// $Id: README.txt,v 1.26.2.4 2008-04-20 21:44:38 agentken Exp $ /** * @file * README file for Domain Access. */ Domain Access A subdomain-based access control system. CONTENTS -------- 1. Introduction 1.1 Use-Case 1.2 Examples 1.3 Sponsors 1.4 Using Multiple Node Access Modules 1.5 Known Issues 1.5.1 Logging In To Multiple Domains 1.5.2 Cron Handling 1.5.3 Updating Your Site 2. Installation 2.1 Patches to Drupal Core 2.1.1 multiple_node_access.patch 2.1.2 custom_url_rewrite_outbound.patch 2.2 Server Configuration 2.3 Creating Subdomain Records 2.4 Setting DOMAIN_INSTALL_RULE 2.5 Setting DOMAIN_EDITOR_RULE 2.6 Setting DOMAIN_SITE_GRANT 3. Permissons 3.1 Module Permissions 3.2 Normal Usage 3.3 Advanced Usage 3.4 Limitations 4. Module Configuration 4.1 Default Domain Settings 4.1.1 Primary Domain Name 4.1.2 Site Name 4.1.3 Domain URL Scheme 4.2 Domain Module Behaviors 4.2.1 New Content Settings 4.2.2 Content Editing Forms 4.2.3 Debugging Status 4.2.4 Sort Domain Lists 4.3 Advanced Settings 4.3.1 Domain-based Editing Controls 4.3.2 Search Settings 4.3.3 Search Engine Optimization 4.3.4 WWW Prefix Handling 4.3.5 Node Access Settings 4.4 Special Page Requests 4.4.1 Cron Handling 4.5 Node Link Patterns 4.6 The Domain List 4.7 Creating Domain Records 4.8 Node Settings 4.8.1 Domain Node Editing 4.8.2 Domain Node Types 4.9 Batch Updating 4.10 Block -- Domain Switcher 5. Node Access 5.1 Assigning Domain Access 5.2. Editor Access 5.3 Realms 5.4 Grants 5.5 Warnings 6. Developer Notes 6.1 Extension Modules 6.2 The $_domain Global 6.3 Database Schema 6.4 API 7. To Do ---- 1. Introduction The Domain Access module group is designed to run an affiliated network of sites from a single Drupal installation. The module thus allows you to share users, content, and configurations across a group of sites such as: - example.com - one.example.com - two.example.com - my.example.com By default, these sites share all tables in your Drupal installation. The module uses Drupal's node_access() system to determine what content is available on each site in the network. Unlike other multi-domain modules for Drupal, the Domain Access module determines user access based on the active subdomain that the user is viewing, rather than which group or site the user belongs to. Additionally, when a user creates content, that content will automatically be assigned to the currently active subdomain unless the user has specific privileges to be able to assign domain access. Under advanced setups, the ability to edit content for a specific subdomain can be segregated from the typical Drupal privilege to 'administer nodes.' For more information about Domain Access privileges, see section 3. For more information about node_access(), see http://api.drupal.org/api/group/node_access/5 ---- 1.1 Use-Case The module was initially developed for a web site that sold franchises of a monthly magazine. The publishing rules were as follows: - Content may belong to the national site, one or more affiliates, or to all affiliates. - National editors may select to promote affiliate content to other affiliates, the national site, or to all affiliates. - Local editors may only create and edit content for their own affiliate sites. These rules are enforced programmatically by the Domain Access module. There was concern that, if given a choice to make, local editors would not assign the content correctly. Therefore, the module handles this automatically, and local editors have no control over which subdomains their content is published to. ---- 1.2 Examples For the original example of the module in use, see http://skirt.com/ ---- 1.3 Sponsors Domain Access is sponsored by Morris DigitalWorks. http://morrisdigitalworks.com ---- 1.4 Using Multiple Node Access Modules Node Access is a complex issue in Drupal. Typically, sites will only use one node access module at a time. In some cases, you may require more advances acceess control rules. Domain Access attempts to integrate with other node access modules in two ways: -- First, the multiple_node_access patch allows you to configure the Domain Access module to use AND logic instead of OR logic when adding Domain Access controls to your site. -- Second, Domain Access does not use db_rewrite_sql in any way. The module lets Drupal's core node access system handle this. As a result, there may exist conflicts between Domain Access and other contributed modules that try to solve this issue. Notably, the OG User Roles module introduces a patch to the node_access() function that seems to be incompatible with Domain Access. Domain Access has been tested to work with the Organic Groups module. If you experience conflicts with other node access modules, you should uninstall the multiple_node_access patch. This will restore the default Drupal behavior that your other modules are expecting. For background, see: -- http://drupal.org/node/196922 -- http://drupal.org/node/191375 -- http://drupal.org/node/122173 -- http://drupal.org/node/201156 ---- 1.5 Known Issues There are some issues that occur when Domain Access is used outside of its original use case. These