HTTP Client / API Call

 

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🌐 HTTP CLIENT – API CALL (net/http)

আমি ধরে নিচ্ছি তুমি API call করবে যেমন:

https://jsonplaceholder.typicode.com

(learning-এর জন্য খুব common test API)

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✅ 1️⃣ GET Request (Client Side)

📌 কাজ

Server থেকে data আনা

📄 Full Code – GET

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	resp, err := http.Get("https://jsonplaceholder.typicode.com/posts/1")
	if err != nil {
		fmt.Println("Error:", err)
		return
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Println("Read Error:", err)
		return
	}

	fmt.Println("Status Code:", resp.StatusCode)
	fmt.Println("Response Body:")
	fmt.Println(string(body))
}

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✅ 2️⃣ POST Request (Client Side)

📌 কাজ

Server-এ নতুন data পাঠানো

📄 Full Code – POST

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
)

func main() {
	jsonData := []byte(`{
		"title": "foo",
		"body": "bar",
		"userId": 1
	}`)

	resp, err := http.Post(
		"https://jsonplaceholder.typicode.com/posts",
		"application/json",
		bytes.NewBuffer(jsonData),
	)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}
	defer resp.Body.Close()

	body, _ := io.ReadAll(resp.Body)

	fmt.Println("Status Code:", resp.StatusCode)
	fmt.Println(string(body))
}

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✅ 3️⃣ PUT Request (Client Side)

📌 কাজ

Existing data update করা

📄 Full Code – PUT

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
)

func main() {
	jsonData := []byte(`{
		"id": 1,
		"title": "updated title",
		"body": "updated body",
		"userId": 1
	}`)

	req, err := http.NewRequest(
		http.MethodPut,
		"https://jsonplaceholder.typicode.com/posts/1",
		bytes.NewBuffer(jsonData),
	)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		fmt.Println("Request Error:", err)
		return
	}
	defer resp.Body.Close()

	body, _ := io.ReadAll(resp.Body)

	fmt.Println("Status Code:", resp.StatusCode)
	fmt.Println(string(body))
}

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✅ 4️⃣ DELETE Request (Client Side)

📌 কাজ

Server-এর data delete করা

📄 Full Code – DELETE

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, err := http.NewRequest(
		http.MethodDelete,
		"https://jsonplaceholder.typicode.com/posts/1",
		nil,
	)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		fmt.Println("Request Error:", err)
		return
	}
	defer resp.Body.Close()

	body, _ := io.ReadAll(resp.Body)

	fmt.Println("Status Code:", resp.StatusCode)
	fmt.Println("Response:")
	fmt.Println(string(body))
}

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🧠 Important Concepts (খুব জরুরি)

কেন GET & POST আলাদা?

1. GET, POST → shortcut function আছে

2. PUT, DELETE → http.NewRequest() ব্যবহার করতে হয়

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🔑 Common Pattern (Interview Tip)

client := &http.Client{}
req, _ := http.NewRequest("METHOD", url, body)
resp, _ := client.Do(req)
defer resp.Body.Close()

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📌 Summary Table

Method	Function Used
GET	http.Get()
POST	http.Post()
PUT	http.NewRequest()
DELETE	http.NewRequest()

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