Spider PureBasic Reference Documentation

Spider

Chilkat Spider web crawler component.

Object Creation

obj.i = CkSpider::ckCreate()

; Make sure to dispose of the object when finished like this:
CkSpider::ckDispose(obj);

Properties

Declare.i ckAbortCurrent(obj.i)
Declare setCkAbortCurrent(obj.i, value.i)

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.)

Declare.i ckAvoidHttps(obj.i)
Declare setCkAvoidHttps(obj.i, value.i)

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

Declare.s ckCacheDir(obj.i)
Declare setCkCacheDir(obj.i, value.s)

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.

Caching Web Pages to the Filesystem

Declare.i ckChopAtQuery(obj.i)
Declare setCkChopAtQuery(obj.i, value.i)

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).

Declare.i ckConnectTimeout(obj.i)
Declare setCkConnectTimeout(obj.i, value.i)

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

Declare.s ckDebugLogFilePath(obj.i)
Declare setCkDebugLogFilePath(obj.i, value.s)

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.

Declare.s ckDomain(obj.i) ; (read-only)

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

Declare.i ckFetchFromCache(obj.i)
Declare setCkFetchFromCache(obj.i, value.i)

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.

Caching Web Pages to the Filesystem

Declare.s ckLastErrorHtml(obj.i) ; (read-only)

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.

Declare.s ckLastErrorText(obj.i) ; (read-only)

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.

Declare.s ckLastErrorXml(obj.i) ; (read-only)

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.

Declare.i ckLastFromCache(obj.i) ; (read-only)

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

Declare.s ckLastHtml(obj.i) ; (read-only)

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

Declare.s ckLastHtmlDescription(obj.i) ; (read-only)

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

Extract HTML Title, Description, Keywords

Declare.s ckLastHtmlKeywords(obj.i) ; (read-only)

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

Extract HTML Title, Description, Keywords

Declare.s ckLastHtmlTitle(obj.i) ; (read-only)

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

Extract HTML Title, Description, Keywords

Declare.i ckLastMethodSuccess(obj.i)
Declare setCkLastMethodSuccess(obj.i, value.i)

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.

Declare.s ckLastModDateStr(obj.i) ; (read-only)

The last modification date/time from the last page fetched by the spider.

Declare.s ckLastUrl(obj.i) ; (read-only)

The URL of the last page spidered.

Declare.i ckMaxResponseSize(obj.i)
Declare setCkMaxResponseSize(obj.i, value.i)

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

Setting a Maximum Response Size

Declare.i ckMaxUrlLen(obj.i)
Declare setCkMaxUrlLen(obj.i, value.i)

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

Setting a Maximum URL Length

Declare.i ckNumAvoidPatterns(obj.i) ; (read-only)

The number of avoid patterns previously set by calling AddAvoidPattern.

Declare.i ckNumFailed(obj.i) ; (read-only)

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

Declare.i ckNumOutboundLinks(obj.i) ; (read-only)

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

Declare.i ckNumSpidered(obj.i) ; (read-only)

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

Declare.i ckNumUnspidered(obj.i) ; (read-only)

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

Getting Started Example

Declare.i ckPreferIpv6(obj.i)
Declare setCkPreferIpv6(obj.i, value.i)

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.

Declare.s ckProxyDomain(obj.i)
Declare setCkProxyDomain(obj.i, value.s)

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

Declare.s ckProxyLogin(obj.i)
Declare setCkProxyLogin(obj.i, value.s)

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

Declare.s ckProxyPassword(obj.i)
Declare setCkProxyPassword(obj.i, value.s)

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

Declare.i ckProxyPort(obj.i)
Declare setCkProxyPort(obj.i, value.i)

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

Declare.i ckReadTimeout(obj.i)
Declare setCkReadTimeout(obj.i, value.i)

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

Declare.i ckUpdateCache(obj.i)
Declare setCkUpdateCache(obj.i, value.i)

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.

Caching Web Pages to the Filesystem

Declare.s ckUserAgent(obj.i)
Declare setCkUserAgent(obj.i, value.s)

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)"

Declare.i ckVerboseLogging(obj.i)
Declare setCkVerboseLogging(obj.i, value.i)

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.

Declare.s ckVersion(obj.i) ; (read-only)

Version of the component/library, such as "9.4.1.42"

Declare.i ckWindDownCount(obj.i)
Declare setCkWindDownCount(obj.i, value.i)

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

Declare ckAddAvoidOutboundLinkPattern(obj.i, pattern.s)

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.

Avoiding Outbound Links Matching Patterns

Declare ckAddAvoidPattern(obj.i, pattern.s)

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.

Avoid URLs Matching Any of a Set of Patterns

Declare ckAddMustMatchPattern(obj.i, pattern.s)

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.

Must-Match Patterns

Declare ckAddUnspidered(obj.i, url.s)

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.

Crawling the Web

Declare.s ckCanonicalizeUrl(obj.i, url.s)

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 an empty string on failure. Use the LastMethodSuccess property to check for success.

Canonicalize a URL

Declare ckClearFailedUrls(obj.i)

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

Declare ckClearOutboundLinks(obj.i)

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

Declare ckClearSpideredUrls(obj.i)

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

Declare.i ckCrawlNext(obj.i)

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.

Crawling the Web

Getting Started Example

Declare.i ckCrawlNextAsync(obj.i)

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

How to Run an Asynchronous Task

Declare.s ckFetchRobotsText(obj.i)

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 an empty string on failure. Use the LastMethodSuccess property to check for success.

Fetch robots.txt for a Site

Declare.i ckFetchRobotsTextAsync(obj.i)

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

How to Run an Asynchronous Task

Declare.s ckGetAvoidPattern(obj.i, index.i)

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

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

Declare.s ckGetBaseDomain(obj.i, domain.s)

To be documented soon.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

Convert a Domain Name into a "domain base"

Declare.s ckGetFailedUrl(obj.i, index.i)

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

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

Declare.s ckGetOutboundLink(obj.i, index.i)

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

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

Declare.s ckGetSpideredUrl(obj.i, index.i)

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

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

Declare.s ckGetUnspideredUrl(obj.i, index.i)

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

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

Declare.s ckGetUrlDomain(obj.i, url.s)

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 an empty string on failure. Use the LastMethodSuccess property to check for success.

Declare ckInitialize(obj.i, domain.s)

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.

Crawling the Web

Getting Started Example

Declare.i ckRecrawlLast(obj.i)

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.

Declare.i ckRecrawlLastAsync(obj.i)

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

How to Run an Asynchronous Task

Declare.i ckSaveLastError(obj.i, path.s)

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

Returns 1 for success, 0 for failure.

Declare ckSkipUnspidered(obj.i, index.i)

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

Declare ckSleepMs(obj.i, numMilliseconds.i)

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