pstuifzand/ekster

// Copyright (C) 2018 Peter Stuifzand
//
// This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
// License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
// later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with this program. If not,
// see <http://www.gnu.org/licenses/>.

/*
Eksterd is a microsub server that is extendable.
*/
package main

import (
    "database/sql"
    "flag"
    "fmt"
    "log"
    "net/http"
    "os"
    "time"

    "github.com/gomodule/redigo/redis"
    "github.com/pkg/errors"
    "p83.nl/go/ekster/pkg/auth"

    "p83.nl/go/ekster/pkg/server"
)

// AppOptions are options for the app
type AppOptions struct {
    Port        int
    AuthEnabled bool
    Headless    bool
    RedisServer string
    BaseURL     string
    TemplateDir string
    pool        *redis.Pool
    database    *sql.DB
}

func init() {
    log.SetFlags(log.Lshortfile | log.Ldate | log.Ltime)
}

func newPool(addr string) *redis.Pool {
    return &redis.Pool{
        MaxIdle:     3,
        IdleTimeout: 240 * time.Second,
        Dial:        func() (redis.Conn, error) { return redis.Dial("tcp", addr) },
    }
}

// WithAuth adds authorization to a http.Handler
func WithAuth(handler http.Handler, b *memoryBackend) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method == http.MethodOptions {
            handler.ServeHTTP(w, r)
            return
        }

        authorization := ""

        values := r.URL.Query()

        if r.Method == http.MethodGet && values.Get("action") == "events" && values.Get("access_token") != "" {
            authorization = "Bearer " + values.Get("access_token")
        } else {
            authorization = r.Header.Get("Authorization")
        }

        var token auth.TokenResponse

        authorized, err := b.AuthTokenAccepted(authorization, &token)
        if err != nil {
            log.Printf("token not accepted: %v", err)
        }
        if !authorized {
            log.Printf("Token could not be validated")
            http.Error(w, "Can't validate token", 403)
            return
        }

        if token.Me != b.Me { // FIXME: Me should be part of the request
            log.Printf("Missing \"me\" in token response: %#v\n", token)
            http.Error(w, "Wrong me", 403)
            return
        }

        handler.ServeHTTP(w, r)
    })
}

// App is the main app structure
type App struct {
    options    AppOptions
    backend    *memoryBackend
    hubBackend *hubIncomingBackend
}

// Run runs the app
func (app *App) Run() error {
    err := initSearch()
    if err != nil {
        return fmt.Errorf("while starting app: %v", err)
    }
    app.backend.run()
    app.hubBackend.run()

    log.Printf("Listening on port %d\n", app.options.Port)
    return http.ListenAndServe(fmt.Sprintf(":%d", app.options.Port), nil)
}

// NewApp initializes the App
func NewApp(options AppOptions) (*App, error) {
    app := &App{
        options: options,
    }

    backend, err := loadMemoryBackend(options.pool, options.database)
    if err != nil {
        return nil, err
    }
    app.backend = backend
    app.backend.AuthEnabled = options.AuthEnabled
    app.backend.baseURL = options.BaseURL
    app.backend.hubIncomingBackend.pool = options.pool
    app.backend.hubIncomingBackend.baseURL = options.BaseURL

    app.hubBackend = &hubIncomingBackend{backend: app.backend, baseURL: options.BaseURL, pool: options.pool}

    http.Handle("/micropub", &micropubHandler{
        Backend: app.backend,
        pool:    options.pool,
    })

    handler, broker := server.NewMicrosubHandler(app.backend)
    if options.AuthEnabled {
        handler = WithAuth(handler, app.backend)
    }

    app.backend.broker = broker

    http.Handle("/microsub", handler)

    http.Handle("/incoming/", &incomingHandler{
        Backend: app.hubBackend,
    })

    if !options.Headless {
        handler, err := newMainHandler(app.backend, options.BaseURL, options.TemplateDir, options.pool)
        if err != nil {
            return nil, errors.Wrap(err, "could not create main handler")
        }
        http.Handle("/", handler)
    }

    return app, nil
}

func main() {
    log.Println("eksterd - microsub server")

    var options AppOptions

    flag.IntVar(&options.Port, "port", 80, "port for serving api")
    flag.BoolVar(&options.AuthEnabled, "auth", true, "use auth")
    flag.BoolVar(&options.Headless, "headless", false, "disable frontend")
    flag.StringVar(&options.RedisServer, "redis", "redis:6379", "redis server")
    flag.StringVar(&options.BaseURL, "baseurl", "", "http server baseurl")
    flag.StringVar(&options.TemplateDir, "templates", "./templates", "template directory")

    flag.Parse()

    if options.AuthEnabled {
        log.Println("Using auth")
    } else {
        log.Println("Authentication disabled")
    }

    if options.BaseURL == "" {
        if envVar, e := os.LookupEnv("EKSTER_BASEURL"); e {
            options.BaseURL = envVar
        } else {
            log.Fatal("EKSTER_BASEURL environment variable not found, please set with external url, -baseurl url option")
        }
    }

    if options.TemplateDir == "" {
        if envVar, e := os.LookupEnv("EKSTER_TEMPLATES"); e {
            options.TemplateDir = envVar
        } else {
            log.Fatal("EKSTER_TEMPLATES environment variable not found, use env var or -templates dir option")
        }
    }

    createBackend := false
    args := flag.Args()

    if len(args) >= 1 {
        if args[0] == "new" {
            createBackend = true
        }
    }

    if createBackend {
        err := createMemoryBackend()
        if err != nil {
            log.Fatalf("Error while saving backend.json: %s", err)
        }

        // TODO(peter): automatically gather this information from login or otherwise
        log.Println(`Config file "backend.json" is created in the current directory.`)
        log.Println(`Update "Me" variable to your website address "https://example.com/"`)
        log.Println(`Update "TokenEndpoint" variable to the address of your token endpoint "https://example.com/token"`)

        return
    }

    pool := newPool(options.RedisServer)
    options.pool = pool
    db, err := sql.Open("postgres", "host=database user=postgres password=simple dbname=ekster sslmode=disable")
    if err != nil {
        log.Fatalf("database open failed: %s", err)
    }
    options.database = db

    app, err := NewApp(options)
    if err != nil {
        log.Fatal(err)
    }

    log.Fatal(app.Run())

    db.Close()
}