Add Global Path Prefix Setter

[Dup4]

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I've checked all the interfaces in the HttpAppFramework and there doesn't seem to be an interface for setting the global path prefix.

This becomes important when we need to deploy an application to a sub-path of a domain, and we need to change this part of the prefix through the configuration.

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like NestJS:

https://docs.nestjs.com/faq/global-prefix

[Dup4]

Temporarily, I can add an advice to achieve this.

For instance:

auto add_global_path_prefix_advice = [this](const HttpRequestPtr& req) {
    auto path_prefix = config_->http_global_path_prefix_;
    if (path_prefix.empty()) {
        return;
    }

    const auto& current_path = req->getPath();
    if (current_path.length() < path_prefix.length()) {
        return;
    }

    auto head_path = current_path.substr(0, path_prefix.length());
    if (head_path != path_prefix) {
        return;
    }

    auto after_path = current_path.substr(path_prefix.length());
    req->setPath(after_path);
};

app().registerPreRoutingAdvice(add_global_path_prefix_advice);

[hwc0919]

Adding a pre-routing advice is actually a good solution. You can make it a plugin, in that case you can easily enable/disable the feature and change configs.