Cache DataFlex Reference Documentation

Cache

Current Version: 9.5.0.73

Object Creation

// (Dataflex programs use the 32-bit Chilkat ActiveX)
Handle hoCache
Get Create(RefClass(cComChilkatCache)) to hoCache

Properties

DebugLogFilePath
Function ComDebugLogFilePath Returns String
Procedure Set ComDebugLogFilePath String value

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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LastBinaryResult
Function ComLastBinaryResult Returns Variant
Introduced in version 9.5.0.52

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to True. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

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LastErrorHtml
Function ComLastErrorHtml Returns String

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
Function ComLastErrorText Returns String

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
Function ComLastErrorXml Returns String

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastEtagFetched
Function ComLastEtagFetched Returns String

The ETag of the last item fetched from cache.

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LastExpirationFetched
Function ComLastExpirationFetched Returns DateTime
This property is deprecated. It will be removed in a future version.

Expiration date/time of the last item fetched from cache.

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LastExpirationFetchedStr
Function ComLastExpirationFetchedStr Returns String

Expiration date/time of the last item fetched from cache in RFC822 string format.

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LastHitExpired
Function ComLastHitExpired Returns Boolean

True if the LastExpirationFetched is before the current date/time. Otherwise False.

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LastKeyFetched
Function ComLastKeyFetched Returns String

The key of the last item fetched from cache. (For web pages, the key is typically the canonicalized URL. Otherwise, the key is a unique identifer used to access the cached item.)

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LastMethodSuccess
Function ComLastMethodSuccess Returns Boolean
Procedure Set ComLastMethodSuccess Boolean value
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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LastStringResult
Function ComLastStringResult Returns String
Introduced in version 9.5.0.52

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to True. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

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LastStringResultLen
Function ComLastStringResultLen Returns Integer
Introduced in version 9.5.0.53

The length, in characters, of the string contained in the LastStringResult property.

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Level
Function ComLevel Returns Integer
Procedure Set ComLevel Integer value

The number of directory levels in the cache. Possible values are:

0: All cache files are in a single directory (the cache root).

1: Cache files are located in 256 sub-directories numbered 0 .. 255 directly under the cache root.

2: There are two levels of sub-directories under the cache root. The 1st level has 256 sub-directories numbered 0 .. 255 directly under the cache root. The 2nd level allows for up to 256 sub-directories (0..255) under each level-1 directory. Cache files are stored in the leaf directories.

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NumRoots
Function ComNumRoots Returns Integer

The number of root directories composing the cache. A typical multi-root cache would place each root on a separate hard drive.

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VerboseLogging
Function ComVerboseLogging Returns Boolean
Procedure Set ComVerboseLogging Boolean value

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Function ComVersion Returns String

Version of the component/library, such as "9.5.0.63"

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Methods

AddRoot
Procedure ComAddRoot String path

Must be called once for each cache root. For example, if the cache is spread across D:\cacheRoot, E:\cacheRoot, and F:\cacheRoot, an application would setup the cache object by calling AddRoot three times -- once with "D:\cacheRoot", once with "E:\cacheRoot", and once with "F:\cacheRoot".

More Information and Examples
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DeleteAll
Function ComDeleteAll Returns Integer

Deletes all items in the cache. This method completely clears the cache. All files in the cache are deleted. (If the cache is multi-level, existing sub-directories are not deleted.)

Returns the number of items (i.e. cache files) deleted.

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DeleteAllExpired
Function ComDeleteAllExpired Returns Integer

Deletes all expired items from the cache.

Returns the number of items (i.e. cache files) deleted.

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DeleteFromCache
Function ComDeleteFromCache String key Returns Boolean

Deletes a single item from the disk cache. Returns False if the item exists in cache but could not be deleted. Otherwise returns True.

Returns True for success, False for failure.

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DeleteOlder
Function ComDeleteOlder DateTime dateTime Returns Integer
This method is deprecated. It will be removed in a future version.

Deletes all items older than a specified date/time.

Returns the number of items (i.e. cache files) deleted. Returns -1 on error.

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DeleteOlderDt
Function ComDeleteOlderDt cComCkDateTime dateTime Returns Integer

The same as DeleteOlder, except the dateTime is passed as a CkDateTime.

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DeleteOlderStr
Function ComDeleteOlderStr String dateTimeStr Returns Integer

The same as DeleteOlder, except the dateTimeStr is passed as a date/time in RFC822 format.

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FetchFromCache
Function ComFetchFromCache String key Returns Variant

Fetches an item from cache.

The key may be any length and may include any characters. It should uniquely identify the cached item. (No two items in the cache should have the same key.)

