cURL

cURL是一個開源專案，主要的產品是curl和libcurl，兩者功能均是：基於網路協定，對指定URL進行網路傳輸。 cURL涉及是任何網路協定傳輸，不涉及對具體資料的具體處理。

Tips

Cheat Sheet

curl-cheat-sheet.png

Options in the integration with Shell
CURL_CMD="curl"
CURL_OPT="-qSfs -m 60"
CURL_OPT_POST="-qSfs -m 60 -X POST"
POST Request

Send an Empty POST Request

curl -X POST https://catonmat.net

Send a POST Request with Form Data

curl -d 'login=emma&password=123' -X POST https://google.com/login
GET Request

Send a GET Request and Print the Response to Screen

curl https://catonmat.net/api?a=1&b=2

Send a GET Request and Save the Response to a File

curl -o response.txt https://catonmat.net/api?a=1&b=2
Self-Signed Certificate

Error: curl: (60) SSL certificate problem: unable to get local issuer certificate

用 curl 連線 HTTPS 網站時，如遇到 self-signed certificate 類型或有些網站憑證，在瀏覽器上顯示是安全；在 curl 會出現錯誤訊息。原因是網站的簽發者憑證不受用戶端 curl 的信任。 

如何解決信任問題：

  1. 用 Firefox 或 Chrome 下載目的網站的簽發者 CA 憑證 *.pem
  2. curl 指定 *.pem  CA 憑證連接網站

curl 要使用特定 CA 憑證檔 *.pem，方法有二：

# 方法一
curl --cacert your-server-ca.pem https://your-server-name

# 方法二
# 先找出 curl 的 CApath, 隨便設定一個錯誤的 CA file
curl --cacert XXX https://your-server-name

curl: (77) error setting certificate verify locations:
  CAfile: xxx
  CApath: /etc/ssl/certs  <===

# 在 CApath 裡有一個檔案 ca-certificates.crt , 這用來信任那些客製的憑證
# 從檔案最底端加上新的憑證
# 加入的憑證一旦信任成功，curl 就不再需要指定 CA file
cat your-server-ca.pem >> /etc/ssl/certs/ca-certificates.crt
curl https://your-server-name
HTTP Status Codes

http_status_codes.jpg

Use a Proxy
curl -x username:Password@myproxy.com:8080 https://catonmat.net
Download
curl --request GET \
  --url 'https://www.tenable.com/downloads/api/v2/pages/nessus/files/Nessus-10.5.1-es9.x86_64.rpm' \
  --output 'Nessus-10.5.1-es9.x86_64.rpm'

Online Tools

More online tools

Public IP
↪ curl ifconfig.me
219.68.222.111⏎   
↪ curl ifconfig.me/ip
219.68.222.111⏎

↪ curl ip.im
↪ curl ipv4.im
↪ curl ip.im/info
↪ curl ip.im/8.8.8.8

curl ifconfig.co
curl checkip.amazonaws.com
curl icanhazip.com
curl ipecho.net/plain
curl -Ls myip.check.place
CryptoCurrency

rate.sx

curl-rate-sx.png

curl rate.sx
curl rate.sx/btc
curl rate.sx/btc@3d  # for last 3 days
curl rate.sx/1btc    # convert 1 BTC to ?? USD
curl rate.sx/:help
Weather

wttr.in

curl-wttr-in.png

curl wttr.in
curl wttr.in/TaoYuan
curl wttr.in/:help
QRcode

qrenco.de

curl-qrenco-de.png

curl qrenco.de
curl qrenco.de/www.yutube.com
curl qrenco.de/:help
printf "$@" | curl -F-=\<- qrenco.de
Shorten URL

0x0.st

curl-0x0-st.png

curl -F 'shorten=https://www.osslab.tw' https://0x0.st

Tinyurl.com: short URL from the terminal

echo https://URL | xargs -r -I {} curl -s -d url={} -G https://tinyurl{.}com/create.php | \
 awk '/indent/ {print substr($2,19,39)}' | sed '2!d' | sed 's/<.*//'



Learning cURL