Spider Tcl Reference Documentation

Spider

Chilkat Spider web crawler component.

Object Creation

set mySpider [new CkSpider]

Properties

AbortCurrent (boolean 1/0)

set boolVal [CkSpider_get_AbortCurrent $mySpider]
CkSpider_put_AbortCurrent $mySpider $boolVal

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.)

AvoidHttps (boolean 1/0)

set boolVal [CkSpider_get_AvoidHttps $mySpider]
CkSpider_put_AvoidHttps $mySpider $boolVal

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

CacheDir (string)

# ckStr is a CkString
CkSpider_get_CacheDir $mySpider $ckStr
set strVal [CkSpider_get_cacheDir $mySpider]
CkSpider_put_CacheDir $mySpider $strVal

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

ChopAtQuery (boolean 1/0)

set boolVal [CkSpider_get_ChopAtQuery $mySpider]
CkSpider_put_ChopAtQuery $mySpider $boolVal

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).

ConnectTimeout (integer)

set intVal [CkSpider_get_ConnectTimeout $mySpider]
CkSpider_put_ConnectTimeout $mySpider $intVal

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

DebugLogFilePath (string)

# ckStr is a CkString
CkSpider_get_DebugLogFilePath $mySpider $ckStr
set strVal [CkSpider_get_debugLogFilePath $mySpider]
CkSpider_put_DebugLogFilePath $mySpider $strVal

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.

Domain (string)

# ckStr is a CkString
CkSpider_get_Domain $mySpider $ckStr
set strVal [CkSpider_get_domain $mySpider]

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

FetchFromCache (boolean 1/0)

set boolVal [CkSpider_get_FetchFromCache $mySpider]
CkSpider_put_FetchFromCache $mySpider $boolVal

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

LastErrorHtml (string)

# ckStr is a CkString
CkSpider_get_LastErrorHtml $mySpider $ckStr
set strVal [CkSpider_get_lastErrorHtml $mySpider]

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.

LastErrorText (string)

# ckStr is a CkString
CkSpider_get_LastErrorText $mySpider $ckStr
set strVal [CkSpider_get_lastErrorText $mySpider]

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 (string)

# ckStr is a CkString
CkSpider_get_LastErrorXml $mySpider $ckStr
set strVal [CkSpider_get_lastErrorXml $mySpider]

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.

LastFromCache (boolean 1/0)

set boolVal [CkSpider_get_LastFromCache $mySpider]

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

LastHtml (string)

# ckStr is a CkString
CkSpider_get_LastHtml $mySpider $ckStr
set strVal [CkSpider_get_lastHtml $mySpider]

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

LastHtmlDescription (string)

# ckStr is a CkString
CkSpider_get_LastHtmlDescription $mySpider $ckStr
set strVal [CkSpider_get_lastHtmlDescription $mySpider]

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

Extract HTML Title, Description, Keywords

LastHtmlKeywords (string)

# ckStr is a CkString
CkSpider_get_LastHtmlKeywords $mySpider $ckStr
set strVal [CkSpider_get_lastHtmlKeywords $mySpider]

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

Extract HTML Title, Description, Keywords

LastHtmlTitle (string)

# ckStr is a CkString
CkSpider_get_LastHtmlTitle $mySpider $ckStr
set strVal [CkSpider_get_lastHtmlTitle $mySpider]

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

Extract HTML Title, Description, Keywords

LastMethodSuccess (boolean 1/0)

set boolVal [CkSpider_get_LastMethodSuccess $mySpider]
CkSpider_put_LastMethodSuccess $mySpider $boolVal

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.

LastModDateStr (string)

# ckStr is a CkString
CkSpider_get_LastModDateStr $mySpider $ckStr
set strVal [CkSpider_get_lastModDateStr $mySpider]

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

LastUrl (string)

# ckStr is a CkString
CkSpider_get_LastUrl $mySpider $ckStr
set strVal [CkSpider_get_lastUrl $mySpider]

The URL of the last page spidered.

MaxResponseSize (integer)

set intVal [CkSpider_get_MaxResponseSize $mySpider]
CkSpider_put_MaxResponseSize $mySpider $intVal

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

MaxUrlLen (integer)

set intVal [CkSpider_get_MaxUrlLen $mySpider]
CkSpider_put_MaxUrlLen $mySpider $intVal

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

NumAvoidPatterns (integer)

set intVal [CkSpider_get_NumAvoidPatterns $mySpider]

The number of avoid patterns previously set by calling AddAvoidPattern.

NumFailed (integer)

set intVal [CkSpider_get_NumFailed $mySpider]

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

NumOutboundLinks (integer)

set intVal [CkSpider_get_NumOutboundLinks $mySpider]

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

NumSpidered (integer)

set intVal [CkSpider_get_NumSpidered $mySpider]

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

NumUnspidered (integer)

set intVal [CkSpider_get_NumUnspidered $mySpider]

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

Getting Started Example

PreferIpv6 (boolean 1/0)

set boolVal [CkSpider_get_PreferIpv6 $mySpider]
CkSpider_put_PreferIpv6 $mySpider $boolVal

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.

