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Articles on Trending Technologies
Technical articles with clear explanations and examples
Redirecting requests in Node.js
Now we have an App.js file shown below, we want to redirect the user back to ‘/’ once user name is received by node server. We will store user name in a file named username.txtInitial App.js file −const http = require('http'); const server = http.createServer((req, res)=>{ const url = req.url; if(url === '/'){ res.write(''); res.write(' Hello TutorialsPoint '); res.write(' Submit '); res.write(''); return res.end(); } res.write(''); res.write(' Hello TutorialsPoint '); ...
Read MoreRouting requests in Node.js
Routing http requests is important because we want to execute different business rules based on request url and the responses will be different for each routes.Earlier we saw, we can get the url by request.url in node. Simple example of user name input with routes is shown below −const http = require('http'); const server = http.createServer((req, res)=>{ const url = req.url; if(url === '/'){ res.write(''); res.write(' Hello TutorialsPoint '); res.write(' Submit '); res.write(''); ...
Read MoreSending response back from Node.js server to browser
App.js −const http = require('http'); const server = http.createServer((req, res)=>{ console.log(req.url, req.method, req. headers); }); server.listen(3000);As shown in above example code, we have request and response parameter object as an argument in createServer method.Response (res) object will be used to send back data to client. It has many properties, some are explained below −res.setHeader(‘Content-Type’, ‘text/html’); this line will set the format of response content o text/html.How to send html content from node.jswrite() function method on response object can be used to send multiple lines of html code like below.res.write(‘’); res.write(‘ Hello TutorialsPoint ’); res.write(‘ Hello Tutorials ...
Read MoreUnderstanding the http requests in Node
App.jsconst http = require('http'); const server = http.createServer((req, res)=>{ console.log(req); }); server.listen(3000);Run it with command: node App.jsWe can see what is inside a request object by opening a browser and navigating to localhost:3000There is lots of information which will get printed on console window. We will see some important properties.Identifying the url from where request came, request method type and headers in request is important.Headers will give us information on host and browser type , accepted response by host etc. Request method can be of any http method type like GET, POST, PUT, DELETE etc.const http = require('http'); const ...
Read MoreUnderstanding the Node lifecycle and event loop in node.js
Simple http server in node.js will register an event loop which will keep on listening for http requests.Execution of file containing code for creation of server will work as shown below −node App.js => Start executing script => Code parsing, Register events and functions => event loop=> keeps on running as long as event are registered.This is the single threaded event driven approach of the node.js. For accessing and updating of values in database also works using the event driven approach. Even though it’s a single threaded, it can handle multiple requests at a time due to its speed of ...
Read MoreCreating a Node.js server
The mostly used core modules of Node.js are −http − used to launch a simple server, send requestshttps − used to launch a ssl secured http serverpath − used to handle path based on operating systemfs − It’s a file system handling moduleos − its used for os related operationsLets build a simple http server using Node.js −Create a javascript file App.js (name it as you like) in an editor like visual studio code .App.jsconst http = require(‘http’); function reqListener(req, res){ console.log(‘Hello’); } const server = http.createServer(reqListener); server.listen(3000);ExplainationWe used const keyword instead of var or let to import a ...
Read MoreHow to get the port number of the processes using PowerShell?
When we use Get-Process cmdlet in PowerShell, it doesn’t have properties to get Port number the processes use. So here we will write a function that will provide us the ports number associated with the processes.There is one windows command NETSTAT which provides the Port number and the associated process ID but doesn’t provide the process name. We have Get-Process command which provides the process name and the PID (Process ID) so we can write a program that can associate both the commands and we can retrieve the process ID, local address, remote address, and if the state of the ...
Read MoreExplain ValueFromPipeline in PowerShell Advanced Functions.
Consider the below example, we have created Advanced function to get the specific process information like Process Name, Process ID (PID), Start Time, Responding status, etc.function Get-ProcessInformation{ [cmdletbinding()] param( [Parameter(Mandatory=$True)] [string[]]$name ) Begin{ Write-Verbose "Program started" } Process{ Write-Verbose "Extracting Process Inforamtion" Get-Process $name | Select Name, ID, StartTime, Responding | ft - AutoSize } End{ Write-Verbose "Function ends here" } }Above is the advanced function example. When we run the above command, it will give ...
Read MoreExplain AllowEmptyString() and AllowEmptyCollection() in PowerShell Advanced Function.
AllowEmptyString() attribute works with the string variable and AllowEmptyCollection() work with the array of different data types (Collection).Consider the example below. Here, we are using a mandatory variable $name which is a string and $stringarray which is a string array.function print_String{ [cmdletbinding()] param( [parameter(Mandatory=$True)] [string]$name, ) Write-Output "Writing a single string" $name }If we get the output of the above variable it will generate an error below.PS C:\WINDOWS\system32> print_String cmdlet print_String at command pipeline position 1 Supply values for the following parameters: name: print_String : Cannot bind argument to ...
Read MoreExplain the Mandatory Attribute in PowerShell Advanced Function.
We have an example of PowerShell advanced function below and we will try to understand how mandatory parameter works.function math_Operation{ [cmdletbinding()] param([int]$val1, [int]$val2) Write-Host "Multiply : $($val1*$val2)" Write-Host "Addition : $($val1+$val2)" Write-Host "Subtraction : $($val1-$val2)" Write-Host "Divide : $($val1+$val2)" }When you execute the above example and don’t supply values then the script won’t ask you for the values, by default it will take the values and execute the program. See the execution below.PS C:\WINDOWS\system32> math_Operation Multiply : 0 Addition : 0 Subtraction : 0 Divide : 0Even if you have mentioned two variables ($val1, ...
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