Apache NiFi Expression Language Guide

Overview
Structure of a NiFi Expression
- Expression Language Hierarchy
Expression Language in the Application
- Escaping Expression Language
- Expression Language Editor
Functions
- Data Types
Boolean Logic
- isNull
- notNull
- isEmpty
- equals
- equalsIgnoreCase
- gt
- ge
- lt
- le
- and
- or
- not
- ifElse
String Manipulation
- toUpper
- toLower
- trim
- substring
- substringBefore
- substringBeforeLast
- substringAfter
- substringAfterLast
- getDelimitedField
- append
- prepend
- replace
- replaceFirst
- replaceAll
- padLeft
- padRight
- replaceNull
- replaceEmpty
- length
- evaluateELString
- repeat
Encode/Decode Functions
- escapeJson
- escapeXml
- escapeCsv
- escapeHtml3
- escapeHtml4
- unescapeJson
- unescapeXml
- unescapeCsv
- unescapeHtml3
- unescapeHtml4
- urlEncode
- urlDecode
- base64Encode
- base64Decode
- UUID3
- UUID5
- hash
Searching
- startsWith
- endsWith
- contains
- in
- find
- matches
- indexOf
- lastIndexOf
- jsonPath
- jsonPathDelete
- jsonPathAdd
- jsonPathSet
- jsonPathPut
Mathematical Operations and Numeric Manipulation
- plus
- minus
- multiply
- divide
- mod
- toRadix
- fromRadix
- random
- math
Date Manipulation
- format
- toDate
- now
Type Coercion
Subjectless Functions
- ip
- hostname
- UUID
- nextInt
- literal
- getStateValue
- thread
Evaluating Multiple Attributes