book

Pro Drupal 7 Development, Third Edition

Name: Pro Drupal 7 Development, Third Edition
ISBN: 9781430228387

by Todd Tomlinson, John K. VanDyk

December 2010

Intermediate to advanced

719 pages

13h 53m

English

Apress

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Copyright
Foreword
About the Authors
About the Technical Reviewers
Acknowledgments
Introduction
1. How Drupal Works
1.1. What Is Drupal?1.2. Technology Stack1.3. Core1.4. Administrative Interface1.5. Modules1.6. Hooks1.7. Themes1.8. Nodes1.9. Fields1.10. Blocks1.11. File Layout1.12. Serving a Request1.12.1. The Web Server's Role1.12.2. The Bootstrap Process1.12.3. Processing a Request1.12.4. Theming the Data1.13. Summary
2. Writing a Module
2.1. Creating the Files2.2. Implementing a Hook2.3. Adding Module-Specific Settings2.4. Defining Your Own Administration Section2.5. Presenting a Settings Form to the User2.6. Validating User-Submitted Settings2.7. Storing Settings2.7.1. Using Drupal's variables Table2.7.2. Retrieving Stored Values with variable_get()2.8. Further Steps2.9. Summary
3. Hooks, Actions, and Triggers
3.1. Understanding Events and Triggers3.2. Understanding Actions3.2.1. The Trigger User Interface3.2.2. Your First Action3.2.3. Assigning the Action3.2.4. Changing Which Triggers an Action Supports3.2.4.1. Actions That Support Any Trigger3.2.4.2. Advanced Actions3.3. Using the Context in Actions3.3.1. How the Trigger Module Prepares the Context3.3.2. Changing Existing Actions with action_info_alter()3.3.3. Establishing the Context3.4. How Actions Are Stored3.4.1. The actions Table3.4.2. Action IDs3.5. Calling an Action Directly with actions_do()3.6. Defining Your Own Triggers with hook_trigger_info()3.7. Adding Triggers to Existing Hooks3.8. Summary
4. The Menu System
4.1. Callback Mapping4.2. Mapping URLs to Functions4.3. Creating a Menu Item4.4. Page Callback Arguments4.5. Page Callbacks in Other Files4.6. Adding a Link to the Navigation Block4.7. Menu Nesting4.8. Access Control4.9. Title Localization and Customization4.10. Defining a Title Callback4.11. Wildcards in Menu Items4.11.1. Basic Wildcards4.11.2. Wildcards and Page Callback Parameters4.11.3. Using the Value of a Wildcard4.11.4. Wildcards and Parameter Replacement4.11.5. Passing Additional Arguments to the Load Function4.11.6. Special, Predefined Load Arguments: %map and %index4.11.7. Building Paths from Wildcards Using to_arg() Functions4.11.8. Special Cases for Wildcards and to_arg() Functions4.12. Altering Menu Items from Other Modules4.13. Altering Menu Links from Other Modules4.14. Kinds of Menu Items4.15. Common Tasks4.15.1. Assigning Callbacks Without Adding a Link to the Menu4.15.2. Displaying Menu Items As Tabs4.15.3. Hiding Existing Menu Items4.15.4. Using menu.module4.15.5. Common Mistakes4.16. Summary

