Week 5 Class1

Android App1 Using ChatGPT API

Let's build OCR + ChatGPT API App

My team won $350 for a hackathon at HackEmory

Topics for Today

1. What is REST API & SERVER -> done

2. Setting up ChatGPT API and tutorial -> done

3. Python intro + API setup -> done

4. Flask RestAPI Setup -> done

6. Hosting on Cloud (Azure)

Camera setup

5. Retrofit Android ->

later week 6 next app +

. Async vs Sync Operations :

7. Coroutines

Live Demo first

Remember we have bounty program fix bug and get Rs. 1000 ($15)

Problems

1. Documentation are not the best

Java -> Kotlin (digitalocean, medium, stackoverflow)

2. You have to go on StackOverflow

3. Don't be shy to ask

4. Ask ChatGPT

What is a server?

Any computer giving services with other computers!

Sharing is caring

REST API

A REST API (Representational State Transfer Application Programming Interface) is a set of rules and conventions for building and interacting with web services.

CRUD Operations

Create: Post

Read: Get

Update: Put

Delete: Delete

Client Server errors

200 -> Success

400s -> Client Side error

500 -> Server Side error

Python 3 Flask Server

Google OCR Kit:

https://developers.google.com/ml-kit/vision/text-recognition/v2/android

Try to integrate

if Stuck you have:

1. ChatGPT

2. Google Dcoumentationa

3. Stack overflow

4. Discord community

IaaS vs PaaS vs SaaS

Gmail

App -> Facebook

I think in most clouds:
IAAS -> gives you a machine(VM/server) with a OS at minimum
PaaS-> service gives you IaaS + a runtime environment to host your apps in
SaaS->gives you IaaS+PaaS+finished app

Elastic Search

IND / CHINA / USA

Default ->

IaaS

Azure / GcP/ AWS Vms

Manage your server on your own on someone else computer

PaaS

AWS Lamda + Azure App Service + Google App Engine

Give a Python file it will do the magic

SaaS -> ready made apps

like Play store apps

Apache -> Web server

Conductor that allows you to host server on a web app and manage the traffic

load balancing

Reverse Proxy

Conductor for trains

80 / 443

maps. google

madeby.google

images..google

same port for all

before server so called reverse proxy

Proxy example

banned websites

Load Balance vs Reverse Proxy

Load balancer on a different server to manage load between severs

but Reverse Proxy is part of 1 Server

Nginx setup

apt-get install nginx

nano /etc/nginx/nginx.conf

Retstart ->sudo nginx -s reload

systemctl reload nginx

https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-ubuntu-20-04

nginx conf file

Text

My Nginx file

events {
        worker_connections 1024;
}
http{
    server {
        listen 80;
        server_name chatgptvm2.eastus.cloudapp.azure.com;
        # access_log /var/log/nginx/access.log;
        # error_log /var/log/nginx/error.log;

        location / {
            proxy_pass http://127.0.0.1:5000/;
            proxy_set_header Host $host;
            # proxy_set_header X-Real-IP $remote_addr;
            # proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            #proxy_set_header X-Forwarded-Proto $scheme;
        }
    }
}

Reverse Proxy

run htop or acivity manager

You are not using complete CPU power

Run Multiple processes in one server

Steps to deploy

1. Create VM

2. Open the right ports on Azure or any cloud (80 / 443)

3. copy code python3 code of flask server

4. Make sure it never turns off -> docker / pm2

5. Ngnix / Apache2 for reverse proxy

Network capture via wifi router

Cert Management

without cert on port 80

Make encrypted using TLS cert

cert installation steps:

https://certbot.eff.org/instructions?ws=nginx&os=ubuntufocal