Re: [boost] [beast] Request for Discussion

On Wed, Sep 28, 2016 at 8:39 PM, David Sankel wrote:

Your investigation into creating a higher level interface, despite your own reluctance to do so, is very much appreciated.

Thanks!

I think that the io_service object should not be hidden with a higher-level interface.

Yep, and that's a mistake that websocketpp made. For both a client and a server, it should be possible for: 1. The caller to provide an io_service with its own threads if they want 2. A choice of using an implicit strand: just one thread in the io_service pool), or an explicit strand (e.g. io_service::strand wrapper equivalent). 3.Some struct tag or construction option that provides an io_service with some reasonable default threading policy, so the caller doesn't have to bother with it at all.

I don't think a synchronous interface is necessary.

Probably true. A synchronous interface would require a redundant code path.

I'd be happy to work with you on creating a proposed higher level interface that I think would stand a chance at WG21. It may improve consensus for the Boost review, but if it has the opposite effect we could just rip it out. What do you think?

There's a lot of merit to a team effort for building a good design. However, I'm not sure that I want to broaden the scope of Beast's current interfaces. Other individuals have tried to create these high level interfaces, and they have all failed review. There was a recent claim in the mailing list that some individual could have written a high quality HTTP client if they wanted to - then why didn't they? We've certainly gone long enough without basic HTTP functionality available with a sensible interface. I think Beast has a better chance if it keeps its scope limited to just the low level protocol. Despite this limited scope, it still provides a useful building block - and one that we need. With respect to a high level client interface, I have to be honest, reading the Python Requests documentation really spoiled me. In a way, its a good thing because I now realize that my own individual effort and resources at producing a client would fall far short of Python Requests - so I'm not wasting any of my energy on that anymore. When I imagine what the most awesome C++ HTTP client library could look like, it looks like Python Requests. I don't think we should reinvent the wheel here, when some folks have already done most of the heavy lifting for us. A C++, full featured HTTP client implementation should be closely modeled after Python Requests. The cool thing about this, is that someone has already created such an interface. It is Huu Nguyen, the author of "C++ Requests: Curl for People". And the repository is here: https://github.com/whoshuu/cpr I reached out to the author and he related to me that his ambition is to iterate on this library to produce a version that does not have curl as a dependency. I think the most productive use of development energies with respect to building a high level HTTP client would go towards supporting the refinement of this library, or if the author does not have the resources then to examine his interface and use it as a model for creating such a library (using Beast for the protocol level support). On the subject of a turn-key generic HTTP server I think there are more possibilities that I could put something together. We have a use case for it at Ripple, and the amount of work to write a server is far less than writing a full featured client. One caveat, when I talk about writing a server I am talking about a low level server. I don't have the knowledge or resources to include features like server side multi-part encoding, cookie jars, redirection, caching of local content, authentication, etc... I am talking about a server class template which lets you write something like this: struct handler { template response_v1 operator()(request_v1 const& req) { // your code here } }; int main() { using beast::http; beast::http::async_server<handler> s{"0.0.0.0", 80}; // Block until SIGINT or SIGTERM is received. sig_wait(); } Like the current Beast interfaces, this would be a low level server. it manages the connections, correctly handles exiting the app cleanly, reads the HTTP requests and buffers the responses. But that's it, the rest is up to the caller. I imagine we would have the same debate about low level versus high level server interface, and my answer would be that someone can use this generic server as a building block to add components to it and make it more full featured. For example by writing a cgi module, or adding a file serving handler, etc.. I've already started some of this work but there are some design issues that I haven't solved yet (I'm open to suggestions): https://github.com/vinniefalco/Beast/blob/6f794e80fd4fad3a4777e68f7fc732ecbb.... I think conversations about these subjects are a good idea, thanks for bringing it to the list. Regards