5. Working with Databases
5.1. Defining Database Parameters5.2. Understanding the Database Abstraction Layer5.3. Connecting to the Database5.4. Performing Simple Queries5.5. Retrieving Query Results5.5.1. Getting a Single Value5.5.2. Getting Multiple Rows5.5.3. Using the Query Builder and Query Objects5.5.4. Getting a Limited Range of Results5.5.5. Getting Results for Paged Display5.5.6. Other Common Queries5.6. Inserts and Updates with drupal_write_record()5.7. The Schema API5.7.1. Using Module .install Files5.7.2. Creating Tables5.7.3. Using the Schema Module5.7.4. Field Type Mapping from Schema to Database5.7.4.1. Textual5.7.4.2. Varchar5.7.4.3. Char5.7.4.4. Text5.7.4.5. Numerical5.7.4.6. Integer5.7.4.7. Serial5.7.4.8. Float5.7.4.9. Numeric5.7.4.10. Date and Time: Datetime5.7.4.11. Binary: Blob5.7.5. Declaring a Specific Column Type with mysql_type5.7.6. Maintaining Tables5.7.7. Deleting Tables on Uninstall5.7.8. Changing Existing Schemas with hook_schema_alter()5.8. Modifying Other Modules' Queries with hook_query_alter()5.9. Connecting to Multiple Databases Within Drupal5.10. Using a Temporary Table5.11. Writing Your Own Database Driver5.12. Summary
6. Working with Users
6.1. The $user Object6.2. Testing If a User Is Logged In6.3. Introduction to user hooks6.3.1. Understanding hook_user_view($account, $view_mode)6.4. The User Registration Process6.5. Using profile.module to Collect User Information6.6. The Login Process6.6.1. Adding Data to the $user Object at Load Time6.6.2. Providing User Information Categories6.7. External Login6.8. Summary
7. Working with Nodes
7.1. So What Exactly Is a Node?7.2. Not Everything Is a Node7.3. Creating a Node Module7.3.1. Creating the .install File7.3.2. Creating the .info File7.3.3. Creating the .module File7.3.4. Providing Information About Our Node Type7.3.5. Modifying the Menu Callback7.3.6. Defining Node-Type–Specific Permissions with hook_permission()7.3.7. Limiting Access to a Node Type with hook__node_access()7.3.8. Customizing the Node Form for Our Node Type7.3.9. Validating Fields with hook_validate()7.3.10. Saving Our Data with hook_insert()7.3.11. Keeping Data Current with hook_update()7.3.12. Cleaning Up with hook_delete()7.3.13. Modifying Nodes of Our Type with hook_load()7.3.14. Using hook_view()7.3.15. Manipulating Nodes That Are Not Our Type with hook_node_xxxxx()7.4. How Nodes Are Stored7.5. Creating a Node Type with Custom Content Types7.6. Restricting Access to Nodes7.6.1. Defining Node Grants7.6.1.1. What Is a Realm?7.6.1.2. What Is a Grant ID?7.6.2. The Node Access Process7.7. Summary
8. Working with Fields
8.1. Creating Content Types8.2. Adding Fields to a Content Type8.3. Creating a Custom Field8.4. Adding Fields Programmatically8.5. Summary
9. The Theme System
9.1. Themes9.1.1. Installing an Off-the-Shelf Theme9.1.2. Building a Theme9.2. The .info File9.2.1. Adding Regions to Your Theme9.2.2. Adding CSS Files to Your Theme9.2.3. Adding JavaScript Files9.2.4. Adding Settings to Your Theme9.3. Understanding Template Files9.3.1. The Big Picture9.3.2. The html.php.tpl File9.3.2.1. The page.tpl.php File9.3.2.2. The region.tpl.php File9.3.2.3. The node.tpl.php File9.3.2.4. The field.tpl.php File9.3.2.5. The block.tpl.php File9.3.3. Overriding Template Files9.3.4. Other Template Files9.3.4.1. Introducing the theme() Function9.3.4.2. An Overview of How theme() Works9.3.5. Overriding Themable Items9.3.6. Overriding with Template Files9.3.7. Adding and Manipulating Template Variables9.3.8. Using the Theme Developer Module9.4. Summary
