---
product: Chilkat
product_version: 11.7.0
language: pascal
language_label: Lazarus Pascal
class: Spider
license: free
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/pascal_SpiderRef.html
---
# Chilkat Spider — Lazarus Pascal — v11.7.0

> Chilkat 11.7.0 · language=pascal · class=Spider
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/Spider.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/guide.md`.

## Purpose

**Crawl a website domain, manage URL queues, filter links, cache pages, and inspect fetched HTML.**

`Chilkat.Spider` crawls pages within a single initialized domain. It maintains internal lists of unspidered, spidered, failed, and outbound URLs; fetches one page at a time; extracts same-domain links for continued crawling; collects outbound links separately; respects `robots.txt`; supports wildcard include and avoid patterns; can use a dedicated cache directory; and exposes the last fetched HTML, title, meta description, keywords, redirect information, cache status, and last-modified date.

**Domain-limited crawling**

Initialize the spider with a domain and crawl only URLs that belong to that same domain.

**URL queue management**

Add starting URLs, crawl the next queued URL, skip selected URLs, and inspect unspidered, spidered, failed, and outbound URL lists.

**Filtering rules**

Add wildcard avoid patterns, must-match patterns, and outbound-link avoid patterns to control which URLs are crawled or collected.

**Page metadata**

Read the last fetched HTML, page title, meta description, meta keywords, final redirect URL, and last-modified timestamp.

**Caching and redirects**

Fetch pages from a Chilkat-managed cache, update the cache, detect when a page was redirected, and inspect whether the last page came from cache.

**Network controls**

Configure user-agent, proxy settings, connect/read timeouts, IPv6 preference, maximum URL length, maximum response size, and abort support.

**Common pattern:** Call `Initialize` with the target domain, add one or more starting URLs with `AddUnspidered`, optionally add filtering patterns, then repeatedly call `CrawlNext`. After each successful crawl, inspect `LastUrl`, `LastHtml`, page metadata, redirect state, and the URL-list counts to decide whether to continue, skip, recrawl, or process the page.

**Scope note:** `Spider` is intended for controlled, domain-oriented crawling and link discovery. Use `Chilkat.Http` or `Chilkat.Rest` when the task is a single HTTP request, API call, form post, or download rather than a crawl of discovered links.

## Object creation, unlocking and error handling

**Create / Free**

```pascal
uses
  Chilkat.Spider;

var
  obj: TSpider;
begin
  obj := TSpider.Create;
  try
    if not obj.IsValid then
      raise Exception.Create('Failed to create a TSpider instance.');

    // ... use obj ...

  finally
    obj.Free;
  end;
end;
```

`constructor Create;`

Allocates the underlying CkSpider object and returns a new TSpider instance. Simply adding **Chilkat.Spider** to the unit's `uses` clause is enough to locate and bind to the Chilkat shared library (DLL / .so / .dylib) at runtime — no separate load step is required. Check `obj.IsValid` after calling `Create`; it is `False` if the underlying library could not be found/loaded or the object could not be allocated (for example, when unlicensed).

`destructor Destroy; override;`

Every TSpider created by calling `Create` should eventually be released by calling `.Free` (inherited from `TObject`). The destructor automatically disposes the underlying CkSpider handle. A native (unmanaged) memory leak occurs if the object is never freed.