ProxyDomain (string)

# ckStr is a CkString
CkSpider_get_ProxyDomain $mySpider $ckStr
set strVal [CkSpider_get_proxyDomain $mySpider]
CkSpider_put_ProxyDomain $mySpider $strVal

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

ProxyLogin (string)

# ckStr is a CkString
CkSpider_get_ProxyLogin $mySpider $ckStr
set strVal [CkSpider_get_proxyLogin $mySpider]
CkSpider_put_ProxyLogin $mySpider $strVal

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

ProxyPassword (string)

# ckStr is a CkString
CkSpider_get_ProxyPassword $mySpider $ckStr
set strVal [CkSpider_get_proxyPassword $mySpider]
CkSpider_put_ProxyPassword $mySpider $strVal

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

ProxyPort (integer)

set intVal [CkSpider_get_ProxyPort $mySpider]
CkSpider_put_ProxyPort $mySpider $intVal

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

ReadTimeout (integer)

set intVal [CkSpider_get_ReadTimeout $mySpider]
CkSpider_put_ReadTimeout $mySpider $intVal

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

UpdateCache (boolean 1/0)

set boolVal [CkSpider_get_UpdateCache $mySpider]
CkSpider_put_UpdateCache $mySpider $boolVal

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

UserAgent (string)

# ckStr is a CkString
CkSpider_get_UserAgent $mySpider $ckStr
set strVal [CkSpider_get_userAgent $mySpider]
CkSpider_put_UserAgent $mySpider $strVal

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)"

Utf8 (boolean 1/0)

set boolVal [CkSpider_get_Utf8 $mySpider]
CkSpider_put_Utf8 $mySpider $boolVal

When set to 1, all "const char *" arguments are interpreted as utf-8 strings. If set to 0 (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to 1, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to 0, all "const char *" return values are ANSI strings.

VerboseLogging (boolean 1/0)

set boolVal [CkSpider_get_VerboseLogging $mySpider]
CkSpider_put_VerboseLogging $mySpider $boolVal

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.

Version (string)

# ckStr is a CkString
CkSpider_get_Version $mySpider $ckStr
set strVal [CkSpider_get_version $mySpider]

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

WindDownCount (integer)

set intVal [CkSpider_get_WindDownCount $mySpider]
CkSpider_put_WindDownCount $mySpider $intVal

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

# pattern is a string
CkSpider_AddAvoidOutboundLinkPattern $pattern

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

# pattern is a string
CkSpider_AddAvoidPattern $pattern

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

# pattern is a string
CkSpider_AddMustMatchPattern $pattern

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

# url is a string
CkSpider_AddUnspidered $url

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

# url is a string
# outStr is a CkString (output)
set status [CkSpider_CanonicalizeUrl $url $outStr]
set retStr [CkSpider_canonicalizeUrl $mySpider $url]

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 1 for success, 0 for failure.

Canonicalize a URL

CkSpider_ClearFailedUrls

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

CkSpider_ClearOutboundLinks

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

CkSpider_ClearSpideredUrls

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

set retBool [CkSpider_CrawlNext]

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

# returns a CkTask
set ret_task [CkSpider_CrawlNextAsync]

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

# outStr is a CkString (output)
set status [CkSpider_FetchRobotsText $outStr]
set retStr [CkSpider_fetchRobotsText $mySpider]

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 1 for success, 0 for failure.

Fetch robots.txt for a Site

# returns a CkTask
set ret_task [CkSpider_FetchRobotsTextAsync]

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

# index is an integer
# outStr is a CkString (output)
set status [CkSpider_GetAvoidPattern $index $outStr]
set retStr [CkSpider_getAvoidPattern $mySpider $index]

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

Returns 1 for success, 0 for failure.

# domain is a string
# outStr is a CkString (output)
set status [CkSpider_GetBaseDomain $domain $outStr]
set retStr [CkSpider_getBaseDomain $mySpider $domain]

To be documented soon.

Returns 1 for success, 0 for failure.

Convert a Domain Name into a "domain base"

# index is an integer
# outStr is a CkString (output)
set status [CkSpider_GetFailedUrl $index $outStr]
set retStr [CkSpider_getFailedUrl $mySpider $index]

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

Returns 1 for success, 0 for failure.

# index is an integer
# outStr is a CkString (output)
set status [CkSpider_GetOutboundLink $index $outStr]
set retStr [CkSpider_getOutboundLink $mySpider $index]

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

Returns 1 for success, 0 for failure.

# index is an integer
# outStr is a CkString (output)
set status [CkSpider_GetSpideredUrl $index $outStr]
set retStr [CkSpider_getSpideredUrl $mySpider $index]

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

Returns 1 for success, 0 for failure.

# index is an integer
# outStr is a CkString (output)
set status [CkSpider_GetUnspideredUrl $index $outStr]
set retStr [CkSpider_getUnspideredUrl $mySpider $index]

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

Returns 1 for success, 0 for failure.

# url is a string
# outStr is a CkString (output)
set status [CkSpider_GetUrlDomain $url $outStr]
set retStr [CkSpider_getUrlDomain $mySpider $url]

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 1 for success, 0 for failure.

# domain is a string
CkSpider_Initialize $domain

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

set retBool [CkSpider_RecrawlLast]

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.

# returns a CkTask
set ret_task [CkSpider_RecrawlLastAsync]

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

# path is a string
set status [CkSpider_SaveLastError $path]

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

Returns 1 for success, 0 for failure.

# index is an integer
CkSpider_SkipUnspidered $index

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

# numMilliseconds is an integer
CkSpider_SleepMs $numMilliseconds

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