Spider

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.)

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

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.

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).

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

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.

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

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.

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

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.

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.

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.

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.

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

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

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

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

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

Indicate whether the last method call succeeded or failed. A value of true indicates success, a value of false 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 = true and failure = false.
• 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 true. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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

The URL of the last page spidered.

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

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

The number of avoid patterns previously set by calling AddAvoidPattern.

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

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

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

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

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.

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

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

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

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

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

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.

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.

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version of the component/library, such as "9.5.0.94"

Indicates whether the last URL crawled was redirected. (true = yes, false = no)

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.

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.

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.

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.

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.

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 null on failure

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

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

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

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.

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 null on failure

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 null on failure

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 null on failure

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

Returns null on failure

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 null on failure

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

Returns null on failure

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

Returns null on failure

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

Returns null on failure

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

Returns null on failure

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 null on failure

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.

Loads the caller of the task's async method.

Returns true for success, false for failure.

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.

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 null on failure

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

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

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.

Chilkat .NET Event Implementation

Args are passed using Chilkat.AbortCheckEventArgs

Event callback implementation:

private void spider_OnAbortCheck(object sender, Chilkat.AbortCheckEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
spider.OnAbortCheck += spider_OnAbortCheck;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

public void handleAbortCheck(out bool abort)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
// ...
Chilkat.Spider.AbortCheck abortCheck = new Chilkat.Spider.AbortCheck(handleAbortCheck);
spider.setAbortCheckCb(abortCheck);

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 true will cause the method to abort and return a failed status (or whatever return value indicates failure).

Chilkat .NET Event Implementation

Args are passed using Chilkat.PercentDoneEventArgs

Event callback implementation:

private void spider_OnPercentDone(object sender, Chilkat.PercentDoneEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
spider.OnPercentDone += spider_OnPercentDone;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

public void handlePercentDone(int pctDone, out bool abort)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
// ...
Chilkat.Spider.PercentDone percentDone = new Chilkat.Spider.PercentDone(handlePercentDone);
spider.setPercentDoneCb(percentDone);

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.

Chilkat .NET Event Implementation

Args are passed using Chilkat.ProgressInfoEventArgs

Event callback implementation:

private void spider_OnProgressInfo(object sender, Chilkat.ProgressInfoEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
spider.OnProgressInfo += spider_OnProgressInfo;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

public void handleProgressInfo(string name, string value)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
// ...
Chilkat.Spider.ProgressInfo progressInfo = new Chilkat.Spider.ProgressInfo(handleProgressInfo);
spider.setProgressInfoCb(progressInfo);

Called in the background thread when an asynchronous task completes.

Chilkat .NET Event Implementation

Args are passed using Chilkat.TaskCompletedEventArgs

Event callback implementation:

private void spider_OnTaskCompleted(object sender, Chilkat.TaskCompletedEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
spider.OnTaskCompleted += spider_OnTaskCompleted;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

public void handleTaskIdCompleted(int taskId)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Spider spider = new Chilkat.Spider();
// ...
Chilkat.Spider.TaskIdCompleted taskIdCompleted = new Chilkat.Spider.TaskIdCompleted(handleTaskIdCompleted);
spider.setTaskIdCompletedCb(taskIdCompleted);