Cache C Reference Documentation

Cache

Current Version: 9.5.0.73

Create/Dispose

HCkCache instance = CkCache_Create();
// ...
CkCache_Dispose(instance);
HCkCache CkCache_Create(void);

Creates an instance of the HCkCache object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.

void CkCache_Dispose(HCkCache handle);

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. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkCache_Dispose.

Properties

DebugLogFilePath
void CkCache_getDebugLogFilePath(HCkCache cHandle, HCkString retval);
void CkCache_putDebugLogFilePath(HCkCache cHandle, const char *newVal);
const char *CkCache_debugLogFilePath(HCkCache cHandle);

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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LastErrorHtml
void CkCache_getLastErrorHtml(HCkCache cHandle, HCkString retval);
const char *CkCache_lastErrorHtml(HCkCache cHandle);

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
void CkCache_getLastErrorText(HCkCache cHandle, HCkString retval);
const char *CkCache_lastErrorText(HCkCache cHandle);

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
void CkCache_getLastErrorXml(HCkCache cHandle, HCkString retval);
const char *CkCache_lastErrorXml(HCkCache cHandle);

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
void CkCache_getLastEtagFetched(HCkCache cHandle, HCkString retval);
const char *CkCache_lastEtagFetched(HCkCache cHandle);

The ETag of the last item fetched from cache.

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LastExpirationFetched
void CkCache_getLastExpirationFetched(HCkCache cHandle, SYSTEMTIME * retval);
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
void CkCache_getLastExpirationFetchedStr(HCkCache cHandle, HCkString retval);
const char *CkCache_lastExpirationFetchedStr(HCkCache cHandle);

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

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LastHitExpired
BOOL CkCache_getLastHitExpired(HCkCache cHandle);

TRUE if the LastExpirationFetched is before the current date/time. Otherwise FALSE.

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LastKeyFetched
void CkCache_getLastKeyFetched(HCkCache cHandle, HCkString retval);
const char *CkCache_lastKeyFetched(HCkCache cHandle);

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
BOOL CkCache_getLastMethodSuccess(HCkCache cHandle);
void CkCache_putLastMethodSuccess(HCkCache cHandle, BOOL newVal);
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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Level
int CkCache_getLevel(HCkCache cHandle);
void CkCache_putLevel(HCkCache cHandle, int newVal);

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
int CkCache_getNumRoots(HCkCache cHandle);

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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Utf8
BOOL CkCache_getUtf8(HCkCache cHandle);
void CkCache_putUtf8(HCkCache cHandle, BOOL newVal);

When set to TRUE, all "const char *" arguments are interpreted as utf-8 strings. If set to FALSE (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to TRUE, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to FALSE, all "const char *" return values are ANSI strings.

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VerboseLogging
BOOL CkCache_getVerboseLogging(HCkCache cHandle);
void CkCache_putVerboseLogging(HCkCache cHandle, BOOL newVal);

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
void CkCache_getVersion(HCkCache cHandle, HCkString retval);
const char *CkCache_version(HCkCache cHandle);

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

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Methods

AddRoot
void CkCache_AddRoot(HCkCache cHandle, const char *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
int CkCache_DeleteAll(HCkCache cHandle);

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
int CkCache_DeleteAllExpired(HCkCache cHandle);

Deletes all expired items from the cache.

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

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DeleteFromCache
BOOL CkCache_DeleteFromCache(HCkCache cHandle, const char *key);

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
int CkCache_DeleteOlder(HCkCache cHandle, SYSTEMTIME * dateTime);
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
int CkCache_DeleteOlderDt(HCkCache cHandle, HCkDateTime dateTime);

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

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DeleteOlderStr
int CkCache_DeleteOlderStr(HCkCache cHandle, const char *dateTimeStr);

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

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FetchFromCache
BOOL CkCache_FetchFromCache(HCkCache cHandle, const char *key, HCkByteData outBytes);

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.

More Information and Examples
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FetchText
BOOL CkCache_FetchText(HCkCache cHandle, const char *key, HCkString outStr);
const char *CkCache_fetchText(HCkCache cHandle, const char *key);

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.

More Information and Examples
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GetEtag
BOOL CkCache_GetEtag(HCkCache cHandle, const char *key, HCkString outStr);
const char *CkCache_getEtag(HCkCache cHandle, const char *key);

Returns the eTag for an item in the cache.

Returns TRUE for success, FALSE for failure.

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GetExpiration
BOOL CkCache_GetExpiration(HCkCache cHandle, const char *key, SYSTEMTIME *outSysTime);
This method is deprecated. It will be removed in a future version.

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

Returns TRUE for success, FALSE for failure.

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GetExpirationDt
HCkDateTime CkCache_GetExpirationDt(HCkCache cHandle, const char *key);

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

Returns NULL on failure

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GetExpirationStr
BOOL CkCache_GetExpirationStr(HCkCache cHandle, const char *url, HCkString outStr);
const char *CkCache_getExpirationStr(HCkCache cHandle, const char *url);

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

Returns TRUE for success, FALSE for failure.

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GetFilename
BOOL CkCache_GetFilename(HCkCache cHandle, const char *key, HCkString outStr);
const char *CkCache_getFilename(HCkCache cHandle, const char *key);

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

Returns TRUE for success, FALSE for failure.

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GetRoot
BOOL CkCache_GetRoot(HCkCache cHandle, int index, HCkString outStr);
const char *CkCache_getRoot(HCkCache cHandle, int index);

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

Returns TRUE for success, FALSE for failure.

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IsCached
BOOL CkCache_IsCached(HCkCache cHandle, const char *key);

Returns TRUE if the item is found in the cache, otherwise returns FALSE.

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SaveLastError
BOOL CkCache_SaveLastError(HCkCache cHandle, const char *path);

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

Returns TRUE for success, FALSE for failure.

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SaveText
BOOL CkCache_SaveText(HCkCache cHandle, const char *key, SYSTEMTIME * expireDateTime, const char *eTag, const char *itemTextData);
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
BOOL CkCache_SaveTextDt(HCkCache cHandle, const char *key, HCkDateTime expireDateTime, const char *eTag, const char *itemTextData);

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
BOOL CkCache_SaveTextNoExpire(HCkCache cHandle, const char *key, const char *eTag, const char *itemTextData);

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
BOOL CkCache_SaveTextStr(HCkCache cHandle, const char *key, const char *expireDateTime, const char *eTag, const char *itemTextData);

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
BOOL CkCache_SaveToCache(HCkCache cHandle, const char *key, SYSTEMTIME * expireDateTime, const char *eTag, HCkByteData itemData);
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
BOOL CkCache_SaveToCacheDt(HCkCache cHandle, const char *key, HCkDateTime expireDateTime, const char *eTag, HCkByteData itemData);

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
BOOL CkCache_SaveToCacheNoExpire(HCkCache cHandle, const char *key, const char *eTag, HCkByteData itemData);

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
BOOL CkCache_SaveToCacheStr(HCkCache cHandle, const char *key, const char *expireDateTime, const char *eTag, HCkByteData itemData);

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
BOOL CkCache_UpdateExpiration(HCkCache cHandle, const char *key, SYSTEMTIME * expireDateTime);
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
BOOL CkCache_UpdateExpirationDt(HCkCache cHandle, const char *key, HCkDateTime expireDateTime);

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

Returns TRUE for success, FALSE for failure.

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UpdateExpirationStr
BOOL CkCache_UpdateExpirationStr(HCkCache cHandle, const char *key, const char *expireDateTime);

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

Returns TRUE for success, FALSE for failure.

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