Spider C Reference Documentation
Spider
Current Version: 10.1.0
Chilkat Spider web crawler object.
Create/Dispose
HCkSpider instance = CkSpider_Create(); // ... CkSpider_Dispose(instance);
Creates an instance of the HCkSpider object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkSpider_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 CkSpider_Dispose.
Callback Functions
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.
See Also:C Example using Callback Functions
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.
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.
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
AbortCurrent
void CkSpider_putAbortCurrent(HCkSpider cHandle, BOOL newVal);
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.)
topAvoidHttps
void CkSpider_putAvoidHttps(HCkSpider cHandle, BOOL newVal);
If set the 1 (true) the spider will avoid all HTTPS URLs. The default is 0 (false).
topCacheDir
void CkSpider_putCacheDir(HCkSpider cHandle, const char *newVal);
const char *CkSpider_cacheDir(HCkSpider 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.
ChopAtQuery
void CkSpider_putChopAtQuery(HCkSpider 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).
topConnectTimeout
void CkSpider_putConnectTimeout(HCkSpider cHandle, int newVal);
The maximum number of seconds to wait while connecting to an HTTP server.
topDebugLogFilePath
void CkSpider_putDebugLogFilePath(HCkSpider cHandle, const char *newVal);
const char *CkSpider_debugLogFilePath(HCkSpider 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:
- a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
- the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
- there is an internal problem (bug) in the Chilkat code that causes the hang.
Domain
const char *CkSpider_domain(HCkSpider cHandle);
The domain name that is being spidered. This is the domain previously set in the Initialize method.
topFetchFromCache
void CkSpider_putFetchFromCache(HCkSpider 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.
FinalRedirectUrl
const char *CkSpider_finalRedirectUrl(HCkSpider cHandle);
If the last URL crawled was redirected (as indicated by the WasRedirected property), this property will contain the final redirect URL.
topHeartbeatMs
void CkSpider_putHeartbeatMs(HCkSpider 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.
topLastErrorHtml
const char *CkSpider_lastErrorHtml(HCkSpider 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.
topLastErrorText
const char *CkSpider_lastErrorText(HCkSpider 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.
LastErrorXml
const char *CkSpider_lastErrorXml(HCkSpider 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.
topLastFromCache
Equal to 1 if the last page spidered was fetched from the cache. Otherwise equal to 0.
topLastHtml
const char *CkSpider_lastHtml(HCkSpider cHandle);
The HTML text of the last paged fetched by the spider.
topLastHtmlDescription
const char *CkSpider_lastHtmlDescription(HCkSpider cHandle);
The HTML META description from the last page fetched by the spider.
LastHtmlKeywords
const char *CkSpider_lastHtmlKeywords(HCkSpider cHandle);
LastHtmlTitle
const char *CkSpider_lastHtmlTitle(HCkSpider cHandle);
LastMethodSuccess
void CkSpider_putLastMethodSuccess(HCkSpider cHandle, BOOL newVal);
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.
topLastModDateStr
const char *CkSpider_lastModDateStr(HCkSpider cHandle);
The last modification date/time from the last page fetched by the spider.
topLastUrl
const char *CkSpider_lastUrl(HCkSpider cHandle);
The URL of the last page spidered.
topMaxResponseSize
void CkSpider_putMaxResponseSize(HCkSpider 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.
MaxUrlLen
void CkSpider_putMaxUrlLen(HCkSpider cHandle, int newVal);
The maximum URL length allowed. URLs longer than this are not added to the unspidered list. The default value is 200.
NumAvoidPatterns
The number of avoid patterns previously set by calling AddAvoidPattern.
topNumFailed
The number of URLs in the object's failed URL list.
topNumOutboundLinks
The number of URLs in the object's outbound links URL list.
topNumSpidered
The number of URLs in the object's already-spidered URL list.
topNumUnspidered
PreferIpv6
void CkSpider_putPreferIpv6(HCkSpider 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.
topProxyDomain
void CkSpider_putProxyDomain(HCkSpider cHandle, const char *newVal);
const char *CkSpider_proxyDomain(HCkSpider cHandle);
The domain name of a proxy host if an HTTP proxy is used.
topProxyLogin
void CkSpider_putProxyLogin(HCkSpider cHandle, const char *newVal);
const char *CkSpider_proxyLogin(HCkSpider cHandle);
If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.
