[Sommaire] [Imprimer]

   1  Permissions in Phorum 5
   2  =======================
   3  
   4  This document describes the way the permission system of Phorum works.
   5  It is targeted at developers that need inside information on the
   6  API calls that are related to permission handling.
   7  
   8  Table of contents:
   9  
  10  1. Checking user permissions
  11  2. Modifying user permissions
  12  3. Some final notes
  13  
  14  
  15  1. Checking user permissions
  16  -------------------------------------------------------------------------------
  17  
  18     First and foremost, your code should use the function called
  19     phorum_user_access_allowed() to check for a given user permission
  20     in the current forum. However, if you find yourself needing to check
  21     the permisssion directly, here is some information.
  22     
  23     Permissions are stored using a bitmask. To check for a certain permission, 
  24     simply use the bitwise AND (&) operator to match the permission against the
  25     user's permissions.
  26     
  27     For example, if we want to check if a user has permission to read
  28     a particular forum, we would use the following if statement:
  29     
  30        if($PHORUM["user"]["permissions"] & PHORUM_USER_ALLOW_READ){
  31            // the user can read this forum
  32        } else {
  33            // the user can NOT read this forum
  34        }
  35  
  36  
  37  2. Modifying user permissions
  38  -------------------------------------------------------------------------------
  39  
  40     If you need to modify the permissions, use the bitwise OR (|) to add
  41     a permission or the bitwise XOR (^) to remove a permission. After you
  42     make the change, save the user. Here is some example code:
  43     
  44        // add new topic permissions
  45        $permissions = $PHORUM["user"]["permissions"] | PHORUM_USER_ALLOW_NEW_TOPIC;
  46        $userdata = array(
  47            "user_id" => $PHORUM["user"]["user_id"],
  48            "permissions" => $permissions
  49        );
  50        phorum_user_save($userdata);
  51    
  52        // remove new topic permissions
  53        $permissions = $PHORUM["user"]["permissions"] ^ PHORUM_USER_ALLOW_NEW_TOPIC;
  54        $userdata = array(
  55            "user_id" => $PHORUM["user"]["user_id"],
  56            "permissions" => $permissions
  57        );
  58        phorum_user_save($userdata);
  59     
  60  
  61  3. Some final notes
  62  -------------------------------------------------------------------------------
  63  
  64     That should be all you need to know about the Phorum permission system.
  65     Here is some stuff that helped explain this to the other developers:
  66     
  67     > select (256 | 16);  
  68     > That OR's the two numbers together.
  69     > you get 272
  70     > then:
  71     > select 16 & 272;
  72     > That returns 16.
  73     > So, in our data, the 272 represents what is in the database.
  74     > The 16 would be one of the permission constancts
  75     > Our constants would look like this:
  76     >     define("PHORUM_USER_ALLOW_READ", 1);  
  77     >     define("PHORUM_USER_ALLOW_REPLY", 2); 
  78     >     define("PHORUM_USER_ALLOW_EDIT", 4); 
  79     >     define("PHORUM_USER_ALLOW_NEW_TOPIC", 8); 
  80     >     define("PHORUM_USER_ALLOW_UPLOAD", 16); 
  81     >     define("PHORUM_USER_ALLOW_ATTACH", 32); 
  82     >     define("PHORUM_USER_ALLOW_MODERATE_MESSAGES", 64); 
  83     >     define("PHORUM_USER_ALLOW_MODERATE_USERS", 128); 
  84     >     define("PHORUM_USER_ALLOW_FORUM_PROPERTIES", 256); 
  85     > To give someone read and reply, we would set their perm to 1 | 2
  86     > Then, to check it, we would $user_perm_value & $perm == $perm
  87     > or in sql
  88     > where permission & $perm = $perm
  89     
  90     Another example to show that the = $perm can be left out:
  91     
  92     > select 1 | 2
  93     > read, reply
  94     > = 3
  95     > select 3 & 16
  96     > =0
  97