forked from tinode/chat
/
s3.go
251 lines (215 loc) · 6.53 KB
/
s3.go
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// Package s3 implements media interface by storing media objects in Amazon S3 bucket.
package s3
import (
"encoding/json"
"errors"
"io"
"log"
"mime"
"net/http"
"sync/atomic"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/request"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/s3"
"github.com/aws/aws-sdk-go/service/s3/s3manager"
"github.com/tinode/chat/server/media"
"github.com/tinode/chat/server/store"
"github.com/tinode/chat/server/store/types"
)
const (
defaultServeURL = "/v0/file/s/"
handlerName = "s3"
)
type awsconfig struct {
AccessKeyId string `json:"access_key_id"`
SecretAccessKey string `json:"secret_access_key"`
Region string `json:"region"`
BucketName string `json:"bucket"`
CorsOrigins []string `json:"cors_origins"`
ServeURL string `json:"serve_url"`
}
type awshandler struct {
svc *s3.S3
conf awsconfig
}
// readerCounter is a byte counter for bytes read through the io.Reader
type readerCounter struct {
io.Reader
count int64
reader io.Reader
}
// Read reads the bytes and records the number of read bytes.
func (rc *readerCounter) Read(buf []byte) (int, error) {
n, err := rc.reader.Read(buf)
atomic.AddInt64(&rc.count, int64(n))
return n, err
}
// Init initializes the media handler.
func (ah *awshandler) Init(jsconf string) error {
var err error
if err = json.Unmarshal([]byte(jsconf), &ah.conf); err != nil {
return errors.New("failed to parse config: " + err.Error())
}
if ah.conf.AccessKeyId == "" {
return errors.New("missing Access Key ID")
}
if ah.conf.SecretAccessKey == "" {
return errors.New("missing Secret Access Key")
}
if ah.conf.Region == "" {
return errors.New("missing Region")
}
if ah.conf.BucketName == "" {
return errors.New("missing Bucket")
}
if ah.conf.ServeURL == "" {
ah.conf.ServeURL = defaultServeURL
}
var sess *session.Session
if sess, err = session.NewSession(&aws.Config{
Region: aws.String(ah.conf.Region),
Credentials: credentials.NewStaticCredentials(ah.conf.AccessKeyId, ah.conf.SecretAccessKey, ""),
}); err != nil {
return err
}
// Create S3 service client
ah.svc = s3.New(sess)
// Check if the bucket exists, create one if not.
_, err = ah.svc.CreateBucket(&s3.CreateBucketInput{Bucket: aws.String(ah.conf.BucketName)})
if err != nil {
if aerr, ok := err.(awserr.Error); !ok ||
(aerr.Code() != s3.ErrCodeBucketAlreadyExists &&
aerr.Code() != s3.ErrCodeBucketAlreadyOwnedByYou) {
return err
}
}
// The following serves two purposes:
// 1. Setup CORS policy to be able to serve media directly from S3.
// 2. Verify that the bucket is accessible to the current user.
origins := ah.conf.CorsOrigins
if len(origins) == 0 {
origins = append(origins, "*")
}
_, err = ah.svc.PutBucketCors(&s3.PutBucketCorsInput{
Bucket: aws.String(ah.conf.BucketName),
CORSConfiguration: &s3.CORSConfiguration{
CORSRules: []*s3.CORSRule{{
AllowedMethods: aws.StringSlice([]string{http.MethodGet, http.MethodHead}),
AllowedOrigins: aws.StringSlice(origins),
AllowedHeaders: aws.StringSlice([]string{"*"}),
}},
},
})
return err
}
// Redirect is used when one wants to serve files from a different external server.
func (ah *awshandler) Redirect(method, url string) (string, error) {
if method == "PUT" || method == "POST" {
return "", nil
}
fid := ah.GetIdFromUrl(url)
if fid.IsZero() {
return "", types.ErrNotFound
}
fd, err := ah.getFileRecord(fid)
if err != nil {
return "", err
}
var req *request.Request
if method == "GET" {
req, _ = ah.svc.GetObjectRequest(&s3.GetObjectInput{
Bucket: aws.String(ah.conf.BucketName),
Key: aws.String(fid.String32()),
ResponseContentType: aws.String(fd.MimeType),
})
} else if method == "HEAD" {
req, _ = ah.svc.HeadObjectRequest(&s3.HeadObjectInput{
Bucket: aws.String(ah.conf.BucketName),
Key: aws.String(fid.String32()),
})
}
if req != nil {
// Presign for 2 minutes.
return req.Presign(time.Minute * 2)
}
return "", nil
}
// Upload processes request for a file upload. The file is given as io.Reader.
func (ah *awshandler) Upload(fdef *types.FileDef, file io.ReadSeeker) (string, error) {
var err error
key := fdef.Uid().String32()
fdef.Location = key
uploader := s3manager.NewUploaderWithClient(ah.svc)
if err = store.Files.StartUpload(fdef); err != nil {
log.Println("failed to create file record", fdef.Id, err)
return "", err
}
rc := readerCounter{reader: file}
_, err = uploader.Upload(&s3manager.UploadInput{
Bucket: aws.String(ah.conf.BucketName),
Key: aws.String(key),
Body: &rc,
})
if err != nil {
store.Files.FinishUpload(fdef.Id, false, 0)
return "", err
}
fdef, err = store.Files.FinishUpload(fdef.Id, true, rc.count)
if err != nil {
// Best effort. Error ignored.
ah.svc.DeleteObject(&s3.DeleteObjectInput{
Bucket: aws.String(ah.conf.BucketName),
Key: aws.String(key),
})
return "", err
}
fname := fdef.Id
ext, _ := mime.ExtensionsByType(fdef.MimeType)
if len(ext) > 0 {
fname += ext[0]
}
log.Println("aws upload success ", fname, "key", key, "id", fdef.Id)
return ah.conf.ServeURL + fname, nil
}
// Download processes request for file download.
// The returned ReadSeekCloser must be closed after use.
func (ah *awshandler) Download(url string) (*types.FileDef, media.ReadSeekCloser, error) {
return nil, nil, types.ErrUnsupported
}
// Delete deletes files from aws by provided slice of locations.
func (ah *awshandler) Delete(locations []string) error {
toDelete := make([]s3manager.BatchDeleteObject, len(locations))
for i, key := range locations {
toDelete[i] = s3manager.BatchDeleteObject{
Object: &s3.DeleteObjectInput{
Key: aws.String(key),
Bucket: aws.String(ah.conf.BucketName),
}}
}
batcher := s3manager.NewBatchDeleteWithClient(ah.svc)
return batcher.Delete(aws.BackgroundContext(), &s3manager.DeleteObjectsIterator{
Objects: toDelete,
})
}
// GetIdFromUrl converts an attahment URL to a file UID.
func (ah *awshandler) GetIdFromUrl(url string) types.Uid {
return media.GetIdFromUrl(url, ah.conf.ServeURL)
}
// getFileRecord given file ID reads file record from the database.
func (ah *awshandler) getFileRecord(fid types.Uid) (*types.FileDef, error) {
fd, err := store.Files.Get(fid.String())
if err != nil {
return nil, err
}
if fd == nil {
return nil, types.ErrNotFound
}
return fd, nil
}
func init() {
store.RegisterMediaHandler(handlerName, &awshandler{})
}