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iffishells — Fri, 02 Oct 2020 13:19:34 +0000

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iffishells — Fri, 02 Oct 2020 13:08:22 +0000

Installation of MongoDb on Ubuntu 18.04

iffishells — Sat, 22 Aug 2020 19:01:42 +0000

Introduction

ManngoDb is a free and open-source NOsql Document database used commonly in the modern web application on the internet.Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas.MongoDB is developed by MongoDB .

Pre-requisites

To follow this tutorial , you will need :

One Ubuntu 18.04
sudo non-root and firewall

step 1 :

Ubuntu official package repositories include an up to date version of mangodb ,which mean can install the necessary packages using

apt

first , update the packages list to have the most latest version of the repository listinggs :

sudo apt update -y

Now can install the Mangodb packages itself

sudo apt install -y mangodb

this command install several packages containing the latest stable version of MongoDb ,along with the helpfull tools.The Databse server is automatically started after installation

step 2 : checking service and DB

The installation process started MongoDb automatically,but lets verify the service is started and database is working or not.

first check the service status :

sudo systemctl status mongodb

you will see th output like this :

According to systemd , the Mongodb server is up and running .

we can verify this further by actually connecting to the dataabase server and executing diagnostic command .

Execute this command

mongo --eval 'db.runCommand([connnectionStatus:1})'

This will output the current database version , the server address and port , and the output of the status command :

A Value of 1 for the ok field in the response indicates that the server is working properly ,Next we 'll look how to manage the server is instance .

step 3 : Managin the MongoDb Service

MongoDb install as a systemd service , which means you that can manage it using standard systemd commands algonside all other system services in Ubuntu .

To verify status of the service type :

sudo systemctl status mongodb

You can stop the server anytime by typing :

sudo systemctl stop mongodb

To start the server when it is stopped , type :

sudo systemctl start mongodb

you can also restart the server with single command :

sudo systemctl restart mognodb

By default Mongodb is configured to start automatically with the server but if you can to disable it .

sudo systemctl disable mongodb

its easy to enable it again

sudo systemctl enable mongodb

Next , let's adjust the firewall setting for our Mongodb installation.

step 4 : adjusting the firewall (choice)

Assumming you have follow the above information for the installation for mogodb . if You intend to use the Mongodb server only locally with application running on the same server .this is the recommended and secure setting .However if you would like to be connect to your Mongodb server from the internet , you have to allow the incoming connection in ufw.

To Allow access to Mongodb on its default port 27017 from the everwhere , you could use .

sudo ufw allow 27017

However enabling internet access to MongoDb server on a default installation gives anyone unrestricted access to the database server and its data .

In Most cases Mongodb should be accessed only from the certain trusted locations , such as another server hosting an application . To achieve this task, you can allow access on MongoDb default port while specifying the IP address of another server that will be explicity allow to connect .

sudo ufw allow from other_server_IP/32 to any port 27017

you can verify the change in firewall setting with UFW :

sudo ufw status

if you have decided to allow only a certain IP address to connect to MongoDb server , the address of the allowed location will be instead of anywhere in the output.

you can find more advance firewall setting for restriction access to services in this community.

Even though the port is open MongoDb is currently only listening on the local address 127.0.0.1 . To allow remote connection , add your server publically-routable IP address to mongod.conf file.

Open the MongoDB Configuration file in your editor .

sudo vim /etc/mongodb.conf

Add your server IP address to the bindip value :

...
logappend=true

bind_ip = 127.0.0.1,your_server_ip
#port = 27017

...

Be sure to place a comma between the existing IP address and one you added . save te file . if you are using vim .

:wq!

Conclusion

This is all from my side if you are facing any problem you feel free to contact me.

Python Generator's and How to used them

iffishells — Sat, 22 Aug 2020 19:00:00 +0000

Agenda :

What are Generators?
Normal function vs Generator
Advantages of using Generator
Generator with loops
Generator with function
Generator Expression
Use Cases

what are Generator in Python?

Generators are basically function that return the traversable object or items. Generator do not produce the output at once time but Generator produce the output when we need them. Generator has lots of advantages some of them we will discuss Here :)

Advantages of using Generator

without the Generator in python producing the iterables is becomes very difficult and lenghty.
Generator easy to implement as they automatically implement is __iter()__ and __next()__ and stopiteration
They can also used pipeline a numbe of operations
can be used to produce an infinite number of items
Memory is saved as item is produced when we required unlike the in normal function. This facts becomes very important when you need to create a huge number of iterators.

Normal Function VS Generator Functions :

The difference between Normal and Generator function is only keyword return to yield. in the normal function return the output but in the Generator function yield return the object of list . using next() we get the number using the object . in the Normal function we call the function by his function name but in the generator function we called them by next().

Generator Function

#Genarator function
def func(a):
    yield a #change keyword return to yield
a = [1,2,3]
b=func(a)
next(b)

output --->
[1 , 2 , 3 ]

using next()

def myfunc(a):
    while a>=3:
        yield a
        a=a+1
b =  myfunc(a)
print(b)
next(b)

Normal function

def func(a):
    return a
a=[1,2,3]
func(a)

output -->
[1 ,2 , 3]

if you look the code above you will observer the return change into the yield but their functional completly opposite. yield return the object of the output using next() and we get it . Normal function called by his name but Generator function called by next(). you will realize after see the below image.

