test(HTTP): add case-insensitive header matching tests

Add comprehensive tests for RFC 7230 compliance (header field names
are case-insensitive):

- HTTPReq: GetHeader, GetNumHeaders, UpdateHeader, RemoveHeader
- HTTPRes: content_length(), is_chunked(), is_gzipped(), add_header,
  del_header, to_string() duplicate prevention

These tests currently fail and document the expected behavior.

tests/test-http-req.cpp

@@ -83,6 +83,59 @@ int main() {
   assert(req->GetHeader("Accept-Encoding") == "");
   delete req;
 
+  /* test: case-insensitive header matching (RFC 7230) */
+  buf =
+    "GET / HTTP/1.1\r\n"
+    "HOST: example.i2p\r\n"
+    "content-type: text/html\r\n"
+    "Content-Length: 100\r\n"
+    "X-Custom-Header: value\r\n"
+    "\r\n";
+  len = strlen(buf);
+  req = new HTTPReq;
+  assert((ret = req->parse(buf, len)) == len);
+  /* GetHeader should be case-insensitive */
+  assert(req->GetHeader("Host") == "example.i2p");
+  assert(req->GetHeader("host") == "example.i2p");
+  assert(req->GetHeader("HOST") == "example.i2p");
+  assert(req->GetHeader("Content-Type") == "text/html");
+  assert(req->GetHeader("content-type") == "text/html");
+  assert(req->GetHeader("CONTENT-TYPE") == "text/html");
+  assert(req->GetHeader("Content-Length") == "100");
+  assert(req->GetHeader("content-length") == "100");
+  assert(req->GetHeader("x-custom-header") == "value");
+  assert(req->GetHeader("X-CUSTOM-HEADER") == "value");
+  /* GetNumHeaders should be case-insensitive */
+  assert(req->GetNumHeaders("Host") == 1);
+  assert(req->GetNumHeaders("host") == 1);
+  assert(req->GetNumHeaders("HOST") == 1);
+  assert(req->GetNumHeaders("content-type") == 1);
+  delete req;
+
+  /* test: UpdateHeader case-insensitivity */
+  req = new HTTPReq;
+  req->AddHeader("Content-Type", "text/plain");
+  assert(req->GetHeader("Content-Type") == "text/plain");
+  req->UpdateHeader("content-type", "application/json");
+  assert(req->GetHeader("Content-Type") == "application/json");
+  assert(req->GetHeader("CONTENT-TYPE") == "application/json");
+  req->UpdateHeader("CONTENT-TYPE", "text/html");
+  assert(req->GetHeader("content-type") == "text/html");
+  delete req;
+
+  /* test: RemoveHeader case-insensitivity */
+  req = new HTTPReq;
+  req->AddHeader("X-Forwarded-For", "1.2.3.4");
+  req->AddHeader("X-Forwarded-Host", "proxy.i2p");
+  req->AddHeader("Accept", "*/*");
+  assert(req->GetNumHeaders() == 3);
+  /* remove headers starting with "x-forwarded" (case-insensitive), exempt "X-Forwarded-Host" */
+  req->RemoveHeader("X-Forwarded", "x-forwarded-host");
+  assert(req->GetNumHeaders() == 2);
+  assert(req->GetHeader("X-Forwarded-Host") == "proxy.i2p");
+  assert(req->GetHeader("X-Forwarded-For") == "");
+  delete req;
+
   return 0;
 }
 

tests/test-http-res.cpp

@@ -44,6 +44,74 @@ int main() {
   res->add_header("Content-Length", "0");
   assert(res->to_string() == buf);
 
+  /* test: case-insensitive header parsing (RFC 7230) */
+  buf =
+    "HTTP/1.1 200 OK\r\n"
+    "content-type: text/html\r\n"
+    "CONTENT-LENGTH: 42\r\n"
+    "transfer-encoding: chunked\r\n"
+    "content-encoding: gzip\r\n"
+    "\r\n";
+  len = strlen(buf);
+  res = new HTTPRes;
+  assert((ret = res->parse(buf, len)) == len);
+  assert(res->code == 200);
+  /* content_length() should work with any case */
+  assert(res->content_length() == 42);
+  /* is_chunked() should work with any case */
+  assert(res->is_chunked() == true);
+  /* is_gzipped() should work with any case */
+  assert(res->is_gzipped() == true);
+  delete res;
+
+  /* test: add_header case-insensitivity (no duplicates) */
+  res = new HTTPRes;
+  res->add_header("Content-Type", "text/plain");
+  res->add_header("content-type", "text/html"); /* should not add duplicate */
+  assert(res->headers.size() == 1);
+  res->add_header("content-type", "application/json", true); /* replace=true */
+  assert(res->headers.size() == 1);
+  delete res;
+
+  /* test: del_header case-insensitivity */
+  res = new HTTPRes;
+  res->add_header("X-Custom-Header", "value");
+  assert(res->headers.size() == 1);
+  res->del_header("x-custom-header");
+  assert(res->headers.size() == 0);
+  delete res;
+
+  /* test: to_string() doesn't add duplicate Date/Content-Length with different case */
+  res = new HTTPRes;
+  res->version = "HTTP/1.1";
+  res->code = 200;
+  res->status = "OK";
+  res->add_header("date", "Thu, 01 Jan 1970 00:00:00 GMT");
+  res->add_header("content-length", "0");
+  res->body = "";
+  std::string response = res->to_string();
+  /* should not have duplicate headers */
+  size_t date_count = 0, pos = 0;
+  while ((pos = response.find("ate:", pos)) != std::string::npos) {
+    date_count++;
+    pos++;
+  }
+  assert(date_count == 1); /* only one Date header */
+  delete res;
+
+  /* test: get_header case-insensitivity (used by Reseed for Location redirect) */
+  buf =
+    "HTTP/1.1 302 Found\r\n"
+    "location: https://example.com/new\r\n"
+    "\r\n";
+  len = strlen(buf);
+  res = new HTTPRes;
+  assert((ret = res->parse(buf, len)) == len);
+  assert(res->get_header("Location") == "https://example.com/new");
+  assert(res->get_header("location") == "https://example.com/new");
+  assert(res->get_header("LOCATION") == "https://example.com/new");
+  delete res;
+
   return 0;
 }