10. Working with Blocks
10.1. What Is a Block?10.2. Block Configuration Options10.2.1. Block Placement10.2.2. Defining a Block10.2.3. Using the Block Hooks10.3. Building a Block10.4. Enabling a Block When a Module Is Installed10.5. Block Visibility Examples10.5.1. Displaying a Block to Logged-In Users Only10.5.2. Displaying a Block to Anonymous Users Only10.6. Summary
11. The Form API
11.1. Understanding Form Processing11.1.1. Initializing the Process11.1.2. Setting a Token11.1.3. Setting an ID11.1.4. Collecting All Possible Form Element Definitions11.1.5. Looking for a Validation Function11.1.6. Looking for a Submit Function11.1.7. Allowing Modules to Alter the Form Before It's Built11.1.8. Building the Form11.1.9. Allowing Functions to Alter the Form After It's Built11.1.10. Checking If the Form Has Been Submitted11.1.11. Finding a Theme Function for the Form11.1.12. Allowing Modules to Modify the Form Before It's Rendered11.1.13. Rendering the Form11.1.14. Validating the Form11.1.14.1. Token Validation11.1.14.2. Built-In Validation11.1.14.3. Element-Specific Validation11.1.14.4. Validation Callbacks11.1.15. Submitting the Form11.1.16. Redirecting the User11.2. Creating Basic Forms11.2.1. Form Properties11.2.2. Form IDs11.2.3. Fieldsets11.2.4. Theming Forms11.2.4.1. Using #prefix, #suffix, and #markup11.2.4.2. Using a Theme Function11.2.4.3. Telling Drupal Which Theme Function to Use11.2.5. Specifying Validation and Submission Functions with hook_forms()11.2.6. Call Order of Theme, Validation, and Submission Functions11.2.7. Writing a Validation Function11.2.7.1.11.2.7.1.1. Using form_set_value() to Pass Data11.2.7.1.2. Using $form_state to Pass Data11.2.7.1.3. Element-Specific Validation11.2.8. Form Rebuilding11.2.9. Writing a Submit Function11.2.10. Changing Forms with hook_form_alter()11.2.10.1. Altering Any Form11.2.10.2. Altering a Specific Form11.2.11. Submitting Forms Programmatically with drupal_form_submit()11.2.12. Dynamic Forms11.3. Form API Properties11.3.1. Properties for the Root of the Form11.3.1.1. #action11.3.1.2. #built11.3.1.3. #method11.3.2. Properties Added to All Elements11.3.2.1. #description11.3.2.2. #attributes11.3.2.3. #required11.3.2.4. #tree11.3.3. Properties Allowed in All Elements11.3.3.1. #type11.3.3.2. #access11.3.3.3. #after_build11.3.3.4. #array_parents11.3.3.5. #attached11.3.3.6. #default_value11.3.3.7. #disabled11.3.3.8. #element_validate11.3.3.9. #parents11.3.3.10. #post_render11.3.3.11. #prefix11.3.3.12. #pre_render11.3.3.13. #process11.3.3.14. #states11.3.3.15. #suffix11.3.3.16. #theme11.3.3.17. #theme_wrappers11.3.3.18. #title11.3.3.19. #tree11.3.3.20. #weight11.3.4. Form Elements11.3.4.1. Text Field11.3.4.2. Password11.3.4.3. Password with Confirmation11.3.4.4. Textarea11.3.4.5. Select11.3.4.6. Radio Buttons11.3.4.7. Check Boxes11.3.4.8. Value11.3.4.9. Hidden11.3.4.10. Date11.3.4.11. Weight11.3.4.12. File Upload11.3.4.13. Fieldset11.3.4.14. Submit11.3.4.15. Button11.3.4.16. Image Button11.3.4.17. Markup11.3.4.18. Item11.3.4.19. #ajax Property11.3.4.19.1. If Javascript is not supported11.3.4.19.2. Additional AJAX features11.3.4.19.3. Additional resources11.4. Summary
