Spider Unicode C Reference Documentation

Spider

Chilkat Spider web crawler component.

Create/Dispose

HCkSpiderW CkSpiderW_Create(void);

Creates an instance of the HCkSpiderW object and returns a handle (i.e. a "void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.

void CkSpiderW_Dispose(HCkSpiderW handle);

Objects created by calling CkSpiderW_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkSpiderW_Dispose.

Callback Functions

Callback Functions are Introduced in Chilkat v9.5.0.56

void CkSpiderW_setAbortCheck(HCkHttp cHandle, BOOL (*fnAbortCheck)());

Provides the opportunity for a method call to be aborted. If TRUE is returned, the operation in progress is aborted. Return FALSE to allow the current method call to continue. This callback function is called periodically based on the value of the HeartbeatMs property. (If HeartbeatMs is 0, then no callbacks are made.) As an example, to make 5 AbortCheck callbacks per second, set the HeartbeatMs property equal to 200.

C Example using Callback Functions

void CkSpiderW_setPercentDone(HCkHttp cHandle, BOOL (*fnPercentDone)(int pctDone));

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 callback is only called 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 methods 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).

This callback counts as an AbortCheck callback, and takes the place of the AbortCheck event when it fires.

The return value indicates whether the method call should be aborted, or whether it should proceed. Return TRUE to abort, and FALSE to proceed.

void CkSpiderW_setProgressInfo(HCkHttp cHandle, void (*fnProgressInfo)(const wchar_t *name, const wchar_t *value));

This is a general callback that provides name/value information about what is happening at certain points during a method call. To see the information provided in ProgressInfo callbacks, if any, write code to handle this event and log the name/value pairs. Most are self-explanatory.

void CkSpiderW_setTaskCompleted(HCkHttp cHandle, void (*fnTaskCompleted)(HCkTask hTask));

Called in the background thread when an asynchronous task completes. (Note: When an async method is running, all callbacks are in the background thread.)

Properties

BOOL CkSpiderW_getAbortCurrent(HCkSpiderW cHandle);

void CkSpiderW_putAbortCurrent(HCkSpiderW cHandle, BOOL newVal);

Introduced in version 9.5.0.58

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.)

BOOL CkSpiderW_getAvoidHttps(HCkSpiderW cHandle);

void CkSpiderW_putAvoidHttps(HCkSpiderW cHandle, BOOL newVal);

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

void CkSpiderW_getCacheDir(HCkSpiderW cHandle, HCkString retval);

void CkSpiderW_putCacheDir(HCkSpiderW cHandle, const wchar_t *newVal);

const wchar_t *CkSpiderW_cacheDir(HCkSpiderW cHandle);

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

BOOL CkSpiderW_getChopAtQuery(HCkSpiderW cHandle);

void CkSpiderW_putChopAtQuery(HCkSpiderW cHandle, BOOL newVal);

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).

int CkSpiderW_getConnectTimeout(HCkSpiderW cHandle);

void CkSpiderW_putConnectTimeout(HCkSpiderW cHandle, int newVal);

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

void CkSpiderW_getDebugLogFilePath(HCkSpiderW cHandle, HCkString retval);

void CkSpiderW_putDebugLogFilePath(HCkSpiderW cHandle, const wchar_t *newVal);

const wchar_t *CkSpiderW_debugLogFilePath(HCkSpiderW cHandle);

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.

void CkSpiderW_getDomain(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_domain(HCkSpiderW cHandle);

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

BOOL CkSpiderW_getFetchFromCache(HCkSpiderW cHandle);

void CkSpiderW_putFetchFromCache(HCkSpiderW cHandle, BOOL newVal);

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

int CkSpiderW_getHeartbeatMs(HCkSpiderW cHandle);

void CkSpiderW_putHeartbeatMs(HCkSpiderW cHandle, int newVal);

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.

void CkSpiderW_getLastErrorHtml(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastErrorHtml(HCkSpiderW cHandle);

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.

void CkSpiderW_getLastErrorText(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastErrorText(HCkSpiderW cHandle);

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.

void CkSpiderW_getLastErrorXml(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastErrorXml(HCkSpiderW cHandle);

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.

