curl --request PUT \
  --url https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "externalReference": "<string>"
}
'

import requests

url = "https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference"

payload = { "externalReference": "<string>" }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.put(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'PUT',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({externalReference: '<string>'})
};

fetch('https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PUT",
  CURLOPT_POSTFIELDS => json_encode([
    'externalReference' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference"

	payload := strings.NewReader("{\n  \"externalReference\": \"<string>\"\n}")

	req, _ := http.NewRequest("PUT", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.put("https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"externalReference\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.bold-factory.com/v1/planning/purchaseOrders/{orderReference}/externalReference")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Put.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"externalReference\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body

{
  "type": "https://api.bold-factory.com/errors/FILTER_PARSING_FAILED",
  "title": "Filter parsing failed",
  "status": 400,
  "detail": "The filter string could not be parsed or contains invalid column references: CreatedBy column does not exist.",
  "instance": "POST /v1/items/products/search",
  "code": "FILTER_PARSING_FAILED"
}

{
  "type": "https://www.rfc-editor.org/rfc/rfc9110.html#name-401-unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "You are not authenticated.",
  "instance": "GET /v1/items/skus"
}

{
  "type": "https://api.bold-factory.com/errors/MISSING_PERMISSIONS",
  "title": "Missing permissions",
  "status": 403,
  "detail": "Missing permissions: Items.Products.Read",
  "instance": "GET /v1/maintenance/assets",
  "code": "MISSING_PERMISSIONS"
}

{
  "type": "https://api.bold-factory.com/errors/ENTITY_NOT_FOUND",
  "title": "The entity was not found.",
  "status": 404,
  "detail": "Entity Product (pr_72f13bd8218h9823dfj9) was not found.",
  "instance": "DELETE /v1/items/products/pr_72f13bd8218h9823dfj9",
  "code": "ENTITY_NOT_FOUND"
}

{
  "type": "https://api.bold-factory.com/errors/CANNOT_MODIFY_CANCELLED_LINE",
  "title": "Cannot modify cancelled line",
  "status": 422,
  "detail": "A cancelled line can't be modified.",
  "instance": "PUT /v1/planning/purchaseOrders/po_sd786f78s78hgf8hg/lines/pol_n7893ytw3et7w4wfo5rf",
  "code": "CANNOT_MODIFY_CANCELLED_LINE"
}