doc/md/REST-API.md

   1 # REST API
   2
   3 ## Server requirements
   4
   5 See the **[REST API documentation](http://shaarli.github.io/api-documentation/)** for a list of available endpoints and parameters.
   6
   7 Please ensure that your server meets the requirements and is properly [configured](Server-configuration):
   8
   9 - URL rewriting is enabled (see specific Apache and Nginx sections)
  10 - the server's timezone is properly defined
  11 - the server's clock is synchronized with [NTP](https://en.wikipedia.org/wiki/Network_Time_Protocol)
  12
  13 The host where the API client is invoked should also be synchronized with NTP, see _payload/token expiration_
  14
  15
  16 ## Clients and examples
  17
  18 - **[python-shaarli-client](https://github.com/shaarli/python-shaarli-client)** - the reference API client ([Documentation](http://python-shaarli-client.readthedocs.io/en/latest/))
  19 - [shaarli-client](https://www.npmjs.com/package/shaarli-client) - NodeJs client ([source code](https://github.com/laBecasse/shaarli-client)) by [laBecasse](https://github.com/laBecasse)
  20 - [Android client example with Kotlin](https://gitlab.com/snippets/1665808) by [Braincoke](https://github.com/Braincoke)
  21
  22
  23 This example uses the [PHP cURL](http://php.net/manual/en/book.curl.php) library.
  24
  25 ```php
  26 <?php
  27 $baseUrl = 'https://shaarli.mydomain.net';
  28 $secret = 'thats_my_api_secret';
  29
  30 function base64url_encode($data) {
  31   return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
  32 }
  33
  34 function generateToken($secret) {
  35     $header = base64url_encode('{
  36         "typ": "JWT",
  37         "alg": "HS512"
  38     }');
  39     $payload = base64url_encode('{
  40         "iat": '. time() .'
  41     }');
  42     $signature = base64url_encode(hash_hmac('sha512', $header .'.'. $payload , $secret, true));
  43     return $header . '.' . $payload . '.' . $signature;
  44 }
  45
  46
  47 function getInfo($baseUrl, $secret) {
  48     $token = generateToken($secret);
  49     $endpoint = rtrim($baseUrl, '/') . '/api/v1/info';
  50
  51     $headers = [
  52         'Content-Type: text/plain; charset=UTF-8',
  53         'Authorization: Bearer ' . $token,
  54     ];
  55
  56     $ch = curl_init($endpoint);
  57     curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
  58     curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  59     curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
  60     curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);
  61
  62     $result = curl_exec($ch);
  63     curl_close($ch);
  64
  65     return $result;
  66 }
  67
  68 var_dump(getInfo($baseUrl, $secret));
  69 ```
  70
  71 ## Implementation
  72
  73 ### Authentication
  74
  75 - All requests to Shaarli's API must include a **JWT token** to verify their authenticity.
  76 - This token must be included as an HTTP header called `Authorization: Bearer <jwt token>`.
  77 - JWT tokens are composed by three parts, separated by a dot `.` and encoded in base64:
  78
  79 ```
  80 [header].[payload].[signature]
  81 ```
  82
  83 ##### Header
  84
  85 Shaarli only allow one hash algorithm, so the header will always be the same:
  86
  87 ```json
  88 {
  89     "typ": "JWT",
  90     "alg": "HS512"
  91 }
  92 ```
  93
  94 Encoded in base64, it gives:
  95
  96 ```
  97 ewogICAgICAgICJ0eXAiOiAiSldUIiwKICAgICAgICAiYWxnIjogIkhTNTEyIgogICAgfQ==
  98 ```
  99
 100 ##### Payload
 101
 102 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](https://tools.ietf.org/html/rfc7519#section-4.1.6)). This token will be valid during **9 minutes**.
 103
 104 ```json
 105 {
 106     "iat": 1468663519
 107 }
 108 ```
 109
 110 ##### Signature
 111
 112 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.
 113
 114 Example signature with PHP:
 115
 116 ```php
 117 $content = base64_encode($header) . '.' . base64_encode($payload);
 118 $signature = hash_hmac('sha512', $content, $secret);
 119 ```
 120
 121
 122
 123 ## Troubleshooting
 124
 125 ### Debug mode
 126
 127 > This should never be used in a production environment.
 128
 129 For security reasons, authentication issues will always return an `HTTP 401` error code without any detail.
 130
 131 It is possible to enable the debug mode in `config.json.php`
 132 to get the actual error message in the HTTP response body with:
 133
 134 ```json
 135 {
 136   "dev": {
 137     "debug": true
 138   }
 139 }
 140 ```
 141
 142 ## References
 143
 144 - [jwt.io](https://jwt.io) (including a list of client per language).
 145 - [RFC - JSON Web Token (JWT)](https://tools.ietf.org/html/rfc7519)
 146 - [JSON Web Tokens (JWT) vs Sessions](https://float-middle.com/json-web-tokens-jwt-vs-sessions/), [HackerNews thread](https://news.ycombinator.com/item?id=11929267)
 147
 148
 149
 150