Atom Delphi DLL Reference Documentation

Atom

Current Version: 9.5.0.97

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

Create/Dispose

var
myObject: HCkAtom;

begin
myObject := CkAtom_Create();

// ...

CkAtom_Dispose(myObject);
end;
function CkAtom_Create: HCkAtom; stdcall;

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

procedure CkAtom_Dispose(handle: HCkAtom); stdcall;

Objects created by calling CkAtom_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.

Properties

AbortCurrent
function CkAtom_getAbortCurrent(objHandle: HCkAtom): wordbool; stdcall;
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.)

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DebugLogFilePath
procedure CkAtom_getDebugLogFilePath(objHandle: HCkAtom; outPropVal: HCkString); stdcall;
procedure CkAtom_putDebugLogFilePath(objHandle: HCkAtom; newPropVal: PWideChar); stdcall;
function CkAtom__debugLogFilePath(objHandle: HCkAtom): PWideChar; stdcall;

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
procedure CkAtom_getLastErrorHtml(objHandle: HCkAtom; outPropVal: HCkString); stdcall;
function CkAtom__lastErrorHtml(objHandle: HCkAtom): PWideChar; stdcall;

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
procedure CkAtom_getLastErrorText(objHandle: HCkAtom; outPropVal: HCkString); stdcall;
function CkAtom__lastErrorText(objHandle: HCkAtom): PWideChar; stdcall;

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
procedure CkAtom_getLastErrorXml(objHandle: HCkAtom; outPropVal: HCkString); stdcall;
function CkAtom__lastErrorXml(objHandle: HCkAtom): PWideChar; stdcall;

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
function CkAtom_getLastMethodSuccess(objHandle: HCkAtom): wordbool; stdcall;
procedure CkAtom_putLastMethodSuccess(objHandle: HCkAtom; newPropVal: wordbool); stdcall;

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.

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NumEntries
function CkAtom_getNumEntries(objHandle: HCkAtom): Integer; stdcall;

Number of entries in the Atom document.

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VerboseLogging
function CkAtom_getVerboseLogging(objHandle: HCkAtom): wordbool; stdcall;
procedure CkAtom_putVerboseLogging(objHandle: HCkAtom; newPropVal: wordbool); stdcall;

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.

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Version
procedure CkAtom_getVersion(objHandle: HCkAtom; outPropVal: HCkString); stdcall;
function CkAtom__version(objHandle: HCkAtom): PWideChar; stdcall;

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

More Information and Examples
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Methods

AddElement
function CkAtom_AddElement(objHandle: HCkAtom;
    tag: PWideChar;
    value: PWideChar): Integer; stdcall;

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
function CkAtom_AddElementDateStr(objHandle: HCkAtom;
    tag: PWideChar;
    dateTimeStr: PWideChar): Integer; stdcall;

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
function CkAtom_AddElementDt(objHandle: HCkAtom;
    tag: PWideChar;
    dateTime: HCkDateTime): Integer; stdcall;

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
function CkAtom_AddElementHtml(objHandle: HCkAtom;
    tag: PWideChar;
    htmlStr: PWideChar): Integer; stdcall;

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
function CkAtom_AddElementXHtml(objHandle: HCkAtom;
    tag: PWideChar;
    xmlStr: PWideChar): Integer; stdcall;

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
function CkAtom_AddElementXml(objHandle: HCkAtom;
    tag: PWideChar;
    xmlStr: PWideChar): Integer; stdcall;

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
procedure CkAtom_AddEntry(objHandle: HCkAtom;
    xmlStr: PWideChar) stdcall;

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

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AddLink
procedure CkAtom_AddLink(objHandle: HCkAtom;
    rel: PWideChar;
    href: PWideChar;
    title: PWideChar;
    typ: PWideChar) stdcall;

Adds a link to the Atom document.

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AddPerson
procedure CkAtom_AddPerson(objHandle: HCkAtom;
    tag: PWideChar;
    name: PWideChar;
    uri: PWideChar;
    email: PWideChar) stdcall;

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
procedure CkAtom_DeleteElement(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer) stdcall;

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
procedure CkAtom_DeleteElementAttr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    attrName: PWideChar) stdcall;

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
procedure CkAtom_DeletePerson(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer) stdcall;

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
function CkAtom_DownloadAtom(objHandle: HCkAtom;
    url: PWideChar): wordbool; stdcall;

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

Returns True for success, False for failure.

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DownloadAtomAsync (1)
function CkAtom_DownloadAtomAsync(objHandle: HCkAtom;
    url: PWideChar): HCkTask; stdcall;

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
function CkAtom_GetElement(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__getElement(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer): PWideChar; stdcall;

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

Returns True for success, False for failure.

