Atom Xojo Plugin Reference Documentation

Atom

Current Version: 9.5.0.98

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

Object Creation

Dim atom As New Chilkat.Atom

Properties

AbortCurrent

AbortCurrent As Boolean (read-only)

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.)

DebugLogFilePath

DebugLogFilePath As String

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.

More Information and Examples

Example showing how to use DebugLogFilePath.

LastErrorHtml

LastErrorHtml As String (read-only)

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.

LastErrorText

LastErrorText As String (read-only)

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.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

LastErrorXml

LastErrorXml As String (read-only)

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.

LastMethodSuccess

LastMethodSuccess As Boolean

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.

NumEntries

NumEntries As Int32 (read-only)

Number of entries in the Atom document.

VerboseLogging

VerboseLogging As Boolean

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.

Version

Version As String (read-only)

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

More Information and Examples

How to get the Chilkat version at runtime.

Methods

AddElement

Function AddElement(tag As String, value As String) As Int32

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.

AddElementDateStr

Function AddElementDateStr(tag As String, dateTimeStr As String) As Int32

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.

AddElementDt

Function AddElementDt(tag As String, dateTime As Chilkat.CkDateTime) As Int32

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.

AddElementHtml

Function AddElementHtml(tag As String, htmlStr As String) As Int32

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

AddElementXHtml

Function AddElementXHtml(tag As String, xmlStr As String) As Int32

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

AddElementXml

Function AddElementXml(tag As String, xmlStr As String) As Int32

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

AddEntry

Sub AddEntry(xmlStr As String)

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

AddLink

Sub AddLink(rel As String, href As String, title As String, typ As String)

Adds a link to the Atom document.

AddPerson

Sub AddPerson(tag As String, name As String, uri As String, email As String)

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.

DeleteElement

Sub DeleteElement(tag As String, index As Int32)

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.

DeleteElementAttr

Sub DeleteElementAttr(tag As String, index As Int32, attrName As String)

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 ).

DeletePerson

Sub DeletePerson(tag As String, index As Int32)

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.

DownloadAtom

Function DownloadAtom(url As String) As Boolean

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

Returns True for success, False for failure.

DownloadAtomAsync ⁽¹⁾

Function DownloadAtomAsync(url As String) As Chilkat.Task

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

GetElement

Function GetElement(tag As String, index As Int32) As String

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

Returns Nil on failure

GetElementAttr

Function GetElementAttr(tag As String, index As Int32, attrName As String) As String

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

GetElementCount

Function GetElementCount(tag As String) As Int32

The number of elements having a specific tag.

GetElementDateStr

Function GetElementDateStr(tag As String, index As Int32) As String

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

GetElementDt

Function GetElementDt(tag As String, index As Int32) As Chilkat.CkDateTime

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

Returns Nil on failure

GetEntry

Function GetEntry(index As Int32) As Chilkat.Atom

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

Returns Nil on failure

GetLinkHref

Function GetLinkHref(relName As String) As String

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

Returns Nil on failure

GetPersonInfo

Function GetPersonInfo(tag As String, index As Int32, tag2 As String) As String

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

Returns Nil on failure

GetTopAttr

Function GetTopAttr(attrName As String) As String

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

HasElement

Function HasElement(tag As String) As Boolean

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

LoadTaskCaller

Function LoadTaskCaller(task As Chilkat.Task) As Boolean

Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

LoadXml

Function LoadXml(xmlStr As String) As Boolean

Loads the Atom document from an XML string.

Returns True for success, False for failure.

NewEntry

Sub NewEntry()

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

NewFeed

Sub NewFeed()

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

SetElementAttr

Sub SetElementAttr(tag As String, index As Int32, attrName As String, attrValue As String)

Adds or replaces an attribute on an element.

SetTopAttr

Sub SetTopAttr(attrName As String, value As String)

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

ToXmlString

Function ToXmlString() As String

Serializes the Atom document to an XML string.

Returns Nil on failure

UpdateElement

Sub UpdateElement(tag As String, index As Int32, value As String)

Replaces the content of an element.

UpdateElementDateStr

Sub UpdateElementDateStr(tag As String, index As Int32, dateTimeStr As String)

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

UpdateElementDt

Sub UpdateElementDt(tag As String, index As Int32, dateTime As Chilkat.CkDateTime)

Replaces the content of a date-formatted element.

UpdateElementHtml

Sub UpdateElementHtml(tag As String, index As Int32, htmlStr As String)

Replaces the content of an HTML element.

UpdateElementXHtml

Sub UpdateElementXHtml(tag As String, index As Int32, xmlStr As String)

Replaces the content of an XHTML element.

UpdateElementXml

Sub UpdateElementXml(tag As String, index As Int32, xmlStr As String)

Replaces the content of an XML element.

UpdatePerson

Sub UpdatePerson(tag As String, index As Int32, name As String, uri As String, email As String)

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.

Events

To implement events, your application would define and implement a class that is a subclass of Chilkat.Atom. Your custom class would implement (i.e. override) some or all of the event methods.

For example:

class MyAtom
    Inherits Chilkat.Atom

    Function AbortCheck() As Boolean

    Function PercentDone(pctDone As Int32) As Boolean

    Sub ProgressInfo(name As String, value As String)

    Sub TaskCompleted(task As Chilkat.Task)


End Class

AbortCheck

Function AbortCheck() As Boolean

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.

PercentDone

Function PercentDone(pctDone As Int32) As Boolean

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

ProgressInfo

Sub ProgressInfo(name As String, value As String)

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.

TaskCompleted

Sub TaskCompleted(task As Chilkat.Task)

Called in the background thread when an asynchronous task completes.

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