TSpider Delphi ActiveX Reference Documentation

TSpider

Current Version: 9.5.0.73

Chilkat Spider web crawler component.

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.

Two things are required to use an ActiveX in Delphi:

  1. 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.
  2. See also: ActiveX Registration Tutorial
  3. 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_v9_5_0_TLB.pas and Chilkat_v9_5_0_TLB.dcr. The Chilkat_v9_5_0_TLB.pas should be added to your project.

To import the Chilkat type library, do the following:

  1. In the Delphi RAD Studio, select the menu item "Component" --> "Import a Type Library".
  2. Find "Chilkat ActiveX v9.5.0" in the list and select it. This will only appear in the list if the ChilkatAx-9.5.0-win32.dll (or ChilkatAx-9.5.0-x64.dll) has been registered w/ regsvr32.
  3. Check the "Generate Component Wrappers" checkbox.
  4. Select a directory where the unit files (.pas and .dcr) should be generated.
  5. Select "Create Unit" and then "Finish".
  6. Add the .pas to your Delphi project.

To use a Chilkat ActiveX object in your Delphi code, add "Chilkat_v9_5_0_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_v9_5_0_TLB;

Object Creation

var
obj: TSpider;
...
begin
obj := TSpider.Create(Self);
...
// When finished, free the object instance.
obj.Free();

Properties

AbortCurrent
property AbortCurrent: Integer
Introduced in version 9.5.0.58

When set to 1, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to 0 when the next method is called. When the abort occurs, this property is reset to 0. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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AvoidHttps
property AvoidHttps: Integer

If set the 1 (true) the spider will avoid all HTTPS URLs. The default is 0 (false).

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CacheDir
property CacheDir: WideString

Specifies a cache directory to use for spidering. If either of the FetchFromCache or UpdateCache properties are true, this is the location of the cache to be used. Note: the Internet Explorer, Netscape, and FireFox caches are completely separate from the Chilkat Spider cache directory. You should specify a new and empty directory.

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ChopAtQuery
property ChopAtQuery: Integer

If equal to 1 (true), then the query portion of all URLs are automatically removed when adding to the unspidered list. The default value is 0 (false).

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ConnectTimeout
property ConnectTimeout: Integer

The maximum number of seconds to wait while connecting to an HTTP server.

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DebugLogFilePath
property DebugLogFilePath: WideString

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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Domain
property Domain: WideString readonly

The domain name that is being spidered. This is the domain previously set in the Initialize method.

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FetchFromCache
property FetchFromCache: Integer

If equal to 1 (true) then pages are fetched from cache when possible. If 0, the cache is ignored. The default value is 1. Regardless, if no CacheDir is set then the cache is not used.

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HeartbeatMs
property HeartbeatMs: Integer

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

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LastBinaryResult
property LastBinaryResult: OleVariant readonly
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 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).

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LastErrorHtml
property LastErrorHtml: WideString readonly

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
property LastErrorText: WideString readonly

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
property LastErrorXml: WideString readonly

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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LastFromCache
property LastFromCache: Integer readonly

Equal to 1 if the last page spidered was fetched from the cache. Otherwise equal to 0.

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LastHtml
property LastHtml: WideString readonly

The HTML text of the last paged fetched by the spider.

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LastHtmlDescription
property LastHtmlDescription: WideString readonly

The HTML META description from the last page fetched by the spider.

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LastHtmlKeywords
property LastHtmlKeywords: WideString readonly

The HTML META keywords from the last page fetched by the spider.

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LastHtmlTitle
property LastHtmlTitle: WideString readonly

The HTML title from the last page fetched by the spider.

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LastMethodSuccess
property LastMethodSuccess: Integer
Introduced in version 9.5.0.52

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.

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LastModDate
property LastModDate: TDateTime readonly
This property is deprecated. It will be removed in a future version.

The last-modification date of the last URL spidered.

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LastStringResult
property LastStringResult: WideString readonly
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 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).

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LastStringResultLen
property LastStringResultLen: Integer readonly
Introduced in version 9.5.0.53

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

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LastUrl
property LastUrl: WideString readonly

The URL of the last page spidered.

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MaxResponseSize
property MaxResponseSize: Integer

The maximum HTTP response size allowed. The spider will automatically fail any pages larger than this size. The default value is 250,000 bytes.

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MaxUrlLen
property MaxUrlLen: Integer

The maximum URL length allowed. URLs longer than this are not added to the unspidered list. The default value is 200.

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NumAvoidPatterns
property NumAvoidPatterns: Integer readonly

The number of avoid patterns previously set by calling AddAvoidPattern.

