CkoAtom Objective-C Reference Documentation

CkoAtom

Current Version: 9.5.0.75

Represents an Atom document. The Atom API allows one to download, create and modify Atom documents.

Object Creation

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

Properties

AbortCurrent
@property (nonatomic, readonly) 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.)

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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.

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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.

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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.

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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.

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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.

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NumEntries
@property (nonatomic, readonly, copy) NSNumber *NumEntries;

Number of entries in the Atom document.

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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.

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

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

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Methods

AddElement
- (NSNumber *)AddElement:(NSString *)tag
    value:(NSString *)value;

Adds a new element to the Atom document. The tag is a string such as "title", "subtitle", "summary", etc. Returns the index of the element added, or -1 for failure.

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AddElementDateStr
- (NSNumber *)AddElementDateStr:(NSString *)tag
    dateTimeStr:(NSString *)dateTimeStr;

Adds a new date-formatted element to the Atom document. The tag is a string such as "created", "modified", "issued", etc. The dateTimeStr should be an RFC822 formatted date/time string such as "Tue, 25 Sep 2012 12:25:32 -0500". Returns the index of the element added, or -1 for failure.

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AddElementDt
- (NSNumber *)AddElementDt:(NSString *)tag
    dateTime:(CkoDateTime *)dateTime;

Adds a new date-formatted element to the Atom document. The tag is a string such as "created", "modified", "issued", etc. Returns the index of the element added, or -1 for failure.

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AddElementHtml
- (NSNumber *)AddElementHtml:(NSString *)tag
    htmlStr:(NSString *)htmlStr;

Adds a new HTML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.

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AddElementXHtml
- (NSNumber *)AddElementXHtml:(NSString *)tag
    xmlStr:(NSString *)xmlStr;

Adds a new XHTML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.

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AddElementXml
- (NSNumber *)AddElementXml:(NSString *)tag
    xmlStr:(NSString *)xmlStr;

Adds a new XML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.

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AddEntry
- (void)AddEntry:(NSString *)xmlStr;

Adds an "entry" Atom XML document to the caller's Atom document.

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AddLink
- (void)AddLink:(NSString *)rel
    href:(NSString *)href
    title:(NSString *)title
    typ:(NSString *)typ;

Adds a link to the Atom document.

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AddPerson
- (void)AddPerson:(NSString *)tag
    name:(NSString *)name
    uri:(NSString *)uri
    email:(NSString *)email;

Adds a person to the Atom document. The tag should be a string such as "author", "contributor", etc. If a piece of information is not known, an empty string or NULL value may be passed.

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DeleteElement
- (void)DeleteElement:(NSString *)tag
    index:(NSNumber *)index;

Removes the Nth occurrence of a given element from the Atom document. Indexing begins at 0. For example, to remove the 2nd category, set tag = "category" and index = 1.

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DeleteElementAttr
- (void)DeleteElementAttr:(NSString *)tag
    index:(NSNumber *)index
    attrName:(NSString *)attrName;

Remove an attribute from an element.The index should be 0 unless there are multiple elements having the same tag, in which case it selects the Nth occurrence based on the index ( 0 = first occurrence ).

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DeletePerson
- (void)DeletePerson:(NSString *)tag
    index:(NSNumber *)index;

Deletes a person from the Atom document. The tag is a string such as "author". The index should be 0 unless there are multiple elements having the same tag, in which case it selects the Nth occurrence based on the index. For example, DeletePerson("author",2) deletes the 3rd author.

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DownloadAtom
- (BOOL)DownloadAtom:(NSString *)url;

Download an Atom feed from the Internet and load it into the Atom object.

Returns YES for success, NO for failure.

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DownloadAtomAsync (1)
- (CkoTask *)DownloadAtomAsync:(NSString *)url;

Creates an asynchronous task to call the DownloadAtom 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

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GetElement
- (NSString *)GetElement:(NSString *)tag
    index:(NSNumber *)index;

Returns the content of the Nth element having a specified tag.

Returns nil on failure

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GetElementAttr
- (NSString *)GetElementAttr:(NSString *)tag
    index:(NSNumber *)index
    attrName:(NSString *)attrName;

Returns the value of an element's attribute. The element is selected by the tag name and the index (the Nth element having a specific tag) and the attribute is selected by name.

Returns nil on failure

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GetElementCount
- (NSNumber *)GetElementCount:(NSString *)tag;

The number of elements having a specific tag.

