feat: add the "addTrailingSlash" option (#655)

The "addTrailingSlash" option allows to control whether a trailing
slash is added to the path of the HTTP requests:

- true (default): "/engine.io/"
- false: "/engine.io"

Related: socketio/engine.io-client@21a6e12

Signed-off-by: iifawzi <iifawzie@gmail.com>

lib/server.ts

@@ -31,6 +31,12 @@ export interface AttachOptions {
    * @default 1000
    */
   destroyUpgradeTimeout?: number;
+
+  /**
+   * Whether we should add a trailing slash to the request path.
+   * @default true
+   */
+  addTrailingSlash?: boolean;
 }
 
 export interface ServerOptions {
@@ -181,6 +187,22 @@ export abstract class BaseServer extends EventEmitter {
 
   protected abstract init();
 
+  /**
+   * Compute the pathname of the requests that are handled by the server
+   * @param options
+   * @protected
+   */
+  protected _computePath(options: AttachOptions) {
+    let path = (options.path || "/engine.io").replace(/\/$/, "");
+
+    if (options.addTrailingSlash !== false) {
+      // normalize path
+      path += "/";
+    }
+
+    return path;
+  }
+
   /**
    * Returns a list of available transports for upgrade given a certain transport.
    *
@@ -635,14 +657,11 @@ export class Server extends BaseServer {
    * @api public
    */
   public attach(server: HttpServer, options: AttachOptions = {}) {
-    let path = (options.path || "/engine.io").replace(/\/$/, "");
-
+    const path = this._computePath(options);
     const destroyUpgradeTimeout = options.destroyUpgradeTimeout || 1000;
 
-    // normalize path
-    path += "/";
-
     function check(req) {
+      // TODO use `path === new URL(...).pathname` in the next major release (ref: https://nodejs.org/api/url.html)
       return path === req.url.slice(0, path.length);
     }
 

lib/userver.ts

@@ -65,7 +65,7 @@ export class uServer extends BaseServer {
     app /* : TemplatedApp */,
     options: AttachOptions & uOptions = {}
   ) {
-    const path = (options.path || "/engine.io").replace(/\/$/, "") + "/";
+    const path = this._computePath(options);
     (app as TemplatedApp)
       .any(path, this.handleRequest.bind(this))
       //

test/server.js

@@ -745,6 +745,36 @@ describe("server", () => {
         });
       });
     });
+
+    it("should support requests without trailing slash", done => {
+      listen({ addTrailingSlash: false }, port => {
+        const partialDone = createPartialDone(done, 2);
+
+        request
+          .get(`http://localhost:${port}/engine.io`)
+          .query({ transport: "polling" })
+          .end((err, res) => {
+            expect(err).to.be(null);
+            expect(res.status).to.be(200);
+            partialDone();
+          });
+
+        request
+          .get(`http://localhost:${port}/engine.io/foo/bar/`)
+          .query({ transport: "polling" })
+          .end((err, res) => {
+            if (process.env.EIO_WS_ENGINE === "uws") {
+              expect(err).to.not.be(null);
+              expect(err.message).to.be("socket hang up");
+            } else {
+              expect(err).to.be(null);
+              // this should not work, but it is kept for backward-compatibility
+              expect(res.status).to.be(200);
+            }
+            partialDone();
+          });
+      });
+    });
   });
 
   describe("close", () => {