are probably fixable, but may not work as you expect. You should pay careful attention to your site behavior. ---- 1.5.1 Logging In To Multiple Domains The Domain Access module allows the creation of domains with different hosts. However, security standards dictate that cookies can only be read from the issuing domain. As a result, you may configure your site as follows, but when you do so, users cannot be logged through a single sign in. example.com one.example.com myexample.com thisexample.com While example.com and one.example.com can share a login cookie, the other two domains cannot read that cookie. This is an internet standard, not a bug. This issue is looking for solutions. Note: See the INSTALL.txt for instructions regarding Drupal's default cookie handling. ---- 1.5.2 Cron Handling When Drupal's cron function runs, it operates on the domain from which the cron.php script is invoked. That is, if you setup cron to run from: http://one.example.com/cron.php In this case, Domain Access will check the access settings for that domain. This behavior has been known to cause issues with other contributed modules. As a solution, we normally disable Domain Access rules when cron runs. For more information, see section 4.4.1 Cron Handling. If you encounter any cron-related issues, please report them at: http://drupal.org/project/issues/domain ---- 1.5.3 Updating Your Site This issue only occurs if you use the Domain Prefix module. It is possible that database updates will not be applied to prefixed tables. For more information, see the Drupal Upgrades section of the Domain Prefix README.txt file. ---- 2. Installation WARNING: The Domain Access module assumes that you have already installed and configured your Drupal site. Please do so before continuing. For detailed instructions, see INSTALL.txt. To install the module, simply untar the download and put it in your site's modules directory. After reading this document, enable the module normally. When you enable the module, it will create a {domain} table in your Drupal database. All existing nodes on your site will be assigned to the default domain for your web site and to all affiliates. If you wish to alter this behavior, see sections 2.4 through 2.6. ---- 2.1 Patches to Drupal Core The following patches are optional. They affect advanced behavior of the Domain Access module. Patches are distributed in the 'patches' folder of the download. To apply these patches, place them in your root Drupal folder. Then follow the instructions at: http://drupal.org/patch/apply ---- 2.1.1 multiple_node_access.patch You should apply this patch only if you use Domain Access along with another Node Access module, such as Organic Groups (OG). The multiple_node_access.patch allows Drupal to run more than one node access control scheme in parallel. Instead of using OR logic to determine node access, this patch uses subselects to enable AND logic for multiple node access rules. WARNING: This patch uses subselect statements and requires pgSQL or MySQL 4.1 or higher. Developers: see http://drupal.org/node/191375 for more information. This patch is being submitted to Drupal core for version 7. ---- 2.1.2 custom_url_rewrite_outbound.patch This patch is only needed if: -- You wish to allow searching of all domains from any domain. -- You use a content aggregation module such as MySite. -- You get "access denied" errors when linking to items on a user's Track page. -- You want to turn on the advanced setting "Search Engine Optimization" to avoid content from being indexed on multiple domains. This patch allows modules to edit the path to a Drupal object. In the above cases, some content can only be viewed from certain domains, so we must write absolute links to that content. This patch introduces backports custom_url_rewrite_outbound() to Drupal 5. After you install this patch, you must copy the function: custom_url_rewrite_outbound() And paste it into your site's settings.php file. This function can be found at the bottom of INSTALL.txt The entire function can be found at the end of this document. Developers: see http://drupal.org/node/207330 for more information. See section 4.5 Node Link Patterns for more details. ---- 2.2 Server Configuration For the module to work correctly, the DNS record of your server must accept multiple DNS entries pointing at a single IP address that hosts your Drupal installation. The two basic methods for doing this are either to: - Setup WildCard DNS, so that *.example.com resolves to your Drupal site. - Setup VirtualHosts so that one.example.com, two.example.com, etc. all resolve to your Drupal site. For example, on my local testing machine, I have VirtualHosts to the following sites setup in httpd.conf: - example.com => 127.0.0.1 - one.example.com => 127.0.0.1 - two.example.com => 127.0.0.1 - three.example.com => 127.0.0.1 It is beyond the scope of this document to explain how to configure your DNS server. For more information, see: - http://en.wikipedia.org/wiki/Wildcard_DNS_record - http://en.wikipedia.org/wiki/Virtual_hosting After you have enabled multiple DNS