book

PHP Cookbook, 3rd Edition

by David Sklar, Adam Trachtenberg

July 2014

Intermediate to advanced

820 pages

17h 6m

English

O'Reilly Media, Inc.

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Who This Book Is ForWhat Is in This BookOther ResourcesConventions Used in This BookComments and QuestionsAcknowledgments
IntroductionAccessing SubstringsExtracting SubstringsReplacing SubstringsProcessing a String One Byte at a TimeReversing a String by Word or ByteGenerating a Random StringExpanding and Compressing TabsControlling CaseInterpolating Functions and Expressions Within StringsTrimming Blanks from a StringGenerating Comma-Separated DataParsing Comma-Separated DataGenerating Fixed-Width Field Data RecordsParsing Fixed-Width Field Data RecordsTaking Strings ApartWrapping Text at a Certain Line LengthStoring Binary Data in StringsProgram: Downloadable CSV File
IntroductionChecking Whether a Variable Contains a Valid NumberComparing Floating-Point NumbersRounding Floating-Point NumbersOperating on a Series of IntegersGenerating Random Numbers Within a RangeGenerating Predictable Random NumbersGenerating Biased Random NumbersTaking LogarithmsCalculating ExponentsFormatting NumbersFormatting Monetary ValuesPrinting Correct PluralsCalculating Trigonometric FunctionsDoing Trigonometry in Degrees, Not RadiansHandling Very Large or Very Small NumbersConverting Between BasesCalculating Using Numbers in Bases Other Than DecimalFinding the Distance Between Two Places
IntroductionFinding the Current Date and TimeConverting Time and Date Parts to an Epoch TimestampConverting an Epoch Timestamp to Time and Date PartsPrinting a Date or Time in a Specified FormatFinding the Difference of Two DatesFinding the Day in a Week, Month, or YearValidating a DateParsing Dates and Times from StringsAdding to or Subtracting from a DateCalculating Time with Time Zones and Daylight Saving TimeGenerating a High-Precision TimeGenerating Time RangesUsing Non-Gregorian CalendarsProgram: Calendar
IntroductionSpecifying an Array Not Beginning at Element 0Storing Multiple Elements per Key in an ArrayInitializing an Array to a Range of IntegersIterating Through an ArrayDeleting Elements from an ArrayChanging Array SizeAppending One Array to AnotherTurning an Array into a StringPrinting an Array with CommasChecking if a Key Is in an ArrayChecking if an Element Is in an ArrayFinding the Position of a Value in an ArrayFinding Elements That Pass a Certain TestFinding the Largest or Smallest Valued Element in an ArrayReversing an ArraySorting an ArraySorting an Array by a Computable FieldSorting Multiple ArraysSorting an Array Using a Method Instead of a FunctionRandomizing an ArrayRemoving Duplicate Elements from an ArrayApplying a Function to Each Element in an ArrayFinding the Union, Intersection, or Difference of Two ArraysIterating Efficiently over Large or Expensive DatasetsAccessing an Object Using Array Syntax
IntroductionAvoiding == Versus = ConfusionEstablishing a Default ValueExchanging Values Without Using Temporary VariablesCreating a Dynamic Variable NamePersisting a Local Variable’s Value Across Function InvocationsSharing Variables Between ProcessesEncapsulating Complex Data Types in a StringDumping Variable Contents as Strings
IntroductionAccessing Function ParametersSetting Default Values for Function ParametersPassing Values by ReferenceUsing Named ParametersEnforcing Types of Function ArgumentsCreating Functions That Take a Variable Number of ArgumentsReturning Values by ReferenceReturning More Than One ValueSkipping Selected Return ValuesReturning FailureCalling Variable FunctionsAccessing a Global Variable Inside a FunctionCreating Dynamic Functions
IntroductionInstantiating ObjectsDefining Object ConstructorsDefining Object DestructorsImplementing Access ControlPreventing Changes to Classes and MethodsDefining Object StringificationRequiring Multiple Classes to Behave SimilarlyCreating Abstract Base ClassesAssigning Object ReferencesCloning ObjectsOverriding Property AccessesCalling Methods on an Object Returned by Another MethodAggregating ObjectsAccessing Overridden MethodsCreating Methods DynamicallyUsing Method PolymorphismDefining Class ConstantsDefining Static Properties and MethodsControlling Object SerializationIntrospecting ObjectsChecking If an Object Is an Instance of a Specific ClassAutoloading Class Files upon Object InstantiationInstantiating an Object DynamicallyProgram: whereis
IntroductionSetting CookiesReading Cookie ValuesDeleting CookiesBuilding a Query StringReading the POST Request BodyUsing HTTP Basic or Digest AuthenticationUsing Cookie AuthenticationReading an HTTP HeaderWriting an HTTP HeaderSending a Specific HTTP Status CodeRedirecting to a Different LocationFlushing Output to the BrowserBuffering Output to the BrowserCompressing Web OutputReading Environment VariablesSetting Environment VariablesCommunicating Within ApacheRedirecting Mobile Browsers to a Mobile Optimized SiteProgram: Website Account (De)activatorProgram: Tiny WikiProgram: HTTP Range
IntroductionProcessing Form InputValidating Form Input: Required FieldsValidating Form Input: NumbersValidating Form Input: Email AddressesValidating Form Input: Drop-Down MenusValidating Form Input: Radio ButtonsValidating Form Input: CheckboxesValidating Form Input: Dates and TimesValidating Form Input: Credit CardsPreventing Cross-Site ScriptingProcessing Uploaded FilesWorking with Multipage FormsRedisplaying Forms with Inline Error MessagesGuarding Against Multiple Submissions of the Same FormPreventing Global Variable InjectionHandling Remote Variables with Periods in Their NamesUsing Form Elements with Multiple OptionsCreating Drop-Down Menus Based on the Current Date

