SwiftFilter

Chainable filters that can be applied to collections to filter (change / correct) form inputs

By Danilo Topalovic.

• Introduction
• Requirements
• Installation
• Usage
• Included Filters
  • Callback
  • CharCase
  • Replace
  • Trim
  • RegexReplace
• Extensibility

Introduction

When I wrote SwiftValidate I encountered some problems in form validation. A bunch of field values weren't really errorneous but needed to be changed in some way.

Of course a validator should not change the value in any way so I decided to do another project with filtering.

Similar to Zend\Filter this also works with a filter chain which applies a bunch of filters to a single value. I Use SwiftFilter along with SwiftValidate together with Eureka.

Requirements

• iOS 8.0+
• Xcode 7.0+

Installation

See CocoaPods for easy installation into your project

Add SwiftFilter to your Podfile

platform :ios, '8.0'
use_frameworks!

pod 'SwiftValidate'

See Carthage

Add ``SwiftFilterto yourCartfile`

github "dtop/SwiftFilter"

Usage

let inValue: String = "  \t \n  Some foo String   \t\t \n "

let chain = FilterChain()
	<~~ TrimFilter()
	<~~ ReplaceFilter {
		$0.replaceType = .ReplaceString(searchStr: "foo", replacementStr: "bar")
	}
	
do {

	let outValue: String? = chain.filter(inValue, nil)
	
} catch _ {

}

Included Filters

CallbackFilter

Enables you to add a verry custom behavior to the filter chain by adding your callback which is executed on the value

Configuration

value	type	default	description
callback	closure	!	the callback you have to provide

Parameters

input	output	explination
Any	Any	-

---

CharCaseFilter

Allows to change the char case of the given string

Configuration

value	type	default	description
charCase	CharCaseFilter.Case	!	.Lowercase, .Uppercase, .Ucfirst, .Ucwords

Parameters

input	output	explination
String	String	only String is supported

---

ReplaceFilter

Allows to replace a String with another

Configuration

value	type	default	description
replaceType	ReplaceFilter.Case	!	@example see below

	// searches and replaces all string occurences
	let filter = ReplaceFilter {
		$0.replaceType = .ReplaceString(searchStr: "foo", replacementStr: "bar")
	}

	// replaces a given range that is seered by advancements of stringIndex
	let filter = ReplaceFilter {
		$0.replaceType = .ReplaceRange(advStart: 0, advEnd: 3, replacementStr: "bar")
	}
	

Parameters

input	output	explination
String	String	only String is supported

---

TrimFilter

Trims whitespace around the given String

Configuration

none

Parameters

input	output	explination
String	String	only String is supported

---

RegexReplaceFilter

Allows the replacement of a substring by regex pattern matching

Configuration

value	type	default	description
pattern	String	!	the pattern to match against
options	NSRegularExpressionOptions	0	options for the regular expression
matchingOptions	NSMatchingOptions	0	options for the matching
replacement	String	!	the replacement

Parameters

input	output	explination
String	String	only String is supported

Extensibility

Adding own filters that are working with the chain is quite easy

class MyFilter: FilterProtocol {
	
	var mySetting: String!
	
	required init(@noescape _ initialize: (RegexReplaceFilter) -> Void = { _ in }) {
        
       initialize(self)
   }
   
   func filter<I: Any, O: Any>(value: I?, _ context: [String: AnyObject]?) throws -> O? {
        
        // your filtering
   }
}

// can be used:

let chain = FilterChain()
	<~~ MyFilter {
		$0.mySetting = "foo"
	}