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in Lazarus Pascal.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `property DebugLogFilePath: string read GetDebugLogFilePath write SetDebugLogFilePath;` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `property LastErrorHtml: string read GetLastErrorHtml;` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `property LastErrorText: string read GetLastErrorText;` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `property LastErrorXml: string read GetLastErrorXml;` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `property LastMethodSuccess: Boolean read GetLastMethodSuccess write SetLastMethodSuccess;` | read/write | Indicates the success or failure of the most recent method call: `True` means success, `False` means failure. |
| `VerboseLogging` | `property VerboseLogging: Boolean read GetVerboseLogging write SetVerboseLogging;` | read/write | If set to `True`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `property Version: string read GetVersion;` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AbortCurrent` | property, read/write | `property AbortCurrent: Boolean read GetAbortCurrent write SetAbortCurrent;` |
| `AvoidHttps` | property, read/write | `property AvoidHttps: Boolean read GetAvoidHttps write SetAvoidHttps;` |
| `CacheDir` | property, read/write | `property CacheDir: string read GetCacheDir write SetCacheDir;` |
| `ChopAtQuery` | property, read/write | `property ChopAtQuery: Boolean read GetChopAtQuery write SetChopAtQuery;` |
| `ConnectTimeout` | property, read/write | `property ConnectTimeout: Integer read GetConnectTimeout write SetConnectTimeout;` |
| `Domain` | property, read-only | `property Domain: string read GetDomain;` |
| `FetchFromCache` | property, read/write | `property FetchFromCache: Boolean read GetFetchFromCache write SetFetchFromCache;` |
| `FinalRedirectUrl` | property, read-only | `property FinalRedirectUrl: string read GetFinalRedirectUrl;` |
| `HeartbeatMs` | property, read/write | `property HeartbeatMs: Integer read GetHeartbeatMs write SetHeartbeatMs;` |
| `LastFromCache` | property, read-only | `property LastFromCache: Boolean read GetLastFromCache;` |
| `LastHtml` | property, read-only | `property LastHtml: string read GetLastHtml;` |
| `LastHtmlDescription` | property, read-only | `property LastHtmlDescription: string read GetLastHtmlDescription;` |
| `LastHtmlKeywords` | property, read-only | `property LastHtmlKeywords: string read GetLastHtmlKeywords;` |
| `LastHtmlTitle` | property, read-only | `property LastHtmlTitle: string read GetLastHtmlTitle;` |
| `LastModDateStr` | property, read-only | `property LastModDateStr: string read GetLastModDateStr;` |
| `LastUrl` | property, read-only | `property LastUrl: string read GetLastUrl;` |
| `MaxResponseSize` | property, read/write | `property MaxResponseSize: Integer read GetMaxResponseSize write SetMaxResponseSize;` |
| `MaxUrlLen` | property, read/write | `property MaxUrlLen: Integer read GetMaxUrlLen write SetMaxUrlLen;` |
| `NumAvoidPatterns` | property, read-only | `property NumAvoidPatterns: Integer read GetNumAvoidPatterns;` |
| `NumFailed` | property, read-only | `property NumFailed: Integer read GetNumFailed;` |
| `NumOutboundLinks` | property, read-only | `property NumOutboundLinks: Integer read GetNumOutboundLinks;` |
| `NumSpidered` | property, read-only | `property NumSpidered: Integer read GetNumSpidered;` |
| `NumUnspidered` | property, read-only | `property NumUnspidered: Integer read GetNumUnspidered;` |
| `PreferIpv6` | property, read/write | `property PreferIpv6: Boolean read GetPreferIpv6 write SetPreferIpv6;` |
| `ProxyDomain` | property, read/write | `property ProxyDomain: string read GetProxyDomain write SetProxyDomain;` |
| `ProxyLogin` | property, read/write | `property ProxyLogin: string read GetProxyLogin write SetProxyLogin;` |
| `ProxyPassword` | property, read/write | `property ProxyPassword: string read GetProxyPassword write SetProxyPassword;` |
| `ProxyPort` | property, read/write | `property ProxyPort: Integer read GetProxyPort write SetProxyPort;` |
| `ReadTimeout` | property, read/write | `property ReadTimeout: Integer read GetReadTimeout write SetReadTimeout;` |
| `UpdateCache` | property, read/write | `property UpdateCache: Boolean read GetUpdateCache write SetUpdateCache;` |
| `UserAgent` | property, read/write | `property UserAgent: string read GetUserAgent write SetUserAgent;` |
| `WasRedirected` | property, read-only | `property WasRedirected: Boolean read GetWasRedirected;` |
| `WindDownCount` | property, read/write | `property WindDownCount: Integer read GetWindDownCount write SetWindDownCount;` |
| `AddAvoidOutboundLinkPattern` | method | `procedure AddAvoidOutboundLinkPattern(const pattern: string);` |
| `AddAvoidPattern` | method | `procedure AddAvoidPattern(const pattern: string);` |
| `AddMustMatchPattern` | method | `procedure AddMustMatchPattern(const pattern: string);` |
| `AddUnspidered` | method | `procedure AddUnspidered(const url: string);` |
| `CanonicalizeUrl` | method | `function CanonicalizeUrl(const url: string): string;` |
| `ClearFailedUrls` | method | `procedure ClearFailedUrls;` |
| `ClearOutboundLinks` | method | `procedure ClearOutboundLinks;` |
| `ClearSpideredUrls` | method | `procedure ClearSpideredUrls;` |
| `CrawlNext` | method | `function CrawlNext: Boolean;` |
| `FetchRobotsText` | method | `function FetchRobotsText: string;` |
| `GetAvoidPattern` | method | `function GetAvoidPattern(index: Integer): string;` |
| `GetBaseDomain` | method | `function GetBaseDomain(const domain: string): string;` |
| `GetFailedUrl` | method | `function GetFailedUrl(index: Integer): string;` |
| `GetOutboundLink` | method | `function GetOutboundLink(index: Integer): string;` |
| `GetSpideredUrl` | method | `function GetSpideredUrl(index: Integer): string;` |
| `GetUnspideredUrl` | method | `function GetUnspideredUrl(index: Integer): string;` |
| `GetUrlDomain` | method | `function GetUrlDomain(const url: string): string;` |
| `Initialize` | method | `procedure Initialize(const domain: string);` |
| `LoadTaskCaller` | method | `// task is a TTask object. function LoadTaskCaller(task: TChilkatBase): Boolean;` |
| `RecrawlLast` | method | `function RecrawlLast: Boolean;` |
| `SkipUnspidered` | method | `procedure SkipUnspidered(index: Integer);` |
| `SleepMs` | method | `procedure SleepMs(numMilliseconds: Integer);` |

