From 073975db86e82308389b42961065d3df40ffdd97 Mon Sep 17 00:00:00 2001
From: Vano Devium <webdevium@gmail.com>
Date: Thu, 24 Oct 2019 15:22:29 +0300
Subject: [PATCH] Added support for path parameters

---
 README.md        | 12 +++++++++++-
 example/index.ts |  2 ++
 mod.ts           | 33 +++++++++++++++++++++++++++++++--
 serve_test.ts    | 21 +++++++++++++++++++++
 4 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 8d3754f..72ec152 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,8 @@ import {
 
 app(
   get('/hello', () => 'hello'),
+  get('/hello/:id', ({ params }) => params.id),
+  get('/hello/:id/and/:name', ({ params }) => `:id is ${params.id}, :name is ${params.name}`),
   get('/error', () => [500, 'an error has occured']),
   get('/callName', ({ params }) => `Hi, ${params.name}!`),
   post('/callName', ({ params }) => `Hi, ${params.name}!`),
@@ -39,6 +41,14 @@ curl http://localhost:8080/hello
 # status: 200
 # body: hello
 
+curl http://localhost:8080/hello/1
+# status: 200
+# body: 1
+
+curl http://localhost:8080/hello/1/and/John
+# status: 200
+# body: :id is 1, :name is John
+
 curl http://localhost:8080/error
 # status: 500
 # body: an error has occured
@@ -160,7 +170,7 @@ interface HTTPResponse {
 ### Request Params
 
 - [x] URL query params (for GET)
-- [ ] route params (like: `/users/:user_id/posts`)
+- [x] route params (like: `/users/:user_id/posts`)
 - [x] x-www-form-urlencoded
 - [x] application/json
 
diff --git a/example/index.ts b/example/index.ts
index f8b95f5..1479106 100644
--- a/example/index.ts
+++ b/example/index.ts
@@ -2,6 +2,8 @@ import { app, get, post, contentType } from '../mod.ts';
 
 app(
   get('/hello', () => 'hello'),
+  get('/hello/:id', ({ params }) => params.id),
+  get('/hello/:id/and/:name', ({ params }) => `:id is ${params.id}, :name is ${params.name}`),
   get('/error', () => [500, 'an error has occured']),
   get('/callName', ({ params }) => `Hi, ${params.name}!`),
   post('/callName', ({ params }) => `Hi, ${params.name}!`),
diff --git a/mod.ts b/mod.ts
index 8d6e52c..2d69072 100644
--- a/mod.ts
+++ b/mod.ts
@@ -87,12 +87,41 @@ export class App {
       return null;
     }
 
-    const handler = map.get(path);
+    const params: Params = {};
+
+    let handler;
+
+    const REGEX_URI_MATCHES = /(:[^/]+)/g;
+    const REGEX_URI_REPLACEMENT = "([^/]+)";
+    const URI_PARAM_MARKER = ':';
+
+    Array.from(map.keys()).forEach((endpoint) => {
+      if (endpoint.indexOf(URI_PARAM_MARKER) !== -1) {
+        const matcher = endpoint.replace(REGEX_URI_MATCHES, REGEX_URI_REPLACEMENT);
+        const matches = path.match(`^${matcher}$`);
+
+        if (matches === null) {
+          return
+        }
+
+        const names = endpoint.match(REGEX_URI_MATCHES).map(name => name.replace(URI_PARAM_MARKER, ''));
+
+        matches.slice(1).forEach((m, i) => {
+          params[names[i]] = m
+        });
+
+        handler = map.get(endpoint)
+      }
+    });
+
+    if (!handler) {
+      handler = map.get(path)
+    }
+
     if (!handler) {
       return null;
     }
 
-    const params: Params = {};
     if (method === Method.GET) {
       if (search) {
         Object.assign(params, parseURLSearchParams(search));
diff --git a/serve_test.ts b/serve_test.ts
index cecf17c..b8acb61 100644
--- a/serve_test.ts
+++ b/serve_test.ts
@@ -35,6 +35,27 @@ const testCases: Array<testCase> = [
     method: Method.GET,
     expected: 'basic',
   },
+  {
+    name: 'valid basic handler with path parameter',
+    registered: get('/parameters/:param', ({ params }) => params.param),
+    path: 'parameters/p',
+    method: Method.GET,
+    expected: 'p',
+  },
+  {
+    name: 'valid basic handler with path parameters',
+    registered: get('/parameters/:param1/:param2', ({ params }) => `${params.param1} ${params.param2}`),
+    path: 'parameters/p1/p2',
+    method: Method.GET,
+    expected: 'p1 p2',
+  },
+  {
+    name: 'valid basic handler with path parameter at start',
+    registered: get('/:param', ({ params }) => params.param),
+    path: 'basic',
+    method: Method.GET,
+    expected: 'basic',
+  },
   {
     name: 'valid async handler',
     registered: get('/async', async () => 'async'),