book

Programming PHP, 4th Edition

by Kevin Tatroe, Peter MacIntyre

March 2020

Intermediate to advanced

542 pages

12h 22m

English

O'Reilly Media, Inc.

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AudienceAssumptions This Book MakesContents of This BookConventions Used in This BookO’Reilly Online LearningHow to Contact UsAcknowledgmentsKevin TatroePeter MacIntyre
What Does PHP Do?A Brief History of PHPThe Evolution of PHPThe Widespread Use of PHPInstalling PHPA Walk Through PHPConfiguration PageFormsDatabasesGraphicsWhat’s Next
Lexical StructureCase SensitivityStatements and SemicolonsWhitespace and Line BreaksCommentsLiteralsIdentifiersKeywordsData TypesIntegersFloating-Point NumbersStringsBooleansArraysObjectsResourcesCallbacksNULLVariablesVariable VariablesVariable ReferencesVariable ScopeGarbage CollectionExpressions and OperatorsNumber of OperandsOperator PrecedenceOperator AssociativityImplicit CastingArithmetic OperatorsString Concatenation OperatorAuto-Increment and Auto-Decrement OperatorsComparison OperatorsBitwise OperatorsLogical OperatorsCasting OperatorsAssignment OperatorsMiscellaneous OperatorsFlow-Control Statementsif switchwhileforforeachtry...catchdeclareexit and returngotoIncluding CodeEmbedding PHP in Web PagesStandard (XML) StyleSGML StyleEchoing Content DirectlyWhat’s Next
Calling a FunctionDefining a FunctionVariable ScopeGlobal VariablesStatic VariablesFunction ParametersPassing Parameters by ValuePassing Parameters by ReferenceDefault ParametersVariable ParametersMissing ParametersType HintingReturn ValuesVariable FunctionsAnonymous FunctionsWhat’s Next
Quoting String ConstantsVariable InterpolationSingle-Quoted StringsDouble-Quoted StringsHere DocumentsPrinting Stringsechoprint()printf()print_r() and var_dump()Accessing Individual CharactersCleaning StringsRemoving WhitespaceChanging CaseEncoding and EscapingHTMLURLsSQLC-String EncodingComparing StringsExact ComparisonsApproximate EqualityManipulating and Searching StringsSubstringsMiscellaneous String FunctionsDecomposing a StringString-Searching FunctionsRegular ExpressionsThe BasicsCharacter ClassesAlternativesRepeating SequencesSubpatternsDelimitersMatch BehaviorCharacter ClassesAnchorsQuantifiers and GreedNoncapturing GroupsBackreferencesTrailing OptionsInline OptionsLookahead and LookbehindCutConditional ExpressionsFunctionsDifferences from Perl Regular ExpressionsWhat’s Next
Indexed Versus Associative ArraysIdentifying Elements of an ArrayStoring Data in ArraysAppending Values to an ArrayAssigning a Range of ValuesGetting the Size of an ArrayPadding an ArrayMultidimensional ArraysExtracting Multiple ValuesSlicing an ArraySplitting an Array into ChunksKeys and ValuesChecking Whether an Element ExistsRemoving and Inserting Elements in an ArrayConverting Between Arrays and VariablesCreating Variables from an ArrayCreating an Array from VariablesTraversing ArraysThe foreach ConstructThe Iterator FunctionsUsing a for LoopCalling a Function for Each Array ElementReducing an ArraySearching for ValuesSortingSorting One Array at a TimeNatural-Order SortingSorting Multiple Arrays at OnceReversing ArraysRandomizing OrderActing on Entire ArraysCalculating the Sum of an ArrayMerging Two ArraysCalculating the Difference Between Two ArraysFiltering Elements from an ArrayUsing Arrays to Implement Data TypesSetsStacksImplementing the Iterator InterfaceWhat’s Next
ObjectsTerminologyCreating an ObjectAccessing Properties and MethodsDeclaring a ClassDeclaring MethodsDeclaring PropertiesDeclaring ConstantsInheritanceInterfacesTraitsAbstract MethodsConstructorsDestructorsAnonymous ClassesIntrospectionExamining ClassesExamining an ObjectSample Introspection ProgramSerializationWhat’s Next
What’s Next
HTTP BasicsVariablesServer InformationProcessing FormsMethodsParametersSelf-Processing PagesSticky FormsMultivalued ParametersSticky Multivalued ParametersFile UploadsForm ValidationSetting Response HeadersDifferent Content TypesRedirectionsExpirationAuthenticationMaintaining StateCookiesSessionsCombining Cookies and SessionsSSLWhat’s Next

