HtmlToXml Dart Reference Documentation
CkHtmlToXml
Current Version: 11.6.1
Chilkat.HtmlToXml
Convert real-world HTML into well-formed XML that can be loaded into
Supply HTML from strings, files, byte arrays,
Remove specific tag types from the output when the application wants a
cleaner XML result focused on relevant content.
Drop common formatting tags when the structure matters more than visual
presentation.
Control how non-breaking spaces are represented, converted, removed, or
preserved in the XML output.
Choose the XML charset and write the converted XML directly to a file
when a persisted result is needed.
For an extended overview, see
HtmlToXml Class Overview.
Convert HTML into well-formed XML for structured parsing and searching.
Chilkat.HtmlToXml converts HTML into well-formed XML so the
content can be parsed, searched, transformed, or processed programmatically
with XML tools. It can accept HTML from strings, files, byte arrays,
BinData, or StringBuilder, and provides options for
dropping selected tags, removing common text-formatting tags, controlling
non-breaking spaces, choosing the XML charset, and saving the converted XML
to a file.
HTML to XML conversion
Chilkat.Xml or other XML processing tools.
Flexible input sources
BinData, or
StringBuilder depending on how the content is received or
built.
Drop selected tags
Text-formatting cleanup
NBSP handling
Charset and file output
Nbsp behavior, and
XmlCharset, then call the conversion method and parse the result
as XML. Use HtmlToXml when structured extraction is needed; use
HtmlToText when the goal is readable plain text.
Object Creation
// pubspec.yaml:
// dependencies:
// chilkat: ^11.6.1
import 'package:chilkat/chilkat.dart';
// Once per process, before any other Chilkat call:
Chilkat.unlockBundle('Anything for 30-day trial'); // shorthand for CkGlobal().unlockBundle(..)
final htmlToXml = CkHtmlToXml();
// ... the native object is released when `htmlToXml` is garbage collected, or now with htmlToXml.dispose().Creates the underlying native Chilkat object. Use a CkHtmlToXml only from the isolate that created it: Chilkat objects cannot be sent between isolates. Every call is synchronous; in a Flutter app, run long operations (network, large files) inside Isolate.run, creating the Chilkat objects inside the isolate.
Releases the native object immediately instead of waiting for garbage collection (useful for a large CkBinData or an open socket). Calling it more than once is harmless; any other use of the object afterwards throws a StateError. isDisposed tells whether it has been called.
Errors
A method that can fail throws a ChilkatException: a method whose only outcome is success or failure returns void and throws on failure; a method producing a String or an object returns it and throws where Chilkat would have returned null. The exception carries the object's LastErrorText at the time of the failure (lastErrorText), the class and method names (className, methodName) and a one-line message. Properties never throw, and methods that answer a question (has..., is..., ...) return a plain bool.
try {
htmlToXml.someMethod(...);
} on ChilkatException catch (e) {
print(e); // CkHtmlToXml.someMethod failed: <reason>
print(e.lastErrorText); // the full Chilkat log of the failed call
}Properties
DebugLogFilePath
String get debugLogFilePath
set debugLogFilePath(String value)
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
DropCustomTags
bool get dropCustomTags
set dropCustomTags(bool value)
Controls whether tags that Chilkat does not recognize as standard HTML elements are omitted from the generated XML.
true when custom or application-specific tags would add noise to the XML structure. Leave it false when those tags are meaningful to the application and should remain represented in the converted output.Html
String get html
set html(String value)
The HTML source to be converted. Set this property to an HTML string, configure any conversion options, and then call ToXml, Xml, or ToXmlSb.
Assigning this property replaces the current in-memory HTML source. For file-to-file conversion, use ConvertFile. To load HTML from a file, BinData, or StringBuilder, use the corresponding SetHtml* method.
