Tachiyomi-Extensions/CONTRIBUTING.md

Contributing

Before you start, please note that the ability to use following technologies is required and it's not possible for us to teach you any of them.

• basic Android software development using Kotlin
• web scraping
  • OkHttp
  • JSoup
  • HTML
  • CSS selectors

Writing an extension

The quickest way to get started is to copy an existing extension's folder structure and renaming it as needed. Of course, that also means that there's plenty of existing extensions that you can reference as you go!

Setting up a module

Make sure that your new extension's build.gradle file follows the following structure:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'

ext {
    appName = 'Tachiyomi: My source name'
    pkgNameSuffix = 'lang.mysourcename'
    extClass = '.MySourceName'
    extVersionCode = 1
    libVersion = '1.2'
}

apply from: "$rootDir/common.gradle"

Field	Description
appName	The name of the Android application. By prefixing it with Tachiyomi: , it will be easier to locate with an Android package manager.
pkgNameSuffix	A unique suffix added to eu.kanade.tachiyomi.extension. The language and the site name should be enough. Remember your catalogue code implementation must be placed in this package.
extClass	Points to the catalogue class. You can use a relative path starting with a dot (the package name is the base path). This is required for Tachiyomi to find and instantiate the catalogue.
extVersionCode	The version code of the catalogue. This must be a positive integer and increased with any change to the implementation.
libVersion	The version of the extensions library used.

The catalogue's version name is based off of libVersion and extVersionCode. With the example used above, the version of the catalogue would be 1.2.1.

Extensions library

Extensions rely on extensions-lib, which simply provides some interfaces and stubs to compile extentsions. The actual implementations are in the app inside eu.kanade.tachiyomi.source package which you can find it here, reading the code inside there will help you with writing your extension.

general guidelines and extension workflow

• Extension Main Class
  • The extension Main class which is refrenced and defined by extClass(inside build.gradle) should be inherited from either SourceFactory or one of Source children: HttpSource or ParsedHttpSource.
  • SourceFactory is used to expose multiple Sources, only use it when there's minor difference between your target sources or they are essentially mirrors to the same website.
  • HttpSource as in it's name is for a online http(s) source, but ParsedHttpSource has a good model of work which makes writing scrapers for normal aggregator websites much easier and streamlined. (again, you can find the implementation of the stubs in the app as mentioned above)
• The app starts by finding your extension and reads these variables:

Field	Description
name	Name to your target source as displayed in the sources tab inside the app
id	identifier of your source, automatically set from HttpSource. It should only be manually set if you need to copy an existing autogenerated ID.
supportsLatest	if true the app adds a latest button to your extension
baseUrl	base URL of the target source without any trailing slashes
lang	as the documentation says "An ISO 639-1 compliant language code (two letters in lower case).", it will be used to catalog your extension

• Popular Manga
  • When user presses on the source name or the Browse button on the sources tab, the app calls fetchPopularManga with page=1, and it returns a MangasPage and will continue to call it for next pages, when the user scrolls the manga list and more results must be fetched(until you pass MangasPage.hasNextPage as false which marks the end of the found manga list)
  • While passing magnas here you should at least set url, title and *thumbnail_url; url must be unique since it's used to index mangas in the DataBase.(this information will be cached and you will have a chance to update them when fetchMangaDetails is called later).
  • You may not set thumbnail_url, which will make the app call fetchMangaDetails over every single manga to show the cover, so it's better to set the thumbnail cover in fetchPopularManga if possible. The same is true with latest and search.
• Latest Manga
  • If supportsLatest is set to true the app shows a Latest button in front for your extension name and when the user taps on it, the app will call fetchLatestUpdates and the rest of the flow is similar to what happens with fetchPopularManga.
  • If supportsLatest is set to false no Latest button will be shown and fetchLatestUpdates and subsequent methods will never be called.
• Manga Search
  • getFilterList will be called to get all filters and filter types. TODO: explain more about Filter
  • when the user searches inside the app, fetchSearchManga will be called and the rest of the flow is similar to what happens with fetchPopularManga.
• Manga Details
  • When user taps on a manga and opens it's information Activity fetchMangaDetails and fetchChapterList will be called the resulting information will be cached.
  • fetchMangaDetails is called to update a manga's details from when it vas initialized earlier(you may want to parse a manga details page here and fill the rest of the fields)
    • Note: During a backup, only url and title are stored, and to restore the rest of the manga data the app calls fetchMangaDetails. so you need to fill the rest of the fields, specially thumbnail_url.
  • fetchChapterList is called to display the chapter list, you want to return a reversed list here(last chapter, first index in the list)
• Chapter
  • After a chapter list for the manga is fetched, prepareNewChapter will be called, after that the chapter will be saved in the app's DataBase and later if the chapter list changes the app will loose any references to the chapter(but chapter files will still be in the device storage)
• Chapter Pages
  • When user opens a chapter, fetchPageList will be called and it will return a list of Page
  • While a chapter is open the reader will call fetchImageUrl to get URLs for each page of the manga
• Notes
  • Some time while you are writing code, you may find no use for some inherited methods, if so just override them and throw exceptions: throw Exception("Not used")
  • You probably will find getUrlWithoutDomain useful when parsing the target source URLs.
  • If possible try to stick to the general workflow fromParsedHttpSource and HttpSource, breaking them may cause you more headache than necessary.
  • When reading the code documentation it helps to follow the subsequent called methods in the the default implementation from the app, while trying to grasp the general workflow.

Additional dependencies

You may find yourself needing additional functionality and wanting to add more dependencies to your build.gradle file. Since extensions are run within the main Tachiyomi app, you can make use of its dependencies.

For example, an extension that needs Gson could add the following:

dependencies {
    compileOnly 'com.google.code.gson:gson:2.8.2'
}

Notice that we're using compileOnly instead of implementation, since the app already contains it. You could use implementation instead, if it's a new dependency, or you prefer not to rely on whatever the main app has (at the expense of app size).

Core stubs and libraries

Duktape stub

duktape-stub provides stubs for using Duktape functionality without pulling in the full library. Functionality is bundled into the main Tachiyomi app.

dependencies {
    compileOnly project(':duktape-stub')
}

Rate limiting library

lib-ratelimit is a library for adding rate limiting functionality.

dependencies {
    implementation project(':lib-ratelimit')
}

Running

To aid in local development, you can use the following run configuration to launch an extension:

If you're running a dev/debug build of Tachiyomi:

-W -S -n eu.kanade.tachiyomi.debug/eu.kanade.tachiyomi.ui.main.MainActivity -a eu.kanade.tachiyomi.SHOW_CATALOGUES

And for a release build of Tachiyomi:

-W -S -n eu.kanade.tachiyomi/eu.kanade.tachiyomi.ui.main.MainActivity -a eu.kanade.tachiyomi.SHOW_CATALOGUES

Debugging

• You are encouraged to clone the app itself and make your own debug build, then you can attach Android Studio's debugger to the app, and then you can print logs in the code and debug your extension using Logcat(link to Android Studio documentation for Logcat)
• Directly debugging your extension(steeping through your extension code) is not possible, but if you keep both projects(tachiyomi and tachiyomi-extensions) open in Android Studio, you can debug the app itself and hence calls to your code.

Building

APKs can be created in Android Studio via Build > Build Bundle(s) / APK(s) > Build APK(s) or Build > Generate Signed Bundle / APK.