## Properties

### Spider.AbortCurrent

`Chilkat 11.7.0 · pascal · Spider · AbortCurrent · property · read/write · since 9.5.0.58`

```pascal
property AbortCurrent: Boolean read GetAbortCurrent write SetAbortCurrent;
```

When set to `True`, 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 `False` when the next method is called. When the abort occurs, this property is reset to `False`. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

### Spider.AvoidHttps

`Chilkat 11.7.0 · pascal · Spider · AvoidHttps · property · read/write`

```pascal
property AvoidHttps: Boolean read GetAvoidHttps write SetAvoidHttps;
```

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

### Spider.CacheDir

`Chilkat 11.7.0 · pascal · Spider · CacheDir · property · read/write`

```pascal
property CacheDir: string read GetCacheDir write SetCacheDir;
```

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.

### Spider.ChopAtQuery

`Chilkat 11.7.0 · pascal · Spider · ChopAtQuery · property · read/write`

```pascal
property ChopAtQuery: Boolean read GetChopAtQuery write SetChopAtQuery;
```

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).

### Spider.ConnectTimeout

`Chilkat 11.7.0 · pascal · Spider · ConnectTimeout · property · read/write`

```pascal
property ConnectTimeout: Integer read GetConnectTimeout write SetConnectTimeout;
```

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

### Spider.Domain

`Chilkat 11.7.0 · pascal · Spider · Domain · property · read-only`

```pascal
property Domain: string read GetDomain;
```

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

### Spider.FetchFromCache

`Chilkat 11.7.0 · pascal · Spider · FetchFromCache · property · read/write`

```pascal
property FetchFromCache: Boolean read GetFetchFromCache write SetFetchFromCache;
```

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.

### Spider.FinalRedirectUrl

`Chilkat 11.7.0 · pascal · Spider · FinalRedirectUrl · property · read-only · since 9.5.0.85`

```pascal
property FinalRedirectUrl: string read GetFinalRedirectUrl;
```

If the last URL crawled was redirected (as indicated by the WasRedirected property), this property will contain the final redirect URL.

### Spider.HeartbeatMs

`Chilkat 11.7.0 · pascal · Spider · HeartbeatMs · property · read/write`

```pascal
property HeartbeatMs: Integer read GetHeartbeatMs write SetHeartbeatMs;
```

**Full documentation for this property (same in every language):** [Event Callback Examples](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/event_callback_examples.md)

The interval in milliseconds between each `AbortCheck` event callback, which enables an application to abort certain method calls before they complete. **By default, HeartbeatMs is set to** `0`**, meaning no AbortCheck event callbacks will trigger.**

### Spider.LastFromCache

`Chilkat 11.7.0 · pascal · Spider · LastFromCache · property · read-only`

```pascal
property LastFromCache: Boolean read GetLastFromCache;
```

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

### Spider.LastHtml

`Chilkat 11.7.0 · pascal · Spider · LastHtml · property · read-only`

```pascal
property LastHtml: string read GetLastHtml;
```

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

### Spider.LastHtmlDescription

`Chilkat 11.7.0 · pascal · Spider · LastHtmlDescription · property · read-only`

```pascal
property LastHtmlDescription: string read GetLastHtmlDescription;
```

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

### Spider.LastHtmlKeywords

`Chilkat 11.7.0 · pascal · Spider · LastHtmlKeywords · property · read-only`

```pascal
property LastHtmlKeywords: string read GetLastHtmlKeywords;
```

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

### Spider.LastHtmlTitle

`Chilkat 11.7.0 · pascal · Spider · LastHtmlTitle · property · read-only`

```pascal
property LastHtmlTitle: string read GetLastHtmlTitle;
```

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

### Spider.LastModDateStr

`Chilkat 11.7.0 · pascal · Spider · LastModDateStr · property · read-only`

```pascal
property LastModDateStr: string read GetLastModDateStr;
```

The last modification date/time (RFC822 format) from the last page fetched by the spider.