topProxyPassword
void CkSpider_putProxyPassword(HCkSpider cHandle, const char *newVal);
const char *CkSpider_proxyPassword(HCkSpider cHandle);
If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.
topProxyPort
void CkSpider_putProxyPort(HCkSpider cHandle, int newVal);
The port number of a proxy server if an HTTP proxy is used.
topReadTimeout
void CkSpider_putReadTimeout(HCkSpider cHandle, int newVal);
The maximum number of seconds to wait when reading from an HTTP server.
topUpdateCache
void CkSpider_putUpdateCache(HCkSpider 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.
UserAgent
void CkSpider_putUserAgent(HCkSpider cHandle, const char *newVal);
const char *CkSpider_userAgent(HCkSpider cHandle);
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.
topUtf8
void CkSpider_putUtf8(HCkSpider cHandle, BOOL newVal);
When set to TRUE, all "const char *" arguments are interpreted as utf-8 strings. If set to FALSE (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to TRUE, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to FALSE, all "const char *" return values are ANSI strings.
topVerboseLogging
void CkSpider_putVerboseLogging(HCkSpider 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.
topVersion
const char *CkSpider_version(HCkSpider cHandle);
WasRedirected
Indicates whether the last URL crawled was redirected. (TRUE = yes, FALSE = no)
topWindDownCount
void CkSpider_putWindDownCount(HCkSpider 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.
topMethods
AddAvoidOutboundLinkPattern
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.
AddAvoidPattern
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.
AddMustMatchPattern
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.
AddUnspidered
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.
CanonicalizeUrl
const char *CkSpider_canonicalizeUrl(HCkSpider cHandle, const char *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.
ClearFailedUrls
Clears the object's internal list of URLs that could not be downloaded.
topClearOutboundLinks
Clears the object's internal list of outbound URLs that will automatically accumulate while spidering.
topClearSpideredUrls
Clears the object's internal list of already-spidered URLs that will automatically accumulate while spidering.
topCrawlNext
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.
CrawlNextAsync (1)
Creates an asynchronous task to call the CrawlNext method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topFetchRobotsText
const char *CkSpider_fetchRobotsText(HCkSpider cHandle);
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 TRUE for success, FALSE for failure.
FetchRobotsTextAsync (1)
Creates an asynchronous task to call the FetchRobotsText method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topGetAvoidPattern
const char *CkSpider_getAvoidPattern(HCkSpider cHandle, int index);
Returns the Nth avoid pattern previously added by calling AddAvoidPattern. Indexing begins at 0.
Returns TRUE for success, FALSE for failure.
topGetBaseDomain
const char *CkSpider_getBaseDomain(HCkSpider cHandle, const char *domain);
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 TRUE for success, FALSE for failure.
GetFailedUrl
const char *CkSpider_getFailedUrl(HCkSpider cHandle, int index);
Returns the Nth URL in the failed URL list. Indexing begins at 0.
Returns TRUE for success, FALSE for failure.
topGetOutboundLink
const char *CkSpider_getOutboundLink(HCkSpider cHandle, int index);
Returns the Nth URL in the outbound link URL list. Indexing begins at 0.
Returns TRUE for success, FALSE for failure.
topGetSpideredUrl
const char *CkSpider_getSpideredUrl(HCkSpider cHandle, int index);
Returns the Nth URL in the already-spidered URL list. Indexing begins at 0.
Returns TRUE for success, FALSE for failure.
topGetUnspideredUrl
const char *CkSpider_getUnspideredUrl(HCkSpider cHandle, int index);
Returns the Nth URL in the unspidered URL list. Indexing begins at 0.
Returns TRUE for success, FALSE for failure.
topGetUrlDomain
const char *CkSpider_getUrlDomain(HCkSpider cHandle, const char *url);
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 TRUE for success, FALSE for failure.
topInitialize
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.
LoadTaskCaller
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.
topRecrawlLastAsync (1)
Creates an asynchronous task to call the RecrawlLast method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)
Returns NULL on failure
topSkipUnspidered
Moves a URL from the unspidered list to the spidered list. This allows an application to skip a specific URL.
topSleepMs
Suspends the execution of the current thread until the time-out interval elapses.
top