CkoSpider Objective-C Reference Documentation

CkoSpider

Current Version: 9.5.0.73

Chilkat Spider web crawler component.

Object Creation

CkoSpider *obj = [[CkoSpider alloc] init];

Properties

AbortCurrent
@property (nonatomic) BOOL AbortCurrent;
Introduced in version 9.5.0.58

When set to YES, 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 NO when the next method is called. When the abort occurs, this property is reset to NO. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

top
AvoidHttps
@property (nonatomic) BOOL AvoidHttps;

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

top
CacheDir
@property (nonatomic, copy) NSString *CacheDir;

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.

More Information and Examples
top
ChopAtQuery
@property (nonatomic) BOOL ChopAtQuery;

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).

top
ConnectTimeout
@property (nonatomic, copy) NSNumber *ConnectTimeout;

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

top
DebugLogFilePath
@property (nonatomic, copy) NSString *DebugLogFilePath;

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.

top
Domain
@property (nonatomic, readonly, copy) NSString *Domain;

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

top
FetchFromCache
@property (nonatomic) BOOL FetchFromCache;

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.

More Information and Examples
top
HeartbeatMs
@property (nonatomic, copy) NSNumber *HeartbeatMs;

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.

top
LastErrorHtml
@property (nonatomic, readonly, copy) NSString *LastErrorHtml;

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.

top
LastErrorText
@property (nonatomic, readonly, copy) NSString *LastErrorText;

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.

top
LastErrorXml
@property (nonatomic, readonly, copy) NSString *LastErrorXml;

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.

top
LastFromCache
@property (nonatomic, readonly) BOOL LastFromCache;

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

top
LastHtml
@property (nonatomic, readonly, copy) NSString *LastHtml;

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

top
LastHtmlDescription
@property (nonatomic, readonly, copy) NSString *LastHtmlDescription;

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

More Information and Examples
top
LastHtmlKeywords
@property (nonatomic, readonly, copy) NSString *LastHtmlKeywords;

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

More Information and Examples
top
LastHtmlTitle
@property (nonatomic, readonly, copy) NSString *LastHtmlTitle;

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

More Information and Examples
top
LastMethodSuccess
@property (nonatomic) BOOL LastMethodSuccess;
Introduced in version 9.5.0.52

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

top
LastModDate
@property (nonatomic, readonly, copy) NSDate *LastModDate;
This property is deprecated. It will be removed in a future version.

The last-modification date of the last URL spidered.

top
LastModDateStr
@property (nonatomic, readonly, copy) NSString *LastModDateStr;

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

top
LastUrl
@property (nonatomic, readonly, copy) NSString *LastUrl;

The URL of the last page spidered.

top
MaxResponseSize
@property (nonatomic, copy) NSNumber *MaxResponseSize;

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

More Information and Examples
top
MaxUrlLen
@property (nonatomic, copy) NSNumber *MaxUrlLen;

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

More Information and Examples
top
NumAvoidPatterns
@property (nonatomic, readonly, copy) NSNumber *NumAvoidPatterns;

The number of avoid patterns previously set by calling AddAvoidPattern.

top
NumFailed
@property (nonatomic, readonly, copy) NSNumber *NumFailed;

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

top
NumOutboundLinks
@property (nonatomic, readonly, copy) NSNumber *NumOutboundLinks;

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

top
NumSpidered
@property (nonatomic, readonly, copy) NSNumber *NumSpidered;

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

top
NumUnspidered
@property (nonatomic, readonly, copy) NSNumber *NumUnspidered;

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

More Information and Examples
top
PreferIpv6
@property (nonatomic) BOOL PreferIpv6;

If YES, then use IPv6 over IPv4 when both are supported for a particular domain. The default value of this property is NO, which will choose IPv4 over IPv6.

top
ProxyDomain
@property (nonatomic, copy) NSString *ProxyDomain;

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

top
ProxyLogin
@property (nonatomic, copy) NSString *ProxyLogin;

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

top
ProxyPassword
@property (nonatomic, copy) NSString *ProxyPassword;

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

top
ProxyPort
@property (nonatomic, copy) NSNumber *ProxyPort;

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

top
ReadTimeout
@property (nonatomic, copy) NSNumber *ReadTimeout;

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

top
UpdateCache
@property (nonatomic) BOOL UpdateCache;

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.