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NumFailed
property NumFailed: Integer readonly

The number of URLs in the component's failed URL list.

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NumOutboundLinks
property NumOutboundLinks: Integer readonly

The number of URLs in the component's outbound links URL list.

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NumSpidered
property NumSpidered: Integer readonly

The number of URLs in the component's already-spidered URL list.

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NumUnspidered
property NumUnspidered: Integer readonly

The number of URLs in the component's unspidered URL list.

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PreferIpv6
property PreferIpv6: Integer

If 1, then use IPv6 over IPv4 when both are supported for a particular domain. The default value of this property is 0, which will choose IPv4 over IPv6.

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ProxyDomain
property ProxyDomain: WideString

The domain name of a proxy host if an HTTP proxy is used.

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ProxyLogin
property ProxyLogin: WideString

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.

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ProxyPassword
property ProxyPassword: WideString

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.

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ProxyPort
property ProxyPort: Integer

The port number of a proxy server if an HTTP proxy is used.

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ReadTimeout
property ReadTimeout: Integer

The maximum number of seconds to wait when reading from an HTTP server.

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UpdateCache
property UpdateCache: Integer

If equal to 1 (true) then pages saved to the cache. If 0, the cache is ignored. The default value is 1. Regardless, if no CacheDir is set then the cache is not used.

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UserAgent
property UserAgent: WideString

The value of the HTTP user-agent header field to be sent with HTTP requests. The default value is "Chilkat/1.0.0 (+http://www.chilkatsoft.com/ChilkatHttpUA.asp)"

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VerboseLogging
property VerboseLogging: Integer

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.

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Version
property Version: WideString readonly

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

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WindDownCount
property WindDownCount: Integer

The "wind-down" phase begins when this number of URLs has been spidered. When in the wind-down phase, no new URLs are added to the unspidered list. The default value is 0 which means that there is NO wind-down phase.

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Methods

AddAvoidOutboundLinkPattern
procedure AddAvoidOutboundLinkPattern(pattern: WideString);

Adds a wildcarded pattern to prevent collecting matching outbound link URLs. For example, if "*google*" is added, then any outbound links containing the word "google" will be ignored. The "*" character matches zero or more of any character.

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AddAvoidPattern
procedure AddAvoidPattern(pattern: WideString);

Adds a wildcarded pattern to prevent spidering matching URLs. For example, if "*register*" is added, then any url containing the word "register" is not spidered. The "*" character matches zero or more of any character.

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AddMustMatchPattern
procedure AddMustMatchPattern(pattern: WideString);

Adds a wildcarded pattern to limit spidering to only URLs that match the pattern. For example, if "*/products/*" is added, then only URLs containing "/products/" are spidered. This is helpful for only spidering a portion of a website. The "*" character matches zero or more of any character.

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AddUnspidered
procedure AddUnspidered(url: WideString);

To begin spidering you must call this method one or more times to provide starting points. It adds a single URL to the component's internal queue of URLs to be spidered.

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CanonicalizeUrl
function CanonicalizeUrl(url: WideString): WideString;

Canonicalizes a URL by doing the following:

  • Drops username/password if present.
  • Drops fragment if present.
  • Converts domain to lowercase.
  • Removes port 80 or 443
  • Remove default.asp, index.html, index.htm, default.html, index.htm, default.htm, index.php, index.asp, default.php, .cfm, .aspx, ,php3, .pl, .cgi, .txt, .shtml, .phtml
  • Remove www. from the domain if present.

Returns a zero-length WideString on failure

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ClearFailedUrls
procedure ClearFailedUrls();

Clears the component's internal list of URLs that could not be downloaded.

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ClearOutboundLinks
procedure ClearOutboundLinks();

Clears the component's internal list of outbound URLs that will automatically accumulate while spidering.

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ClearSpideredUrls
procedure ClearSpideredUrls();

Clears the component's internal list of already-spidered URLs that will automatically accumulate while spidering.

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CrawlNext
function CrawlNext(): Integer;

Crawls the next URL in the internal list of unspidered URLs. The URL is moved from the unspidered list to the spidered list. Any new links within the same domain and not yet spidered are added to the unspidered list. (providing that they do not match "avoid" patterns, etc.) Any new outbound links are added to the outbound URL list. If successful, the HTML of the downloaded page is available in the LastHtml property. If there are no more URLs left unspidered, the method returns 0. Information about the URL crawled is available in the properties LastUrl, LastFromCache, and LastModDate.