12. Manipulating User Input: The Filter System
12.1. Filters12.2. Filters and Text formats12.2.1. Installing a Filter12.2.2. Knowing When to Use Filters12.3. Creating a Custom Filter12.3.1. Implementing hook_filter_info()12.3.2. The Process Function12.3.3. Helper Function12.4. Summary
13. Searching and Indexing Content
13.1. Building a Custom Search Page13.1.1. The Default Search Form13.1.2. The Advanced Search Form13.1.3. Adding to the Search Form13.1.3.1. Introducing the Search Hooks13.1.3.2. Formatting Search Results with hook_search_page()13.1.3.3. Making Path Aliases Searchable13.2. Using the Search HTML Indexer13.2.1. When to Use the Indexer13.2.2. How the Indexer Works13.2.2.1. Adding Metadata to Nodes: hook_node_update_index()13.2.2.2. Indexing Content That Isn't a Node: hook_update_index()13.3. Summary
14. Working with Files
14.1. How Drupal Serves Files14.2. Managed and Unmanaged Drupal APIs14.2.1. Public Files14.2.2. Private Files14.3. PHP Settings14.4. Media Handling14.4.1. Upload Field14.4.2. Video and Audio14.5. File API14.5.1. Database Schema14.5.2. Common Tasks and Functions14.5.2.1. Finding the Default Files URI14.5.2.1.1. Saving Data to a File14.5.2.1.2. file_save_data($data, $destination = NULL, $replace = FILE_EXISTS_RENAME)14.5.2.2. Copying and Moving Files14.5.2.2.1. file_copy($source, $destination = NULL, $replace = FILE_EXISTS_RENAME)14.5.2.2.2. file_move($source, $destination = NULL, $replace = FILE_EXISTS_RENAME)14.5.2.3. Checking Directories14.5.2.4. Uploading Files14.5.2.4.1. file_save_upload($source, $validators = array(), $destination = FALSE, $replace = FILE_EXISTS_RENAME)14.5.2.4.2. file_validate_extensions($file, $extensions)14.5.2.4.3. file_validate_is_image($file)14.5.2.4.4. file_validate_image_resolution($file, $maximum_dimensions = 0, $minimum_dimensions = 0)14.5.2.4.5. file_validate_name_length($file)14.5.2.4.6. file_validate_size($file, $file_limit = 0, $user_limit = 0)14.5.2.5. Getting the URL for a File14.5.2.5.1. file_create_url($uri)14.5.2.6. Finding Files in a Directory14.5.2.6.1. file_scan_directory($dir, $mask, $options = array(), $depth = 0)14.5.2.7. Finding the Temp Directory14.5.2.8. Neutralizing Dangerous Files14.5.2.8.1. file_munge_filename($filename, $extensions, $alerts = TRUE)14.5.2.8.2. file_unmunge_filename($filename)14.5.2.9. Checking Disk Space14.5.2.9.1. file_space_used($uid = NULL, $status = FILE_STATUS_PERMANENT)14.5.3. Authentication Hooks for Downloading14.6. Summary
15. Working with Taxonomy
15.1. The Structure of Taxonomy15.2. Creating a Vocabulary15.3. Creating Terms15.4. Assigning a Vocabulary to a Content Type15.5. Kinds of Taxonomy15.5.1. Flat15.5.2. Hierarchical15.5.3. Multiple Hierarchical15.6. Viewing Content by Term15.6.1. Using AND and OR in URLs15.6.2. Specifying Depth for Hierarchical Vocabularies15.6.3. Automatic RSS Feeds15.7. Storing Taxonomies15.8. Module-Based Vocabularies15.8.1. Creating a Module-Based Vocabulary15.8.2. Keeping Informed of Vocabulary Changes with Taxonomy Hooks15.9. Common Tasks15.9.1. Displaying Taxonomy Terms Associated with a Node15.9.2. Building Your Own Taxonomy Queries15.9.3. Using taxonomy_select_nodes()15.10. Taxonomy Functions15.10.1. Retrieving