Ksoup - Kotlin Multiplatform HTML Parser

Ksoup is a lightweight Kotlin Multiplatform library for parsing HTML, extracting HTML tags, attributes, and text, and encoding and decoding HTML entities.

Features

Parse HTML from String
Extract HTML tags, attributes, and text
Encode and decode HTML entities
Lightweight and does not depend on any other library
Kotlin Multiplatform support
Fast and efficient
Unit tested

Installation

Add the dependency below to your module's build.gradle.kts or build.gradle file:

Kotlin version	Ksoup version
1.9.x	0.2.1
1.8.x	0.1.4

val version = "0.2.1"

// For parsing HTML
implementation("com.mohamedrejeb.ksoup:ksoup-html:$version")

// Only for encoding and decoding HTML entities 
implementation("com.mohamedrejeb.ksoup:ksoup-entites:$version")

Usage

Parsing HTML

To parse HTML from a String, use the KsoupHtmlParser class, and provide an implementation of the KsoupHtmlHandler interface, and a KsoupHtmlOptions object. Both of them are optional, you can use the default ones if you want.

KsoupHtmlParser

You can create a parser using the KsoupHtmlParser(), there are several methods that you can use, for example write to parse a String, and end to close the parser when you are done:

val ksoupHtmlParser = KsoupHtmlParser()

// String to parse
val html = "<h1>My Heading</h1>"

// Pass the HTML to the parser (It is going to parse the HTML and call the callbacks)
ksoupHtmlParser.write(html)

// Close the parser when you are done
ksoupHtmlParser.end()

KsoupHtmlHandler

You can directly implement KsoupHtmlHandler interface or use KsoupHtmlHandler.Builder():

// Implement `KsoupHtmlHandler` interface
val firstHandler = object : KsoupHtmlHandler {
    override fun onOpenTag(name: String, attributes: Map<String, String>, isImplied: Boolean) {
        println("Open tag: $name")
    }
}

// Use `KsoupHtmlHandler.Builder()`
val secondHandler = KsoupHtmlHandler
    .Builder()
    .onOpenTag { name, attributes, isImplied ->
        println("Open tag: $name")
    }
    .build()

There are several methods that you can override, for example is you want to just extract the text from the HTML, you can override the onText method:

// String to parse
val html = """
    <html>
        <head>
            <title>My Title</title>
        </head>
        <body>
            <h1>My Heading</h1>
            <p>My paragraph.</p>
        </body>
    </html>
""".trimIndent()

// String to store the extracted text
var string = ""

// Create a handler
val handler = KsoupHtmlHandler
    .Builder()
    .onText { text ->
        string += text
    }
    .build()

// Create a parser
val ksoupHtmlParser = KsoupHtmlParser(
    handler = handler,
)

// Pass the HTML to the parser (It is going to parse the HTML and call the callbacks)
ksoupHtmlParser.write(html)

// Close the parser when you are done
ksoupHtmlParser.end()

You can also use onOpenTag and onCloseTag to know when a tag is opened or closed, it can be used for scrapping data from a website or powering a rich text editor, Also you can use onComment to know when a comment is found in the HTML and onAttribute to know when attributes are found in a tag.

KsoupHtmlOptions

You can also pass KsoupHtmlOptions to the parser to change the behavior of the parser, you can for example disable the decoding of HTML entities which is enabled by default:

val options = KsoupHtmlOption(
    decodeEntities = false,
)

Encoding and Decoding HTML Entities

You can use the KsoupEntities class to encode and decode HTML entities:

// Encode HTML entities
val encoded = KsoupEntities.encodeHtml("Hello & World") // return: Hello &amp; World

// Decode HTML entities
val decoded = KsoupEntities.decodeHtml("Hello &amp; World") // return: Hello & World

KsoupEntities also provides methods to encode and decode only XML entities or HTML4. The KsoupEntities class is available in the ksoup-entites module.

Both encodeHtml and decodeHtml methods support all HTML5 entities, XML entities, and HTML4 entities.

Coming Features

Add clear documentation
Add Markdown parser

Contribution

If you've found an error in this sample, please file an issue.
Feel free to help out by sending a pull request ❤️.

Code of Conduct

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License

Copyright 2023 Mohamed Rejeb

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

spacecowboy/Ksoup