Define protocol update as a Gradle task instead of script

This avoids having to setup kotlin in Github Actions
(which currently has this problem: fwilhe2/setup-kotlin#85).

.github/workflows/update-protocol.yml

@@ -18,21 +18,6 @@ jobs:
         with:
           java-version: 11
 
-      - name: Set up Kotlin
-        uses: fwilhe2/[email protected]
-        with:
-          version: 1.4.20
-
-      - name: Update protocol
-        run: kotlinc -script update-protocol.kts
-
-      - name: Read protocol version
-        uses: pCYSl5EDgo/cat@master
-        id: version
-        with:
-          path: protocol/version.txt
-          trim: true
-
       - name: Gradle build cache
         uses: actions/[email protected]
         with:
@@ -46,6 +31,16 @@ jobs:
           path: ~/.gradle/wrapper
           key: ${{ runner.os }}-gradle-wrapper-${{ hashFiles('**/gradle-wrapper.properties') }}
 
+      - name: Update protocol
+        run: ./gradlew updateProtocolDefinitions
+
+      - name: Read protocol version
+        uses: pCYSl5EDgo/cat@master
+        id: version
+        with:
+          path: protocol/version.txt
+          trim: true
+
       - name: Update public ABI descriptors
         run: ./gradlew apiDump
 

build.gradle.kts

@@ -51,6 +51,8 @@ kotlin {
     }
 }
 
+val updateProtocolDefinitions by tasks.registering(org.hildan.chrome.devtools.build.UpdateProtocolDefinitionsTask::class)
+
 val generateProtocolApi by tasks.registering(org.hildan.chrome.devtools.build.GenerateProtocolApiTask::class)
 
 tasks {

buildSrc/src/main/kotlin/UpdateProtocolDefinitionsTask.kt

@@ -0,0 +1,54 @@
+package org.hildan.chrome.devtools.build
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.TaskAction
+import java.net.URL
+import java.nio.file.Files
+import java.nio.file.Path
+
+private const val baseUrl = "https://raw.githubusercontent.com/ChromeDevTools/devtools-protocol"
+private const val branch = "master"
+private const val browserProtocolUrl = "$baseUrl/$branch/json/browser_protocol.json"
+private const val jsProtocolUrl = "$baseUrl/$branch/json/js_protocol.json"
+private const val packageJsonUrl = "$baseUrl/$branch/package.json"
+
+private val protocolDescriptorUrls = listOf(browserProtocolUrl, jsProtocolUrl)
+
+open class UpdateProtocolDefinitionsTask : DefaultTask() {
+
+    init {
+        // never consider this task up-to-date, the point is to check for updates
+        outputs.upToDateWhen { false }
+    }
+
+    @OutputDirectory
+    val outputDir: Path = project.rootDir.resolve("protocol").toPath()
+
+    @TaskAction
+    fun generate() {
+        Files.createDirectories(outputDir)
+
+        protocolDescriptorUrls.forEach { url ->
+            print("Downloading protocol JSON spec from $url ... ")
+            downloadTextFile(url, outputDir)
+            println("Done.")
+        }
+
+        val newVersion = fetchProtocolNpmVersion()
+        outputDir.resolve("version.txt").toFile().writeText(newVersion)
+        println("Chrome Devtools Protocol definition updated to $newVersion")
+    }
+}
+
+private fun fetchProtocolNpmVersion(): String {
+    val packageJson = URL(packageJsonUrl).readText()
+    return Regex(""""version"\s*:\s*"([^"]+)"""").find(packageJson)?.groupValues?.get(1) ?: "not-found"
+}
+
+private fun downloadTextFile(fileUrl: String, targetDir: Path) {
+    val url = URL(fileUrl)
+    val text = url.readText()
+    val outputFilePath = targetDir.resolve(url.path.substringAfterLast('/'))
+    outputFilePath.toFile().writeText(text)
+}