Add HTTP respondHtml sugar

docs/lyng.io.http.server.md

@@ -38,6 +38,7 @@ Route handlers use `RequestContext` as the receiver, so inside handlers you norm
 
 - `jsonBody<T>()`
 - `respondJson(...)`
+- `respondHtml { ... }`
 - `respondText(...)`
 - `setHeader(...)`
 - `request.path`
@@ -45,6 +46,41 @@ Route handlers use `RequestContext` as the receiver, so inside handlers you norm
 
 This keeps ordinary HTTP endpoints compact and avoids passing an explicit request or exchange parameter through every route lambda.
 
+## HTML Response Sugar
+
+Use `respondHtml { ... }` to render an HTML document with the `lyng.io.html` DSL and send it as `text/html; charset=utf-8`.
+
+```lyng
+import lyng.io.http.server
+import lyng.io.html
+
+val server = HttpServer()
+
+server.get("/") {
+    respondHtml {
+        head {
+            title { +"Lyng status" }
+        }
+        body {
+            h3 { +"Service is running" }
+            p { +("Path: " + request.path) }
+        }
+    }
+}
+
+server.listen(8080, "127.0.0.1")
+```
+
+Pass `code:` when the route should return a non-200 status:
+
+```lyng
+server.get("/accepted") {
+    respondHtml(code: 202) {
+        body { h3 { +"Accepted" } }
+    }
+}
+```
+
 ## JSON API Sugar
 
 For ordinary JSON APIs, `RequestContext` includes two primary helpers:
@@ -54,25 +90,28 @@ For ordinary JSON APIs, `RequestContext` includes two primary helpers:
 
 These helpers intentionally use ordinary JSON projection for HTTP interop, not canonical `Json.encode(...)`.
 