entries to resolve to your Drupal installation, you may activate the module and configure its settings. No matter how many domains resolve to the same IP, you only need one instance of Drupal's settings.php file. The sites folder should be named 'default' or named for your root domain. ---- 2.3 Creating Subdomain Records After you enable the module, you will have a user interface for registering new subdomains with your site. For these to work correctly, they must also be configured by your DNS server. To be clear: creating a new subdomain record through this module will not alter the DNS server of your web server. ---- 2.4 Setting DOMAIN_INSTALL_RULE This is an advanced instruction, and may be ignored. At the top of the domain.module file, you will find this line: define('DOMAIN_INSTALL_RULE', TRUE); This setting controls the default behavior of the module when installing over an existing installation. If set to TRUE, the Domain Access module will assign all existing nodes to be viewable by all affiliate sites. If you set this value to FALSE, existing nodes will only be visible to users on your root domain. For more details, see section 5. ---- 2.5 Setting DOMAIN_EDITOR_RULE This is an advanced instruction, and may be ignored. At the top of the domain.module file, you will find this line: define('DOMAIN_EDITOR_RULE', FALSE); This setting controls the default behavior for affiliate editors. If DOMAIN_INSTALL_RULE is set to FALSE, you may change this value to TRUE if you intend to use editing controls. If this is set to TRUE, all existing nodes on your site will be editable by users who are assigned as editors of your root domain. See section 3 and section 5 for more information. ---- 2.6 Setting DOMAIN_SITE_GRANT At the top of the domain.module file, you will find this line: define('DOMAIN_SITE_GRANT', TRUE); This setting controls the default behavior for viewing affiliate content. By design, the Domain Access module allows site administrators to assign content to 'all affiliates.' If this value is set to TRUE, then content assigned to all affiliates can be seen by all users on all current domains. Normally, you will not need to edit this value. ---- 3. Permissions After enabling the module, go to Access Control to configure the module's permissions. ---- 3.1 Module Permissions The Domain Access module has three standard permissions. - 'administer domains' This permission allows users to create and manage subdomain records and settings. 'assign domain editors' This permission allows users to assign themselves and other users as affiliate editors. For those users to act as editors, their role(s) must also have the 'edit domain nodes' permission. - 'edit domain nodes' This permission is for advanced use and substitutes for the normal 'administer nodes' permission for sites that give restricted administrative privileges. See section 3.3 for more information. - 'set domain access' This permission is key. Users with this permission will be given a user interface for assigning users and nodes to specific domains. Users without this permission cannot assign domain access; their nodes will automatically be assigned to the currently active domain. For example, if a user has this permission and creates a book page on one.example.com, the user will be given a series of options to assign that book page to any or all of the registered domains on the site. If the user does not have this permission, the book page will only be shown to users who are on http://one.example.com. - 'view domain publishing' This permission provides a limited set of options for users to create and edit content on your site. Users who have this permission will have their node editing forms processed according to the "Content Editing Form" settings described in section 4.2.2. This feature was added in response to http://drupal.org/node/188275. ---- 3.2 Normal Usage Under a normal Drupal site, a single administrator (or a handful of equally trusted administrators) typically have the 'administer nodes' permission and individual 'edit TYPE nodes' permissions. If your site follows this method, you will not need to enable the advanced editing controls provided by Domain Access. Under the module settings, leave the setting 'Domain-based editing controls' as 'Do not use access control for editors'. In this case, the 'edit domain nodes' permission becomes irrelevant. The only choices for permissions would be who gets to administer the module settings and who gets to assign nodes to specific domains. Generally, only users who you trust to 'administer site configuration' should be given the 'administer domains' permission. As for 'set domain access,' that can be given to any user you trust to use the UI properly. ---- 3.3 Advanced Usage In the event that you wish to segregate which content certain editors can control, you should not use the normal 'edit TYPE nodes' permission provided by Drupal's core Node module. This permisson grants the ability for a user to edit all nodes of a given type. In the Domain Access model, this permission is not used in favor of the provided 