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GetElementAttr
function CkAtom_GetElementAttr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    attrName: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__getElementAttr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    attrName: PWideChar): PWideChar; stdcall;

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 True for success, False for failure.

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GetElementCount
function CkAtom_GetElementCount(objHandle: HCkAtom;
    tag: PWideChar): Integer; stdcall;

The number of elements having a specific tag.

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GetElementDateStr
function CkAtom_GetElementDateStr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__getElementDateStr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer): PWideChar; stdcall;

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 True for success, False for failure.

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GetElementDt
function CkAtom_GetElementDt(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer): HCkDateTime; stdcall;

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

Returns nil on failure

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GetEntry
function CkAtom_GetEntry(objHandle: HCkAtom;
    index: Integer): HCkAtom; stdcall;

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

Returns nil on failure

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GetLinkHref
function CkAtom_GetLinkHref(objHandle: HCkAtom;
    relName: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__getLinkHref(objHandle: HCkAtom;
    relName: PWideChar): PWideChar; stdcall;

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

Returns True for success, False for failure.

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GetPersonInfo
function CkAtom_GetPersonInfo(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    tag2: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__getPersonInfo(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    tag2: PWideChar): PWideChar; stdcall;

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

Returns True for success, False for failure.

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GetTopAttr
function CkAtom_GetTopAttr(objHandle: HCkAtom;
    attrName: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__getTopAttr(objHandle: HCkAtom;
    attrName: PWideChar): PWideChar; stdcall;

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 True for success, False for failure.

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HasElement
function CkAtom_HasElement(objHandle: HCkAtom;
    tag: PWideChar): wordbool; stdcall;

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

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LoadTaskCaller
function CkAtom_LoadTaskCaller(objHandle: HCkAtom;
    task: HCkTask): wordbool; stdcall;
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

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LoadXml
function CkAtom_LoadXml(objHandle: HCkAtom;
    xmlStr: PWideChar): wordbool; stdcall;

Loads the Atom document from an XML string.

Returns True for success, False for failure.

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NewEntry
procedure CkAtom_NewEntry(objHandle: HCkAtom) stdcall;

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

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NewFeed
procedure CkAtom_NewFeed(objHandle: HCkAtom) stdcall;

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

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SetElementAttr
procedure CkAtom_SetElementAttr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    attrName: PWideChar;
    attrValue: PWideChar) stdcall;

Adds or replaces an attribute on an element.

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SetTopAttr
procedure CkAtom_SetTopAttr(objHandle: HCkAtom;
    attrName: PWideChar;
    value: PWideChar) stdcall;

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

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ToXmlString
function CkAtom_ToXmlString(objHandle: HCkAtom;
    outStr: HCkString): wordbool; stdcall;
function CkAtom__toXmlString(objHandle: HCkAtom): PWideChar; stdcall;

Serializes the Atom document to an XML string.

Returns True for success, False for failure.

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UpdateElement
procedure CkAtom_UpdateElement(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    value: PWideChar) stdcall;

Replaces the content of an element.

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UpdateElementDateStr
procedure CkAtom_UpdateElementDateStr(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    dateTimeStr: PWideChar) stdcall;

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

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UpdateElementDt
procedure CkAtom_UpdateElementDt(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    dateTime: HCkDateTime) stdcall;

Replaces the content of a date-formatted element.

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UpdateElementHtml
procedure CkAtom_UpdateElementHtml(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    htmlStr: PWideChar) stdcall;

Replaces the content of an HTML element.

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UpdateElementXHtml
procedure CkAtom_UpdateElementXHtml(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    xmlStr: PWideChar) stdcall;

Replaces the content of an XHTML element.

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UpdateElementXml
procedure CkAtom_UpdateElementXml(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    xmlStr: PWideChar) stdcall;

Replaces the content of an XML element.

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UpdatePerson
procedure CkAtom_UpdatePerson(objHandle: HCkAtom;
    tag: PWideChar;
    index: Integer;
    name: PWideChar;
    uri: PWideChar;
    email: PWideChar) stdcall;

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

Chilkat supports event callbacks for the Delphi DLL starting in version 9.5.0.82.

AbortCheck
function MyAbortCheck(): Integer; cdecl;
Introduced in version 9.5.0.82

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. Return True to abort; return False to continue (not abort)

More Information and Examples
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PercentDone
function MyPercentDone(pctDone: Integer): Integer; cdecl;
Introduced in version 9.5.0.82

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.

Return True to abort; return False to continue (not abort)

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ProgressInfo
procedure MyProgressInfo(name: PWideChar; value: PWideChar) cdecl;
Introduced in version 9.5.0.82

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
procedure MyTaskCompleted(task: HCkTask) cdecl;
Introduced in version 9.5.0.82

Called in the background thread when an asynchronous task completes.

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