### Spider.LastUrl

`Chilkat 11.7.0 · pascal · Spider · LastUrl · property · read-only`

```pascal
property LastUrl: string read GetLastUrl;
```

The URL of the last page spidered.

### Spider.MaxResponseSize

`Chilkat 11.7.0 · pascal · Spider · MaxResponseSize · property · read/write`

```pascal
property MaxResponseSize: Integer read GetMaxResponseSize write SetMaxResponseSize;
```

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

### Spider.MaxUrlLen

`Chilkat 11.7.0 · pascal · Spider · MaxUrlLen · property · read/write`

```pascal
property MaxUrlLen: Integer read GetMaxUrlLen write SetMaxUrlLen;
```

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

### Spider.NumAvoidPatterns

`Chilkat 11.7.0 · pascal · Spider · NumAvoidPatterns · property · read-only`

```pascal
property NumAvoidPatterns: Integer read GetNumAvoidPatterns;
```

The number of avoid patterns previously set by calling AddAvoidPattern.

### Spider.NumFailed

`Chilkat 11.7.0 · pascal · Spider · NumFailed · property · read-only`

```pascal
property NumFailed: Integer read GetNumFailed;
```

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

### Spider.NumOutboundLinks

`Chilkat 11.7.0 · pascal · Spider · NumOutboundLinks · property · read-only`

```pascal
property NumOutboundLinks: Integer read GetNumOutboundLinks;
```

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

### Spider.NumSpidered

`Chilkat 11.7.0 · pascal · Spider · NumSpidered · property · read-only`

```pascal
property NumSpidered: Integer read GetNumSpidered;
```

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

### Spider.NumUnspidered

`Chilkat 11.7.0 · pascal · Spider · NumUnspidered · property · read-only`

```pascal
property NumUnspidered: Integer read GetNumUnspidered;
```

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

### Spider.PreferIpv6

`Chilkat 11.7.0 · pascal · Spider · PreferIpv6 · property · read/write`

```pascal
property PreferIpv6: Boolean read GetPreferIpv6 write SetPreferIpv6;
```

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

### Spider.ProxyDomain

`Chilkat 11.7.0 · pascal · Spider · ProxyDomain · property · read/write`

```pascal
property ProxyDomain: string read GetProxyDomain write SetProxyDomain;
```

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

### Spider.ProxyLogin

`Chilkat 11.7.0 · pascal · Spider · ProxyLogin · property · read/write`

```pascal
property ProxyLogin: string read GetProxyLogin write SetProxyLogin;
```

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

### Spider.ProxyPassword

`Chilkat 11.7.0 · pascal · Spider · ProxyPassword · property · read/write`

```pascal
property ProxyPassword: string read GetProxyPassword write SetProxyPassword;
```

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

### Spider.ProxyPort

`Chilkat 11.7.0 · pascal · Spider · ProxyPort · property · read/write`

```pascal
property ProxyPort: Integer read GetProxyPort write SetProxyPort;
```

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

### Spider.ReadTimeout

`Chilkat 11.7.0 · pascal · Spider · ReadTimeout · property · read/write`

```pascal
property ReadTimeout: Integer read GetReadTimeout write SetReadTimeout;
```

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

### Spider.UpdateCache

`Chilkat 11.7.0 · pascal · Spider · UpdateCache · property · read/write`

```pascal
property UpdateCache: Boolean read GetUpdateCache write SetUpdateCache;
```

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.

### Spider.UserAgent

`Chilkat 11.7.0 · pascal · Spider · UserAgent · property · read/write`

```pascal
property UserAgent: string read GetUserAgent write SetUserAgent;
```

The value of the HTTP user-agent header field to be sent with HTTP requests. This can be set to any desired value, but be aware that some websites may reject requests from unknown user agents.

