Split preview server output at the first blank line

2 files changed, 96 insertions, 0 deletions

diff --git a/tests/serve-split-check.py b/tests/serve-split-check.py
new file mode 100644
index 0000000..63c8f97
--- /dev/null
+++ b/tests/serve-split-check.py
@@ -0,0 +1,76 @@
+"""Check that tools/serve.py splits a CGI response at the right place.
+
+A CGI response ends its header block at the first blank line. cgit writes its
+own headers with bare LF endings, so a body carrying a CRLF blank line, which
+any commit message written on DOS does, must not be mistaken for that end.
+Getting it wrong takes the document head into the header block, and the page
+that reaches the browser then has no stylesheet and no chrome. Run with the
+repository root as the only argument.
+"""
+
+import importlib.util
+import sys
+
+
+def load_serve(root):
+    path = root + "/tools/serve.py"
+    spec = importlib.util.spec_from_file_location("serve", path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def main():
+    split = load_serve(sys.argv[1]).split_cgi_output
+    cases = (
+        (
+            "bare LF headers, CRLF blank line inside the body",
+            b"Content-Type: text/html\n\n<!DOCTYPE html>\nmsg\r\n\r\ntail",
+            200,
+            [("Content-Type", "text/html")],
+            b"<!DOCTYPE html>\nmsg\r\n\r\ntail",
+        ),
+        (
+            "CRLF headers, LF blank line inside the body",
+            b"Content-Type: text/plain\r\nX: y\r\n\r\nline\n\nline2",
+            200,
+            [("Content-Type", "text/plain"), ("X", "y")],
+            b"line\n\nline2",
+        ),
+        (
+            "a status line is taken off the headers",
+            b"Status: 404 Not Found\nContent-Type: text/html\n\nnope",
+            404,
+            [("Content-Type", "text/html")],
+            b"nope",
+        ),
+        (
+            "an empty body survives, as a redirect leaves one",
+            b"Status: 302 Found\nLocation: /x\n\n",
+            302,
+            [("Location", "/x")],
+            b"",
+        ),
+        (
+            "output with no blank line at all is all headers",
+            b"Content-Type: text/html\n",
+            200,
+            [("Content-Type", "text/html")],
+            b"",
+        ),
+    )
+
+    failed = 0
+    for name, raw, status, headers, body in cases:
+        got = split(raw)
+        if (got.status, got.headers, got.body) == (status, headers, body):
+            continue
+        failed += 1
+        sys.stderr.write(
+            "%s\n  expected %r\n  got      %r\n"
+            % (name, (status, headers, body), (got.status, got.headers, got.body))
+        )
+    return 1 if failed else 0
+
+
+sys.exit(main())
diff --git a/tests/t0300-serve.sh b/tests/t0300-serve.sh
new file mode 100755
index 0000000..513c33a
--- /dev/null
+++ b/tests/t0300-serve.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+# Checks how tools/serve.py, the preview server that runs the built binary and
+# hands its output back over HTTP, tells the CGI headers from the body. That
+# split once keyed on the wrong blank line and swallowed the document head,
+# which left a page that still validated but arrived with no stylesheet and no
+# chrome. The cases live in serve-split-check.py beside this file.
+
+test_description='Check the preview server splits CGI output correctly'
+. ./setup.sh
+
+if ! command -v python3 >/dev/null 2>&1; then
+	test_done
+fi
+
+test_expect_success 'CGI headers and body are split at the first blank line' '
+	python3 "$PWD/../serve-split-check.py" "$PWD/../.."
+'
+
+test_done