Chilkat VB.NET Spider Class Reference
Spider
* This is a freeware class/component/library.
Chilkat Spider web crawler component.
Properties
AvoidHttps As Boolean
If set the 1 (true) the spider will avoid all HTTPS URLs. The default is 0 (false).
CacheDir As String
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.
ChopAtQuery As Boolean
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 As Integer
The maximum number of seconds to wait while connecting to an HTTP server.
Domain As String (ReadOnly)
The domain name that is being spidered. This is the domain previously set in the Initialize method.
FetchFromCache As Boolean
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.
HeartbeatMs As Integer
To be documented soon...
LastErrorHtml As String (ReadOnly)
Error information in HTML format for the last method called.
LastErrorText As String (ReadOnly)
Error information in plain-text format for the last method called.
LastErrorXml As String (ReadOnly)
Error information in XML format for the last method called.
LastFromCache As Boolean (ReadOnly)
Equal to 1 if the last page spidered was fetched from the cache. Otherwise equal to 0.
LastHtml As String (ReadOnly)
The HTML text of the last paged fetched by the spider.
LastHtmlDescription As String (ReadOnly)
The HTML META description from the last page fetched by the spider.
LastHtmlKeywords As String (ReadOnly)
The HTML META keywords from the last page fetched by the spider.
LastHtmlTitle As String (ReadOnly)
The HTML title from the last page fetched by the spider.
LastModDateStr As String (ReadOnly)
The last modification date/time from the last page fetched by the spider.
LastUrl As String (ReadOnly)
The URL of the last page spidered.
MaxResponseSize As 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.
MaxUrlLen As Integer
The maximum URL length allowed. URLs longer than this are not added to the unspidered list. The default value is 200.
NumAvoidPatterns As Integer (ReadOnly)
The number of avoid patterns previously set by calling AddAvoidPattern.
NumFailed As Integer (ReadOnly)
The number of URLs in the component's failed URL list.
NumOutboundLinks As Integer (ReadOnly)
The number of URLs in the component's outbound links URL list.
NumSpidered As Integer (ReadOnly)
The number of URLs in the component's already-spidered URL list.
NumUnspidered As Integer (ReadOnly)
The number of URLs in the component's unspidered URL list.
ProxyDomain As String
(PreRelease) The domain name of a proxy host if an HTTP proxy is used.
ProxyLogin As String
(PreRelease) If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.
ProxyPassword As String
(PreRelease) If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.
ProxyPort As Integer
(PreRelease) The port number of a proxy server if an HTTP proxy is used.
ReadTimeout As Integer
The maximum number of seconds to wait when reading from an HTTP server.
UpdateCache As Boolean
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.
UserAgent As String
To be documented soon...
WindDownCount As 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.
Methods
Sub AddAvoidOutboundLinkPattern(ByVal pattern As 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.
Sub AddAvoidPattern(ByVal pattern As 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.
Sub AddMustMatchPattern(ByVal pattern As 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.
Sub AddUnspidered(ByVal url As String)
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.
Function CanonicalizeUrl(ByVal url As String) As String
To be documented soon...
Sub ClearFailedUrls()
Clears the component's internal list of URLs that could not be downloaded.
Sub ClearOutboundLinks()
Clears the component's internal list of outbound URLs that will automatically accumulate while spidering.
Sub ClearSpideredUrls()
Clears the component's internal list of already-spidered URLs that will automatically accumulate while spidering.
Function CrawlNext() As 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.
This method returns the HTML of the page downloaded. If there are no more URLs left unspidered, a NULL value is returned. Information about the URL crawled is available in the properties LastUrl, LastFromCache, and LastModDate.
Function FetchRobotsText() As String
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 Nothing on failure
Function GetAvoidPattern(ByVal index As Integer) As String
Returns the Nth avoid pattern previously added by calling AddAvoidPattern. Indexing begins at 0. Returns Nothing on failure
Function GetBaseDomain(ByVal domain As String) As String
To be documented soon...
Function GetDomain(ByVal url As String) As String
To be documented soon...
Function GetFailedUrl(ByVal index As Integer) As String
Returns the Nth URL in the failed URL list. Indexing begins at 0. Returns Nothing on failure
Function GetOutboundLink(ByVal index As Integer) As String
Returns the Nth URL in the outbound link URL list. Indexing begins at 0. Returns Nothing on failure
Function GetSpideredUrl(ByVal index As Integer) As String
Returns the Nth URL in the already-spidered URL list. Indexing begins at 0. Returns Nothing on failure
Function GetUnspideredUrl(ByVal index As Integer) As String
Returns the Nth URL in the unspidered URL list. Indexing begins at 0. Returns Nothing on failure
Sub Initialize(ByVal domain As String)
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.
Function RecrawlLast() As 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.
Function SaveLastError(ByVal filename As String) As Boolean
Saves the last error information to an XML formatted file.
Sub SkipUnspidered(ByVal index As Integer)
Moves a URL from the unspidered list to the spidered list. This allows an application to skip a specific URL.
Sub SleepMs(ByVal millisec As Integer)
To be documented soon...
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