Notes

Flask

Flask is a web framework for Python. It facilitates the creation of web apps (dynamic web pages). Run Flask Flask comes with its own server for debugging purposes, which can be started with: flask run Folder Structure app.py # main code requirements.txt # required libraries static/ # files that never change templates/ # dynamic files “Hello, name” — Example App templates/index.html <!DOCTYPE html> <html lang="en"> <head> <meta name = "viewport" content="initial-scale=1, width=device-width"> <title>Hello</title> </head> <body> hello, {{ name_placeholder }}  </body> </html> app.py http://website.domain/?name=Trude ...

HTML

HTML is a markup language: The foundation of every website, as it structures content and provides information such as text, images and other media to the browser. Hello World HTML is not a programming language, only formatting to write a document as. The following ‘code’ is valid HTML. Hello, world. A more complete solution, however, would be to define a structure for the document. <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>Document</title> </head> <body> <p>Hello, world.</p> </body> </html> HTML uses tags to define a hierarchy. The <head> tag defines metadata for the site, such as the page’s title, encoding types, and any external resources. The <body> tag is the content itself: any paragraphs (<p>), images, forms and scripts, to name a few. ...

HTTP [CURL]

HTTP HTTP (Hypertext Transfer Protocol) is a communication protocol used to send messages between the client and server, mainly used for the web. It’s stateless, meaning each request is independent, which is why web browsers often use cookies to save state. Request Structure Request Line: Method, URI, HTTP version (e.g., GET /index.html HTTP/1.1). Headers: Metadata about the request. Body (Optional): Data for POST, PUT, PATCH requests. Response Structure Status Line: HTTP version, status code, reason phrase (e.g., HTTP/1.1 200 OK). Headers: Metadata about the response. Body (Optional): Response data (HTML, JSON, etc.). Methods GET: Retrieve a resource. Should only retrieve data and not have side effects. POST: Submit data to be processed. PUT: Replace a resource. DELETE: Delete a resource. PATCH: Partially modify a resource. HEAD: Retrieve headers only. OPTIONS: Describe communication options. HTTP Headers HTTP headers are key-value pairs providing additional information about requests and responses. ...

HTTPS and SSL Certificates

HTTP(s) The http protocol sends data as plaintext, which is an issue when sharing sensitive data such as messages and passwords. https uses TLS to encrypt sensitive traffic between the client and server, creating a secure connection between the two. TLS TLS is a form of encryption, used to secure HTTPS connections. TLS replaces SSL (a deprecated protocol), however, the term SSL is still used often. Handshake To establish a secure connection, a ‘handshake’ is performed between the client and the server. ...

IRC

The IRC Protocol IRC is a very simple communication protocol that allows users to chat in real time. IRC is very lightweight, but does not encrypt messages by default. Using IRC Server To be able to communicate, users must connect to a server. Each server has its own rules, bots and commands. The IRC protocol itself does not implement encryption, however, SSL Certificates can be used to establish a secure connection with the server. Every message sent can be read by the server, including private messages between users. Separate IRC instances can communicate. This concept is often called server federation. This allows for users in different servers to send messages to each other. ...