Information About Vocabularies15.10.1.1. taxonomy_vocabulary_load($vid)15.10.1.2. taxonomy_get_vocabularies()15.10.2. Adding, Modifying, and Deleting Vocabularies15.10.2.1. taxonomy_vocabulary_save($vocabulary)15.10.2.2. taxonomy_vocabulary_delete($vid)15.10.3. Retrieving Information About Terms15.10.3.1. taxonomy_load_term($tid)15.10.3.2. taxonomy_get_term_by_name($name)15.10.4. Adding, Modifying, and Deleting Terms15.10.4.1. taxonomy_term_save($term)15.10.4.2. taxonomy_term_delete($tid)15.10.5. Retrieving Information About Term Hierarchy15.10.5.1. taxonomy_get_parents($tid, $key)15.10.5.2. taxonomy_get_parents_all($tid)15.10.5.3. taxonomy_get_children($tid, $vid, $key)15.10.5.4. taxonomy_get_tree($vid, $parent, $max_depth, $load_entities = FALSE)15.10.6. Finding Nodes with Certain Terms15.11. Additional Resources15.12. Summary
16. Caching
16.1. Knowing When to Cache16.2. How Caching Works16.3. How Caching Is Used Within Drupal Core16.3.1. Menu System16.3.2. Caching Filtered Text16.3.3. Administration Variables and Module Settings16.3.3.1. Disabling Caching16.3.3.2. Page Caching16.3.3.3. Static Page Caching16.3.4. Blocks16.3.5. Using the Cache API16.3.5.1. Caching Data with cache_set()16.3.5.2. Retrieving Cached Data with cache_get() and cache_get_multiple()16.3.5.3. Checking to See If Cache Is Empty with cache_is_empty()16.3.5.4. Clearing Cache with cache_clear_all()16.3.5.4.1. Using the $reset Parameter16.3.5.4.2. Using cache_clear_all()16.3.5.4.3. Using hook_flush_caches()16.4. Summary
17. Sessions
17.1. What Are Sessions?17.2. Usage17.3. Session-Related Settings17.3.1. In .htaccess17.3.2. In settings.php17.3.3. In bootstrap.inc17.3.4. Requiring Cookies17.4. Storage17.5. Session Life Cycle17.6. Session Conversations17.6.1. First Visit17.6.2. Second Visit17.6.3. User with an Account17.7. Common Tasks17.7.1. Changing the Length of Time Before a Cookie Expires17.7.2. Changing the Name of the Session17.7.3. Storing Data in the Session17.8. Summary
18. Using jQuery
18.1. What Is jQuery?18.2. The Old Way18.3. How jQuery Works18.3.1. Using a CSS ID Selector18.3.2. Using a CSS Class Selector18.4. jQuery Within Drupal18.4.1. Your First jQuery Code18.4.2. Targeting an Element by ID18.4.3. Method Chaining18.4.4. Adding or Removing a Class18.4.5. Wrapping Existing Elements18.4.6. Changing Values of CSS Elements18.4.7. Where to Put JavaScript18.4.7.1. Adding JavaScript via a Theme .info File18.4.7.2. A Module That Uses jQuery18.4.8. Overridable JavaScript18.5. Building a jQuery Voting Widget18.5.1. Building the Module18.5.2. Using Drupal.behaviors18.5.3. Ways to Extend This Module18.5.4. Compatibility18.6. Next Steps18.7. Summary
19. Localization and Translation
19.1. Enabling the Locale Module19.2. User Interface Translation19.2.1. Strings19.2.2. Translating Strings with t()19.2.3. Replacing Built-In Strings with Custom Strings19.2.3.1. String Overrides in settings.php19.2.3.2. Replacing Strings with the Locale Module19.2.3.3. Exporting Your Translation19.2.3.3.1. Portable Object Files19.2.3.3.2. Portable Object Templates19.3. Starting a New Translation19.3.1. Generating .pot Files with Translation Template Extractor19.3.2. Creating a .pot File for Your Module19.3.2.1. Using the Command Line19.3.2.2. Using the Web-Based Extractor19.3.3. Creating .pot Files