Ciprian Dorin Craciun ciprian.craciun at gmail.com
Fri Feb 28 07:30:53 GMT 2020
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On Fri, Feb 28, 2020 at 4:44 AM Sean Conner <sean at conman.org> wrote:
> I disagree. Using "proper symbols" is over all harder to deal with.
> First, it tends to be English-centric. I mean, we could go with:
>
> defectum:tempus:tardius
>
> or how about
>
> teip:sealadach:níos-moille
The protocol is already English centric, for example the MIME types(which are IANA standards), it uses lef-to-right writing, it usesUTF-8 which is optimized for Latin-based alphabets, etc.; so if wewant to be politically correct, we could use Latin or Esperanto.
> First off, the code has to be parsed, and while this is easy in languages
> like Python or Perl, you run into ... issues, with Rust, C++ or Go (not to
> mention the complete mess that is C). A number is easy to parse, easy to
> check and whose meaning can be translated into another language. The Gemini
> status codes (as well as HTTP and other three-digit status codes) don't even
> have to be converted into a number---you can easily do a two level check:
>
> if (status[0] == '2')
> /* happy path */
> else if (status[0] == '3')
> /* redirection path */
> else if (status[0] == '4')
> /* tempoary failure */
> else if (status[0] == '5')
> /* permanent failure */
> else if (status[0] == '6')
> {
> /* authorizatio needed */
> if (status[1] == '1')
> /* client cert required */
> else if (status[1] == '3')
> /* rejected! */
> }
OK, although I understand why things are harder in C, you presentabove only the "easy part". Please take into account theline-reading, splitting into code and meta (and the protocol does sayone or multiple whitespaces in between), checking the `CRLF` at theend. Now assuming you've done all that even the code above has acouple of bugs:* what if the server sends `99`? (it is not covered);* what if the server sends just `6`? (it is not covered, althoughgiven that perhaps `status` is `\0` terminated it won't be a largeproblem, but still it would fall through;)* what if the server just sends an empty status code? (is it checkedby the parser?)
So if simplicity is a real concern, then why not introduce somethinglike `0:success` `1:failure:temporary`. (I.e. the first character iseither `0` or `1`; other more advanced clients should parse therest.)
Also taking into account that the client still has to handle relativeredirects, I think the status code parsing pales in comparison.
As minor issues:* why `CRLF`? it's easier (both in terms of availability of functionsand efficiency) to split lines by a single character `\n` than by astring;* why allow "one-or-more whitespaces" especially in protocol relatedparts? why not mandate a strict syntax?
>
> Now on the transport side, somewhat related to the previous point, I
>
> think TLS transient certificates are an overkill... If one wants to
>
> implement "sessions", one could introduce
>
> This is the fault of both myself and solderpunk. When I implemented the
> first Gemin server (yes, even more solderpunk, who created the protocol) I
> included support for client certificates as a means of authentication of the
> client. My intent (besides playing around with that technology) was to have
> fine grained control over server requests without the user to have a
> password, and to that end, I have two areas on my Gemini server that require
> client certificates:
>
> [...]
>
> It wasn't my intent to introduce a "cookie" like feature. solderpunk
> interpreted this as a "cookie" like feature and called it "transient
> certificates". I still view this feature as "client certificates" myself.
> I personally think the user of "transient certificates" is confusing.
I was specifically targeting only the "transient certificates", notproper "client certificates".
In fact I appreciate very much the usage of client certificates asmeans to authenticate known clients. (This is something I personallyuse in production for back-office endpoints.)
>
> On a second thought, why TLS? Why not something based on NaCL /
>
> `libsodium` constructs, or even the "Noise Protocol"
>
> (http://www.noiseprotocol.org/)?
>
> 1) Never, *NEVER* implement crypto yourself.
I was never proposing to implement crypto ourselves. `libsodium` /NaCL provides very useful high-level constructs, tailored for specificuse-cases (like for example message encryption and signing), that areproven to be safe, and exports them with a very simple API that can beeasily understood and used.
> 3) I never even heard of the Noise Protocol.
The "Noise Protocol" is currently used by WireGuard, WhatsApp andpossibly other applications that target network-based communications.Although it is more complex than NaCL.
(It was just an example of more "current" frameworks.)
> 2) OpenSSL exists and has support in most (if not all) popular
> languages.
