cwtch/functionality/filesharing/filesharing_functionality.go

100 lines
3.4 KiB
Go

package filesharing
import (
"crypto/rand"
"cwtch.im/cwtch/model"
"cwtch.im/cwtch/model/attr"
"cwtch.im/cwtch/peer"
"cwtch.im/cwtch/protocol/files"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"git.openprivacy.ca/openprivacy/log"
"io"
"math"
path "path/filepath"
"strconv"
)
// Functionality groups some common UI triggered functions for contacts...
type Functionality struct {
}
// FunctionalityGate returns contact.Functionality always
func FunctionalityGate(experimentMap map[string]bool) (*Functionality, error) {
if experimentMap["filesharing"] == true {
return new(Functionality), nil
}
return nil, errors.New("filesharing is not enabled")
}
// OverlayMessage presents the canonical format of the File Sharing functionality Overlay Message
// This is the format that the UI will parse to display the message
type OverlayMessage struct {
Name string `json:"f"`
Hash string `json:"h"`
Nonce string `json:"n"`
Size uint64 `json:"s"`
}
// DownloadFile given a profile, a conversation handle and a file sharing key, start off a download process
// to downloadFilePath
func (f *Functionality) DownloadFile(profile peer.CwtchPeer, handle string, downloadFilePath string, manifestFilePath string, key string) {
// Store local.filesharing.filekey.manifest as the location of the manifest
profile.SetScopedZonedAttribute(attr.LocalScope, attr.FilesharingZone, fmt.Sprintf("%s.manifest", key), manifestFilePath)
// Store local.filesharing.filekey as the location of the download
profile.SetScopedZonedAttribute(attr.LocalScope, attr.FilesharingZone, key, downloadFilePath)
// Get the value of conversation.filesharing.filekey.manifest.size from `handle`
profile.SendScopedZonedGetValToContact(handle, attr.ConversationScope, attr.FilesharingZone, fmt.Sprintf("%s.manifest.size", key))
}
// ShareFile given a profile and a conversation handle, sets up a file sharing process to share the file
// at filepath
func (f *Functionality) ShareFile(filepath string, profile peer.CwtchPeer, handle string) error {
manifest, err := files.CreateManifest(filepath)
if err != nil {
return err
}
var nonce [24]byte
if _, err := io.ReadFull(rand.Reader, nonce[:]); err != nil {
log.Errorf("Cannot read from random: %v\n", err)
return err
}
message := OverlayMessage{
Name: path.Base(manifest.FileName),
Hash: hex.EncodeToString(manifest.RootHash),
Nonce: hex.EncodeToString(nonce[:]),
Size: manifest.FileSizeInBytes,
}
data, _ := json.Marshal(message)
wrapper := model.MessageWrapper{
Overlay: model.OverlayFileSharing,
Data: string(data),
}
wrapperJSON, _ := json.Marshal(wrapper)
key := fmt.Sprintf("%x.%x", manifest.RootHash, nonce)
serializedManifest, _ := json.Marshal(manifest)
// Store the size of the manifest (in chunks) as part of the public scope so contacts who we share the file with
// can fetch the manifest as if it were a file.
// manifest.FileName gets redacted in filesharing_subsystem (to remove the system-specific file hierarchy),
// but we need to *store* the full path because the sender also uses it to locate the file
lenDiff := len(filepath) - len(path.Base(filepath))
profile.SetScopedZonedAttribute(attr.ConversationScope, attr.FilesharingZone, fmt.Sprintf("%s.manifest.size", key), strconv.Itoa(int(math.Ceil(float64(len(serializedManifest)-lenDiff)/float64(files.DefaultChunkSize)))))
profile.ShareFile(key, string(serializedManifest))
profile.SendMessage(handle, string(wrapperJSON))
return nil
}