TChilkatCache Delphi ActiveX Reference Documentation
TChilkatCache
Current Version: 10.0.0
Importing the Chilkat ActiveX into Delphi
Important: When upgrading to a new version of Chilkat, make sure to re-imported ActiveX DLL into Delphi to regenerate the files described below.
Chilkat v9.5.*: If using Chilkat v9.5.*, then use "Chilkat_v9_5_0_TLB" instead of "Chilkat_TLB", and the DLLs are named ChilkatAx-9.5.0-win32.dll (or ChilkatAx-9.5.0-x64.dll).
Two things are required to use an ActiveX in Delphi:
- The ActiveX DLL needs to be registered via regsvr32 on the system where the Delphi application runs. See How To Register ActiveX DLLs for detailed information.
- See also: ActiveX Registration Tutorial
- The ActiveX component needs to be "imported". Use the Delphi Import Component Wizard to import the Chilkat type library. This creates the following files: Chilkat_TLB.pas and Chilkat_TLB.dcr. The Chilkat_TLB.pas should be added to your project.
To import the Chilkat type library, do the following:
- In the Delphi RAD Studio, select the menu item "Component" --> "Import a Type Library".
- Find "Chilkat ActiveX" in the list and select it. This will only appear in the list if the ChilkatAx-win32.dll (or ChilkatAx-x64.dll) has been registered w/ regsvr32.
- Check the "Generate Component Wrappers" checkbox.
- Select a directory where the unit files (.pas and .dcr) should be generated.
- Select "Create Unit" and then "Finish".
- Add the .pas to your Delphi project.
To use a Chilkat ActiveX object in your Delphi code, add "Chilkat_TLB" to the "uses" statement. For example:
uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;
Object Creation
var obj: TChilkatCache; ... begin obj := TChilkatCache.Create(Self); ... // When finished, free the object instance. obj.Free();
Properties
DebugLogFilePath
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:
- a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
- the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
- there is an internal problem (bug) in the Chilkat code that causes the hang.
LastBinaryResult
The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to 1. 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).
topLastErrorHtml
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.
topLastErrorText
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.
LastErrorXml
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.
topLastEtagFetched
The ETag of the last item fetched from cache.
topLastExpirationFetchedStr
Expiration date/time of the last item fetched from cache in RFC822 string format.
topLastHitExpired
1 if the LastExpirationFetched is before the current date/time. Otherwise 0.
topLastKeyFetched
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.)
topLastMethodSuccess
Indicate whether the last method call succeeded or failed. A value of 1 indicates success, a value of 0 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 = 1 and failure = 0.
- 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 1. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.
topLastStringResult
The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to 1. 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).
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topLevel
The number of directory levels in the cache. Possible values are:
0: All cache files are in a single directory (the cache root).top
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.
NumRoots
The number of root directories composing the cache. A typical multi-root cache would place each root on a separate hard drive.
topVerboseLogging
If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
topVersion
Methods
AddRoot
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".
DeleteAll
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.
topDeleteAllExpired
Deletes all expired items from the cache.
Returns the number of items (i.e. cache files) deleted.
topDeleteFromCache
Deletes a single item from the disk cache. Returns 0 if the item exists in cache but could not be deleted. Otherwise returns 1.
Returns 1 for success, 0 for failure.
topDeleteOlderDt
The same as DeleteOlder, except the dateTime is passed as a CkDateTime.
topDeleteOlderStr
The same as DeleteOlder, except the dateTimeStr is passed as a date/time in RFC822 format.
topFetchBd
Fetches an item from cache and returns in bd.
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 1 for success, 0 for failure.
topFetchFromCache
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 a zero-length byte array (as an OleVariant) on failure.
An empty array will have a VarArrayHighBound of -1 meaning 0 elements.
FetchSb
Fetches a text item from the cache and returns in sb.
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 1 for success, 0 for failure.
topFetchText
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 a zero-length WideString on failure
GetEtag
GetExpirationDt
Returns the expiration date/time for an item in the cache as a CkDateTime object.
Returns nil on failure
topGetExpirationStr
Returns the expiration date/time for an item in the cache in RFC822 string format.
Returns a zero-length WideString on failure
topGetFilename
Returns the absolute file path of the cache file associated with the key.
Returns a zero-length WideString on failure
topGetRoot
Returns the directory path of the Nth cache root. (Indexing begins at 0.)
Returns a zero-length WideString on failure
topIsCached
Returns 1 if the item is found in the cache, otherwise returns 0.
topSaveTextDt
The same as SaveText, except the expire date/time is passed as a CkDateTime object.
Returns 1 for success, 0 for failure.
topSaveTextNoExpire
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 1 for success, 0 for failure.
SaveTextStr
The same as SaveText, except the expire date/time is passed as a string in RFC822 format.
Returns 1 for success, 0 for failure.
topSaveToCacheDt
The same as SaveToCache, except the expire date/time is passed as a CkDateTime object.
Returns 1 for success, 0 for failure.
topSaveToCacheNoExpire
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 1 for success, 0 for failure.
SaveToCacheStr
The same as SaveToCache, except the expire date/time is passed in RFC822 string format.
Returns 1 for success, 0 for failure.
topUpdateExpirationDt
The same as UpdateExpiration, except the expireDateTime is passed as a CkDateTime.
Returns 1 for success, 0 for failure.
topUpdateExpirationStr
The same as UpdateExpiration, except the expireDateTime is passed in RFC822 string format.
Returns 1 for success, 0 for failure.
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