Don't know what to say... I find the OpenSSL documentation terrible,and it's hard to use... In fact given the complexity of TLS I wouldsay any wrapper, reimplementation, or alternative is as bad. Forexample I played with Go's TLS library and even though it's manageableit requires lots of attention to get things right.
>
> For example I've tried to build the
>
> Asuka Rust-based client and it pulled ~104 dependencies and took a few
>
> minutes to compile, this doesn't seem too lightweight...
>
> So wait? You try to use something other than OpenSSL and it had too many
> dependencies and took too long to compile? Or is did you mean to say that
> the existing Rust-based client for OpenSSL had too many dependencies? I
> think you mean the later, but it could be read as the former.
Looking in https://tildegit.org/julienxx/asuka/src/branch/master/Cargo.tomlapparently it is using `native-tls`(https://crates.io/crates/native-tls) which apparently is usingOpenSSL on Linux; and this `native-tls` library isn't an "odd" one, itis used by many high profile Rust libraries. Removing it and checkingthe dependency tree it seems it drops the dependencies with about 15packages.
However as said earlier, perhaps it's Rust's ecosystem fault, mostlikely other used libraries might also be to blame for this, butregardless mandating the use of TLS doesn't simplify things.
>
> Why not just re-use PGP to sign / encrypt requests and replies? With
>
> regard to PGP,
>
> There are issues with using PGP:
>
> https://latacora.micro.blog/2019/07/16/the-pgp-problem.html
There are issues with any technology, TLS included.
However I would say it's easier to integrate GnuPG (even throughsubprocesses) in order to encrypt / decrypt payloads (especially givenhow low in count they are for Gemini's ecosystem) than implementingTLS. Moreover it offers out-of-the-box the whole client sidecertificate management, which adding to a TLS-based client would bemuch more involved, more on this bellow...
>
> given that Gopher communities tend to be quite small,
>
> and composed of mostly "techie" people, this goes hand-in-hand with
>
> the "web-of-trust" that is enabled by PGP and can provide something
>
> that TLS can't at this moment: actual "attribution" of servers to
>
> human beings and trust delegation; for example for a server one could
>
> generate a pair of keys and other people could sign those keys as a
>
> way to denote their "trust" in that server (and thus the hosted
>
> content). Why not take this a step further and allow each document
>
> served to be signed, thus extending this "attribution" not only to the
>
> servers, but to the actual contents. This way a server could provide
>
> a mirror / cached version of a certain document, while still proving
>
> it is the original one.
>
> The hardest problem with crypto is key management. If anything, key
> management with PGP seems more problematic than with OpenSSL and the CA
> infrastructure (as bad as the CA infrastructure is).
One of the `gemini://` specifications explicitly states that theserver certificate authentication model is similar to SSH's first useaccept and cache afterward. However say you'll go with the actual CAmodel, now you need to juggle Let's Encrypt (each 3 months) (or addsupport for ACME in your server), then juggle PEM files, etc.Regardless, either way one will have to implement all this certificatemanagement from scratch.
Now on the client certificate side, again a client would have toimplement all that from scratch.
Thus on the contrary, PGP (with perhaps GnuPG) would simplify all thisbecause it already implements all these features, and has clearlydefined operations over all these entities, including a web-of-trust.
(In fact none of the package managers I know of use S/MIME, i.e. X.509certificates and CA's, for package signatures, but instead delegate toGnuPG...)
>
> Now getting back to the `gemini://` protocol, another odd thing I
>
> found is the "query" feature. Gemini explicitly supports only `GET`
>
> requests, and the `text/gemini` format doesn't support forms, yet it
>
> still tries to implement a "single input-box form"... Granted it's a
>
> nice hack, but it's not "elegant"... (Again, like in the case of
>
> sessions, it seems more as an afterthought, even though this is the
>
> way Gopher does it...)
>
>
>
> Perhaps a simple "form" solution would be better? Perhaps completely
>
> eliminating for the time these "queries"? Or perhaps introducing a
>
> new form of URL's like for example:
>
> `gemini-query:?url=gemini://server/path&prompt=Please+enter+something`
>
> which can be served either in-line (as was possible in Gopher) and /
>
> or served as a redirect (thus eliminating another status code family).
>
> Forms lead to applications. Applications lead to client side scripting.
> Client side scripting leads to the web ...
>
> Of course there's pressure to expand the protocol. solderpunk is trying
> his hardest to keep that from happening and turning Gemini into another web
> clone.