BOOL CkSpiderW_getLastFromCache(HCkSpiderW cHandle);

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

void CkSpiderW_getLastHtml(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastHtml(HCkSpiderW cHandle);

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

void CkSpiderW_getLastHtmlDescription(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastHtmlDescription(HCkSpiderW cHandle);

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

Extract HTML Title, Description, Keywords

void CkSpiderW_getLastHtmlKeywords(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastHtmlKeywords(HCkSpiderW cHandle);

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

Extract HTML Title, Description, Keywords

void CkSpiderW_getLastHtmlTitle(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastHtmlTitle(HCkSpiderW cHandle);

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

Extract HTML Title, Description, Keywords

BOOL CkSpiderW_getLastMethodSuccess(HCkSpiderW cHandle);

void CkSpiderW_putLastMethodSuccess(HCkSpiderW cHandle, BOOL newVal);

Introduced in version 9.5.0.52

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.

void CkSpiderW_getLastModDate(HCkSpiderW cHandle, SYSTEMTIME *retval);

This property is deprecated. It will be removed in a future version.

The last-modification date of the last URL spidered.

void CkSpiderW_getLastModDateStr(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastModDateStr(HCkSpiderW cHandle);

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

void CkSpiderW_getLastUrl(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_lastUrl(HCkSpiderW cHandle);

The URL of the last page spidered.

int CkSpiderW_getMaxResponseSize(HCkSpiderW cHandle);

void CkSpiderW_putMaxResponseSize(HCkSpiderW cHandle, int newVal);

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

int CkSpiderW_getMaxUrlLen(HCkSpiderW cHandle);

void CkSpiderW_putMaxUrlLen(HCkSpiderW cHandle, int newVal);

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

int CkSpiderW_getNumAvoidPatterns(HCkSpiderW cHandle);

The number of avoid patterns previously set by calling AddAvoidPattern.

int CkSpiderW_getNumFailed(HCkSpiderW cHandle);

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

int CkSpiderW_getNumOutboundLinks(HCkSpiderW cHandle);

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

int CkSpiderW_getNumSpidered(HCkSpiderW cHandle);

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

int CkSpiderW_getNumUnspidered(HCkSpiderW cHandle);

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

Getting Started Example

BOOL CkSpiderW_getPreferIpv6(HCkSpiderW cHandle);

void CkSpiderW_putPreferIpv6(HCkSpiderW cHandle, BOOL newVal);

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.

void CkSpiderW_getProxyDomain(HCkSpiderW cHandle, HCkString retval);

void CkSpiderW_putProxyDomain(HCkSpiderW cHandle, const wchar_t *newVal);

const wchar_t *CkSpiderW_proxyDomain(HCkSpiderW cHandle);

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

void CkSpiderW_getProxyLogin(HCkSpiderW cHandle, HCkString retval);

void CkSpiderW_putProxyLogin(HCkSpiderW cHandle, const wchar_t *newVal);

const wchar_t *CkSpiderW_proxyLogin(HCkSpiderW cHandle);

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

void CkSpiderW_getProxyPassword(HCkSpiderW cHandle, HCkString retval);

void CkSpiderW_putProxyPassword(HCkSpiderW cHandle, const wchar_t *newVal);

const wchar_t *CkSpiderW_proxyPassword(HCkSpiderW cHandle);

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

int CkSpiderW_getProxyPort(HCkSpiderW cHandle);

void CkSpiderW_putProxyPort(HCkSpiderW cHandle, int newVal);

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

int CkSpiderW_getReadTimeout(HCkSpiderW cHandle);

void CkSpiderW_putReadTimeout(HCkSpiderW cHandle, int newVal);

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

BOOL CkSpiderW_getUpdateCache(HCkSpiderW cHandle);

void CkSpiderW_putUpdateCache(HCkSpiderW cHandle, BOOL newVal);

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

void CkSpiderW_getUserAgent(HCkSpiderW cHandle, HCkString retval);

void CkSpiderW_putUserAgent(HCkSpiderW cHandle, const wchar_t *newVal);

const wchar_t *CkSpiderW_userAgent(HCkSpiderW cHandle);

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)"

BOOL CkSpiderW_getVerboseLogging(HCkSpiderW cHandle);

void CkSpiderW_putVerboseLogging(HCkSpiderW cHandle, BOOL newVal);

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.

void CkSpiderW_getVersion(HCkSpiderW cHandle, HCkString retval);

const wchar_t *CkSpiderW_version(HCkSpiderW cHandle);

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

int CkSpiderW_getWindDownCount(HCkSpiderW cHandle);

void CkSpiderW_putWindDownCount(HCkSpiderW cHandle, int newVal);