Using PHP to Access a DatabaseRelational Databases and SQLPHP Data ObjectsMySQLi Object InterfaceRetrieving Data for DisplaySQLiteDirect File-Level ManipulationMongoDBRetrieving DataInserting More Complex DataWhat’s Next
Embedding an Image in a PageBasic Graphics ConceptsCreating and Drawing ImagesThe Structure of a Graphics ProgramChanging the Output FormatTesting for Supported Image FormatsReading an Existing FileBasic Drawing FunctionsImages with TextFontsTrueType FontsDynamically Generated ButtonsCaching the Dynamically Generated ButtonsA Faster CacheScaling ImagesColor HandlingUsing the Alpha ChannelIdentifying ColorsTrue Color IndexesText Representation of an ImageWhat’s Next
PDF ExtensionsDocuments and PagesA Simple ExampleInitializing the DocumentOutputting Basic Text CellsTextCoordinatesText AttributesPage Headers, Footers, and Class ExtensionImages and LinksTables and DataWhat’s Next
Lightning Guide to XMLGenerating XMLParsing XMLElement HandlersCharacter Data HandlerProcessing InstructionsEntity HandlersDefault HandlerOptionsUsing the ParserErrorsMethods as HandlersSample Parsing ApplicationParsing XML with the DOMParsing XML with SimpleXMLTransforming XML with XSLTWhat’s Next
Using JSONSerializing PHP ObjectsOptionsWhat’s Next
SafeguardsFiltering InputEscaping Output DataSecurity VulnerabilitiesCross-Site ScriptingSQL InjectionFilename VulnerabilitiesSession FixationFile Upload TrapsUnauthorized File AccessPHP Code IssuesShell Command WeaknessesData Encryption ConcernsFurther ResourcesSecurity RecapWhat’s Next
Code LibrariesTemplating SystemsHandling OutputOutput BufferingOutput CompressionPerformance TuningBenchmarkingProfilingOptimizing Execution TimeOptimizing Memory RequirementsReverse Proxies and ReplicationWhat’s Next
REST ClientsResponsesRetrieving ResourcesUpdating ResourcesCreating ResourcesDeleting ResourcesXML-RPCServersClientsWhat’s Next
The Development EnvironmentThe Staging EnvironmentThe Production Environmentphp.ini SettingsError HandlingError ReportingExceptionsError SuppressionTriggering ErrorsDefining Error HandlersManual DebuggingError LogsIDE DebuggingAdditional Debugging TechniquesWhat’s Next
Writing Portable Code for Windows and UnixDetermining the PlatformHandling Paths Across PlatformsNavigating the Server EnvironmentSending MailEnd-of-Line HandlingEnd-of-File HandlingUsing External CommandsAccessing Platform-Specific ExtensionsInterfacing with COMBackgroundPHP FunctionsAPI Specifications
PHP Functions by CategoryArraysClasses and ObjectsData FilteringDate and TimeDirectoriesErrors and LoggingFilesystemFunctionsMailMathMiscellaneous FunctionsNetworkOutput BufferingPHP Language TokenizerPHP Options/InfoProgram ExecutionSession HandlingStreamsStringsURLsVariablesZlibAlphabetical Listing of PHP Functions

Content preview from Programming PHP, 4th Edition

Chapter 6. Objects

In this chapter you’ll learn how to define, create, and use objects in PHP. Object-oriented programming (OOP) opens the door to cleaner designs, easier maintenance, and greater code reuse. OOP has proven so valuable that few today would dare to introduce a language that wasn’t object-oriented. PHP supports many useful features of OOP, and this chapter shows you how to use them, covering basic OOP concepts as well as advanced topics such as introspection and serialization.

Objects

Object-oriented programming acknowledges the fundamental connection between data and the code that works on it, and lets you design and implement programs around that connection. For example, a bulletin-board system usually keeps track of many users. In a procedural programming language, each user is represented by a data structure, and there would probably be a set of functions that work with those data structures (to create the new users, get their information, etc.). In an OOP language, each user is represented by an object—a data structure with attached code. The data and the code are still there, but they’re treated as an inseparable unit. The object, as a union of code and data, is the modular unit for application development and code reuse.

In this hypothetical bulletin-board design, objects can represent not just users but also messages and threads. A user object has a username and password for that user, and code to identify all the messages by that author. A message object ...