'edit domain nodes' permission. This permission allows editors only to edit (and delete) nodes that belong to their subdomain. To enable this feature, you should grant the 'edit domain nodes' permission to some roles. Then you should enable the 'Use access control for editors' setting under the Domain Access configuration screen. ---- 3.4 Limitations Due to the way node_access() works, the following limitations should be noted. - Any node that is assigned to more than one subdomain can be edited by any editor who belongs to one of the subdomains. - Users who look at the sites and have the 'administer nodes' permission can always see all content on all sites, which can be confusing. This is unavoidable. It is best to preview your site as an anonymous or authenticated user who does not have special permissions. - Users who have the 'edit TYPE nodes' permission will be able to edit nodes that do not belong to their subdomain. These limitations are due to the permissive nature of node_access(). If any access rule grants you permission, it cannot be taken away. ---- 4. Module Configuration The settings for Domain Access are listed under Site Building. The path is 'admin/build/domain'. ---- 4.1 Default Domain Settings These elements define the 'root' domain for your site. In the event that a user tries to access an invalid domain, this domain will be used. ---- 4.1.1 Primary Domain Name The primary domain for your site. Typically example.com or www.example.com. Do not use http or slashes. This domain will be used as the default URL for your site. If an invalid domain is requested, users will be sent to the primary domain. Enter the primary domain for your site here. Typically, you will also enter this value into settings.php for cookie handling. Do not use http:// or a trailing slash when entering this value. NOTE: If you have installed Drupal in a subfolder, such as http://example.com/drupal you should not include the folder path as part of the primary domain. Simply use example.com -- Drupal will automatically detect the presence of the subfolder. ---- 4.1.2 Site Name This value is taken from your system settings and need not be changed. It is provided to allow readbility in the domain list. ---- 4.1.3 Domain URL Scheme Allows the site to use 'http' or 'https' as the URL scheme. Default is 'http'. All links and redirects to root site will use the selected scheme. ---- 4.2 Domain Module Behaviors These options affect the basic options for how the module behaves. ---- 4.2.1 New Content Settings Defines the default behavior for content added to your site. By design, the module automatically assigns all content to the currently active subdomain. If this value is set to 'Show on all sites,' then all new content will be assigned to all sites _in addition to_ the active subdomain. ---- 4.2.2 Content Editing Forms Defines how to present the forms for node creation and editing to users who do not have permission to 'set domain access' but need some control over where their content is published. Users with the 'view domain publishing' permission will be subject to the rules defined below. -- Pass the default form values as hidden fields The default option. It will assign all content to the root domain and to the domain from which the form is entered. -- Take user to the default domain Before being presented the editing form, users will be taken to the root domain. If the node is not visible on the root domain, the user may not be able to edit the node. -- Take user to their assigned domain Before being presented the editing form, users will be taken to the first domain assigned to their user account. This function is most useful when you users are only allowed to enter content from a single domain. Note that for users who have more than one assigned domain, this option will take them to the first match and the user will not be allowed to change the domain affiliation. -- Show user their publishing options The node editing form is shown normally, and the user is presented a list of checkboxes. These options represent the affilaite domains that the user is allowed to publish content to, according to the domains assigned to their user account. Note that if this option is selected, users with the 'view domain publshing' permission will also be shown a list of affilates to which the node is assigned. This list shows only the affiliates that the user cannot edit. Note also that the user is not given the ability to promote content to 'all affiliates'. Users who need this ability should be given the 'set domain access' permission instead. ---- 4.2.3 Debugging Status If enabled, this will append node access information to the bottom of each node. This data is only viewable by uses with the 'set domain access' privilege. It is provided for debugging, since 'adminiseter nodes' will make all nodes viewable to some users. ---- 4.2.4 Sort Domain Lists Both the Domain Switcher block and the Domain Nav module provide an end-user visible list of domains. The domain sorting settings control how these lists are generated and presented to the user. ---- 