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

void CkSpiderW_AddAvoidOutboundLinkPattern(HCkSpiderW cHandle, const wchar_t *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

void CkSpiderW_AddAvoidPattern(HCkSpiderW cHandle, const wchar_t *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

void CkSpiderW_AddMustMatchPattern(HCkSpiderW cHandle, const wchar_t *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

void CkSpiderW_AddUnspidered(HCkSpiderW cHandle, const wchar_t *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

BOOL CkSpiderW_CanonicalizeUrl(HCkSpiderW cHandle, const wchar_t *url, HCkString outStr);

const wchar_t *CkSpiderW_canonicalizeUrl(HCkSpiderW cHandle, const wchar_t *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 TRUE for success, FALSE for failure.

Canonicalize a URL

void CkSpiderW_ClearFailedUrls(HCkSpiderW cHandle);

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

void CkSpiderW_ClearOutboundLinks(HCkSpiderW cHandle);

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

void CkSpiderW_ClearSpideredUrls(HCkSpiderW cHandle);

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

BOOL CkSpiderW_CrawlNext(HCkSpiderW cHandle);

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.

Crawling the Web

Getting Started Example

HCkTaskW CkSpiderW_CrawlNextAsync(HCkSpiderW cHandle);

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

BOOL CkSpiderW_FetchRobotsText(HCkSpiderW cHandle, HCkString outStr);

const wchar_t *CkSpiderW_fetchRobotsText(HCkSpiderW cHandle);

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 TRUE for success, FALSE for failure.

Fetch robots.txt for a Site

HCkTaskW CkSpiderW_FetchRobotsTextAsync(HCkSpiderW cHandle);

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

BOOL CkSpiderW_GetAvoidPattern(HCkSpiderW cHandle, int index, HCkString outStr);

const wchar_t *CkSpiderW_getAvoidPattern(HCkSpiderW cHandle, int index);

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

Returns TRUE for success, FALSE for failure.

BOOL CkSpiderW_GetBaseDomain(HCkSpiderW cHandle, const wchar_t *domain, HCkString outStr);

const wchar_t *CkSpiderW_getBaseDomain(HCkSpiderW cHandle, const wchar_t *domain);

To be documented soon.

Returns TRUE for success, FALSE for failure.

Convert a Domain Name into a "domain base"

BOOL CkSpiderW_GetFailedUrl(HCkSpiderW cHandle, int index, HCkString outStr);

const wchar_t *CkSpiderW_getFailedUrl(HCkSpiderW cHandle, int index);

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

Returns TRUE for success, FALSE for failure.

BOOL CkSpiderW_GetOutboundLink(HCkSpiderW cHandle, int index, HCkString outStr);

const wchar_t *CkSpiderW_getOutboundLink(HCkSpiderW cHandle, int index);

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

Returns TRUE for success, FALSE for failure.

BOOL CkSpiderW_GetSpideredUrl(HCkSpiderW cHandle, int index, HCkString outStr);

const wchar_t *CkSpiderW_getSpideredUrl(HCkSpiderW cHandle, int index);

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

Returns TRUE for success, FALSE for failure.

BOOL CkSpiderW_GetUnspideredUrl(HCkSpiderW cHandle, int index, HCkString outStr);

const wchar_t *CkSpiderW_getUnspideredUrl(HCkSpiderW cHandle, int index);

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

Returns TRUE for success, FALSE for failure.

BOOL CkSpiderW_GetUrlDomain(HCkSpiderW cHandle, const wchar_t *url, HCkString outStr);

const wchar_t *CkSpiderW_getUrlDomain(HCkSpiderW cHandle, const wchar_t *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 TRUE for success, FALSE for failure.

void CkSpiderW_Initialize(HCkSpiderW cHandle, const wchar_t *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

BOOL CkSpiderW_RecrawlLast(HCkSpiderW cHandle);

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.

HCkTaskW CkSpiderW_RecrawlLastAsync(HCkSpiderW cHandle);

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

BOOL CkSpiderW_SaveLastError(HCkSpiderW cHandle, const wchar_t *path);

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

Returns TRUE for success, FALSE for failure.

void CkSpiderW_SkipUnspidered(HCkSpiderW cHandle, int index);

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

void CkSpiderW_SleepMs(HCkSpiderW cHandle, int numMilliseconds);

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