Building Server Applications Using Objective C And Gn Ustep
- 2. Server Applications “Server Applications” = programs with no GUI In GNUstep, server applications are based on GNUstep-base. GNUstep-base is the most complete and extensively polished and tested part of GNUstep ... … but is little known to the public. People often identify GNUstep only with the GUI framework/development environment.
- 3. Objective-C it is a programming language
- 4. it is a strict superset of C it is C with some new additional constructs
- 5. C code compiles as Objective-C code
- 6. C libraries can be linked and used natively from Objective-C it adds Object-Oriented features to C Defining classes
- 8. Instantiating classes and objects
- 9. Invoking class and object methods
- 10. Protocols, categories, selectors, forwarding
- 11. Why is Objective-C so special ? It is compatible with C libraries
- 12. Is is a simple extension of C
- 13. It is a hybrid between C and Smalltalk It can be as fast as raw C if you avoid the object-oriented extensions
- 14. It can be as high-level and flexible as Smalltalk if you use the object-oriented extensions
- 15. It allows experienced programmers to mix different programming styles in the same program It is extremely flexible
- 16. Powerful “ Foundation ” class library
- 17. Why use Objective-C for Server Applications ? Very fast. You can freely mix it with C and even assembler if you need.
- 18. High-level language. Organize your server code using high-level, object-orientated design patterns.
- 19. Powerful Foundation library (GNUstep-base). The API originates from OpenStep and the implementation has been polished for 13+ years.
- 20. OpenStep API - Foundation Kit (1994) Foundation Kit Non-graphical classes Root classes : NSObject, NSProxy
- 21. Basic data classes : NSString, NSNumber, NSData, NSNull
- 22. Collection classes : NSArray, NSDictionary, NSSet
- 23. Execution control classes : NSRunLoop, NSTimer, NSThread, NSLock
- 24. I/O classes : NSTask, NSFileHandle
- 25. Notification classes: NSNotification, NSDistributedNotification
- 26. Serialization classes: NSArchiver, NSCoder
- 27. Resource management classes: NSBundle, NSUserDefaults
- 28. Distributed Objects Classes: NSConnection, NSPort
- 29. And many more... Application Foundation Kit Application Kit Operating System OS Graphical System Objective-C Runtime
- 30. GNUstep-base Application GNUstep Base GNUstep GUI Operating System (Any!) Graphical System (Any!) GNU Objective-C Runtime GNUstep Back
- 31. Server Applications – what do you need ? gcc-objc Objective-C compiler
- 32. Objective-C runtime gnustep-make Official GNUstep Building System
- 33. Makefile library that automatically takes care of configuring and building on different platforms gnustep-base OpenStep Foundation Kit implementation
- 34. Provides “core” non-graphical Objective-C classes
- 35. Important dependencies libffi Required by gnustep-base
- 36. You may need to download it and install it from www.gnustep.org libxml Required by gnustep-base
- 37. Install it from your GNU/Linux distribution gnutls or openssl Allow gnustep-base to support https://
- 38. Install it from your GNU/Linux distribution
- 39. Typical Quick Installation (Ubuntu) apt-get libgnustep-base-dev
- 40. Typical Manual Installation (RedHat) yum install gcc-objc libxml-devel openssl-devel wget ftp://sourceware.org/pub/libffi/libffi-3.0.1.tar.gz tar xfvz libffi-3.0.1.tar.gz cd libffi-3.0.1 ./configure make su -c 'make install' <edit /etc/ld.so.conf adding /usr/local/lib, then run ldconfig as root> wget ftp://ftp.gnustep.org/pub/gnustep/core/gnustep-make-2.0.8.tar.gz tar xfvz gnustep-make-2.0.8.tar.gz cd gnustep-make-2.0.8.tar.gz ./configure make su -c 'make install' . /usr/GNUstep/System/Library/Makefiles/GNUstep.sh wget ftp://ftp.gnustep.org/pub/gnustep/core/gnustep-base-1.18.0.tar.gz tar xfvz gnustep-base-1.18.0.tar.gz cd gnustep-base-1.18.0 ./configure –enable-openssl make su -c 'make install'
- 41. “Hello World!” Program “Hello World” using Objective-C / GNUstep-base hello.m #import <Foundation/Foundation.h> int main (void) { NSLog (@“Hello world!”); return 0; }
- 42. “Hello World!” Program “Hello World” using Objective-C / GNUstep-base GNUmakefile include $(GNUSTEP_MAKEFILES)/common.make TOOL_NAME = hello hello_OBJC_FILES = hello.m include $(GNUSTEP_MAKEFILES)/tool.make
- 43. “Hello World!” Program “Hello World” using Objective-C / GNUstep-base Usual compilation commands make make clean make distclean make install make messages=yes make install messages=yes
- 44. “Hello World!” Program “Hello World” using Objective-C / GNUstep-base Compilation results are in ./obj Let's try it out: Tutorial Compilation Session
- 45. GNUstep-base coding: where to start GNUstep Mini Tutorials (Introduction): http://www.gnustep.it/nicola/Tutorials/index.html GNUstep Base Documentation (API Reference): http://www.gnustep.org/resources/documentation/Developer/Base/Reference/index.html
- 46. GNUstep-base coding: basic classes Class cluster Design Transparent way of optimizing classes without changing the public API