But you are already implementing "applications" on-top of Gemini (andGopher) through CGI... And you already are implementing forms,although "single-input" ones... Even with this single input form onecould implement a wizard style "one input at a time" form...Basically you give the technical possibility for "applications".
I wasn't talking about "client side scripting"; I was just sayingeither drop this completely from the protocol, either specify it. (Atthe moment nothing stops a client / server implementer to just reusethe "question" and "answer" to send back and forth an actual formspecification and answer...)
(Also "client side scripting" can't be eradicated through theprotocol. One is free to include for example JavaScript in theclient, and the protocol can't say "no".)
>
> Regarding the `text/gemini` format -- and taking into account various
>
> emails in the archive about reflowing, etc -- makes me wonder if it is
>
> actually needed. Why can't CommonMark be adopted as the HTML
>
> equivalent, and a more up-to-date Gopher map variant as an alternative
>
> for menus? There are already countless safe CommonMark parsers
>
> out-there (for example in Rust there is one implemented by Google) and
>
> the format is well understood and accepted by a large community
>
> (especially the static side generators community).
>
> It can. RFC-7763 defines the media type text/markdown and RFC-7764 define
> known variations that can be specified. Could be done right now without any
> changes to Gemini. Go for it.
I know "I can"; I can even use PDF as the default "document format"in my own client / server. I could even use Flash. :)
However I was speaking as the "default", Gemini endorsed format.
>
> Regarding an up-to-date Gopher map alternative, I think this is an
>
> important piece of the Gopher ecosystem that is missing from today's
>
> world: a machine-parsable standard format of indexing documents. I
>
> very fondly remember "directory" sites of yesteryear (like DMOZ or the
>
> countless other clones) that strives to categorize the internet not by
>
> "machine learning" but by human curation.
>
> Could you provide an example of what you mean by this? I'm not sure why a
> map alternative is needed.
One problem with today's web is that the actual "web structure" isembedded in unstructured documents as links. What I liked aboutGopher maps is that it gave a machine-readable, but stilluser-friendly, way to map and categorize the "web contents".
Think about the following example: I want to look for a cheap telecomplan; I open multiple telecom provider web sites, and now for eachone I have to "navigate" their "UX optimized" layouts (expandingmenus, drop-downs, burger buttons, etc.) (some placed on the top, someon the right, etc.) to find the proper page that lists these plans.Now imagine how that looks in Gopher: each site would in fact providea Gopher-map that looks the same (at least in terms of layout) and Ican find the information I'm looking for much easier.
To be more "academic": the current web pages (HTML) serve a couple ofdistinct purposes:* actual documents -- documentation, essays, blogs, etc. that uselinks mainly as bibliographic references; (this would be equivalentto PDF files;)* actual client-side applications -- single page apps (React, Angular,etc.); (this would be equivalent to Flash;)* index pages -- meant to give a structure to a particular site andhelp the user find what he is searching for; (this would beequivalent to site-maps, Gopher maps, RSS, etc.)
Now getting back to Gemini:* actual documents -- we have `text/gemini` (or CommonMark, etc.)* we don't support client-side applications;* index pages -- we once more have `text/gemiin` (or others) but whicharen't specifically designed for this purpose;
How would such an "index" document look like? A machine readable(don't have the specific syntax yet, perhaps JSON?, perhaps somethingelse?) that allows one to:* provide a way to describe links with short description (perhaps asummary, author, date, some other standard meta-data like RSS/Atomdoes);* provide a way to group links in a hierarchical tree-like menu (sothat one doesn't need multiple transactions to load a small depth,well structured menu);* provide hints for crawlers, etc.;
>
> * and perhaps add support for content-based addressing (as opposed to
>
> server-based addressing) (i.e. persistent URL's);
>
> There already exist such protocols---I'm not sure what a new one based
> around Gemini would buy.
I agree that `gemini://` is first and foremost a "transfer" protocol.However one can include a document's identity as a first class citizenof the protocol.
For example say each document is identified by its SHA; then whenreplying with a document also send that SHA in form of a permanent URLlike say `gemini-object:?sha={SHA}&location=gemini://first-server/...&location=gemini://second-server/...`; then a client (that perhaps has bookmarked that particular version ofthat document) could send that URL to a server (of his choosing viaconfiguration, to the first one specified in `location`, etc.) and ifthat server has that document just reply with that, else use`location`, else return 404.
Ciprian.