Intro to sbt-web
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The document provides an introduction to sbt-web, a tool for asset handling in Play Framework 2.3, discussing its motivation and advantages over Play's default client-side support. It covers the structure and configuration of sbt projects, error reporting, and various sbt-web plugins for asset management, including integration with Webjars and npm. The content emphasizes the flexibility of sbt-web in adapting to modern JavaScript innovations and enhancing dependency management.
![Just Enough sbt
âą .sbt and .Scala build files
âą Build is an immutable collection of
key-value pairs (String -> T)
âą Tasks are computed settings
âą Assign / override values via :=
Setting[Task[T]]
name := âdemoâ
âą Append / override values via +=, ++=
Setting[T]
libraryDependencies += âorg.webjarsâ % âŠ](https://image.slidesharecdn.com/sbt-web-intro-141016110438-conversion-gate02/85/Intro-to-sbt-web-4-320.jpg)
Intro to sbt-web
- 1. Intro to sbt-web Asset handling in Play 2.3 Marius Soutier! Freelance Scala Developer @mariussoutier
- 2. Motivation âą Playâs client-side support not flexible enough, too opinionated which technologies it supports âą Canât keep up with speed of innovation in the JavaScript world (see JavaScript drinking game) âą If you canât beat âem, join âem Adopt Node APIs and make them run on the JVM at full speed âą Factor out asset handling into sbt plugins to build community independent from Play
- 3. Enter sbt-web sbt sbt-web! Project Layout! Assets! Error Reporting sbt-js-engine! Execute JavaScript in sbt! Trireme / Node / Nashorn sbt-js-task! Write sbt tasks that execute! JavaScript using js-engine! WebJars! Dependency Management sbt-web-driver! Execute DOM-based JavaScript! WebDriver - But letâs focus on sbt-web today -
- 4. Just Enough sbt âą .sbt and .Scala build files âą Build is an immutable collection of key-value pairs (String -> T) âą Tasks are computed settings âą Assign / override values via := Setting[Task[T]] name := âdemoâ âą Append / override values via +=, ++= Setting[T] libraryDependencies += âorg.webjarsâ % âŠ
- 5. Scopes âą Settings are scoped by project, configuration, or task; default configuration is Global âą Reuse existing settings and scope them for your needs compile in Compile compile in Test sourceDirectory in (Compile, packageBin)
- 6. Setting Dependencies target webTarget staging Directory Settings depend on other settings Eases making small changes target/web/stage/ target := âtargetâ webTarget := target.value / âwebâ webStaging := webTarget.value / âstageâ Global Configuration
- 7. Inspecting settings âą show <setting-key> to check the value of a setting or result of a task âą inspect <setting-key> to understand settingâs hierarchy and dependencies âą Use the key, not the name of the val in code âą Access scoped settings via <scope>:<setting-key>
- 8. Default Project Layout - Play overrides src/main to app -
- 9. public Global webTarget Test Assets Directories Assets Plugin source Directory source Managed resource Directory resource Managed webModules Lib nodeModule Directory webModule Directory nodeModule Directory public source Directory source Managed resource Directory resource Managed webModule Directory nodeModule Directory staging Directory
- 10. Test Assets Tasks Assets assets Global node Modules web Modules webJars stage pipeline assets assets ⊠compile compile test
- 11. Source Tasks Compile sources to public assets Analyze sources Integrates with error reporting CoffeeScript *.coffee JavaScript LESS *.less CSS src/main/assets/ target/ web/ public/ sourceDirectory in Assets public in Assets sources in Assets resources-managed/ main/ resourceManaged in Assets
- 12. Asset Pipeline Input Assets Name Hashing (digest) GZip Output Assets Tasks operating on assets sequentially Each stage operates on mappings and passes to next one pipelineStages := Seq(digest, gzip) Playâs Assets router is aware of both digested and gzipped assets
- 13. Source Plugins sbt-coffeescript Convert CoffeeScript to JavaScript sbt-jshint JavaScript linting sbt-stylus CSS preprocessor sbt-less CSS preprocessor sbt-mocha Server-Side JS Testing sbt-scalajs Convert ScalaJS to JavaScript (TODO)
- 14. Asset Plugins sbt-digest Fingerprinting sbt-gzip Gzip assets sbt-rjs RequireJS integration, minify JavaScript sbt-uglify Minify/uglify JavaScript (without RequireJS)
- 15. WebJars âą Client-side dependency management, including transitive dependencies âą Packed in Jars, resolved like normal dependencies by sbt libraryDependencies += "org.webjars" % "bootstrap" % "3.2.0" âą sbt-web auto-extracts WebJars to target/web/web-modules/lib âą Mapped to jsDelivr CDN automatically by Playâs Assets controller âą Assets in sub-projects are exported as a WebJar
- 16. NPM âą Node Package Manager âą Becoming popular for client-side dependencies âą js-engine resolves and auto-extracts dependencies defined in package.json âą Disclaimer: Does not seem to work 100% yet
- 17. Writing sbt-web tasks - Demo -