Generator with loops

In case you want to execute the same function at once, you can make use of the ‘for’ loop. This loop helps iterate over the objects and after all implementations it executes StopIteration.

def z():
    n=1
    yield n
    n=n+3
    yield n
for x in z():
    print(x)


output --->>
1 
4

Generator Expression :

You can also use the expression along with the loop for loop procedure iterators. this makes the generation iterables and easy to understand.

print("Generator Expression " , end= " :n ")
range_list=range(6)
ret =  (number for number in range_list)
print(c)
for ret_number in ret:
   print(ret_number)

Major Difference

As we said Generator makes the code pretty and readable and taking less memory and less code and as well as reduce the code . now its time to look first i will write the code without the generator and then with generators then you will see the difference and blessing of the generator in python.

Code without using Generator

class Nums:
    MAX = 4
    def __init__(self):
        self.current = 0
    def __iter__(self):
        return self
    def __next__(self):
        next_value = self.current
        if next_value >= self.MAX:
            raise StopIteration
        self.current += 1
        return next_value

Code with Generator

def func(var1):
    yield var1
    var1 +=1

Installation and Configuration of Apache Server and Mysql Phpmyadmin on Ubuntu 18 .04

iffishells — Sat, 22 Aug 2020 18:58:47 +0000

Agenda

What is Apache Server ?
Installation and Configuration of Apache2
What is Mysql-Server?
Installation and Configuration of Mysql-Server
What is Phpmyadmin?
Installation and Configuration of Phpmyadmin

What is Apache Server?

Apache is popular open-source , cross platform web Server that is , by number , the most popular web server in existence. Some high profile companies are using the Apache include IBM , CIsco , General Electric Adobe , VMWare ets . I don't do in more deeper but if want to now more deeply then you can read this post.

installation and configuration of apache2

first of all you will need to update the Ubuntu using following command .

sudo apt update

check it there if there need to upgrade then do using Following command .

sudo apt upgrade -y

for the installation of apache2 server you will need to run the following command .

sudo apt install apache2

Installing Apache2

Now your installation of Apache2 is complet but for checking i will cross check whether is it wrong or right .for this you run the following command .

sudo apache2ctl configtest

Output of this command is syntax Ok but if you see any error other then this you need to fix it using this way. In my case there is no error.

sudo apache2ctl configtest

In order to fixing the error if you are facing that you will need to add ServerName 127.0.0.1 on the last line in /etc/apache2/apache2.cong.

 sudo vim /etc/apache2/apache2.conf

sudo vim /etc/apache2/apache2.conf

Now check it again by following command .after the configuration you need to restart the apache server by following command.

sudo apache2ctl configtest

sudo systemctl restart apache2

What is Mysql Server?

Mysql server is a sql complaint server , in other word it is relational model database server . it is very popular it because its is free. It was developed by sun and moved to Oracle When Oracle acquired Sun. Oracle continued improving it . and further more the relational model is way to organize data in the table. where each table as a primary key(which is Unique) and rows can relate to each other using key. If you want to know Further you can read this Post.

Installation and Configuration of Mysql-Server

for the configuration of mysql Server you need to change the permission of localhost file . In Ubuntu we can change the permission using terminal or GUI. I will do using Terminal because it is to follow.In order to do this by run the following Command.

sudo chmod 777 /var/www/html/

Now it's time to install Mysql -server by following command.

sudo apt install mysql-server

sudo apt isntall mysql-server

In order to works on the mysql server you will need more utilities/packages . but Don't worry you can install by following command.

sudo apt install php

sudo apt install libapache2-mod-php

sudo apt install php-mysql

sudo apt install php-mcrypt

or you can run by one's time instead of one by one.but This is good practice to run one by one by knowing about the packages

sudo apt-get install php libapache2-mod-php php-mcrypt php-mysql

now Remaining part to config the files inside /etc/apache2/mods-enabled/dir.conf . you will need to add the index.php on the front of seconed line in that file. Don't worry! i 'll do on the live screenshot.

sudo vim /etc/apache2/mods-enabled/dir.conf

sudo vim /etc/apache2/mods-enabled/dir.conf

again restart the apache Server by following command .

sudo systemctl restart apache2

for establish the connection from localhost to the local files I need to do little coding in PHP and keep this file in the specific directory.

sudo vim /var/www/html/index.php
# Add the following code on the index.php
<?php
        phpinfo();
?>

What is Phpmyadmin?

Phpmyadmin is a free software tool that allow you to manage the mysql database of your websites. for example for Wordpress websites specifically , the MYSQL database stores all the data related to your posts , pages , comments , links and much more.if you want to know more abou the phpmyadmin you can read Post.

Installation and Configuration of Phpmyadmin

In order to install Phpmyadmin by run the following command ,

sudo apt install phpmyadmin

sudo apt install phpmyadmin

set the password whatever you want.Approximately all the installation is completed.But you need to some config with files .For that you need to add one line in a Specific files.

sudo vim /etc/apache2/apache2.conf
## add the line on the bottom 
include /etc/phpmyadmin/apache.conf
## restart the Apache Server Again
sudo systemctl restart apache2

Conclusion

First i installed the Apache Server and config the files then establish the connection to localhost from the local file like index.php and then install the phpmyadmin. if you facing the any error please let me know on the comments. Allah Hafiz