From 153d2d9fe44a8993da94ebc513e7b520f0b7eea8 Mon Sep 17 00:00:00 2001
From: Ruben Verborgh <ruben@verborgh.org>
Date: Tue, 26 Jan 2021 10:30:05 +0100
Subject: [PATCH] feat: Set Accept-Patch header.

---
 config/presets/ldp/response-writer.json        | 4 ++++
 config/presets/middleware.json                 | 1 +
 test/integration/LdpHandlerWithoutAuth.test.ts | 1 +
 test/integration/Middleware.test.ts            | 6 ++++++
 4 files changed, 12 insertions(+)

diff --git a/config/presets/ldp/response-writer.json b/config/presets/ldp/response-writer.json
index 57c6b5183..3a474dd16 100644
--- a/config/presets/ldp/response-writer.json
+++ b/config/presets/ldp/response-writer.json
@@ -8,6 +8,10 @@
         {
           "@type": "ConstantMetadataWriter",
           "ConstantMetadataWriter:_headers": [
+            {
+              "ConstantMetadataWriter:_headers_key": "Accept-Patch",
+              "ConstantMetadataWriter:_headers_value": "application/sparql-update"
+            },
             {
               "ConstantMetadataWriter:_headers_key": "MS-Author-Via",
               "ConstantMetadataWriter:_headers_value": "SPARQL"
diff --git a/config/presets/middleware.json b/config/presets/middleware.json
index e82f72ebf..6aa2c9be3 100644
--- a/config/presets/middleware.json
+++ b/config/presets/middleware.json
@@ -18,6 +18,7 @@
           ],
           "CorsHandler:_options_credentials": true,
           "CorsHandler:_options_exposedHeaders": [
+            "Accept-Patch",
             "Location",
             "MS-Author-Via",
             "Updates-Via"
diff --git a/test/integration/LdpHandlerWithoutAuth.test.ts b/test/integration/LdpHandlerWithoutAuth.test.ts
index cb137aa13..492f7ac67 100644
--- a/test/integration/LdpHandlerWithoutAuth.test.ts
+++ b/test/integration/LdpHandlerWithoutAuth.test.ts
@@ -81,6 +81,7 @@ describe.each(stores)('An LDP handler without auth using %s', (name, { storeUrn,
     expect(response.statusCode).toBe(200);
     expect(response._getBuffer().toString()).toContain('TESTFILE0');
     expect(response.getHeaders().link).toBe(`<${LDP.Resource}>; rel="type"`);
+    expect(response.getHeaders()['accept-patch']).toBe('application/sparql-update');
     expect(response.getHeaders()['ms-author-via']).toBe('SPARQL');
 
     // DELETE
diff --git a/test/integration/Middleware.test.ts b/test/integration/Middleware.test.ts
index 19f569b0c..323260043 100644
--- a/test/integration/Middleware.test.ts
+++ b/test/integration/Middleware.test.ts
@@ -86,6 +86,12 @@ describe('An Express server with middleware', (): void => {
     expect(res.header).toEqual(expect.objectContaining({ 'access-control-allow-origin': 'test.com' }));
   });
 
+  it('exposes the Accept-Patch header via CORS.', async(): Promise<void> => {
+    const res = await request(server).get('/').expect(200);
+    const exposed = res.header['access-control-expose-headers'];
+    expect(exposed.split(/\s*,\s*/u)).toContain('Accept-Patch');
+  });
+
   it('exposes the Location header via CORS.', async(): Promise<void> => {
     const res = await request(server).get('/').expect(200);
     const exposed = res.header['access-control-expose-headers'];