IntroductionUsing DBM DatabasesUsing an SQLite DatabaseConnecting to an SQL DatabaseQuerying an SQL DatabaseRetrieving Rows Without a LoopModifying Data in an SQL DatabaseRepeating Queries EfficientlyFinding the Number of Rows Returned by a QueryEscaping QuotesLogging Debugging Information and ErrorsCreating Unique IdentifiersBuilding Queries ProgrammaticallyMaking Paginated Links for a Series of RecordsCaching Queries and ResultsAccessing a Database Connection Anywhere in Your ProgramProgram: Storing a Threaded Message BoardUsing Redis
IntroductionUsing Session TrackingPreventing Session HijackingPreventing Session FixationStoring Sessons in MemcachedStoring Sessions in a DatabaseStoring Arbitrary Data in Shared MemoryCaching Calculated Results in Summary Tables
IntroductionGenerating XML as a StringGenerating XML with DOMParsing Basic XML DocumentsParsing Complex XML DocumentsParsing Large XML DocumentsExtracting Information Using XPathTransforming XML with XSLTSetting XSLT Parameters from PHPCalling PHP Functions from XSLT StylesheetsValidating XML DocumentsHandling Content EncodingReading RSS and Atom FeedsWriting RSS FeedsWriting Atom Feeds
IntroductionMarking Up a Web PageCleaning Up Broken or Nonstandard HTMLExtracting Links from an HTML FileConverting Plain Text to HTMLConverting HTML to Plain TextRemoving HTML and PHP TagsResponding to an Ajax RequestIntegrating with JavaScriptProgram: Finding Stale LinksProgram: Finding Fresh Links
IntroductionFetching a URL with the GET MethodFetching a URL with the POST Method and Form DataFetching a URL with an Arbitrary Method and POST BodyFetching a URL with CookiesFetching a URL with Arbitrary HeadersFetching a URL with a TimeoutFetching an HTTPS URLDebugging the Raw HTTP ExchangeMaking an OAuth 1.0 RequestMaking an OAuth 2.0 Request
IntroductionExposing and Routing to a ResourceExposing Clean Resource PathsExposing a Resource for ReadingCreating a ResourceEditing a ResourceDeleting a ResourceIndicating Errors and FailuresSupporting Multiple Formats
IntroductionSending MailSending MIME MailReading Mail with IMAP or POP3Getting and Putting Files with FTPLooking Up Addresses with LDAPUsing LDAP for User AuthenticationPerforming DNS LookupsChecking If a Host Is AliveGetting Information About a Domain Name
IntroductionDrawing Lines, Rectangles, and PolygonsDrawing Arcs, Ellipses, and CirclesDrawing with Patterned LinesDrawing TextDrawing Centered TextBuilding Dynamic ImagesGetting and Setting a Transparent ColorOverlaying WatermarksCreating Thumbnail ImagesReading EXIF DataServing Images SecurelyProgram: Generating Bar Charts from Poll Results
IntroductionPreventing Session FixationProtecting Against Form SpoofingEnsuring Input Is FilteredAvoiding Cross-Site ScriptingEliminating SQL InjectionKeeping Passwords Out of Your Site FilesStoring PasswordsDealing with Lost PasswordsVerifying Data with HashesEncrypting and Decrypting DataStoring Encrypted Data in a File or DatabaseSharing Encrypted Data with Another WebsiteDetecting SSLEncrypting Email with GPG
IntroductionDetermining the User’s LocaleLocalizing Text MessagesLocalizing Dates and TimesLocalizing NumbersLocalizing Currency ValuesLocalizing ImagesLocalizing Included FilesSorting in a Locale-Aware OrderManaging Localization ResourcesSetting the Character Encoding of Outgoing DataSetting the Character Encoding of Incoming DataManipulating UTF-8 Text
IntroductionFinding and Fixing Parse ErrorsCreating Your Own Exception ClassesPrinting a Stack TraceReading Configuration VariablesSetting Configuration VariablesHiding Error Messages from UsersTuning Error HandlingUsing a Custom Error HandlerLogging ErrorsEliminating “headers already sent” ErrorsLogging Debugging Information
IntroductionUsing a Debugger ExtensionWriting a Unit TestWriting a Unit Test SuiteApplying a Unit Test to a Web PageSetting Up a Test EnvironmentUsing the Built-in Web Server
