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Highly concurrent and multi-threaded gemini client and server library for theDrogon web application framework

This library is in early development. API may clange without notice

• Drogon >= 1.7.3 (or 1.7.2 with MIME patch)

Async-callback API

There's several ways to use the Gemini client. The most general one is by the async-callback API. The supplied callback function will be invoked once the cliend recived a response from the server.

dremini::sendRequest("gemini://gemini.circumlunar.space/"    , [](ReqResult result,const HttpResponsePtr& resp) {if(result != ReqResult::Ok)        {            LOG_ERROR <<"Failed to send request";return;        }        LOG_INFO <<"Body size:" << resp->body().size();    });

C++ Coroutines

If C++ coroutines (requires MSVC 19.25, GCC 11 or better) is avaliable to you. You can also use the more stright forward coroutine API.

try{auto resp =co_awaitdremini::sendRequestCoro("gemini://gemini.circumlunar.space/");    LOG_INFO <<"Body size:" << resp->body().size();}catch(...){    LOG_ERROR <<"Failed to send request";}

Thedremini::GeminiServer plugin that parses and forwards Gemini requests as HTTP Get requests.

Thus, first enable the Gemini server plugin. And tell the server to serve gemini files (if you are also using it as a file server):

// config.json{"app":{"document_root":"./","file_types": ["gmi"        ],"use_implicit_page":true,"implicit_page":"index.gmi","home_page":"index.gmi","mime": {"text/gemini": ["gmi","gemini"]        }    },"plugins": [        {"name":"dremini::GeminiServerPlugin","config": {"listeners": [                    {"key":"key.pem","cert":"cert.pem","ip":"127.0.0.1"                    }                ],"numThread":3            }        }    ]}

Then let's code up ca basic request handler:

app().registerHandler("/hi", [](const HttpRequestPtr& req, std::function<void(const HttpResponsePtr&)>&& callback){auto resp =HttpResponse::newHttpResponse();    resp->setBody("# Hello Gemini\nHello!\n");    resp->setContentTypeCodeAndCustomString(CT_CUSTOM,"text/gemini");callback(resp);});

Finally, the handler can be triggered by using a Gemini client

> gmni gemini://localhost/hi -j once# Hello GeminiHello>

Drogon is a HTTP framework. Dremini reuses a large portion of it's original functionality to provide easy Gemini server programming.We try hard to keep to Gemini sementic in HTTP.

Like HTTP, Gemini uses status codes for servers to indicate the status of the response. Gemini status codes must have 2 digits.Thus a range between 0 and 99. Dremini maps common HTTP status codes into Gemini ones automatically. And converts the rest toan apporiprate category. Here's a list of conversions

If the returned HTTP status is not listed above. The Gemini status is simply the HTTP status divied by 100.Exception being 4xx and 5xx. They 4xx is mapped as 50 and 5xx is mapped as 40. Since there's no HTTP status code lesser than 100 exists. Any status code in that range is treads as a Gemini native code. Which does notgo through any translation.

HttpResponses from a Gemini client automaticallyi have agemini-status header that stores the Gemini status code before mapping. And ameta header to store the meta.

Drogon by design is a HTTP server. Thus is has no idea about Gemini files and convension. The following config tells Drogon the following things. Which are required to properly serve gemini pages

• Sets the page root folder to/path/to/the/files
• Serve*.gmi files
  • Add more types if needed
• *.gmi and*.gemini files have the MIME typetext/gemini
• When asked to serve a directory, Try servingindex.gmi
• The homepage is/index.gmi

{"app":{"document_root":"/path/to/the/files","file_types": ["gmi","gemini"        ],"use_implicit_page":true,"implicit_page":"index.gmi","home_page":"index.gmi","mime": {"text/gemini": ["gmi","gemini"]        }    }}

Gemini URLs supports a query parameter using the? symbol. For example,gemini://localhost/search?Hello has a query of "Hello". Dremini adds aquery parameter to the HttpRequest when a query is detected.

Dremini adds aprotocol header to the proxyed HTTP request to singnal it's comming from a Gemini request. Whom's value is always "gemini"

Dermini supports translating Gemini into HTML automatically! Add"translate_to_html": true into plugin config. This makes Dremini translatetext/gemini contents into HTML when a regular browser requests content

Dremini library does not verify server and client certificates yet. Nor client certs are supported.