- HTTP vs HTTPS
HTTP (HyperText Transfer Protocol) • A protocol used for communication between a client (browser, app) and a server (website). • Data is sent in plain text → anyone intercepting it (like a hacker) can read it. Example: http://example.com
HTTPS (HyperText Transfer Protocol Secure) • Same protocol as HTTP but with encryption (SSL/TLS). • Data is encrypted before being transferred, so hackers cannot read sensitive info (like passwords, card numbers). • More secure, trusted by browsers (padlock 🔒 icon). Example: https://example.com
- API (Application Programming Interface) • An API is like a messenger between two systems → it allows software to talk to each other. • Example: When your app fetches weather data, it calls an API that returns the temperature, humidity, etc.
How APIs work with HTTP/HTTPS • APIs usually use HTTP/HTTPS for communication.
Example request to an API (over HTTPS): https://api.openweathermap.org/data/2.5/weather?q=London&appid=API_KEY
Here: • https:// → secure communication. • api.openweathermap.org → API server. • /data/2.5/weather → endpoint (specific data you want). • q=London&appid=API_KEY → query parameters.
Types of APIs 1. REST API → uses HTTP methods (GET, POST, PUT, DELETE). 2. SOAP API → XML-based, heavier than REST. 3. GraphQL API → query only the data you need.
- Intro to JSON What is JSON?
JSON stands for JavaScript Object Notation. It’s a lightweight format for storing and sharing data between systems. • Human-readable (easy to understand). • Language-independent (used by almost all programming languages). • Based on key-value pairs.
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Basic JSON Example { "name": "John", "age": 22, "isStudent": true, "skills": ["JavaScript", "HTML", "CSS"], "address": { "city": "Moscow", "country": "Russia" } } 🔎 Explanation: • Curly braces {} → JSON object. • Keys ("name", "age", "skills") must always be in double quotes " ". • Values can be: • String → "Mobassir" • Number → 22 • Boolean → true / false • Array → ["JavaScript", "HTML", "CSS"] • Object → another { ... }
Why JSON is Important? • Used in APIs to send/receive data. • Easy to convert between JavaScript objects and JSON strings.
---- Convert Object → JSON string ----
const person = { name: "Mobassir", age: 22 }; const jsonString = JSON.stringify(person); console.log(jsonString); // Output: {"name":"Mobassir","age":22}
----- Convert JSON string → Object -----
const jsonData = '{"name":"Mobassir","age":22}'; const obj = JSON.parse(jsonData); console.log(obj.name); // Mobassir console.log(obj.age); // 22