PlantUML Web Server

@startuml
!$UseTheme = "C4_green"

' convert it with additional command line argument -DRELATIVE_INCLUDE="./.." to use locally
!if %variable_exists("RELATIVE_INCLUDE")
  ' !theme C4_FirstTest from %get_variable_value("RELATIVE_INCLUDE")/themes
  !theme $UseTheme from ./../themes
!else
  !theme $UseTheme from https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/themes
!endif

' <<<<<<<<<<<<<<<<<< PART OF THEME

' $BOUNDARY_BG_COLOR... have to be defined in theme itself that it can be used in styles,...
' (no default values which are defined in C4.puml) 
' If skinparams and styles are defined with concrete values no variables are required 
!$BOUNDARY_BG_COLOR ?= "transparent"
!$BOUNDARY_COLOR ?= "#444444"
!$ARROW_COLOR ?= "#666666"

' replace transparent with concrete background that it can be used as font color too
!if ($BOUNDARY_BG_COLOR == "transparent")
  !$SEQUENCE_BG_COLOR = white
!else
  !$SEQUENCE_BG_COLOR = $BOUNDARY_BG_COLOR
!endif

' "C4 styled" default is no foot boxes
hide footbox
' "C4 styled" default is that lifeline is arrow color
skinparam SequenceLifelineBorderColor $ARROW_COLOR

skinparam SequenceGroupBodyBackgroundColor $SEQUENCE_BG_COLOR
skinparam SequenceGroupFontColor $BOUNDARY_COLOR
skinparam SequenceGroupBackgroundColor $BOUNDARY_COLOR
skinparam SequenceGroupHeaderFontColor $SEQUENCE_BG_COLOR
skinparam SequenceGroupBorderColor $BOUNDARY_COLOR

skinparam SequenceReferenceBackgroundColor $SEQUENCE_BG_COLOR
skinparam SequenceReferenceFontColor $BOUNDARY_COLOR
skinparam SequenceReferenceHeaderBackgroundColor $BOUNDARY_COLOR
' VIA STYLE
' skinparam SequenceReferenceHeaderFontColor $SEQUENCE_BG_COLOR
<style>
referenceHeader {
  fontcolor $SEQUENCE_BG_COLOR
}
</style>
skinparam SequenceReferenceBorderColor $BOUNDARY_COLOR

skinparam SequenceDividerBackgroundColor $SEQUENCE_BG_COLOR
skinparam SequenceDividerFontColor $BOUNDARY_COLOR
skinparam SequenceDividerBorderColor $BOUNDARY_COLOR

' VIA STYLE
' skinparam SequenceDelayFontColor green
<style>
sequenceDiagram {
  delay {
    FontColor $BOUNDARY_COLOR
  }
}
</style>

' >>>>>>>>>>>>>>>>>> PART OF THEME

!if %variable_exists("RELATIVE_INCLUDE")
  !include %get_variable_value("RELATIVE_INCLUDE")/C4_Sequence.puml
!else
  !include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Sequence.puml
!endif

Person(Alice, "Alice")
Person(Bob, "Bob")

activate Bob

Rel(Alice, Bob, "Authentication Request")

alt successful case
    Rel(Bob, Alice, "Authentication Accepted")
else some kind of failure
    loop 1000 times
        Rel(Alice, Bob, "DNS Attack")
    end
end

ref over Alice, Bob : init

Rel(Alice, Bob, "hello")

ref over Bob
  This can be on
  several lines
end ref

== Initialization ==

Rel(Alice, Bob, "Authentication Request")
Rel(Bob, Alice, "Authentication Response")

== Repetition ==

Rel(Alice, Bob, "Another authentication Request")
Rel(Bob, Alice, "another authentication Response")

... 5 minutes later ...

Rel(Alice, Bob, "calls via phone")

SHOW_LEGEND()
@enduml

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