PHP API打包的一个实例，来自EtherPad

<?phpclass EtherpadLiteClient {  const API_VERSION             = 1;  const CODE_OK                 = 0;  const CODE_INVALID_PARAMETERS = 1;  const CODE_INTERNAL_ERROR     = 2;  const CODE_INVALID_FUNCTION   = 3;  const CODE_INVALID_API_KEY    = 4;  protected $apiKey = "";  protected $baseUrl = "http://localhost:9001/api";    public function __construct($apiKey, $baseUrl = null){    $this->apiKey  = $apiKey;    if (isset($baseUrl)){      $this->baseUrl = $baseUrl;    }    if (!filter_var($this->baseUrl, FILTER_VALIDATE_URL)){      throw new InvalidArgumentException("[{$this->baseUrl}] is not a valid URL");    }  }  protected function call($function, array $arguments = array()){    $query = array_merge(      array('apikey' => $this->apiKey),      $arguments    );    $url = $this->baseUrl."/".self::API_VERSION."/".$function."?".http_build_query($query);    // not all PHP installs have access to curl    if (function_exists('curl_init')){      $c = curl_init($url);      curl_setopt($c, CURLOPT_RETURNTRANSFER, true);      curl_setopt($c, CURLOPT_TIMEOUT, 20);      $result = curl_exec($c);      curl_close($c);    } else {      $result = file_get_contents($url);    }        if($result == ""){      throw new UnexpectedValueException("Empty or No Response from the server");    }        $result = json_decode($result);    if ($result === null){      throw new UnexpectedValueException("JSON response could not be decoded");    }    return $this->handleResult($result);  }  protected function handleResult($result){    if (!isset($result->code)){      throw new RuntimeException("API response has no code");    }    if (!isset($result->message)){      throw new RuntimeException("API response has no message");    }    if (!isset($result->data)){      $result->data = null;    }    switch ($result->code){      case self::CODE_OK:        return $result->data;      case self::CODE_INVALID_PARAMETERS:      case self::CODE_INVALID_API_KEY:        throw new InvalidArgumentException($result->message);      case self::CODE_INTERNAL_ERROR:        throw new RuntimeException($result->message);      case self::CODE_INVALID_FUNCTION:        throw new BadFunctionCallException($result->message);      default:        throw new RuntimeException("An unexpected error occurred whilst handling the response");    }  }  // GROUPS  // Pads can belong to a group. There will always be public pads that doesnt belong to a group (or we give this group the id 0)    // creates a new group   public function createGroup(){    return $this->call("createGroup");  }  // this functions helps you to map your application group ids to etherpad lite group ids   public function createGroupIfNotExistsFor($groupMapper){    return $this->call("createGroupIfNotExistsFor", array(      "groupMapper" => $groupMapper    ));  }  // deletes a group   public function deleteGroup($groupID){    return $this->call("deleteGroup", array(      "groupID" => $groupID    ));  }  // returns all pads of this group  public function listPads($groupID){    return $this->call("listPads", array(      "groupID" => $groupID    ));  }  // creates a new pad in this group   public function createGroupPad($groupID, $padName, $text){    return $this->call("createGroupPad", array(      "groupID" => $groupID,      "padName" => $padName,      "text"    => $text    ));  }  // AUTHORS  // Theses authors are bind to the attributes the users choose (color and name).   // creates a new author   public function createAuthor($name){    return $this->call("createAuthor", array(      "name" => $name    ));  }  // this functions helps you to map your application author ids to etherpad lite author ids   public function createAuthorIfNotExistsFor($authorMapper, $name){    return $this->call("createAuthorIfNotExistsFor", array(      "authorMapper" => $authorMapper,      "name"         => $name    ));  }  // SESSIONS  // Sessions can be created between a group and a author. This allows  // an author to access more than one group. The sessionID will be set as  // a cookie to the client and is valid until a certian date.  // creates a new session   public function createSession($groupID, $authorID, $validUntil){    return $this->call("createSession", array(      "groupID"    => $groupID,      "authorID"   => $authorID,      "validUntil" => $validUntil    ));  }  // deletes a session   public function deleteSession($sessionID){    return $this->call("deleteSession", array(      "sessionID" => $sessionID    ));  }  // returns informations about a session   public function getSessionInfo($sessionID){    return $this->call("getSessionInfo", array(      "sessionID" => $sessionID    ));  }  // returns all sessions of a group   public function listSessionsOfGroup($groupID){    return $this->call("listSessionsOfGroup", array(      "groupID" => $groupID    ));  }  // returns all sessions of an author   public function listSessionsOfAuthor($authorID){    return $this->call("listSessionsOfAuthor", array(      "authorID" => $authorID    ));  }  // PAD CONTENT  // Pad content can be updated and retrieved through the API  // returns the text of a pad   // should take optional $rev  public function getText($padID){    return $this->call("getText", array(      "padID" => $padID    ));  }  // sets the text of a pad   public function setText($padID, $text){    return $this->call("setText", array(      "padID" => $padID,       "text"  => $text    ));  }  // PAD  // Group pads are normal pads, but with the name schema  // GROUPID$PADNAME. A security manager controls access of them and its  // forbidden for normal pads to include a $ in the name.  // creates a new pad  public function createPad($padID, $text){    return $this->call("createPad", array(      "padID" => $padID,       "text"  => $text    ));  }  // returns the number of revisions of this pad   public function getRevisionsCount($padID){    return $this->call("getRevisionsCount", array(      "padID" => $padID    ));  }  // deletes a pad   public function deletePad($padID){    return $this->call("deletePad", array(      "padID" => $padID    ));  }  // returns the read only link of a pad   public function getReadOnlyID($padID){    return $this->call("getReadOnlyID", array(      "padID" => $padID    ));  }  // sets a boolean for the public status of a pad   public function setPublicStatus($padID, $publicStatus){    return $this->call("setPublicStatus", array(      "padID"        => $padID,      "publicStatus" => $publicStatus    ));  }  // return true of false   public function getPublicStatus($padID){    return $this->call("getPublicStatus", array(      "padID" => $padID    ));  }  // returns ok or a error message   public function setPassword($padID, $password){    return $this->call("setPassword", array(      "padID"    => $padID,      "password" => $password    ));  }  // returns true or false   public function isPasswordProtected($padID){    return $this->call("isPasswordProtected", array(      "padID" => $padID    ));  }}