IntroductionUsing an AcceleratorTiming Function ExecutionTiming Program Execution by FunctionTiming Program Execution by StatementTiming Program Execution by SectionProfiling with a Debugger ExtensionStress-Testing Your WebsiteAvoiding Regular Expressions
IntroductionSwitching from ereg to pregMatching WordsFinding the nth Occurrence of a MatchChoosing Greedy or Nongreedy MatchesFinding All Lines in a File That Match a PatternCapturing Text Inside HTML TagsPreventing Parentheses from Capturing TextEscaping Special Characters in a Regular ExpressionReading Records with a Pattern SeparatorUsing a PHP Function in a Regular Expression
IntroductionCreating or Opening a Local FileCreating a Temporary FileOpening a Remote FileReading from Standard InputReading a File into a StringCounting Lines, Paragraphs, or Records in a FileProcessing Every Word in a FilePicking a Random Line from a FileRandomizing All Lines in a FileProcessing Variable-Length Text FieldsReading Configuration FilesModifying a File in Place Without a Temporary FileFlushing Output to a FileWriting to Standard OutputWriting to Many Filehandles SimultaneouslyEscaping Shell MetacharactersPassing Input to a ProgramReading Standard Output from a ProgramReading Standard Error from a ProgramLocking a FileReading and Writing Custom File TypesReading and Writing Compressed Files
IntroductionGetting and Setting File TimestampsGetting File InformationChanging File Permissions or OwnershipSplitting a Filename into Its Component PartsDeleting a FileCopying or Moving a FileProcessing All Files in a DirectoryGetting a List of Filenames Matching a PatternProcessing All Files in a Directory RecursivelyMaking New DirectoriesRemoving a Directory and Its ContentsProgram: Web Server Directory ListingProgram: Site Search
IntroductionParsing Program ArgumentsParsing Program Arguments with getoptReading from the KeyboardRunning PHP Code on Every Line of an Input FileReading PasswordsColorizing Console OutputProgram: DOM Explorer
IntroductionDefining and Installing Composer DependenciesFinding Composer PackagesInstalling Composer PackagesUsing the PEAR InstallerFinding PEAR PackagesFinding Information About a PackageInstalling PEAR PackagesUpgrading PEAR PackagesUninstalling PEAR PackagesInstalling PECL Packages

Content preview from PHP Cookbook, 3rd Edition

Chapter 9. Forms

Introduction

The genius of PHP is its seamless integration of form variables into your programs. It makes web programming smooth and simple, speeding the cycle from web form to PHP code to HTML output.

With that convenience, however, comes the responsibility to make sure that the user-provided information that flows so easily into your program contains appropriate content. External input can never be trusted, so it’s imperative always to validate all incoming data. Recipes through show how to validate common kinds of information as well as providing general guidelines on arbitrary form validation you might need to do. Preventing Cross-Site Scripting discusses escaping HTML entities to allow the safe display of user-entered data. Processing Uploaded Files covers how to process files uploaded by a user.

HTTP is a ’stateless’ protocol—it has no built-in mechanism that helps you to save information from one page so you can access it in other pages. Recipes , , and all show ways to work around the fundamental problem of figuring out which user is making which requests to your web server.

Whenever PHP processes a page, it checks for URL and form variables, uploaded files, applicable cookies, and web server and environment variables. These are then directly accessible in the following arrays: $_GET, $_POST, $_FILES, $_COOKIE, $_SERVER, and $_ENV. They hold, respectively, all variables set in the query string, in the body of a post request, by uploaded files, by cookies, ...