4.3 Advanced Settings These settings control advanced features for the module. Some of these features require patches to Drupal core. Please read the documentation carefully before implementing these features. NOTE: Some of these options may be disabled in the event that patches have not been applied. By default, these features are all disabled. ---- 4.3.1 Domain-based Editing Controls Uses the Domain Access module to control which editors can edit content. See section 3.3 for a full discussion of this feature. ---- 4.3.2 Search Settings For this feature to work, you must follow the instructions in INSTALL.txt regarding custom_url_rewrite(). If you have not followed the instructions, you should see a warning at the top of the Admin > Build > Domains page. Allows the admin to decide if content searches should be run across all affiliates or just the currently active domain. By design, Drupal will only find matches for the current domain. Enabling this feature requires the custom_url_rewrite_outbound patch discussed in 2.1.2 ---- 4.3.3 Search Engine Optimization For this feature to work, you must follow the instructions in INSTALL.txt regarding custom_url_rewrite(). If you have not followed the instructions, you should see a warning at the top of the Admin > Build > Domains page. There is a risk with these modules that your site could be penalized by search engines such as Google for having duplicate content. This setting controls the behavior of URLs written for nodes on your affiliated sites. - If SEO settings are turned on, all node links are rewritten as absolute URLs. - If assigned to 'all affiliates' the node link goes to the root domain. - If assigned to a single affiliate, the node link goes to that affiliate. - If assigned to multiple affiliates, the node link goes to the first matching domain. (Determined by the order in which domains were created, with your primary domain matched first.) The optional Domain Source module (included in the download) allows you to assign the link to specific domains. Enabling this feature requires the hook_url_alter() patch discussed in 2.1.2. ---- 4.3.4 WWW Prefix Handling This setting controls how requests to www.example.com are treated with respect to example.com. The default behavior is to process all host names against the registered domain list. If you set this value to 'Treat www.*.example.com as an alias of *.example.com' then all host requests will have the 'www.' string stripped before the domain lookup is processed. Users going to a www.one.example.com in this case will not automatically be sent to one.example.com, but your Drupal site will behave as if they had requested one.example.com. This feature was requested by Rick and Matt at DZone.com ---- 4.3.5 Node Access Settings This setting controls how you want Domain Access to interact with other node access modules. If you _are not_ using a module such as Organic Groups or Taxonomy Access Control, this setting may be disabled. This setting is only required IF: -- You are using more than one node access control module. -- You want to strictly enforce access permissions by requiring both Domain Access and your other module to grant permission. By design, the node access system in Drupal 5 is a permissive system. That is, if you are using multiple node access modules, the permissions are checked using an OR syntax. As a result, if any node access module grants access to a node, the user is granted access. The included multiple_node_access.patch (discussed in 2.1.1) alters this behavior. The patch allows Drupal to use AND logic when running more than one node access module. For example, when using OG and DA, Drupal's default behavior is: -- Return TRUE if OG is TRUE -or- DA is TRUE. This patch allows you to enforce the rule as: -- Return TRUE if OG is TRUE -and- DA is TRUE. By design, the default behavior is to use Drupal's OR logic. For more information, see http://drupal.org/node/191375. Enabling this feature requires the multiple_node_access patch discussed in 2.1.1. ---- 4.4 Special Page Requests For this feature to work, you must follow the instructions in INSTALL.txt regarding custom_url_rewrite(). If you have not followed the instructions, you should see a warning at the top of the Admin > Build > Domains page. In normal uses, such as the default home page, you want to restrict access to content based on the active domain. However, in certain cases, this behavior is not desired. Take the Track page for each user, for example. The Track page is at 'user/UID/track' and shows a list of all posts by that user. By design, this page may show different results if seen from different domains: -- one.example.com/user/1/track Shows all posts by user 1 assigned to the domain one.example.com -- two.example.com/user/1/track Shows all posts by user 1 assigned to the domain two.example.com The behavior we really want is to show ALL posts by the user regardless of the active domain. The Special Page Requests setting lets you specify Drupal paths for which this behavior is active. These paths are entered in the same way as block settings