<text> elements to simplify programmatic extraction.LastErrorHtml
String get lastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
String get lastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
String get lastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
bool get lastMethodSuccess
set lastMethodSuccess(bool value)
Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
Nbsp
int get nbsp
set nbsp(int value)
Controls how HTML non-breaking-space entities are handled during conversion. The default value is 0.
| Value | Behavior for |
|---|---|
0 | Convert to a normal space character (U+0020). |
1 | Convert to the numeric character reference   (U+00A0). |
2 | Drop the non-breaking-space entity. |
3 | Leave the entity unconverted by this option. |
This setting applies specifically to the HTML entity ; it does not define general whitespace normalization.
VerboseLogging
bool get verboseLogging
set verboseLogging(bool value)
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
String get version
XmlCharset
String get xmlCharset
set xmlCharset(String value)
Specifies the character encoding to identify for the generated XML, such as utf-8 or iso-8859-1. If this property is empty, Chilkat uses the character encoding of the HTML input. Otherwise, the converted XML uses the specified charset.
ToXml or Xml is a string in the programming language's native string representation, while the XML declaration reflects XmlCharset. When writing that string to a file, use the same charset so the file bytes agree with the XML declaration. ConvertFile performs the file conversion directly.Methods
ConvertFile
Converts the HTML file at inHtmlPath to a well-formed XML file at destXmlPath. The output encoding is controlled by XmlCharset; if XmlCharset is empty, Chilkat uses the HTML source encoding.
Returns true on success and false on failure.
Returns normally on success; throws a ChilkatException on failure.
DropTagType
Marks the specified HTML tag type to be dropped from the generated XML. To drop multiple tag types, call this method once for each tag name.
The setting remains in effect for subsequent conversions performed by this HtmlToXml object. Use UndropTagType to reverse the setting for a particular tag type.
DropTextFormattingTags
Configures the converter to drop common text-formatting tags from the generated XML. The affected tag names are:
b, font, i, u, br, center, em, strong, big, tt, s, small, strike, sub, and sup.
This is useful when the formatting markup is not relevant to later XML parsing and the application wants a simpler structural representation. Call UndropTextFormattingTags to keep these tags instead.
SetHtmlBd
Replaces the current HTML source with the complete contents of bd.
The data is copied from the supplied BinData object and becomes the input for a later call to ToXml, Xml, or ToXmlSb. Returns true on success and false on failure.
Returns normally on success; throws a ChilkatException on failure.
SetHtmlFromFile
Loads HTML from filename and replaces the current Html input with the file contents.
Returns true on success and false if the file cannot be read or the HTML input cannot be loaded. Call ToXml, Xml, or ToXmlSb afterward to perform the conversion.
Returns normally on success; throws a ChilkatException on failure.
SetHtmlSb
Replaces the current HTML source with the complete contents of sb.
The text is copied from the supplied StringBuilder and becomes the input for a later call to ToXml, Xml, or ToXmlSb. Returns true on success and false on failure.
Returns normally on success; throws a ChilkatException on failure.
ToXml
Converts the current Html input to well-formed XML and returns the XML string. The generated XML uses the conversion settings currently configured on this object, including DropCustomTags, dropped tag types, Nbsp, and XmlCharset.
<text> elements to make extraction with XML tools straightforward.Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).
ToXmlSb
Converts the current Html input to well-formed XML and appends the generated XML to sb.
Returns true on success and false on failure. Because the result is appended, clear the destination StringBuilder first when replacement rather than concatenation is desired.
Returns normally on success; throws a ChilkatException on failure.
UndropTagType
Reverses a previous DropTagType setting for the specified tag name so that tag type is no longer intentionally dropped from subsequent XML output.
This affects only the named tag type. Other tag types previously configured to be dropped remain unchanged.
topUndropTextFormattingTags
Configures the converter to retain the common text-formatting tags that are otherwise dropped by default:
b, font, i, u, br, center, em, strong, big, tt, s, small, strike, sub, and sup.
Call DropTextFormattingTags to return to dropping these formatting tags.
Xml
Equivalent to ToXml. Converts the current Html input to well-formed XML and returns the XML string using the object's current conversion settings.
This method is provided as an alternate name for ToXml; it does not perform a different conversion.
Throws a ChilkatException on failure (where the description says null is returned, the Dart method throws instead).