-### Typed JSON POST
+### Typed JSON POST With Route Params
 
 ```lyng
 import lyng.io.http.server
 
-closed class CreateUserRequest(name: String, age: Int)
+closed class CreateResultRequest(title: String, score: Int)
-closed class CreateUserResponse(id: Int, name: String, age: Int)
+closed class CreateResultResponse(id: String, userId: String, title: String, score: Int)
 
 val server = HttpServer()
 
-server.postPath("/api/users") {
+server.postPath("/api/users/{userId}/results") {
-    val req = jsonBody<CreateUserRequest>()
+    val req = jsonBody<CreateResultRequest>()
 
-    if (req.name.isBlank()) {
+    if (req.title.isBlank()) {
-        respondJson({ error: "name must not be empty" }, 400)
+        respondJson({ error: "title must not be empty" }, 400)
         return
     }
 
-    respondJson(CreateUserResponse(101, req.name, req.age), 201)
+    respondJson(
+        CreateResultResponse("r-101", routeParams["userId"], req.title, req.score),
+        201
+    )
 }
 
 server.listen(8080, "127.0.0.1")
@@ -118,6 +157,7 @@ server.listen(8080, "127.0.0.1")
 - `respond(...)`
 - `respondText(...)`
 - `respondJson(body, status = 200)`
+- `respondHtml(code: 200) { ... }`
 - `setHeader(...)`
 - `addHeader(...)`
 - `acceptWebSocket(...)`

lyngio/src/commonMain/kotlin/net/sergeych/lyng/io/http/server/LyngHttpServerModule.kt

@@ -2,6 +2,7 @@ package net.sergeych.lyng.io.http.server
 
 import kotlinx.serialization.json.Json
 import net.sergeych.lyng.ModuleScope
+import net.sergeych.lyng.Pos
 import net.sergeych.lyng.Scope
 import net.sergeych.lyng.ScopeFacade
 import net.sergeych.lyng.Source
@@ -28,6 +29,7 @@ import net.sergeych.lyng.obj.requiredArg
 import net.sergeych.lyng.obj.thisAs
 import net.sergeych.lyng.io.http.ObjHttpHeaders
 import net.sergeych.lyng.io.http.createHttpTypesModule
+import net.sergeych.lyng.io.html.createHtmlModule
 import net.sergeych.lyng.io.ws.ObjWsMessage
 import net.sergeych.lyng.io.ws.createWsTypesModule
 import net.sergeych.lyng.serialization.ObjJsonClass
@@ -60,6 +62,7 @@ fun createHttpServer(policy: NetAccessPolicy, scope: Scope): Boolean = createHtt
 fun createHttpServerModule(policy: NetAccessPolicy, manager: ImportManager): Boolean {
     createHttpTypesModule(manager)
     createWsTypesModule(manager)
+    createHtmlModule(manager)
     if (manager.packageNames.contains(HTTP_SERVER_MODULE_NAME)) return false
     manager.addPackage(HTTP_SERVER_MODULE_NAME) { module ->
         buildHttpServerModule(module, policy)
@@ -119,6 +122,7 @@ private val regexType = TypeDecl.Simple("Regex", false)
 private val nullableRegexMatchType = TypeDecl.Simple("RegexMatch", true)
 private val voidType = TypeDecl.Simple("Void", false)
 private val httpHeadersType = TypeDecl.Simple("HttpHeaders", false)
+private val htmlTagType = TypeDecl.Simple("HtmlTag", false)
 private val serverRequestType = TypeDecl.Simple("ServerRequest", false)
 private val requestContextType = TypeDecl.Simple("RequestContext", false)
 private val serverWebSocketType = TypeDecl.Simple("ServerWebSocket", false)
@@ -876,6 +880,33 @@ private class ObjServerExchange(
                         self.setHttpResponse(status, bodyText.encodeToByteArray())
                         ObjVoid
                     }
+                    bridgeFn(
+                        this,
+                        "respondHtml",
+                        base.getInstanceMemberOrNull("respondHtml")?.typeDecl as? TypeDecl.Function
+                            ?: fnType(voidType, intType, receiverFnType(htmlTagType, voidType)),
+                        callSignature = receiverCallSignature("HtmlTag")
+                    ) {
+                        val self = thisAs<ObjServerExchange>()
+                        val first = args.list.getOrNull(0)
+                        val second = args.list.getOrNull(1)
+                        val status = args.named["code"]?.let { objToInt(this, it, "code") } ?: when {
+                            first is ObjInt && second != null -> first.value.toInt()
+                            second is ObjInt -> second.value.toInt()
+                            else -> 200
+                        }
+                        val builder = when {
+                            first is ObjInt -> second
+                            else -> first
+                        } ?: raiseIllegalArgument("respondHtml requires a builder")
+                        val htmlModule = requireScope().importManager.createModuleScope(Pos.builtIn, "lyng.io.html")
+                        val htmlFn = htmlModule.get("html")?.value ?: raiseIllegalState("lyng.io.html.html is not available")
+                        val bodyText = (call(htmlFn, Arguments(listOf(builder))) as ObjString).value
+                        self.ensureMutable(this)
+                        self.responseHeaders["Content-Type"] = mutableListOf("text/html; charset=utf-8")
+                        self.setHttpResponse(status, bodyText.encodeToByteArray())
+                        ObjVoid
+                    }
                     bridgeFn(this, "setHeader", fnType(voidType, stringType, stringType)) {
                         val self = thisAs<ObjServerExchange>()
                         val name = requiredArg<ObjString>(0).value

lyngio/src/jvmTest/kotlin/net/sergeych/lyng/io/http/server/LyngHttpServerModuleTest.kt

@@ -315,6 +315,53 @@ class LyngHttpServerModuleTest {
         handle.invokeInstanceMethod(scope, "close")
     }
 
+    @Test
+    fun respondHtmlRendersHtmlDslAndSetsContentType() = runBlocking {
+        val engine = getSystemNetEngine()
+        if (!engine.isSupported || !engine.isTcpAvailable) return@runBlocking
+
+        val scope = Script.newScope()
+        createHttpServerModule(PermitAllNetAccessPolicy, scope)
+
+        val code = """
+            import lyng.io.http.server
+            import lyng.io.html
+
+            val server = HttpServer()
+            server.getPath("/html/{name}") {
+                respondHtml(code: 202) {
+                    head { title { +"Greeting" } }
+                    body {
+                        h3 { +("Hello, " + routeParams["name"]) }
+                    }
+                }
+            }
+            server.listen(0, "127.0.0.1")
+        """.trimIndent()
+
+        val handle = Compiler.compile(code).execute(scope)
+        val port = waitForPort(handle, scope)
+
+        val client = engine.tcpConnect("127.0.0.1", port, 2_000, true)
+        try {
+            client.writeUtf8("GET /html/alice%26bob HTTP/1.1\r\nHost: localhost\r\nConnection: close\r\n\r\n")
+            client.flush()
+            val response = readHttpResponse(client)
+            assertTrue(response.contains("202"), response)
+            assertTrue(response.contains("Content-Type: text/html; charset=utf-8"), response)
+            assertTrue(
+                response.endsWith(
+                    "<!doctype html><html><head><title>Greeting</title></head><body><h3>Hello, alice&amp;bob</h3></body></html>"
+                ),
+                response
+            )
+        } finally {
+            client.close()
+        }
+
+        handle.invokeInstanceMethod(scope, "close")
+    }
+
     @Test
     fun routerMountPreservesBuiltInRoutingSemantics() = runBlocking {
         val engine = getSystemNetEngine()

lyngio/stdlib/lyng/io/http_server.lyng

@@ -3,6 +3,7 @@ package lyng.io.http.server
 import lyng.io.http.types
 import lyng.serialization
 import lyng.io.ws.types
+import lyng.io.html
 
 /* Immutable parsed incoming server request. */
 extern class ServerRequest {
@@ -36,6 +37,7 @@ extern class RequestContext {
     fun respond(status: Int = 200, body: Buffer? = null): void
     fun respondText(status: Int = 200, bodyText: String = ""): void
     fun respondJson(body: Object?, status: Int = 200): void
+    fun respondHtml(code: Int = 200, builder: HtmlTag.()->void): void
     fun setHeader(name: String, value: String): void
     fun addHeader(name: String, value: String): void
     fun acceptWebSocket(handler: RequestContext.(ServerWebSocket) -> Object?): void

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -853,7 +853,16 @@ class Compiler(
             else -> null
         }
         if (name == null) return null
-        val signature = callSignatureForName(name)
+        val signature = when (left) {
+            is ImplicitThisMemberRef -> {
+                val receiverType = left.preferredThisTypeName() ?: implicitReceiverTypeForMember(name)
+                receiverType
+                    ?.let { resolveClassByName(it) }
+                    ?.getInstanceMemberOrNull(name)
+                    ?.callSignature
+            }
+            else -> null
+        } ?: callSignatureForName(name)
         return signature?.tailBlockReceiverType ?: if (name == "flow") "FlowBuilder" else null
     }