The document provides an overview of various communication methods in a cloud kitchen system, detailing their applications, data flow diagram (DFD) representations, and security considerations. Methods include HTTP/HTTPS, AJAX, WebSockets, APIs, database communication, email/SMS, push notifications, and inter-process communication (IPC), each essential for different interactions within the system. Emphasis is placed on using secure channels and encryption to protect sensitive data during these communications.

1. Communication Methods in a
Cloud Kitchen System
A detailed overview of various
communication methods and their
representations in a Data Flow
Diagram (DFD)

2. HTTP/HTTPS (Web
Communication)
• - Use: Communication between the user's
browser and the web server.
• - DFD Representation: Arrows from the user to
the web server and back, indicating requests
(GET, POST) and responses.
• - Security: HTTPS should be used to encrypt
data, ensuring secure communication.

3. AJAX (Asynchronous JavaScript and
XML)
• - Use: For dynamic, asynchronous
communication between the client and server
without reloading the entire web page.
• - DFD Representation: Indicate AJAX calls for
operations like fetching menu items, updating
order status, etc.
• - Security: Same as HTTP/HTTPS, ensure these
requests are encrypted.

4. WebSockets
• - Use: Real-time communication, useful for
instant updates like order status changes.
• - DFD Representation: A bidirectional arrow
between the client and server, indicating
continuous communication.
• - Security: Secure WebSocket (wss://) should
be used for encryption.

5. APIs (Application Programming
Interfaces)
• - Use: Interaction between different parts of
the system or with external services (e.g.,
payment gateways, third-party delivery
services).
• - DFD Representation: Arrows indicating API
calls to and from external services.
• - Security: Ensure API requests and responses
are encrypted and authenticated.

6. Database Communication
(SQL/NoSQL)
• - Use: Interaction between the application
server and the database.
• - DFD Representation: Arrows between the
server processes (PHP scripts) and the
database, showing queries and results.
• - Security: Use secure connections (SSL/TLS)
for database interactions, especially for
sensitive data.

7. Email and SMS
• - Use: For notifications, confirmations, and
alerts (e.g., order confirmation, delivery
updates).
• - DFD Representation: Arrows from server
processes to email/SMS services.
• - Security: Ensure that sensitive information is
not sent through unsecured channels; use
encryption where possible.

8. Push Notifications
• - Use: Sending real-time updates to users via
their web browsers or mobile devices.
• - DFD Representation: Arrows indicating
communication from the server to the user's
device for push notifications.
• - Security: Use secure channels and ensure
proper user authentication for sensitive
updates.

9. Inter-Process Communication (IPC)
• - Use: Communication between different
processes within the server (e.g.,
microservices).
• - DFD Representation: Arrows between server-
side components or microservices.
• - Security: Secure the communication
channels within the server infrastructure.