- 47. When you create a NSString or NSArray you actually get an instance of a subclass optimized to perform best in your situation
- 48. Method dispatch is dynamic, so that works
- 49. You can implement your own subclasses for performance Mutable and non-mutable Classes NSString vs NSMutableString
- 50. NSString is for constant strings that never change
- 51. NSMutableString is for strings that might change
- 52. Allows a lot of optimizations inside the library
- 53. GNUstep-base coding: basic classes NSString, NSMutableString String class
- 55. Class cluster implementation means ASCII strings are still extremely fast
- 56. Static strings NSString *string = @”This is a test string”;
- 57. GNUstep-base coding: basic classes NSArray, NSMutableArray Array class
- 58. NSMutableArray provides arrays that grow dynamically NSDictionary, NSMutableDictionary Hashtable/associative array class
- 59. NSMutableDictionary provides associative arrays that grow dynamically { Name = “Gorm.app”;
- 60. Description = “GNUstep GUI Builder Application”;
- 61. } (“one”, “two”, “three”);
- 62. GNUstep-base: Runloops and threads NSRunLoop NSRunLoop
- 64. NSFileHandle
- 66. NSLock
- 67. GNUstep-base: Notifications GNUstep-base supports notifications and observers Flexible way to connect objects NSNotificationCenter
- 68. Objects can “observe” a notification and specify which method
- 69. they want invoked when that notification is posted
- 70. Anything can “post” a notification
- 71. The notification is delivered to all “observer” See NSNotificationCenter documentation for more information
- 72. GNUstep-base: Delegates Objective-C and GNUstep-base encourage using delegates
- 73. A delegate allows you to extend a class without subclassing it
- 74. Subclassing can be heavy, and not that flexible
- 75. Delegates are more flexible – you can delegate part of the code to
- 76. an object of any class
- 78. -delegate;
- 79. GNUstep-base: Distributed Objects Remote method invocation
- 80. High-level
- 81. You can expose objects in one process to other processes
- 82. Other processes can then contact the object and invoke methods
- 83. of the objects, as if they were local objects
- 84. Very natural to use
- 85. Excellent for building networks of processes that work cooperatively
- 86. See http://www.gnustep.it/nicola/Tutorials/ for a tutorial on Distributed Objects.
- 87. A look at some useful libraries You can use any C library you want
- 88. Objective-C libraries provided by GNUstep check the dev-libs module in subversion Objective-C libraries provided by other parties SOPE (opengroupware.org)
- 89. Apple Cocoa non-GUI frameworks can sometime be used
- 90. GNUstep Database Libraries You can use your own preferite C library
- 91. GNUstep Database Libraries SQLClient
- 92. GDL2 SOPE The best choice if you use the SOPE application server
- 93. Not so interesting if you're not
- 94. GNUstep Database Libraries SQLClient SQL Layer (low-level) Standard SQL layer to execute SQL queries/commands
- 95. “Backend bundles” (plugins) for the different databases (standard bundles: PostgreSQL, MySQL, SQLite, Oracle) High-performance features Connection pooling
- 97. Query caching
- 98. Update Batching
- 99. GNUstep Database Libraries GDL2 (GNUstep Database Library v2) High-level features SQL layer with EOAdaptors (plugins) for different database (standard bundles: PostgreSQL, SQLite)
- 101. Extensive use of KVC
- 102. Supports and encourages MVC patterns Rapid development/integration support EOInterface
- 104. GNUstep Database Libraries SQLClient SQL only
- 105. You have to write your SQL code
- 106. Performance-oriented
- 107. Excellent for very high-performance servers where you write and tune each and every single SQL command GDL2 High-level framework
- 108. You works with models and objects – you do not need to write SQL
- 109. Can be a bit hard to get into, but people love it once they get used to it
- 110. Excellent for large and properly structured OO projects
- 111. Performance is generally good
- 112. GNUstep WebServer Library WebServer Library A library to implement quickly http/https server applications
- 113. Appropriate to develop efficient APIs for your system
- 114. Could be used for web pages but that is not the focus
- 115. Provides a full web server
- 116. Usually used with Apache in front as a reverse-proxy
- 117. Jigs: GNUstep Java Interface What is it Allows you to use Objective-C libraries or objects from Java
- 118. And allows you to use Java libraries or objects from Objective-C
- 119. Objects and classes in Objective-C are mapped to objects and
- 120. classes in Java and vice versa Pros Is very cool Cons Can be slow, use it with moderation
- 121. Problems can be hard to debug
- 122. Limited support for cross-language subclassing
- 123. Not easy to port to other platforms
- 124. SOPE An extensive set of frameworks
- 125. A complete “Web application server” environment
- 126. Apple WebObjects compatible app server extended with Zope concepts
- 127. XML processing (SAX2, DOM, XML-RPC)
- 129. LDAP connectivity
- 130. RDBMS connectivity
- 132. Questions ?
- 133. Thank you For more information www.gnustep.org