contented/Server.go

package contented

import (
	"encoding/json"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"github.com/boltdb/bolt"
)

var SERVER_HEADER string = `contented/0.1`

type ServerPublicProperties struct {
	AppTitle       string
	MaxUploadBytes int64
}

type ServerOptions struct {
	DataDirectory string
	DBPath        string
	ServerPublicProperties
}

type Server struct {
	opts           ServerOptions
	db             *bolt.DB
	metadataBucket []byte
}

func NewServer(opts *ServerOptions) (*Server, error) {
	s := &Server{
		opts:           *opts,
		metadataBucket: []byte(`METADATA`),
	}

	b, err := bolt.Open(opts.DBPath, 0644, bolt.DefaultOptions)
	if err != nil {
		return nil, err
	}

	err = b.Update(func(tx *bolt.Tx) error {
		_, err := tx.CreateBucketIfNotExists(s.metadataBucket)
		return err
	})
	if err != nil {
		return nil, err
	}

	s.db = b

	return s, nil
}

func (this *Server) handleView(w http.ResponseWriter, r *http.Request, fileID string) error {
	// Load file
	f, err := os.Open(filepath.Join(this.opts.DataDirectory, fileID))
	if err != nil {
		return err
	}

	defer f.Close()

	// Load metadata
	m, err := this.Metadata(fileID)
	if err != nil {
		return err
	}

	// ServeContent only uses the filename to get the mime type, which we can
	// set accurately (including blacklist)
	w.Header().Set(`Content-Type`, m.MimeType)
	if m.MimeType == `application/octet-stream` {
		w.Header().Set(`Content-Disposition`, `attachment; filename="`+m.Filename+`"`)
	}

	http.ServeContent(w, r, "", m.UploadTime, f)

	return nil
}

func (this *Server) handleInformation(w http.ResponseWriter, fileID string) {
	m, err := this.Metadata(fileID)
	if err != nil {
		if os.IsNotExist(err) {
			http.Error(w, "Not found", 404)
			return
		}

		log.Println(err.Error())
		http.Error(w, "Internal error", 500)
		return
	}

	this.serveJsonObject(w, m)
}

func (this *Server) serveJsonObject(w http.ResponseWriter, o interface{}) {
	jb, err := json.Marshal(o)
	if err != nil {
		log.Println(err.Error())
		http.Error(w, "Internal error", 500)
		return
	}

	w.Header().Set(`Content-Type`, `application/json`)
	w.WriteHeader(200)
	w.Write(jb)
}

func (this *Server) handleAbout(w http.ResponseWriter) {
	this.serveJsonObject(w, this.opts.ServerPublicProperties)
}

func (this *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	w.Header().Set(`Server`, SERVER_HEADER)
	if this.opts.MaxUploadBytes > 0 {
		r.Body = http.MaxBytesReader(w, r.Body, this.opts.MaxUploadBytes)
	}

	if r.Method == "GET" && strings.HasPrefix(r.URL.Path, `/view/`) {
		err := this.handleView(w, r, r.URL.Path[6:])
		if err != nil {
			log.Printf("%s View failed: %s\n", r.RemoteAddr, err.Error())
			if os.IsNotExist(err) {
				http.Error(w, "File not found", 404)
			} else {
				http.Error(w, "Couldn't provide content", 500)
			}
		}

	} else if r.Method == "GET" && strings.HasPrefix(r.URL.Path, `/info/`) {
		this.handleInformation(w, r.URL.Path[6:])

	} else if r.Method == "GET" && r.URL.Path == `/about` {
		this.handleAbout(w)

	} else if r.Method == "POST" && r.URL.Path == `/upload` {
		this.handleUpload(w, r)

	} else {
		// TODO embed into binary
		http.FileServer(http.Dir(`static`)).ServeHTTP(w, r)

	}
}