Add relative routing path support (#166)

Co-authored-by: hfhbd <[email protected]>

Author: hfhbd

integrationTest/src/jsMain/kotlin/demo.kt

@@ -71,6 +71,10 @@ fun RouteBuilder.Users() {
         NavLink(to = "/") {
             Text("Go back to main page")
         }
+        Br()
+        NavLink(to = "./answer") {
+            Text("Relative route to ./answer")
+        }
     }
 }
 

src/commonMain/kotlin/app/softwork/routingcompose/Path.kt

@@ -1,7 +1,24 @@
 package app.softwork.routingcompose
 
-internal data class Path(val path: String, val parameters: Parameters?) {
-    fun newPath(currentPath: String) = Path(path = path.removePrefix("/$currentPath"), parameters)
+public data class Path(val path: String, val parameters: Parameters?) {
+    internal fun newPath(currentPath: String) = Path(path = path.removePrefix("/$currentPath"), parameters)
+
+    /**
+     * https://datatracker.ietf.org/doc/html/rfc1808
+     */
+    internal fun relative(to: String): Path {
+        val paths = path.split("/")
+        val split = to.split("./")
+        val result = split.last().let {
+            if (it.isNotEmpty()) "/$it" else it
+        }
+        val number = split.count() - 1
+        return from(
+            paths.dropLast(number).joinToString(postfix = result, separator = "/") {
+                it
+            }
+        )
+    }
 
     internal companion object {
         fun from(rawPath: String): Path {
@@ -10,9 +27,11 @@ internal data class Path(val path: String, val parameters: Parameters?) {
                 1 -> {
                     pathAndQuery.first() to null
                 }
+
                 2 -> {
                     pathAndQuery.first() to pathAndQuery.last().let { Parameters.from(it) }
                 }
+
                 else -> {
                     error("path contains more than 1 '?' delimiter: $rawPath")
                 }
@@ -29,5 +48,5 @@ internal data class Path(val path: String, val parameters: Parameters?) {
         "$path?$parameters"
     }
 
-    val currentPath get() = path.removePrefix("/").takeWhile { it != '/' }
+    internal val currentPath get() = path.removePrefix("/").takeWhile { it != '/' }
 }

src/commonMain/kotlin/app/softwork/routingcompose/RouteBuilder.kt

@@ -162,6 +162,10 @@ private class DelegatingRouter(val basePath: String, val router: Router) : Route
             basePath == "/" -> {
                 router.navigate("/$to", hide)
             }
+            to.startsWith(".") -> {
+                val newPath = router.currentPath.relative(to)
+                router.navigate(newPath.path)
+            }
             else -> {
                 router.navigate("$basePath/$to", hide)
             }

src/commonMain/kotlin/app/softwork/routingcompose/Router.kt

@@ -7,7 +7,7 @@ public interface Router {
     /**
      * The current path
      */
-    public val currentPath: String
+    public val currentPath: Path
 
     public fun navigate(to: String, hide: Boolean = false)
 

src/commonTest/kotlin/app/softwork/routingcompose/MockRouter.kt

@@ -3,8 +3,8 @@ package app.softwork.routingcompose
 import androidx.compose.runtime.*
 
 class MockRouter : Router {
-    override val currentPath: String
-        get() = currentState.value!!
+    override val currentPath: Path
+        get() = Path.from(currentState.value!!)
 
     private val currentState = mutableStateOf<String?>(null)
 

src/commonTest/kotlin/app/softwork/routingcompose/PathTest.kt

@@ -9,4 +9,14 @@ class PathTest {
         assertEquals(Path("/a", null), Path.from(prefixPath))
         assertEquals(Path("/a", null), Path.from("a"))
     }
+
+    @Test
+    fun relative() {
+        val base = Path.from("/a/b/c/d")
+        assertEquals("/a/b/c", base.relative("./").path)
+        assertEquals("/a/b", base.relative("././").path)
+        assertEquals("/a/b/g", base.relative("././g").path)
+
+        assertEquals("/a/b/g?foo=bar", base.relative("././g?foo=bar").toString())
+    }
 }

src/jsMain/kotlin/app/softwork/routingcompose/BrowserRouter.kt

@@ -30,8 +30,8 @@ public fun BrowserRouter(
 }
 
 public class BrowserRouter : Router {
-    override val currentPath: String
-        get() = currentLocation.value
+    override val currentPath: Path
+        get() = Path.from(currentLocation.value)
 
     private val currentLocation: MutableState<String> = mutableStateOf(window.location.newPath())
 

src/jsMain/kotlin/app/softwork/routingcompose/HashRouter.kt

@@ -18,8 +18,8 @@ public fun HashRouter(
 }
 
 public class HashRouter : Router {
-    override val currentPath: String
-        get() = currentHash.value
+    override val currentPath: Path
+        get() = Path.from(currentHash.value)
 
     private val currentHash: MutableState<String> = mutableStateOf(window.location.hash.currentURL(null))
 

src/jsMain/kotlin/app/softwork/routingcompose/NavLink.kt

@@ -20,7 +20,7 @@ public fun NavLink(
     A(
         attrs = {
             attrs?.invoke(this)
-            if (router.currentPath.startsWith(to.removePrefix("/"))) {
+            if (router.currentPath.path.startsWith(to.removePrefix("/"))) {
                 classes("active")
             }
             onClick {

src/jvmMain/kotlin/app/softwork/routingcompose/DesktopRouter.kt

@@ -3,8 +3,8 @@ package app.softwork.routingcompose
 import androidx.compose.runtime.*
 
 public class DesktopRouter private constructor() : Router {
-    override val currentPath: String
-        get() = stack.last().path
+    override val currentPath: Path
+        get() = Path.from(stack.last().path)
 
     private data class Entry(val path: String, val hide: Boolean)
     private val stack = mutableStateListOf<Entry>()