More Information and Examples
top
UserAgent
@property (nonatomic, copy) NSString *UserAgent;

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)"

top
VerboseLogging
@property (nonatomic) BOOL VerboseLogging;

If set to YES, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is NO. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

top
Version
@property (nonatomic, readonly, copy) NSString *Version;

Version of the component/library, such as "9.5.0.63"

top
WindDownCount
@property (nonatomic, copy) NSNumber *WindDownCount;

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.

top

Methods

AddAvoidOutboundLinkPattern
- (void)AddAvoidOutboundLinkPattern:(NSString *)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.

More Information and Examples
top
AddAvoidPattern
- (void)AddAvoidPattern:(NSString *)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.

More Information and Examples
top
AddMustMatchPattern
- (void)AddMustMatchPattern:(NSString *)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.

More Information and Examples
top
AddUnspidered
- (void)AddUnspidered:(NSString *)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.

More Information and Examples
top
CanonicalizeUrl
- (NSString *)CanonicalizeUrl:(NSString *)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 nil on failure

More Information and Examples
top
ClearFailedUrls
- (void)ClearFailedUrls;

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

top
ClearOutboundLinks
- (void)ClearOutboundLinks;

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

top
ClearSpideredUrls
- (void)ClearSpideredUrls;

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

top
CrawlNext
- (BOOL)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 NO. Information about the URL crawled is available in the properties LastUrl, LastFromCache, and LastModDate.

More Information and Examples
top
CrawlNextAsync (1)
- (CkoTask *)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.)

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 nil on failure

top
FetchRobotsText
- (NSString *)FetchRobotsText;

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 nil on failure

More Information and Examples
top
FetchRobotsTextAsync (1)
- (CkoTask *)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.)

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 nil on failure

top
GetAvoidPattern
- (NSString *)GetAvoidPattern:(NSNumber *)index;

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

Returns nil on failure

top
GetBaseDomain
- (NSString *)GetBaseDomain:(NSString *)domain;

To be documented soon.

Returns nil on failure

More Information and Examples
top
GetFailedUrl
- (NSString *)GetFailedUrl:(NSNumber *)index;

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

Returns nil on failure

top
GetOutboundLink
- (NSString *)GetOutboundLink:(NSNumber *)index;

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

Returns nil on failure

top
GetSpideredUrl
- (NSString *)GetSpideredUrl:(NSNumber *)index;

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

Returns nil on failure

top
GetUnspideredUrl
- (NSString *)GetUnspideredUrl:(NSNumber *)index;

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

Returns nil on failure

top
GetUrlDomain
- (NSString *)GetUrlDomain:(NSString *)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 nil on failure

top
Initialize
- (void)Initialize:(NSString *)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.

More Information and Examples
top
RecrawlLast
- (BOOL)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.

top
RecrawlLastAsync (1)
- (CkoTask *)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.)

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 nil on failure

top
SaveLastError
- (BOOL)SaveLastError:(NSString *)path;

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

Returns YES for success, NO for failure.

top
SkipUnspidered
- (void)SkipUnspidered:(NSNumber *)index;

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

top
SleepMs
- (void)SleepMs:(NSNumber *)millisec;

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

top

Events

To implement an event callback, your application would define and implement a class that inherits from CkoBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkoBaseProgress base class.

For example:

  CkoSpider *spider = [[CkoSpider alloc] init];

  MySpiderProgress *callbackObj = [[MySpiderProgress alloc] init];

  [spider setEventCallbackObject:callbackObj];

MySpiderProgress interface example:

#import "CkoSpiderProgress.h"

@interface MySpiderProgress : CkoBaseProgress {

}

    - (id)init;
    - (void)dealloc;
    - (void)dispose;

    - (void)AbortCheck:(BOOL *)abort;

    - (void)BinaryData:(NSData *)data 
        length:(NSNumber *)length;

    - (void)PercentDone:(NSNumber *)pctDone 
        abort:(BOOL *)abort;

    - (void)ProgressInfo:(NSString *)name 
        value:(NSString *)value;

    - (void)TaskCompleted:(CkoTask *)task;

    - (void)TextData:(NSString *)data;

@end
AbortCheck
- (void)AbortCheck:(BOOL *)abort;

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.

top
PercentDone
- (void)PercentDone:(NSNumber *)pctDone
    abort:(BOOL *)abort;

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

top
ProgressInfo
- (void)ProgressInfo:(NSString *)name
    value:(NSString *)value;

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.

top
TaskCompleted
- (void)TaskCompleted:(CkoTask *)task;

Called in the background thread when an asynchronous task completes.

top