ZnClient subclass with cache

gistfile1.txt

ZnClient subclass: #ZnCachingClient
	instanceVariableNames: ''
	classVariableNames: ''
	package: 'Zinc-HTTP-CachingClient'
  
execute
	"Execute the currently set up request to generate a response.
	If the request was performed before, retrieve the cached version.
	Return the #contents of the response, if any."

	^ self request method = #GET
		ifTrue: [ self executeCached ]
		ifFalse: [ super execute ]
    
executeCached
	| requestHash cachedFileReference |
	requestHash := (MD5 hashMessage: self request url asString) hex.
	cachedFileReference := FileLocator localDirectory / 'zinc-cache'
		/ requestHash.
	^ cachedFileReference exists
		ifTrue: [ cachedFileReference contents ]
		ifFalse: [ | result |
			result := super execute.
			response isSuccess
				ifTrue: [ cachedFileReference
						ensureCreateFile;
						writeStreamDo: [ :ws | ws nextPutAll: result ] ].
			result ]