for an Entire Site19.4. Installing a Language Translation19.4.1. Setting Up a Translation at Install Time19.4.2. Installing a Translation on an Existing Site19.5. Right-to-Left Language Support19.6. Language Negotiation19.6.1. Default19.6.1.1. User-Preferred Language19.6.1.2. The Global $language Object19.6.2. Path Prefix Only19.6.3. Path Prefix with Language Fallback19.6.4. URL Only19.7. Content Translation19.7.1. Introducing the Content Translation Module19.7.2. Multilingual Support19.7.3. Multilingual Support with Translation19.8. Localization- and Translation-Related Files19.9. Additional Resources19.10. Summary
20. XML-RPC
20.1. What Is XML-RPC?20.2. Prerequisites for XML-RPC20.3. XML-RPC Clients20.3.1. XML-RPC Client Example: Getting the Time20.3.2. XML-RPC Client Example: Getting the Name of a State20.3.3. Handling XML-RPC Client Errors20.3.3.1. Network Errors20.3.3.2. HTTP Errors20.3.3.3. Call Syntax Errors20.4. A Simple XML-RPC Server20.4.1. Mapping Your Method with hook_xmlrpc()20.4.2. Automatic Parameter Type Validation with hook_xmlrpc()20.5. Built-In XML-RPC Methods20.5.1. system.listMethods20.5.2. system.methodSignature20.5.3. system.methodHelp20.5.4. system.getCapabilities20.5.5. system.multiCall20.6. Summary
21. Writing Secure Code
21.1. Handling User Input21.1.1. Thinking About Data Types21.1.1.1. Plain Text21.1.1.2. HTML Text21.1.1.3. Rich Text21.1.1.4. URL21.1.2. Using check_plain() and t() to Sanitize Output21.1.3. Using filter_xss() to Prevent Cross-Site Scripting Attacks21.1.4. Using filter_xss_admin()21.2. Handling URLs Securely21.3. Making Queries Secure with db_query()21.4. Keeping Private Data Private with hook_query_alter()21.5. Dynamic Queries21.6. Permissions and Page Callbacks21.7. Cross-Site Request Forgeries (CSRF)21.8. File Security21.8.1. File Permissions21.8.2. Protected Files21.8.3. File Uploads21.8.4. Filenames and Paths21.9. Encoding Mail Headers21.10. Files for Production Environments21.11. SSL Support21.12. Stand-Alone PHP21.13. AJAX Security, a.k.a. Request Replay Attack21.14. Form API Security21.15. Protecting the Superuser Account21.16. Summary
22. Development Best Practices
22.1. Coding Standards22.1.1. Line Indention and Whitespace22.1.2. Operators22.2. Casting22.3. Control Structures22.3.1. Function Calls22.3.2. Function Declarations22.3.3. Function Names22.3.4. Class Constructor Calls22.3.5. Arrays22.3.6. Quotes22.3.7. String Concatenators22.4. Comments22.4.1. Documentation Examples22.4.2. Documenting Constants22.4.3. Documenting Functions22.4.4. Documenting Hook Implementations22.4.5. Including Code22.4.6. PHP Code Tags22.4.7. Semicolons22.4.8. Example URLs22.5. Naming Conventions22.6. Checking Your Coding Style with Coder Module22.7. Finding Your Way Around Code with grep22.8. Summary
23. Optimizing Drupal
23.1. Caching Is the Key to Drupal Performance23.2. Optimizing PHP23.2.1. Setting PHP Opcode Cache File to /dev/zero23.2.2. PHP Process Pool Settings23.3. Tuning Apache23.3.1. mod_expires23.3.2. Moving Directives from .htaccess to httpd.conf23.3.3. MPM Prefork vs. Apache MPM Worker23.3.4. Balancing the Apache Pool Size23.3.5. Decreasing Apache Timeout23.3.6. Disabling Unused Apache Modules23.4. Using Nginx Instead of Apache23.5. Using Pressflow23.6. Varnish23.6.1. Normalizing incoming requests for