Cache Delphi DLL Reference Documentation

Cache

Create/Dispose

function CkCache_Create: HCkCache; stdcall;

Creates an instance of the HCkCache object and returns a handle (i.e. a Pointer). The handle is passed in the 1st argument for the functions listed on this page.

procedure CkCache_Dispose(handle: HCkCache); stdcall;

Objects created by calling CkCache_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.

Properties

procedure CkCache_getDebugLogFilePath(objHandle: HCkCache; outPropVal: HCkString); stdcall;
procedure CkCache_putDebugLogFilePath(objHandle: HCkCache; newPropVal: PWideChar); stdcall;

function CkCache__debugLogFilePath(objHandle: HCkCache): PWideChar; stdcall;

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.

procedure CkCache_getLastErrorHtml(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__lastErrorHtml(objHandle: HCkCache): PWideChar; stdcall;

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.

procedure CkCache_getLastErrorText(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__lastErrorText(objHandle: HCkCache): PWideChar; stdcall;

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.

Concept of LastErrorText

LastErrorText Standard Information

procedure CkCache_getLastErrorXml(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__lastErrorXml(objHandle: HCkCache): PWideChar; stdcall;

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.

procedure CkCache_getLastEtagFetched(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__lastEtagFetched(objHandle: HCkCache): PWideChar; stdcall;

The ETag of the last item fetched from cache.

procedure CkCache_getLastExpirationFetchedStr(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__lastExpirationFetchedStr(objHandle: HCkCache): PWideChar; stdcall;

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

function CkCache_getLastHitExpired(objHandle: HCkCache): wordbool; stdcall;

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

procedure CkCache_getLastKeyFetched(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__lastKeyFetched(objHandle: HCkCache): PWideChar; stdcall;

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.)

function CkCache_getLastMethodSuccess(objHandle: HCkCache): wordbool; stdcall;
procedure CkCache_putLastMethodSuccess(objHandle: HCkCache; newPropVal: wordbool); stdcall;

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.

function CkCache_getLevel(objHandle: HCkCache): Integer; stdcall;
procedure CkCache_putLevel(objHandle: HCkCache; newPropVal: Integer); stdcall;

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.

function CkCache_getNumRoots(objHandle: HCkCache): Integer; stdcall;

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

function CkCache_getVerboseLogging(objHandle: HCkCache): wordbool; stdcall;
procedure CkCache_putVerboseLogging(objHandle: HCkCache; newPropVal: wordbool); stdcall;

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.

procedure CkCache_getVersion(objHandle: HCkCache; outPropVal: HCkString); stdcall;

function CkCache__version(objHandle: HCkCache): PWideChar; stdcall;

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

Methods

procedure CkCache_AddRoot(objHandle: HCkCache;
    path: PWideChar) stdcall;

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".

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function CkCache_DeleteAll(objHandle: HCkCache): Integer; stdcall;

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.

function CkCache_DeleteAllExpired(objHandle: HCkCache): Integer; stdcall;

Deletes all expired items from the cache.

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

function CkCache_DeleteFromCache(objHandle: HCkCache;
    key: PWideChar): wordbool; stdcall;

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.

function CkCache_DeleteOlderDt(objHandle: HCkCache;
    dateTime: HCkDateTime): Integer; stdcall;

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

function CkCache_DeleteOlderStr(objHandle: HCkCache;
    dateTimeStr: PWideChar): Integer; stdcall;

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

function CkCache_FetchFromCache(objHandle: HCkCache;
    key: PWideChar;
    outBytes: HCkByteData): wordbool; stdcall;

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 True for success, False for failure.

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function CkCache_FetchText(objHandle: HCkCache;
    key: PWideChar;
    outStr: HCkString): wordbool; stdcall;

function CkCache__fetchText(objHandle: HCkCache;
    key: PWideChar): PWideChar; stdcall;

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 True for success, False for failure.

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function CkCache_GetEtag(objHandle: HCkCache;
    key: PWideChar;
    outStr: HCkString): wordbool; stdcall;

function CkCache__getEtag(objHandle: HCkCache;
    key: PWideChar): PWideChar; stdcall;

Returns the eTag for an item in the cache.

Returns True for success, False for failure.

function CkCache_GetExpirationDt(objHandle: HCkCache;
    key: PWideChar): HCkDateTime; stdcall;

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

Returns nil on failure

function CkCache_GetExpirationStr(objHandle: HCkCache;
    url: PWideChar;
    outStr: HCkString): wordbool; stdcall;

function CkCache__getExpirationStr(objHandle: HCkCache;
    url: PWideChar): PWideChar; stdcall;

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

Returns True for success, False for failure.

function CkCache_GetFilename(objHandle: HCkCache;
    key: PWideChar;
    outStr: HCkString): wordbool; stdcall;

function CkCache__getFilename(objHandle: HCkCache;
    key: PWideChar): PWideChar; stdcall;

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

Returns True for success, False for failure.

function CkCache_GetRoot(objHandle: HCkCache;
    index: Integer;
    outStr: HCkString): wordbool; stdcall;

function CkCache__getRoot(objHandle: HCkCache;
    index: Integer): PWideChar; stdcall;

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

Returns True for success, False for failure.

function CkCache_IsCached(objHandle: HCkCache;
    key: PWideChar): wordbool; stdcall;

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

function CkCache_SaveLastError(objHandle: HCkCache;
    path: PWideChar): wordbool; stdcall;

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns True for success, False for failure.

function CkCache_SaveTextDt(objHandle: HCkCache;
    key: PWideChar;
    expireDateTime: HCkDateTime;
    eTag: PWideChar;
    itemTextData: PWideChar): wordbool; stdcall;

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

Returns True for success, False for failure.

function CkCache_SaveTextNoExpire(objHandle: HCkCache;
    key: PWideChar;
    eTag: PWideChar;
    itemTextData: PWideChar): wordbool; stdcall;

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.

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function CkCache_SaveTextStr(objHandle: HCkCache;
    key: PWideChar;
    expireDateTime: PWideChar;
    eTag: PWideChar;
    itemTextData: PWideChar): wordbool; stdcall;

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

Returns True for success, False for failure.

function CkCache_SaveToCacheDt(objHandle: HCkCache;
    key: PWideChar;
    expireDateTime: HCkDateTime;
    eTag: PWideChar;
    itemData: HCkByteData): wordbool; stdcall;

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

Returns True for success, False for failure.

function CkCache_SaveToCacheNoExpire(objHandle: HCkCache;
    key: PWideChar;
    eTag: PWideChar;
    itemData: HCkByteData): wordbool; stdcall;

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.

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function CkCache_SaveToCacheStr(objHandle: HCkCache;
    key: PWideChar;
    expireDateTime: PWideChar;
    eTag: PWideChar;
    itemData: HCkByteData): wordbool; stdcall;

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

Returns True for success, False for failure.

function CkCache_UpdateExpirationDt(objHandle: HCkCache;
    key: PWideChar;
    expireDateTime: HCkDateTime): wordbool; stdcall;

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

Returns True for success, False for failure.

function CkCache_UpdateExpirationStr(objHandle: HCkCache;
    key: PWideChar;
    expireDateTime: PWideChar): wordbool; stdcall;

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

Returns True for success, False for failure.