method == 'GET') {
var url_parts = url.parse(request.url,true);
//console.log(url_parts.query);
response.writeHead( 200 );
response.write( JSON.stringify( url_parts.query ) );
response.end();
}
}
);
server.listen(9080);
Save it as parse.js, and run it on the console by entering "node parse.js".
Whitequark responded nicely. But with the current versions of Node.js and Express.js it requires one more line. Make sure to add the 'require http' (second line). I've posted a fuller example here that shows how this call can work. Once running, type http://localhost:8080/?name=abel&fruit=apple in your browser, and you will get a cool response based on the code.
var express = require('express');
var http = require('http');
var app = express();
app.configure(function(){
app.set('port', 8080);
});
app.get('/', function(req, res){
res.writeHead(200, {'content-type': 'text/plain'});
res.write('name: ' + req.query.name + '\n');
res.write('fruit: ' + req.query.fruit + '\n');
res.write('query: ' + req.query + '\n');
queryStuff = JSON.stringify(req.query);
res.end('That\'s all folks' + '\n' + queryStuff);
});
http.createServer(app).listen(app.get('port'), function(){
console.log("Express server listening on port " + app.get('port'));
})
It is so simple:
Example URL:
http://stackoverflow.com:3000/activate_accountid=3&activatekey=$2a$08$jvGevXUOvYxKsiBt.PpMs.zgzD4C/wwTsvjzfUrqLrgS3zXJVfVRK
You can print all the values of query string by using:
console.log("All query strings: " + JSON.stringify(req.query));
Output
All query strings : { "id":"3","activatekey":"$2a$08$jvGevXUOvYxKsiBt.PpMs.zgzD4C/wwTsvjz
fUrqLrgS3zXJVfVRK"}
To print specific:
console.log("activatekey: " + req.query.activatekey);
Output
activatekey: $2a$08$jvGevXUOvYxKsiBt.PpMs.zgzD4C/wwTsvjzfUrqLrgS3zXJVfVRK
You can use
request.query.<varible-name>;
You can use with express ^4.15.4:
var express = require('express'),
router = express.Router();
router.get('/', function (req, res, next) {
console.log(req.query);
});
Hope this helps.
In express.js you can get it pretty easy, all you need to do in your controller function is:
app.get('/', (req, res, next) => {
const {id} = req.query;
// rest of your code here...
})
And that's all, assuming you are using es6 syntax.
PD. {id} stands for Object destructuring, a new es6 feature.
app.get('/user/:id', function(req, res) {
res.send('user' + req.params.id);
});
You can use this or you can try body-parser for parsing special element from the request parameters.
consider this url -> /api/endpoint/:id?name=sahil
here id is param where as name is query. You can get this value in nodejs like this
app.get('/api/endpoint/:id', (req, res) => {
const name = req.query.name; // query
const id = req.params.id //params
});
There are many answers here regarding accessing the query using request.query however, none have mentioned its type quirk. The query string type can be either a string or an array, and this type is controlled by the user.
For instance using the following code:
const express = require("express");
const app = express();
app.get("/", function (req, res) {
res.send(`Your name is ${(req.query.name || "").length} characters long`);
});
app.listen(3000);
Requesting /?name=bob will return Your name is 3 characters long but requesting /?name=bob&name=jane will return Your name is 2 characters long because the parameter is now an array ['bob', 'jane'].
Express offers 2 query parsers: simple and extended, both will give you either a string or an array. Rather than checking a method for possible side effects or validating types, I personally think you should override the parser to have a consistent type: all arrays or all strings.
const express = require("express");
const app = express();
const querystring = require("querystring");
// if asArray=false only the first item with the same name will be returned
// if asArray=true all items will be returned as an array (even if they are a single item)
const asArray = false;
app.set("query parser", (qs) => {
const parsed = querystring.parse(qs);
return Object.entries(parsed).reduce((previous, [key, value]) => {
const isArray = Array.isArray(value);
if (!asArray && isArray) {
value = value[0];
} else if (asArray && !isArray) {
value = [value];
}
previous[key] = value;
return previous;
}, {});
});
app.get("/", function (req, res) {
res.send(`Your name is ${(req.query.name || "").length} characters long`);
});
app.listen(3000);
So, there are two ways in which this "id" can be received:
1) using params: the code params will look something like :
Say we have an array,
const courses = [{
id: 1,
name: 'Mathematics'
},
{
id: 2,
name: 'History'
}
];
Then for params we can do something like:
app.get('/api/posts/:id',(req,res)=>{
const course = courses.find(o=>o.id == (req.params.id))
res.send(course);
});
2) Another method is to use query parameters.
so the url will look something like ".....\api\xyz?id=1" where "?id=1" is the query part. In this case we can do something like:
app.get('/api/posts',(req,res)=>{
const course = courses.find(o=>o.id == (req.query.id))
res.send(course);
});
In case you want to avoid express, use this example:
var http = require('http');
const url = require('url');
function func111(req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
var q = url.parse(req.url, true);
res.end("9999999>>> " + q.query['user_name']);
}
http.createServer(func111).listen(3000);
usage:
curl http://localhost:3000?user_name=user1
by yl
you can use url module to collect parameters by using url.parse
var url = require('url');
var url_data = url.parse(request.url, true);
var query = url_data.query;
In expressjs it's done by,
var id = req.query.id;
Eg:
var express = require('express');
var app = express();
app.get('/login', function (req, res, next) {
console.log(req.query);
console.log(req.query.id); //Give parameter id
});
If you ever need to send GET request to an IP as well as a Domain (Other answers did not mention you can specify a port variable), you can make use of this function:
function getCode(host, port, path, queryString) {
console.log("(" + host + ":" + port + path + ")" + "Running httpHelper.getCode()")
// Construct url and query string
const requestUrl = url.parse(url.format({
protocol: 'http',
hostname: host,
pathname: path,
port: port,
query: queryString
}));
console.log("(" + host + path + ")" + "Sending GET request")
// Send request
console.log(url.format(requestUrl))
http.get(url.format(requestUrl), (resp) => {
let data = '';
// A chunk of data has been received.
resp.on('data', (chunk) => {
console.log("GET chunk: " + chunk);
data += chunk;
});
// The whole response has been received. Print out the result.
resp.on('end', () => {
console.log("GET end of response: " + data);
});
}).on("error", (err) => {
console.log("GET Error: " + err);
});
}
Don't miss requiring modules at the top of your file:
http = require("http");
url = require('url')
Also bare in mind that you may use https module for communicating over secured domains and ssl. so these two lines would change:
https = require("https");
...
https.get(url.format(requestUrl), (resp) => { ......
do like me
npm query-string
import queryString from "query-string";
export interface QueryUrl {
limit?: number;
range?: string;
page?: number;
filed?: string;
embody?: string;
q?: string | object;
order?: number;
sort?: string;
}
let parseUri: QueryUrl = queryString.parse(uri.query);
I am using MEANJS 0.6.0 with express#4.16, it's good
Client:
Controller:
var input = { keyword: vm.keyword };
ProductAPi.getOrder(input)
services:
this.getOrder = function (input) {return $http.get('/api/order', { params: input });};
Server
routes
app.route('/api/order').get(products.order);
controller
exports.order = function (req, res) {
var keyword = req.query.keyword
...