better Varnish hits23.6.2. Varnish: finding extraneous cookies23.7. Boost23.8. Boost vs. Varnish23.9. Linux System Tuning for High Traffic Servers23.10. Using Fast File Systems23.11. Dedicated Servers vs. Virtual Servers23.12. Avoiding Calling External Web Services23.13. Decreasing Server Timeouts23.14. Database Optimization23.14.1. Enabling MySQL's Query Cache23.14.2. MySQL InnoDB Performance on Windows23.15. Drupal Performance23.15.1. Eliminating 404 Errors23.15.2. Disabling Modules You're Not Using23.16. Drupal-Specific Optimizations23.16.1. Page Caching23.16.2. Bandwidth Optimization23.16.3. Pruning the Sessions Table23.16.4. Managing the Traffic of Authenticated Users23.16.4.1. Logging to the Database23.16.4.2. Logging to Syslog23.16.5. Running cron23.17. Architectures23.17.1. Single Server23.17.2. Separate Database Server23.17.3. Separate Database Server and a Web Server Cluster23.17.3.1. Load Balancing23.17.3.2. File Uploads and Synchronization23.17.3.2.1. Using a Shared, Mounted File System23.17.3.2.2. Beyond a Single File System23.17.4. Multiple Database Servers23.17.4.1. Database Replication23.17.4.2. Database Partitioning23.18. Finding the Bottleneck23.18.1.23.18.1.1. Web Server Running Out of CPU23.18.1.2. Web Server Running Out of RAM23.18.1.3. Identifying Expensive Database Queries23.18.1.4. Identifying Expensive Pages23.18.1.5. Identifying Expensive Code23.18.1.6. Optimizing Tables23.18.1.7. Caching Queries Manually23.18.1.8. Changing the Table Type from MyISAM to InnoDB23.19. Summary
24. Installation Profiles
24.1. Creating a New Installation Profile24.1.1. The enhanced.info File24.1.2. The enhanced.profile File24.1.3. The enhanced.install File24.2. Using hook_install_tasks and hook_install_tasks_alter24.3. Summary
25. Testing
25.1. Setting Up the Test Environment25.2. How Tests Are Defined25.3. Test Functions25.4. Test Assertions25.5. Summary
A. Database Table Reference
B. Resources
B.1. CodeB.1.1. The Drupal Source Code Repository on GITB.1.2. ExamplesB.1.3. Drupal API ReferenceB.1.4. Security AdvisoriesB.1.5. Updating ModulesB.1.6. Updating ThemesB.2. HandbooksB.3. ForumsB.4. Mailing ListsB.4.1. DevelopmentB.4.2. ThemesB.4.3. TranslationsB.5. User Groups and Interest GroupsB.6. Internet Relay ChatB.6.1. North AmericaB.6.2. EuropeB.6.3. AsiaB.6.4. Latin America / CaribbeanB.6.5. OceaniaB.6.6. AfricaB.7. VideocastsB.8. WeblogsB.9. ConferencesB.10. Contribute

Content preview from Pro Drupal 7 Development, Third Edition

Chapter 17. Sessions

HTTP is a stateless protocol, which means that each interaction between the web browser and server stands alone. So how do you track a user as he or she navigates through a series of web pages on a web site? You use sessions. Starting with version 4, PHP offers built-in support for sessions via the session family of functions. In this chapter, you'll see how Drupal uses PHP's sessions.

What Are Sessions?

A session is a mechanism for storing information across page visits for a specific user on a web site. Sessions are stored in a cookie and are assigned a unique ID, allowing the web site to access information in the cookie and associate that information with a specific user. Once a session has been created, Drupal core and contributed ...

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