如何通过cURL正确向REST API发送POST请求？Webex令牌获取异常排查

Let's break down the issues in your code and fix them step by step to get your access token request working:

1. Fix PHP Syntax Errors (The Most Likely Cause of Blank Page) #

Looking at your $postRequest array, you've got misplaced commas and comments that break PHP's parser:

// Your original problematic line:
"client_id" => ""//actual client id,

The comma sits after the comment, which PHP doesn't recognize as valid syntax. This triggers a fatal error, and if error display is disabled, your page will load as blank.

Fix the array by placing comments correctly and ensuring all key-value pairs end with a comma (except the last one):

$postRequest = array(
    "client_id" => "your_real_client_id", // Keep comments after the comma
    "client_secret" => "your_real_client_secret",
    "code" => $_GET["code"],
    "redirect_uri" => "http://localhost/test/webex_integration_test/callback.php",
    "grant_type" => "authorization_code", // Add this missing required parameter
    "code_verifier" => "your_valid_code_verifier"
);

2. Correct the Curl Request Structure #

You're currently passing parameters both in the URL and via CURLOPT_POSTFIELDS, which creates conflicting request data. Webex's OAuth2 token endpoint expects a POST request with parameters encoded as application/x-www-form-urlencoded in the request body, not the URL.

• Remove all parameters from the curl_init URL (just use https://api.webex.com/v1/oauth2/token)
• Use http_build_query() to convert your parameter array into a properly encoded string for the POST body
• Explicitly set CURLOPT_POST to true to ensure it's a POST request

3. Enable Error Debugging to Diagnose Issues #

Blank pages often hide errors that aren't being displayed. Add these lines at the top of your script to show PHP errors and curl issues:

error_reporting(E_ALL);
ini_set('display_errors', 1);

Also, add a check for curl errors after executing the request:

if(curl_errno($cURLConnection)){
    echo 'Curl Error: ' . curl_error($cURLConnection);
}

4. Validate Critical Parameters #

• redirect_uri: Make sure this matches exactly what you configured in the Webex Developer Portal (case, slashes, and all). You don't need to URL-encode it manually—http_build_query() will handle that.
• code_verifier: If you used PKCE during the authorization step (when you sent the user to Webex's login page), this verifier must be the exact same string you used to generate the code_challenge. Using a hardcoded "abc" will fail unless that's the actual verifier you used earlier.

Full Corrected Code Example #

Here's the revised script incorporating all these fixes:

<?php
// Enable error display for debugging
error_reporting(E_ALL);
ini_set('display_errors', 1);

// Check if the code parameter exists
if (!isset($_GET["code"])) {
    die("Error: Authorization code is missing from the request!");
}
$code = $_GET["code"];

// Your Webex app credentials
$client_id = "your_actual_client_id";
$client_secret = "your_actual_client_secret";
$redirect_uri = "http://localhost/test/webex_integration_test/callback.php";
$code_verifier = "your_valid_code_verifier"; // Match this to your authorization step's code_challenge

// Build POST parameters
$postData = [
    "grant_type" => "authorization_code",
    "client_id" => $client_id,
    "client_secret" => $client_secret,
    "code" => $code,
    "redirect_uri" => $redirect_uri,
    "code_verifier" => $code_verifier
];

// Initialize curl request
$curl = curl_init("https://api.webex.com/v1/oauth2/token");

// Configure curl options
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($postData));
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER, [
    'Content-Type: application/x-www-form-urlencoded',
    'Connection: Keep-Alive'
]);

// Execute request
$response = curl_exec($curl);

// Check for curl errors
if (curl_errno($curl)) {
    echo "Curl Request Failed: " . curl_error($curl);
}

// Close curl connection
curl_close($curl);

// Parse and display the response
$jsonResponse = json_decode($response, true);
if (json_last_error() !== JSON_ERROR_NONE) {
    echo "Failed to parse JSON response:<br>";
    echo "Raw Response: " . htmlspecialchars($response);
} else {
    echo "Access Token Response:<br>";
    print_r($jsonResponse);
}
?>

Run this revised script, and you should either get a valid access token response or clear error messages that will help you resolve any remaining issues (like mismatched code_verifier or incorrect credentials).

内容的提问来源于stack exchange，提问作者Neeraj Malwal