### Spider.WasRedirected

`Chilkat 11.7.0 · pascal · Spider · WasRedirected · property · read-only · since 9.5.0.85`

```pascal
property WasRedirected: Boolean read GetWasRedirected;
```

Indicates whether the last URL crawled was redirected. (`True` = yes, `False` = no)

### Spider.WindDownCount

`Chilkat 11.7.0 · pascal · Spider · WindDownCount · property · read/write`

```pascal
property WindDownCount: Integer read GetWindDownCount write SetWindDownCount;
```

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.

## Methods

### Spider.AddAvoidOutboundLinkPattern

`Chilkat 11.7.0 · pascal · Spider · AddAvoidOutboundLinkPattern · method`

```pascal
procedure AddAvoidOutboundLinkPattern(const pattern: string);
```

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.

### Spider.AddAvoidPattern

`Chilkat 11.7.0 · pascal · Spider · AddAvoidPattern · method`

```pascal
procedure AddAvoidPattern(const pattern: string);
```

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.

### Spider.AddMustMatchPattern

`Chilkat 11.7.0 · pascal · Spider · AddMustMatchPattern · method`

```pascal
procedure AddMustMatchPattern(const pattern: string);
```

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.

### Spider.AddUnspidered

`Chilkat 11.7.0 · pascal · Spider · AddUnspidered · method`

```pascal
procedure AddUnspidered(const url: string);
```

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

### Spider.CanonicalizeUrl

`Chilkat 11.7.0 · pascal · Spider · CanonicalizeUrl · method`

```pascal
function  CanonicalizeUrl(const url: string): string;
```

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 True for success, False for failure.

### Spider.ClearFailedUrls

`Chilkat 11.7.0 · pascal · Spider · ClearFailedUrls · method`

```pascal
procedure ClearFailedUrls;
```

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

### Spider.ClearOutboundLinks

`Chilkat 11.7.0 · pascal · Spider · ClearOutboundLinks · method`

```pascal
procedure ClearOutboundLinks;
```

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

### Spider.ClearSpideredUrls

`Chilkat 11.7.0 · pascal · Spider · ClearSpideredUrls · method`

```pascal
procedure ClearSpideredUrls;
```

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

### Spider.CrawlNext

`Chilkat 11.7.0 · pascal · Spider · CrawlNext · method`

```pascal
function  CrawlNext: Boolean;
```

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 `False`. Information about the URL crawled is available in the properties LastUrl, LastFromCache, and LastModDate.

### Spider.FetchRobotsText

`Chilkat 11.7.0 · pascal · Spider · FetchRobotsText · method`

```pascal
function  FetchRobotsText: string;
```

Returns the contents of the robots.txt file from the domain being crawled. This spider object 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 True for success, False for failure.

### Spider.GetAvoidPattern

`Chilkat 11.7.0 · pascal · Spider · GetAvoidPattern · method`

```pascal
function  GetAvoidPattern(index: Integer): string;
```

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

Returns True for success, False for failure.

### Spider.GetBaseDomain

`Chilkat 11.7.0 · pascal · Spider · GetBaseDomain · method`

```pascal
function  GetBaseDomain(const domain: string): string;
```

Returns the second-level + top-level domain of the `domain`. For example, if `domain` is `xyz.example.com`, this returns `example.com`. For some domains, such as `xyz.example.co.uk`, the top 3 levels are returned, such as `example.co.uk`.

Returns True for success, False for failure.

### Spider.GetFailedUrl

`Chilkat 11.7.0 · pascal · Spider · GetFailedUrl · method`

```pascal
function  GetFailedUrl(index: Integer): string;
```

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

Returns True for success, False for failure.

### Spider.GetOutboundLink

`Chilkat 11.7.0 · pascal · Spider · GetOutboundLink · method`

```pascal
function  GetOutboundLink(index: Integer): string;
```

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

Returns True for success, False for failure.

### Spider.GetSpideredUrl

`Chilkat 11.7.0 · pascal · Spider · GetSpideredUrl · method`

```pascal
function  GetSpideredUrl(index: Integer): string;
```

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

Returns True for success, False for failure.

### Spider.GetUnspideredUrl

`Chilkat 11.7.0 · pascal · Spider · GetUnspideredUrl · method`

```pascal
function  GetUnspideredUrl(index: Integer): string;
```

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

Returns True for success, False for failure.

### Spider.GetUrlDomain

`Chilkat 11.7.0 · pascal · Spider · GetUrlDomain · method`

```pascal
function  GetUrlDomain(const url: string): string;
```

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

Returns True for success, False for failure.

### Spider.Initialize

`Chilkat 11.7.0 · pascal · Spider · Initialize · method`

```pascal
procedure Initialize(const domain: string);
```

Initializes the object 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.