for page visibility. Some sample pages that might require this setting. Note, some of these are contributed modules: -- user/*/track -- blog/* -- the user blog page -- mysite/* -- the MySite module -- popular/alltime -- a View page -- popular/latest -- a View page -- taxonomy/term/* -- to show all taxonomy terms at all times -- taxonomy/term/10 -- to show only term 10 at all times -- taxonomy/term/*/feed/* -- all taxonomy term feeds Default and custom Views are often good candidates here as well. By default, 'user/*/track' is in this list. The logic for how these links are written is documented in 4.3.3 Search Engine Optimization. Note that the 'search' path is handled separately and need not be added here. ---- 4.4.1 Cron Handling When Drupal's cron function runs, it runs on a specific domain. This forces Domain Access to invoke its access control rules, which may not be desired. In most use cases, you will want Domain Access to allow access to all nodes during cron runs. For modules such as Subscriptions, this behavior is required unless all your content is assigned to "all affiliates." To reflect this, Domain Access provides a configuration option labelled: [x] Treat cron.php as a special page request This option is turned on by default. In almost all cases, you should leave this option checked. Doing so allows Domain Access to ignore access checks for nodes when cron runs. Note that this does not affect node access permissions set by other modules. ---- 4.5 Node Link Patterns When using this module, there are times when hook_url_alter() will need to rewrite a node link. Note that these settings are not available if the hook_url_alter() patch is not applied. Since Drupal is an extensible system, we cannot account for all possible links to specific nodes. Node Link Patterns are designed to allow you to extend the module as you add new contributed modules. By default, the following core link paths will be rewritten as needed if you have installed the hook_url_alter() patch. -- node/%n -- comment/reply/%n -- node/add/book/parent/%n -- book/export/html/%n Where %n is a placeholder for the node id. If you install additional modules such as Forward (http://drupal.org/project/forward) or Print (http://drupal.org/project/print), you will want to add their paths to this list: -- forward/%n -- print/%n This is an advanced, but necessary feature. Please report any core node path omissions at http://drupal.org/project/issues/domain. ---- 4.6 Domain List This screen shows all active subdomains registered for use with the site. Record zero (0) is hardcoded to refer to the "root" site defined as your Primary domain name. ---- 4.7 Create domain record As noted above, this screen does not register DNS records with Apache. Use this screen to register new allowed subdomains with your site. This process is especially important for sites using Wildcard DNS, as it prevents non-registered sites from resolving. When you create a new domain record, simply fill in the two fields: - Domain This is the full path.example.com, without http:// or a trailing slash. - Site name This is the name of the site that will be shown when users access this site. -- Domain URL scheme Allows the domain to use 'http' or 'https' as the URL scheme. Default is 'http'. All links and redirects to the domain will use the selected scheme. Both the Domain and the Site name are required to be unique values. After you create a record, you may edit or delete it as you see fit. ---- 4.8 Node Settings The Node settings page is divided into two parts, each with a different purpose. ---- 4.8.1 Domain Node Editing The top section 'Domain node editing' is required for those sites that use the advanced editing techniques outlined in section 3. For users without the 'administer nodes' permission, certain elements of the node editing form are hidden. These settings allow the site administrator to enable users with the 'edit domain nodes' permission to have access to those restricted fields. By default, 'Comment settings', 'Delete node', 'Publshing options', and 'Path aliasing' are enabled. ---- 4.8.2 Domain Node Types The lower section 'Domain node types' is used to extend the 'New content settings' described in 4.1. Domain node types presents a list of all active node types on your site. By checking the box, nodes for that given type will automatically be assigned to 'all affiliate sites' during node creation and editing. ---- 4.9 Batch Updating The module provides for batch actions for common tasks. These actions are useful for making rapid changes across all domains. The following actions are available by default. - Edit all domain values - Edit all site names - Edit all URL schemes - Edit all domain status flags Additional batch actions are made available for the Domain Configuration module. Other modules may implement hook_domainbatch() to provide additional batch actions. ---- 4.10 Block -- Domain Switcher The Domain Access module provides on block, which can be used to help you debug your use of the module. The Domain Switcher block presents a list of all active