Returns null on failure

More Information and Examples
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FetchText
Function ComFetchText String key Returns String

Fetches a text item from the cache and returns it's text content.

The key may be any length and may include any characters. It should uniquely identify the cached item. (No two items in the cache should have the same key.)

Returns null on failure

More Information and Examples
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GetEtag
Function ComGetEtag String key Returns String

Returns the eTag for an item in the cache.

Returns null on failure

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GetExpiration
Function ComGetExpiration String key Returns DateTime
This method is deprecated. It will be removed in a future version.

Returns the expire date/time for an item in the cache.

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GetExpirationDt
Function ComGetExpirationDt String key Returns cComCkDateTime

Returns the expiration date/time for an item in the cache as a CkDateTime object.

Returns null on failure

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GetExpirationStr
Function ComGetExpirationStr String url Returns String

Returns the expiration date/time for an item in the cache in RFC822 string format.

Returns null on failure

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GetFilename
Function ComGetFilename String key Returns String

Returns the absolute file path of the cache file associated with the key.

Returns null on failure

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GetRoot
Function ComGetRoot Integer index Returns String

Returns the directory path of the Nth cache root. (Indexing begins at 0.)

Returns null on failure

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IsCached
Function ComIsCached String key Returns Boolean

Returns True if the item is found in the cache, otherwise returns False.

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SaveText
Function ComSaveText String key DateTime expireDateTime String eTag String itemTextData Returns Boolean
This method is deprecated. It will be removed in a future version.

Inserts or replaces an text item in the cache. The eTag is optional and may be set to a zero-length string. Applications may use it as a place to save additional information about the cached item. The key may be any length and may include any characters. It should uniquely identify the cached item. (No two items in the cache should have the same key.)

Returns True for success, False for failure.

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SaveTextDt
Function ComSaveTextDt String key cComCkDateTime expireDateTime String eTag String itemTextData Returns Boolean

The same as SaveText, except the expire date/time is passed as a CkDateTime object.

Returns True for success, False for failure.

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SaveTextNoExpire
Function ComSaveTextNoExpire String key String eTag String itemTextData Returns Boolean

Inserts or replaces an text item in the cache with no expiration date/time. The eTag is optional and may be set to a zero-length string. Applications may use it as a place to save additional information about the cached item.

Returns True for success, False for failure.

More Information and Examples
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SaveTextStr
Function ComSaveTextStr String key String expireDateTime String eTag String itemTextData Returns Boolean

The same as SaveText, except the expire date/time is passed as a string in RFC822 format.

Returns True for success, False for failure.

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SaveToCache
Function ComSaveToCache String key DateTime expireDateTime String eTag Variant itemData Returns Boolean
This method is deprecated. It will be removed in a future version.

Inserts or replaces an item in the cache. The eTag is optional and may be set to a zero-length string. Applications may use it as a place to save additional information about the cached item. (The Chilkat HTTP component, when caching a page, writes the eTag (entity-tag) from the HTTP response header to this field.)

The key may be any length and may include any characters. It should uniquely identify the cached item. (No two items in the cache should have the same key.)

Returns True for success, False for failure.

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SaveToCacheDt
Function ComSaveToCacheDt String key cComCkDateTime expireDateTime String eTag Variant itemData Returns Boolean

The same as SaveToCache, except the expire date/time is passed as a CkDateTime object.

Returns True for success, False for failure.

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SaveToCacheNoExpire
Function ComSaveToCacheNoExpire String key String eTag Variant itemData Returns Boolean

Inserts or replaces an item in the cache. The cached item will have no expiration. The eTag is optional and may be set to a zero-length string. Applications may use it as a place to save additional information about the cached item.

Returns True for success, False for failure.

More Information and Examples
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SaveToCacheStr
Function ComSaveToCacheStr String key String expireDateTime String eTag Variant itemData Returns Boolean

The same as SaveToCache, except the expire date/time is passed in RFC822 string format.

Returns True for success, False for failure.

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UpdateExpiration
Function ComUpdateExpiration String key DateTime expireDateTime Returns Boolean
This method is deprecated. It will be removed in a future version.

Updates the expire date/time for a cached item.

Returns True for success, False for failure.

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UpdateExpirationDt
Function ComUpdateExpirationDt String key cComCkDateTime expireDateTime Returns Boolean

The same as UpdateExpiration, except the expireDateTime is passed as a CkDateTime.

Returns True for success, False for failure.

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UpdateExpirationStr
Function ComUpdateExpirationStr String key String expireDateTime Returns Boolean

The same as UpdateExpiration, except the expireDateTime is passed in RFC822 string format.

Returns True for success, False for failure.

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