REST API with cURL

☝

Official Docs

In Postman we can click on Code Snippet to show the cURL command (and other command
too).

General

Note that, -X = --request

curl -X [method] [options] [URL]

The most important options/flags

-B: Use ASCII for text and transfer.
-C: Resume an interrupted transfer.
-d: Data for the HTTP POST or PUT commands.
-E: Use a client certificate file and optional password.
-F: Update a HTTP form request from a file.
-H: Pass a custom header to the server.
-K: Use a file for the configuration.
-m: Set a maximum time for the transfer.
-N: Disable buffering.
-o: Write the output to a file.
-s: Run in silent mode.
-u: Add a user name and password for the server.
-v: Verbose mode, for more details.
-X: Specifies the HTTP command to use.
-4: Use Ipv4 addresses.
-6: Use Ipv6 addresses.
-#: Display a progress bar. This is useful for large transfers.

cURL in PHP

☝

We need to install extensions php-curl to use it. Checkthe
Official Documentation to learn more

Send Request

Init cURL

// create & initialize a curl session
$curl = curl_init();

/**
* Some code
**/

// close curl resource to free up system resources
// (deletes the variable made by curl_init)
curl_close($curl);

GET method

curl_setopt($curl, CURLOPT_URL, '<https://api.github.com/events>');
# request header
curl_setopt($curl, CURLOPT_HTTPHEADER, array(
  'Content-Type: application/json',
  'User-Agent: cURL'
));
$raw = curl_exec($curl);

POST method

curl_setopt($curl, CURLOPT_URL, '<https://httpbin.org/post>');
curl_setopt($curl, CURLOPT_POST, 1);
# request header
curl_setopt($curl, CURLOPT_HTTPHEADER, array(
  'Content-Type: application/json'
));
curl_setopt($curl, CURLOPT_POSTFIELDS, '{"key": "value"}');
$raw = curl_exec($curl);

Response

Body response

// Raw text
...
$raw = curl_exec($curl);

# JSON
json_decode($raw, true);

Status code ???

$statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE); // $statusCode = 200

Some examples

GET

curl -X GET '<http://abc:3000/xyz/enpoint?paramOne=1&paramTwo=2>' \
 --header 'clientEmail: abc@xyz.com' \
 --header 'privateKey: XXXX'
 }'

POST

The JSON data must be in the form of '{with the "double quotes" inside}'. This "{single 'quote' inside}" will not
work!

curl -X POST '<http://abc:3000/xyz/enpoint?paramOne=1&paramTwo=2>' \
 --header 'clientEmail: abc@xyz.com' \
 --header 'privateKey: LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCk1JSUV2Z0lCQU' \
 --header 'Content-Type: application/json' \
 --data-raw '{
  "dataMain": {
   "keyOne": "valueOne",
   "keyTwo": 2
  }
 }'

or with JSON file

curl -X POST \
  --header "Content-Type: application/json" \
  --data @.folder/file.json \
  <http://localhost:8080/ui/webapp/conf>

or form data

We have a form that can upload file

<form method="POST" enctype="multipart/form-data" action="upload.cgi">
  <input type="file" name="upload" />
  <input type="submit" name="press" value="OK" />
</form>

curl --form upload=@/home/user/Pictures/wallpaper.jpg --form press=OK [URL]