# Referensi Cepat curl

*HTTP request, header, auth, form, debugging*

> Source: curl Documentation (curl.se/docs) · MIT

## Penggunaan Dasar

### Request Sederhana

```
curl https://example.com          # GET request
curl -o file.html https://url     # save to file
curl -O https://url/file.tar.gz   # save with remote name
curl -L https://url               # follow redirects
```

### Flag Umum

| Command | Description |
|---------|-------------|
| `-s` | Mode silent (tanpa progress) |
| `-S` | Tampilkan error dalam mode silent |
| `-f` | Gagal diam-diam pada error HTTP |
| `-L` | Ikuti redirect |
| `-o file` | Tulis output ke file |
| `-O` | Simpan dengan nama file remote |
| `-C -` | Lanjutkan unduhan yang terputus |
| `--max-time 30` | Timeout setelah 30 detik |

## HTTP Method

### GET & HEAD

```
curl https://api.example.com/users
curl -I https://example.com       # HEAD (headers only)
curl -i https://example.com       # include response headers
```

### POST

```
curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name":"Jo","email":"jo@ex.com"}'
```

### PUT & PATCH & DELETE

```
curl -X PUT https://api.example.com/users/1 \
  -d '{"name":"Updated"}'
curl -X PATCH https://api.example.com/users/1 \
  -d '{"email":"new@ex.com"}'
curl -X DELETE https://api.example.com/users/1
```

## Header

### Mengatur Header

```
curl -H "Content-Type: application/json" URL
curl -H "Accept: text/html" URL
curl -H "X-Custom: value" URL
curl -H "Header1: v1" -H "Header2: v2" URL
```

### Header Response

| Command | Description |
|---------|-------------|
| `-i` | Sertakan header response dalam output |
| `-I` | Ambil header saja (HEAD) |
| `-D file` | Dump header response ke file |
| `-w '%{http_code}'` | Cetak HTTP status code |

## Autentikasi

### Basic & Token Auth

```
curl -u user:pass https://api.example.com
curl -H "Authorization: Bearer TOKEN" URL
curl -u user:pass --digest URL
curl --negotiate -u : URL   # Kerberos/SPNEGO
```

### Metode Auth

| Command | Description |
|---------|-------------|
| `-u user:pass` | Autentikasi Basic |
| `--digest` | HTTP Digest auth |
| `--negotiate` | Kerberos/SPNEGO auth |
| `--ntlm` | Autentikasi NTLM |
| `-n` | Gunakan kredensial ~/.netrc |

## Data & Form

### Mengirim Data

```
curl -d "key=val&key2=val2" URL   # form urlencoded
curl -d @data.json URL            # data from file
curl --data-raw '{"raw":"json"}' URL
curl --data-urlencode "q=hello world" URL
```

### Upload File

```
curl -F "file=@photo.jpg" URL
curl -F "file=@doc.pdf;type=application/pdf" URL
curl -F "field=value" -F "file=@img.png" URL
```

### Multipart vs URL-Encoded

| Command | Description |
|---------|-------------|
| `-d` | application/x-www-form-urlencoded |
| `-F` | multipart/form-data |
| `--json` | Shorthand: set Content-Type + Accept ke JSON |
| `-T file` | Upload file via PUT |

## SSL/TLS

### Opsi Sertifikat

```
curl --cacert ca.pem URL          # custom CA bundle
curl --cert client.pem URL        # client certificate
curl --cert client.pem --key key.pem URL
curl -k URL                       # skip TLS verify (dev only)
```

### Flag TLS

| Command | Description |
|---------|-------------|
| `-k / --insecure` | Lewati verifikasi sertifikat TLS |
| `--cacert file` | Gunakan CA sertifikat kustom |
| `--cert file` | Sertifikat client |
| `--key file` | Private key client |
| `--tlsv1.2` | Paksa minimum TLS 1.2 |
| `--tlsv1.3` | Paksa minimum TLS 1.3 |

## Output & Debugging

### Verbose & Trace

```
curl -v URL                       # verbose output
curl --trace dump.txt URL         # full trace to file
curl --trace-ascii - URL          # trace to stdout
curl -w "\n%{http_code}\n" URL    # custom output format
```

### Variabel Write-Out

| Command | Description |
|---------|-------------|
| `%{http_code}` | HTTP response status code |
| `%{time_total}` | Total waktu dalam detik |
| `%{time_connect}` | Waktu untuk membuat koneksi |
| `%{size_download}` | Byte yang diunduh |
| `%{speed_download}` | Kecepatan unduhan rata-rata |
| `%{redirect_url}` | URL redirect (jika ada) |
| `%{ssl_verify_result}` | Hasil verifikasi SSL (0 = OK) |

### Contoh Write-Out

```
curl -s -o /dev/null -w \
  "code: %{http_code}\ntime: %{time_total}s\n" \
  https://example.com
```

## Pola Umum

### Alur Kerja API

```
# GET JSON and pipe to jq
curl -s https://api.example.com/data | jq '.items[]'
# POST JSON with auth
curl -s -H "Authorization: Bearer $TOKEN" \
  --json '{"key":"val"}' https://api.example.com
```

### Pola Unduhan

```
# Download with progress bar
curl -# -O https://releases.example.com/v2.tar.gz
# Resume interrupted download
curl -C - -O https://releases.example.com/v2.tar.gz
# Download multiple files
curl -O https://url/file1 -O https://url/file2
```

### Helper Scripting

```
# Check if URL is reachable
curl -sf -o /dev/null https://example.com && echo OK
# Save cookies and reuse
curl -c cookies.txt -b cookies.txt URL
# Rate-limit request
curl --limit-rate 100k URL
```

## Proxy & Jaringan

### Pengaturan Proxy

```
curl -x http://proxy:8080 URL
curl -x socks5://proxy:1080 URL
curl --proxy-user user:pass -x http://proxy:8080 URL
curl --noproxy "*.local,localhost" URL
```

### DNS & Resolve

| Command | Description |
|---------|-------------|
| `--resolve host:port:addr` | Paksa resolusi DNS ke addr |
| `--dns-servers 8.8.8.8` | Gunakan server DNS kustom |
| `--interface eth0` | Gunakan interface jaringan tertentu |
| `-4 / -6` | Paksa IPv4 / IPv6 |

## Konfigurasi & Lanjutan

### File Konfigurasi

```
# ~/.curlrc — default options
--silent
--location
--max-time 30

# Use config file explicitly
curl -K myconfig.txt URL
```

### Flag Berguna

| Command | Description |
|---------|-------------|
| `--retry 3` | Coba ulang pada error transien |
| `--retry-delay 2` | Jeda antar percobaan ulang (detik) |
| `--compressed` | Minta dan dekompresi gzip/br |
| `--limit-rate 100k` | Throttle kecepatan transfer |
| `-Z` | Transfer paralel (curl 7.66+) |
| `--create-dirs` | Buat direktori path untuk -o |