Upload path comment does not stand

[Mis1eader-dev]

Describe the bug
In config.example.json it is stated:

upload_path: The path to save the uploaded file. "uploads" by default.
If the path isn't prefixed with /, ./ or ../,
it is relative path of document_root path

However, if I setup a project where I put a relative path to the running context for both document_root and upload_path:

"document_root": "./frontend",
"upload_path": "./confidential/database/uploads"

Drogon creates the uploads folder within the document_root path, ./frontend/confidential/database/uploads. This contradicts with the statement written as a comment in the example.

Expected behavior
Pages should be served in ./frontend, and uploads should be uploaded to ./confidential/database/uploads.

Desktop (please complete the following information):

• OS: Ubuntu

Additional context
Currently it's possible to achieve the desired result with either /home/user/project/confidential/database/uploads or ../confidential/database/uploads.

[Mis1eader-dev]

To add to this, it seems we can't even alias the uploads folder with "locations" configuration.

{
	"app": {
		"document_root": "./frontend",
		"upload_path": "../confidential/database/uploads",
		"locations": [
			{
				"uri_prefix": "/uploads",
				"is_case_sensitive": false,
				"is_recursive": true,
				"alias": "../confidential/database/uploads",
				"filters": [ "UploadsFilter" ]
			}
		]
	}
}

We have to create an HTTP controller and do a file response with the uploads path.

[Mis1eader-dev]

This is the way I had to do it:

#include "drogon/HttpAppFramework.h"
#include "drogon/HttpResponse.h"
#include "drogon/utils/FunctionTraits.h"
#include <functional>
#include <iostream>
#include <string>
#include <string_view>

static constexpr std::string_view
	uploadsPrefix = "/uploads/",
	uploadsPathRegex = "^/uploads/.+";

static_assert(uploadsPathRegex.substr(1).starts_with(uploadsPrefix), "Uploads path and regex must match");

static const std::string uploadsRegex = std::string(uploadsPathRegex);

int main()
{
	drogon::app()
		.registerHandlerViaRegex(::uploadsRegex,
		[](
			const drogon::HttpRequestPtr &req,
			std::function<void(const drogon::HttpResponsePtr &)> &&callback)
		{
			std::string_view uploads = drogon::app().getUploadPath();

			std::string_view path = req->path();
			path.remove_prefix(::uploadsPrefix.size());

			std::string file;
			file.reserve(uploads.size() + 1 + path.size());

			file = uploads;
			file += '/';
			file += path;

			callback(drogon::HttpResponse::newFileResponse(file));
		})
		.loadConfigFile("./config.json")
		.addListener("127.0.0.1", 8080)
		.run();
}

config.json:

{
	"app": {
		"document_root": "./frontend",
		"upload_path": "../confidential/database/uploads"
	}
}