domains. Clicking on one of the links will take you from your current URL to the same URL on the selected domain. For example, if you are looking at example.com/?q=node and click on another domain, the link will take you to one.example.com/?q=node. In the Domain Switcher block, domains are listed using their human-readable sitename variables. NOTE: This block is for debugging purposes. The included Domain Navigation module provides block and menu items intended for end users. ---- 5. Node Access The Domain Access module is a node_access() module. For additional developer information, see http://api.drupal.org/api/group/node_access/5. By design, the module sets access to content based on the current domain that a user is viewing. If a user is at one.example.com, they can see content that is assigned to that domain or to all domains. ---- 5.1 Assigning Domain Access Users who have the 'set domain access' permission can assign any node to any or all registered sites. During node editing, a series of options will be displayed as checkboxes under the heading "Domain access options": Publishing options: [] Send to all affiliates Select if this content can be shown to all affiliates. This setting will override the options below. Publish to: * (required) [] Drupal [] One site [] Two site Select which affiliates can access this content. If you select 'Send to all affiliates,' the node will be viewable on all domains for your site. If you do not select this option, you must select at least one domain for the node. If you do not select at least one option, the module will automatically assign the node to your default domain. When creating new content, the currently active domain will be selected for you. For users who do not have the 'set domain access' permission, the assignment will be done through a hidden form element. The node will be assigned to the currently active domain or, if configured , to all domains. ---- 5.2. Editor Access Whenever a user account is created and the Domain Access module is active, user accounts will automatically be tagged with the name of the active domain from which they registered their account. Users with the 'set domain access' permission may assign individual users to specific domains in the same way that nodes can be defined. These user settings are used to determine what domains an editor belongs to. Users with the 'edit domain nodes' permission can edit any node that belongs to the same domain that the user does. (Remember that users and nodes can both belong to multiple domains.) However, nodes that are assigned to 'all affiliates' do not grant editing privileges to all editors. ---- 5.3 Realms This section contains technical details about Drupal's node access system. In Domain Access, the following realms are defined: - domain_all Indicates whether the view grant should be passed for all nodes on a given page request. Used in cases such as Search and MySite to enable aggregation of content across affiliates. The only valid nid and gid for this grant are zero (0). - domain_site Indicates whether a node is assigned to all affliaites. The only valid grant id for this realm is zero (0). - domain_id Indicates that a node belongs to one or more registered domains. The domain_id key is taken from the {domain} table and is unique. - domain_editor Indicates that a node can be edited or deleted by an editor for a specific domain. This advanced usage is optional. ---- 5.4 Grants In each of the realms, there are specific rules for node access grants, as follows. - domain_all In some specific cases, like Search, or MySite, or the user's Tracker page we want people to be able to see content across all affiliates. Only the domain_all grant is assigned in these cases. This grants only 'grant_view'. - domain_site By design, all site users, including anonymous users, are granted access to the gid '0' for realm 'domain_site'. This grant allows all users to see content assigned to 'all affliates'. This grants only 'grant_view'. - domain_id When a user, including anonymous users, views a page, the active domain is identified by the registered domain_id. For that page view, the user is granted gid of the active domain_id for the realm 'domain_id'. This allows content to be partitioned to one or many affilaites. This grants only 'grant_view', since 'grant_edit' would allow content to appear to some users regardless of the active domain. - domain_editor Advanced. If used, this sets the access for users who have the 'edit domain nodes' permission. This grant works like the domain_id grant, but only grants editors access if the node belongs to one of their assigned domains. This grants both the 'grant_edit' and 'grant_delete' permission. ---- 5.5 Warnings Node access in Drupal is a permissive system. Once a grant has been issued, it cannot be revoked. As a result, it is possible for multiple editors to be able to edit or delete a single node. Here's the use case: - Node 10 (a book page) is assigned to one.example.com and three.example.com - User A is an editor for one.example.com. - User B is an editor for two.example.com - User C is an editor for three.example.com Under this scenario, User A and User C will be able to edit node 10. To be more clear about Drupal permissions: - User D has 'administer nodes' permission for the site. - User E has 'edit book nodes' permission for the site. In this case, User D and User E can also edit or delete node 10. This is why only super-admins are given 'administer nodes' and 'edit TYPE nodes' permissions with the Domain Access module. If you want your affiliate editors to have limited permissions, only grant them 'edit domain nodes'. However, you still need to give users the 'create TYPE nodes' permission normally. Domain Access does not affect node creation. Since Domain Access implements node_access() fully, if you uninstall the module -- using Drupal's uninstall sequence -- all node_access entries should be reset to grant 'grant_view' to realm 'all' with gid '0'. ---- 6. Developer Notes The Domain Access module is meant to be the core module for a system of small modules which add functionality. ---- 6.1 Extension Modules Currently, the following modules are included in the download. They are not required, but each adds functionality to the core module. - Domain Configuration -- Allows you to change select system variables for each subdomain, such as files directory, offline status, footer message and default home page. - Domain Content -- Provides a content administration page for each subdomain, so that affiliate editors can administer content for their section of the site. - Domain Navigation -- Supplies a navigation block with three themes. Creates menu items for each subdomain, suitable for using as primary or secondary links. - Domain Prefix -- A powerful module that allows for selective table prefixing for each subdomain in your installation. - Domain Source -- Allows editors to specify a primary "source" domain to be used when linking to content from another domain. - Domain Strict -- Forces users to be assigned to a domain in order to view content on that domain. Note that anonymous users may only see content assigned to "all affiliates" if this module is enabled. - Domain Theme -- Allows separate themes for each subdomain. - Domain User -- Allows the creation of specific subdomains for each active site user. - Domain Views -- Provides a Views filter for the Domain Access module. ---- 6.2 The $_domain Global During hook_init(), the Domain Access module creates a nwe global variable, $_domain, which can be used by other Drupal elements (themes, blocks, modules). The $_domain global is an array of data taken from the {domain} table for the currently active domain. If no active domain is found, default values are used: $_domain['domain_id'] = 0; $_domain['sitename'] = variable_get('domain_sitename', variable_get('sitename', 'Drupal')) $_domain['subdomain'] = variable_get('domain_root', '') $_domain['scheme'] = 'http' $_domain['valid'] = TRUE $_domain['path'] = http://example.com Some uses for this global variable might include: - Block placement based on active subdomain (using PHP for block visibility). - Ad tags inserted based on active subdomain. - Theme switching based on subdomain. ---- 6.3 Database Schema The Domain Access module creates two tables in a Drupal installation. {domain} contains the following structure: - domain_id Integer, unique, auto-incrementing. The primary key for all domain records. - subdomain Varchar, 80, unique (enforced by code) 'Domain' is a sql-reserved word, so subdomain is used. This value must match the url 'host' string derived from parse_url() on the current page request. - sitename Varchar, 80, unique (enforced by code) The name for this affiliate, used for readability. - scheme Varchar, 8 default 'http' Indicates the URL scheme to use when accessing this domain. Allowed values, are currently 'http' and 'https'. - valid Char, 1 default 1 Indicates that this domain is active and can be accessed by site users. The {domain_access} table is a partial mirror of the {node_access} table and stores information specific to Domain Access. Its structure is: - nid Integer, unsigned NOT NULL default '0, - gid Integer, unsigned NOT NULL default '0' - realm Varchar, 255 NOT NULL default '' ---- 6.4 API The Domain Access module has an API for internal module hooks. Documentation is included in the download as API.php and can be viewed online at: http://therickards.com/api The most important developer functions are the internal module hooks: http://therickards.com/api/group/hooks/Domain ---- 7. To Do Currently, the module does not support logins across more than one top-level domain. That is, it will only work for the following: - example.com - one.example.com - two.example.com Even though domains are registered with fully-qualifed names, this setup will not work, since Drupal's login cookie is domain-specific. - example.com - one.example.com - myexample.com [will fail login because it cannot read *.example.com cookie] Possible soultions for this issue are welcome -- the Single SignOn module may work, with some modification. Solutions should be rolled as separate sub-modules.