HtmlToText Rust Reference Documentation

HtmlToText

Current Version: 11.6.1
Requires Chilkat Bundle License

Chilkat.HtmlToText

Convert HTML into readable plain text with control over links, wrapping, and encoding.

Chilkat.HtmlToText converts HTML content into readable plain text. It can decode HTML entities, wrap output at a configurable right margin, optionally include or suppress hyperlink URLs, convert HTML supplied as a string or StringBuilder, and read or write files using an explicit character encoding.

HTML to plain text

Convert HTML markup into readable text suitable for display, logging, indexing, email alternatives, or text-only output.

Entity decoding

Decode HTML entities so text such as named entities and numeric character references becomes normal readable output.

Line wrapping

Use RightMargin to wrap text at a chosen width, or set it to 0 when no right-margin wrapping is wanted.

Link handling

Suppress hyperlink URLs for cleaner text, or emit URLs when the output needs to preserve the destination of HTML links.

StringBuilder support

Convert HTML directly from a StringBuilder when working with larger or incrementally built HTML content.

File and charset helpers

Read HTML from files and write text output using a specified character encoding.

Common pattern: Provide the HTML as a string, file, or StringBuilder, choose whether to decode entities and include link URLs, set the desired right margin, then convert the result to plain text. Use HtmlToText when the goal is readable text, not structured XML or DOM-style parsing.

For an extended overview, see HtmlToText Class Overview.

Object Creation

// Cargo.toml:
//     [dependencies]
//     chilkat = "11.6"

use chilkat::HtmlToText;

// Once per process, before any other Chilkat call:
chilkat::unlock_bundle("Anything for 30-day trial")?;  // shorthand for Global::new().unlock_bundle(..)

let html_to_text = HtmlToText::new();
// ... the native object is freed when `html_to_text` goes out of scope.
pub fn new() -> HtmlToText

Creates the underlying native Chilkat object (HtmlToText also implements Default). Every method takes &self, so the object never needs to be declared mut. A HtmlToText is Send but not Sync: it may be moved to another thread, but a reference to it cannot be shared between threads at the same time.

impl Drop for HtmlToText

The native object is freed when the HtmlToText is dropped — when it goes out of scope, or explicitly with drop(html_to_text). There is no Dispose method to call.

Errors

Methods that can fail return chilkat::Result<T>, which is Result<T, chilkat::Error>: a method whose only outcome is success or failure returns Result<()>, a method producing a string or an object returns Result<String> or Result<HtmlToText>. The error carries the object's LastErrorText at the time of the failure (Error::last_error_text), the class and method names, and implements std::error::Error, so ? works in any function returning chilkat::Result or a Box<dyn Error>. Properties never fail, and methods that answer a question (has_..., is_..., ...) return a plain bool.

match html_to_text.some_method(...) {
    Ok(value) => println!("{value:?}"),
    Err(e) => eprintln!("{}", e.last_error_text()),
}

Properties

DebugLogFilePath
// read/write
pub fn debug_log_file_path(&self) -> String
pub fn set_debug_log_file_path(&self, value: &str)

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.

More Information and Examples
Example showing how to use DebugLogFilePath.
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DecodeHtmlEntities
// read/write
pub fn decode_html_entities(&self) -> bool
pub fn set_decode_html_entities(&self, value: bool)

Controls whether HTML character references are decoded when converting HTML to plain text. The default value is true.

Value Behavior
true HTML entities and numeric character references are decoded to their corresponding characters. For example, &amp; becomes &.
false Character references are left encoded in the plain-text output.
Typical use: Leave this property set to true when the goal is human-readable text. Set it to false when the original entity notation itself must be preserved.

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LastErrorHtml
// read-only
pub fn last_error_html(&self) -> String

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.

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LastErrorText
// read-only
pub fn last_error_text(&self) -> String

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.

More Information and Examples
Concept of LastErrorTextLastErrorText Standard Information
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LastErrorXml
// read-only
pub fn last_error_xml(&self) -> String

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.

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LastMethodSuccess
// read/write
pub fn last_method_success(&self) -> bool
pub fn set_last_method_success(&self, value: bool)

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.

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RightMargin
// read/write
pub fn right_margin(&self) -> i32
pub fn set_right_margin(&self, value: i32)

Controls line wrapping in the generated plain text. The default value is 80. As a line approaches the configured margin, Chilkat attempts to wrap at a SPACE character. Set this property to 0 to disable right-margin wrapping.

Soft margin: The right margin is a preferred wrapping point, not a guaranteed maximum line length. A long sequence with no suitable SPACE character may extend beyond the configured margin.

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SuppressLinks
// read/write
pub fn suppress_links(&self) -> bool
pub fn set_suppress_links(&self, value: bool)

Controls whether hyperlink destination URLs are included in the generated plain text. The default value is true.

Value Behavior
true The visible anchor text is retained, but hyperlink destination URLs are omitted.
false Hyperlink URLs are included. By default, they are collected in a References: section at the end of the plain text.
For example, with SuppressLinks set to false, an HTML link whose visible text is chilkat and whose URL is https://www.chilkatsoft.com/ produces the visible text and a numbered reference at the end of the output.
Related options: When link URLs are enabled, UncommonOptions can be used to suppress the trailing references list with NoReferencesList or emit URLs inline with EmitUrls.

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UncommonOptions
// read/write
pub fn uncommon_options(&self) -> String
pub fn set_uncommon_options(&self, value: &str)
Introduced in version 11.0.0

Specifies uncommon HTML-to-text conversion options as a comma-separated list of keywords. The default is the empty string, which is appropriate for normal use.

Keyword Effect
NoReferencesList Does not generate the hyperlink-reference list at the end of the plain-text output.
EmitUrls Emits hyperlink URLs inline in the plain-text output instead of relying on the default trailing reference list.
Interaction with SuppressLinks: These options control the presentation of hyperlink URLs when URL output is enabled. If SuppressLinks is true, hyperlink URLs are suppressed.

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VerboseLogging
// read/write
pub fn verbose_logging(&self) -> bool
pub fn set_verbose_logging(&self, value: bool)

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
// read-only
pub fn version(&self) -> String

Version of the component/library, such as "10.1.0"

More Information and Examples
How to get the Chilkat version at runtime.
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Methods

ToText
pub fn to_text(&self, html: &str) -> Result<String>

Converts the HTML in html to readable plain text and returns the result. The conversion honors DecodeHtmlEntities, RightMargin, SuppressLinks, and UncommonOptions. HTML markup is interpreted to produce readable text rather than simply being removed with a tag-stripping operation.

Plain-text conversion: The output is intended for reading, indexing, logging, email text alternatives, and similar text-oriented uses. It is not intended to preserve the original HTML markup or visual layout exactly.

Returns Err(chilkat::Error) on failure.

More Information and Examples
HTML Tables to Plain Text Conversion Gallery
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ToTextSb
pub fn to_text_sb(&self, sb: &StringBuilder) -> Result<()>
Introduced in version 9.5.0.97

Converts the HTML currently contained in sb to plain text in place. On success, the same StringBuilder contains the converted plain-text result. The conversion honors DecodeHtmlEntities, RightMargin, SuppressLinks, and UncommonOptions.

StringBuilder workflow: Use this method when the HTML is already held in a StringBuilder and you want the conversion result returned through that same object rather than as a separate string.

Returns Ok(()) for success, Err(chilkat::Error) for failure.

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