MyShaarli/doc/md/REST-API.md

REST API

Server requirements

See the REST API documentation for a list of available endpoints and parameters.

Please ensure that your server meets the requirements and is properly configured:

• URL rewriting is enabled (see specific Apache and Nginx sections)
• the server's timezone is properly defined
• the server's clock is synchronized with NTP

The host where the API client is invoked should also be synchronized with NTP, see payload/token expiration

Clients and examples

• python-shaarli-client - the reference API client (Documentation)
• shaarli-client - NodeJs client (source code) by laBecasse
• Android client example with Kotlin by Braincoke

This example uses the PHP cURL library.

<?php
$baseUrl = 'https://shaarli.mydomain.net';
$secret = 'thats_my_api_secret';

function base64url_encode($data) {
  return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
}

function generateToken($secret) {
    $header = base64url_encode('{
        "typ": "JWT",
        "alg": "HS512"
    }');
    $payload = base64url_encode('{
        "iat": '. time() .'
    }');
    $signature = base64url_encode(hash_hmac('sha512', $header .'.'. $payload , $secret, true));
    return $header . '.' . $payload . '.' . $signature;
}


function getInfo($baseUrl, $secret) {
    $token = generateToken($secret);
    $endpoint = rtrim($baseUrl, '/') . '/api/v1/info';

    $headers = [
        'Content-Type: text/plain; charset=UTF-8',
        'Authorization: Bearer ' . $token,
    ];

    $ch = curl_init($endpoint);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
    curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);

    $result = curl_exec($ch);
    curl_close($ch);

    return $result;
}

var_dump(getInfo($baseUrl, $secret));

Implementation

Authentication

• All requests to Shaarli's API must include a JWT token to verify their authenticity.
• This token must be included as an HTTP header called Authentication: Bearer <jwt token>.
• JWT tokens are composed by three parts, separated by a dot . and encoded in base64:

[header].[payload].[signature]

Header

Shaarli only allow one hash algorithm, so the header will always be the same:

{
    "typ": "JWT",
    "alg": "HS512"
}

Encoded in base64, it gives:

ewogICAgICAgICJ0eXAiOiAiSldUIiwKICAgICAgICAiYWxnIjogIkhTNTEyIgogICAgfQ==

Payload

Token expiration: To avoid infinite token validity, JWT tokens must include their creation date in UNIX timestamp format (timezone independent - UTC) under the key iat (issued at) field (1). This token will be valid during 9 minutes.

{
    "iat": 1468663519
}

Signature

The signature authenticates the token validity. It contains the base64 of the header and the body, separated by a dot ., hashed in SHA512 with the API secret available in Shaarli administration page.

Example signature with PHP:

$content = base64_encode($header) . '.' . base64_encode($payload);
$signature = hash_hmac('sha512', $content, $secret);

Troubleshooting

Debug mode

This should never be used in a production environment.

For security reasons, authentication issues will always return an HTTP 401 error code without any detail.

It is possible to enable the debug mode in config.json.php to get the actual error message in the HTTP response body with:

{
  "dev": {
    "debug": true
  }
}

References

• jwt.io (including a list of client per language).
• RFC - JSON Web Token (JWT)
• JSON Web Tokens (JWT) vs Sessions, HackerNews thread