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GetElementDateStr
- (NSString *)GetElementDateStr:(NSString *)tag
    index:(NSNumber *)index;

Returns an element's value as a date/time in an RFC822 formatted string, such as such as "Tue, 25 Sep 2012 12:25:32 -0500".

Returns nil on failure

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GetElementDt
- (CkoDateTime *)GetElementDt:(NSString *)tag
    index:(NSNumber *)index;

Returns an element's value as a date/time object.

Returns nil on failure

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GetEntry
- (CkoAtom *)GetEntry:(NSNumber *)index;

Returns the Nth entry as an Atom object. (Indexing begins at 0)

Returns nil on failure

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GetLinkHref
- (NSString *)GetLinkHref:(NSString *)relName;

Returns the href attribute of the link having a specified "rel" attribute (such as "service.feed", "alternate", etc.).

Returns nil on failure

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GetPersonInfo
- (NSString *)GetPersonInfo:(NSString *)tag
    index:(NSNumber *)index
    tag2:(NSString *)tag2;

Returns a piece of information about a person. To get the 2nd author's name, call GetPersonInfo("author",1,"name").

Returns nil on failure

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GetTopAttr
- (NSString *)GetTopAttr:(NSString *)attrName;

Returns the value of an attribute on the top-level XML node. The tag of a top-level Atom XML node is typically "feed" or "entry", and it might have attributes such as "xmlns" and "xml:lang".

Returns nil on failure

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HasElement
- (BOOL)HasElement:(NSString *)tag;

True (1) if the element exists in the Atom document. Otherwise 0.

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LoadXml
- (BOOL)LoadXml:(NSString *)xmlStr;

Loads the Atom document from an XML string.

Returns YES for success, NO for failure.

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NewEntry
- (void)NewEntry;

Initializes the Atom document to be a new "entry".

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NewFeed
- (void)NewFeed;

Initializes the Atom document to be a new "feed".

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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.

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SetElementAttr
- (void)SetElementAttr:(NSString *)tag
    index:(NSNumber *)index
    attrName:(NSString *)attrName
    attrValue:(NSString *)attrValue;

Adds or replaces an attribute on an element.

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SetTopAttr
- (void)SetTopAttr:(NSString *)attrName
    value:(NSString *)value;

Adds or replaces an attribute on the top-level XML node of the Atom document.

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ToXmlString
- (NSString *)ToXmlString;

Serializes the Atom document to an XML string.

Returns nil on failure

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UpdateElement
- (void)UpdateElement:(NSString *)tag
    index:(NSNumber *)index
    value:(NSString *)value;

Replaces the content of an element.

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UpdateElementDateStr
- (void)UpdateElementDateStr:(NSString *)tag
    index:(NSNumber *)index
    dateTimeStr:(NSString *)dateTimeStr;

Replaces the content of a date-formatted element. The index should be an RFC822 formatted date/time string.

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UpdateElementDt
- (void)UpdateElementDt:(NSString *)tag
    index:(NSNumber *)index
    dateTime:(CkoDateTime *)dateTime;

Replaces the content of a date-formatted element.

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UpdateElementHtml
- (void)UpdateElementHtml:(NSString *)tag
    index:(NSNumber *)index
    htmlStr:(NSString *)htmlStr;

Replaces the content of an HTML element.

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UpdateElementXHtml
- (void)UpdateElementXHtml:(NSString *)tag
    index:(NSNumber *)index
    xmlStr:(NSString *)xmlStr;

Replaces the content of an XHTML element.

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UpdateElementXml
- (void)UpdateElementXml:(NSString *)tag
    index:(NSNumber *)index
    xmlStr:(NSString *)xmlStr;

Replaces the content of an XML element.

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UpdatePerson
- (void)UpdatePerson:(NSString *)tag
    index:(NSNumber *)index
    name:(NSString *)name
    uri:(NSString *)uri
    email:(NSString *)email;

Replaces the content of a person. To update the 3rd author, call UpdatePerson("author",2,"new name","new URL","new email"). If a piece of information is not known, pass an empty string or a NULL.

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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:

  CkoAtom *atom = [[CkoAtom alloc] init];

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

  [atom setEventCallbackObject:callbackObj];

MyAtomProgress interface example:

#import "CkoAtomProgress.h"

@interface MyAtomProgress : 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.

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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).

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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.

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

Called in the background thread when an asynchronous task completes.

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