sr-71/gemini.go

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"strings"

	sr "tildegit.org/tjp/sliderule"
	"tildegit.org/tjp/sliderule/contrib/cgi"
	"tildegit.org/tjp/sliderule/contrib/fs"
	"tildegit.org/tjp/sliderule/gemini"
	"tildegit.org/tjp/sliderule/gemini/gemtext/atomconv"
	"tildegit.org/tjp/sliderule/logging"
	"tildegit.org/tjp/syw"
)

func buildGeminiServers(servers []Server, config *Configuration) ([]sr.Server, error) {
	_, info, _, errlog := Loggers(config)

	groups := map[string][]*Server{}
	for i := range servers {
		addr := fmt.Sprintf("%s:%d", servers[i].IP.String(), servers[i].Port)
		grp, ok := groups[addr]
		if !ok {
			groups[addr] = []*Server{&servers[i]}
		} else {
			groups[addr] = append(grp, &servers[i])
		}
	}

	result := []sr.Server{}
	for addr, configs := range groups {
		_ = info.Log("msg", "starting gemini server", "addr", addr)
		var handler sr.Handler
		if len(configs) == 1 {
			handler = routes(*configs[0])
		} else {
			mapping := map[string]sr.Handler{}
			for _, config := range configs {
				router := routes(*config)
				for _, hostname := range config.Hostnames {
					mapping[hostname] = router
				}
			}

			handler = sr.VirtualHosts(mapping, sr.HandlerFunc(func(_ context.Context, _ *sr.Request) *sr.Response {
				return gemini.RefuseProxy("Proxy request refused")
			}))
		}

		var hostname string
		for _, conf := range configs {
			if len(conf.Hostnames) > 0 {
				hostname = conf.Hostnames[0]
				break
			}
		}

		tlsConfigs := map[string]*tls.Config{}
		var fallback *tls.Config = nil
		for _, config := range configs {
			if len(config.Hostnames) > 0 && config.TLS != nil {
				for _, hostname := range config.Hostnames {
					tlsConfigs[hostname] = config.TLS
				}
			} else {
				fallback = config.TLS
			}
		}
		tlsConfig := gemini.MultiTLS(tlsConfigs, fallback)

		gemsrv, err := gemini.NewServer(
			context.Background(),
			hostname,
			"tcp",
			addr,
			logging.LogRequests(info)(handler),
			errlog,
			tlsConfig,
		)
		if err != nil {
			return nil, err
		}

		result = append(result, gemsrv)
	}

	return result, nil
}

func addGeminiRoute(router *sr.Router, route RouteDirective) {
	switch route.Type {
	case "static":
		addGeminiStaticRoute(router, route)
	case "cgi":
		buildAndAddRoute(router, route, func(route RouteDirective) sr.Handler {
			handler := cgi.GeminiCGIDirectory(route.FsPath, route.URLPath, route.Modifiers.ExecCmd)
			if route.Modifiers.AutoAtom {
				handler = atomconv.Auto(handler)
			}
			return GeminiAuthMiddleware(route.Modifiers.Auth)(handler)
		})
	case "git":
		addGeminiGitRoute(router, route)
	}
}

func addGeminiStaticRoute(router *sr.Router, route RouteDirective) {
	buildAndAddRoute(router, route, func(route RouteDirective) sr.Handler {
		handlers := []sr.Handler{}

		if route.Modifiers.Exec {
			handlers = append(handlers, cgi.GeminiCGIDirectory(route.FsPath, route.URLPath, route.Modifiers.ExecCmd))
		}

		handlers = append(handlers, fs.GeminiFileHandler(route.FsPath, route.URLPath))

		if route.Modifiers.DirDefault != "" {
			handlers = append(
				handlers,
				fs.GeminiDirectoryDefault(route.FsPath, route.URLPath, route.Modifiers.DirDefault),
			)
		}

		if route.Modifiers.DirList {
			handlers = append(handlers, fs.GeminiDirectoryListing(route.FsPath, route.URLPath, nil))
		}

		handler := sr.FallthroughHandler(handlers...)

		if route.Modifiers.AutoAtom {
			handler = atomconv.Auto(handler)
		}

		handler = GeminiAuthMiddleware(route.Modifiers.Auth)(handler)

		if route.Modifiers.Titan != nil {
			titan := fs.TitanUpload(route.FsPath, route.URLPath, route.Modifiers.Titan.Strategy.Approve)(handler)
			handler = sr.Filter(func(ctx context.Context, request *sr.Request) bool {
				return request.Scheme == "titan"
			}, handler)(titan)
		}

		return handler
	})
}

func addGeminiGitRoute(router *sr.Router, route RouteDirective) {
	buildAndAddRoute(router, route, func(route RouteDirective) sr.Handler {
		subrouter := syw.GeminiRouter(route.FsPath, route.Modifiers.Templates)
		handler := sr.HandlerFunc(func(ctx context.Context, request *sr.Request) *sr.Response {
			reqclone := cloneRequest(request)
			reqclone.Path = strings.TrimPrefix(reqclone.Path, route.URLPath)

			handler, params := subrouter.Match(reqclone)
			if handler == nil {
				return nil
			}
			return handler.Handle(context.WithValue(ctx, sr.RouteParamsKey, params), request)
		})
		if route.Modifiers.AutoAtom {
			handler = atomconv.Auto(handler)
		}
		return GeminiAuthMiddleware(route.Modifiers.Auth)(handler)
	})
}