UNIX cUrl command

cUrl is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP). The command is designed to work without user interaction. I am sharing some of the instances below I've used so far..

• Basic Authentication

# Use -u attribute to provide credentials as <username>:<password>
# Use -X or --request attribute to mention HTTP method
# Use --url (applicable by default) to mention destination URL
curl -X POST -u johndoe01:pass1234 --url https://www.amitpetkar.com

• Getting HTTP response code from cUrl

username='john.doe'
password='password'
authURL='http://www.amitpetkar.com/authSignon'

# Getting response text into variable 'response'. 
# Due to -w ${http_code} attribute, you'd get the HTTP response code 
# along with end text line of response.

response=$(curl -X POST -w %{http_code} -u $username:$password $authURL);

# If response doesn't contain SUCCESS (HTTP Code 200) then exit.
if [[ $response != *"200"* ]]; then 
  echo $(date '+%Y-%m-%d-%H:%M:%S')" " "SIGNON Unsuccessful. Exiting..."
  exit;
fi

• Getting/Saving Cookie from response

cookiePath='./cookie'

# Use --cookie-jar attribute followed by filename which will 
# contain response header cookies.

# Use backslash (ensure no white space after that) for multi line commands
curl -X POST -w %{http_code} \
-u $username:$password \
--cookie-jar $cookiePath \
$authURL;

# Reading cookie file contents into variable
cookies=cat $cookiePath;

• Saving response into file

response='./responseFile.txt'

# Use -o attribute to set cUrl's response into an output file 
curl -X POST -w %{http_code} \
-u $username:$password \
--cookie-jar $cookiePath \
$authURL -o $response;

• Use eval() to run any command set in a variable

authCurl="curl -X POST -w %{http_code} -u $username:$password $authURL"
echo "URL to be processed: "$authCurl
$(eval ${authCurl})

• Setting cookies for cUrl request

JSESSIONID='1234ABCD'
# Use --header attribute for setting cookie as Cookie: '<cookieValue1><cookieValue2>'
curl -X POST -w %{http_code} -u $username:$password \
--header 'Cookie: $JSESSIONID;' $authURL 

# OR use --cookie attribute followed by '<cookieValue1><cookieValue2>'
curl -X POST -w %{http_code} -u $username:$password \
--cookie $JSESSIONID $authURL

• SOAP Request using cUrl

requestBody="<some SOAP request>"

# Writing request body into file. 
# Use > for creating new file every time
# Use >> for appending over same file
echo $requestBody > "./requestFile.xml" 

# Use --header attribute to provide request headers
# Use -d attribute to provide request body.
soapCurl="curl --request POST \
--url '$authUrl' \
--header 'Cookie: $JSESSIONID;' \
--header 'Content-type: text/xml; charset=UTF-8' \
--header 'request-type: SOAP' \
--header 'SOAPAction: \"\"' \
--header 'cache-control: no-cache' \
-d @'./requestFile.xml' \
-o soapResponse.txt";

$(eval ${soapCurl})