### Spider.LoadTaskCaller

`Chilkat 11.7.0 · pascal · Spider · LoadTaskCaller · method · since 9.5.0.80`

```pascal
// task is a TTask object.

function  LoadTaskCaller(task: TChilkatBase): Boolean;
```

Loads the caller of the task's async method.

Returns True for success, False for failure.

### Spider.RecrawlLast

`Chilkat 11.7.0 · pascal · Spider · RecrawlLast · method`

```pascal
function  RecrawlLast: Boolean;
```

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.

### Spider.SkipUnspidered

`Chilkat 11.7.0 · pascal · Spider · SkipUnspidered · method`

```pascal
procedure SkipUnspidered(index: Integer);
```

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

### Spider.SleepMs

`Chilkat 11.7.0 · pascal · Spider · SleepMs · method`

```pascal
procedure SleepMs(numMilliseconds: Integer);
```

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

## Events and callbacks

Chilkat for Pascal supports three synchronous event callbacks: `OnAbortCheck`, `OnPercentDone`, and `OnProgressInfo`. Each is a property of the class; assign a method of one of your own objects (an *of object* handler) to receive the callbacks, or assign `nil` to unhook. The handler types are declared in the `Chilkat.Base` unit:

```pascal
TChilkatAbortCheckEvent   = function(Sender: TChilkatBase): Boolean of object;
TChilkatPercentDoneEvent  = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object;
TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object;
```

All Chilkat methods are synchronous, so callbacks are invoked on the thread that called the method -- if the method was called from the main thread, it is safe to access UI elements from the handler. The `HeartbeatMs` property controls the frequency of `OnAbortCheck` callbacks (the default of 0 means no AbortCheck events fire). Returning `True` from an `OnAbortCheck` or `OnPercentDone` handler aborts the running method.

### Spider.AbortCheck (event)

`Chilkat 11.7.0 · pascal · Spider · AbortCheck · event`

```pascal
// TChilkatAbortCheckEvent = function(Sender: TChilkatBase): Boolean of object;

property OnAbortCheck: TChilkatAbortCheckEvent;
```

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the `HeartbeatMs` property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.

**Event callback implementation:**

```pascal
// A handler is a method of one of your own classes, e.g. a form:
function TMyObject.SpiderAbortCheck(Sender: TChilkatBase): Boolean;
begin
  // Called every HeartbeatMs milliseconds while a method is running.
  // Return True to abort the method; return False to continue.
  Result := False;
end;
```

**To add an event handler:**

```pascal
spider := TSpider.Create;
spider.HeartbeatMs := 250;   // fire OnAbortCheck 4 times per second
spider.OnAbortCheck := MyObject.SpiderAbortCheck;
```

### Spider.PercentDone (event)

`Chilkat 11.7.0 · pascal · Spider · PercentDone · event`

```pascal
// TChilkatPercentDoneEvent = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object;

property OnPercentDone: TChilkatPercentDoneEvent;
```

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The `pctDone` argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have `pctDone` equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an `AbortCheck` event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

To abort the operation, set the `abort` output argument to `True`. This will cause the method to terminate and return a failure status or corresponding failure value.

**Event callback implementation:**

```pascal
// A handler is a method of one of your own classes, e.g. a form:
function TMyObject.SpiderPercentDone(Sender: TChilkatBase; PctDone: Integer): Boolean;
begin
  // PctDone ranges from 1 to 100.
  WriteLn('Percent done: ', PctDone);
  // Return True to abort the method; return False to continue.
  Result := False;
end;
```

**To add an event handler:**

```pascal
spider := TSpider.Create;
spider.OnPercentDone := MyObject.SpiderPercentDone;
```

### Spider.ProgressInfo (event)

`Chilkat 11.7.0 · pascal · Spider · ProgressInfo · event`

```pascal
// TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object;

property OnProgressInfo: TChilkatProgressInfoEvent;
```

This event callback provides `tag name`/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

Note: Some Chilkat methods don't fire any ProgressInfo events.

**Event callback implementation:**

```pascal
// A handler is a method of one of your own classes, e.g. a form:
procedure TMyObject.SpiderProgressInfo(Sender: TChilkatBase; const Name, Value: string);
begin
  WriteLn(Name, ': ', Value);
end;
```

**To add an event handler:**

```pascal
spider := TSpider.Create;
spider.OnProgressInfo := MyObject.SpiderProgressInfo;
```