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CrawlNextAsync (1)
function CrawlNextAsync(): TChilkatTask;

Creates an asynchronous task to call the CrawlNext method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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FetchRobotsText
function FetchRobotsText(): WideString;

Returns the contents of the robots.txt file from the domain being crawled. This spider component will not crawl URLs excluded by robots.txt. If you believe the spider is not behaving correctly, please notify us at support@chilkatsoft.com and provide information detailing a case that allows us to reproduce the problem.

Returns a zero-length WideString on failure

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FetchRobotsTextAsync (1)
function FetchRobotsTextAsync(): TChilkatTask;

Creates an asynchronous task to call the FetchRobotsText method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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GetAvoidPattern
function GetAvoidPattern(index: Integer): WideString;

Returns the Nth avoid pattern previously added by calling AddAvoidPattern. Indexing begins at 0.

Returns a zero-length WideString on failure

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GetBaseDomain
function GetBaseDomain(domain: WideString): WideString;

To be documented soon.

Returns a zero-length WideString on failure

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GetFailedUrl
function GetFailedUrl(index: Integer): WideString;

Returns the Nth URL in the failed URL list. Indexing begins at 0.

Returns a zero-length WideString on failure

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GetOutboundLink
function GetOutboundLink(index: Integer): WideString;

Returns the Nth URL in the outbound link URL list. Indexing begins at 0.

Returns a zero-length WideString on failure

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GetSpideredUrl
function GetSpideredUrl(index: Integer): WideString;

Returns the Nth URL in the already-spidered URL list. Indexing begins at 0.

Returns a zero-length WideString on failure

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GetUnspideredUrl
function GetUnspideredUrl(index: Integer): WideString;

Returns the Nth URL in the unspidered URL list. Indexing begins at 0.

Returns a zero-length WideString on failure

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GetUrlDomain
function GetUrlDomain(url: WideString): WideString;

Returns the domain name part of a URL. For example, if the URL is "http://www.chilkatsoft.com/test.asp", then "www.chilkatsoft.com" is returned.

Returns a zero-length WideString on failure

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Initialize
procedure Initialize(domain: WideString);

Initializes the component to begin spidering a domain. Calling Initialize clears any patterns added via the AddAvoidOutboundLinkPattern, AddAvoidPattern, and AddMustMatchPattern methods. The domain name passed to this method is what is returned by the Domain property. The spider only crawls URLs within the same domain.

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RecrawlLast
function RecrawlLast(): Integer;

Re-crawls the last URL spidered. This helpful when cookies set in a previous page load cause the page to be loaded differently the next time.

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RecrawlLastAsync (1)
function RecrawlLastAsync(): TChilkatTask;

Creates an asynchronous task to call the RecrawlLast method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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SkipUnspidered
procedure SkipUnspidered(index: Integer);

Moves a URL from the unspidered list to the spidered list. This allows an application to skip a specific URL.

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SleepMs
procedure SleepMs(numMilliseconds: Integer);

Suspends the execution of the current thread until the time-out interval elapses.

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Events

AbortCheck
procedure AbortCheck(ASender: TObject; out abort: Integer);

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

Delphi ActiveX Event callback implementation:

procedure TForm1.spiderENTRY_NAME(ASender: TObject;  out abort: Integer);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  spider: TChilkatSpider;

begin
  spider := TChilkatSpider.Create(Self);
  spider.OnAbortCheck := spiderAbortCheck;
  // ...
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PercentDone
procedure PercentDone(ASender: TObject; pctDone: Integer; out abort: Integer);

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to 1 will cause the method to abort and return a failed status (or whatever return value indicates failure).

Delphi ActiveX Event callback implementation:

procedure TForm1.spiderENTRY_NAME(ASender: TObject;  pctDone: Integer; out abort: Integer);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  spider: TChilkatSpider;

begin
  spider := TChilkatSpider.Create(Self);
  spider.OnPercentDone := spiderPercentDone;
  // ...
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ProgressInfo
procedure ProgressInfo(ASender: TObject; const name: WideString; const value: WideString);

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

Delphi ActiveX Event callback implementation:

procedure TForm1.spiderENTRY_NAME(ASender: TObject;  const name: WideString; const value: WideString);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  spider: TChilkatSpider;

begin
  spider := TChilkatSpider.Create(Self);
  spider.OnProgressInfo := spiderProgressInfo;
  // ...
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TaskCompleted
procedure TaskCompleted(ASender: TObject; const task: IChilkatTask);

Called in the background thread when an asynchronous task completes.

More Information and Examples

Delphi ActiveX Event callback implementation:

procedure TForm1.spiderENTRY_NAME(ASender: TObject;  const task: IChilkatTask);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  spider: TChilkatSpider;

begin
  spider := TChilkatSpider.Create(Self);
  spider.OnTaskCompleted := spiderTaskCompleted;
  // ...
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