server: custom redirect status code and expiration

.env.example

@@ -12,3 +12,6 @@ AWS_SECRET_KEY=example-minio-secret
 # accessible S3 gateway
 OBS_REDIRECT_SECURE=false
 OBS_HOST_REDIRECT=127.0.0.1:9000
+
+# OBS_REDIRECT_CODE=307 # temporary redirect
+# OBS_URL_EXPIRY=48h # 2 days

.gitignore

@@ -1 +1,2 @@
 .env
+obs-access-signer

README.md

@@ -10,6 +10,8 @@ There's an example of using it with Varnish Cache, which you can see [here](dock
 
 Some S3-compatible gateways might not support ACL endpoints but they support presigned access. Currently, the behavior of `obs-access-signer` is similar to `public-read` ACL where clients can access objects anonymously and redirect them (permanently) to presigned URL with `Expires` set to the max signed value of `int64` which has roughly 250yrs lifetime since UNIX time started.
 
+Update: starting at v0.0.3, obs-access-signer support custom redirection status code and expiry.
+
 ## License
 
 Apache-2.0

main.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"os"
 	"strconv"
+	"time"
 
 	_ "github.com/joho/godotenv/autoload"
 	"go.uber.org/zap"
@@ -13,7 +14,6 @@ import (
 var (
 	httpAddr      string
 	logLevel      string
-	// obsSignedUrlExpiry time.Duration
 	zapLogLevel   zapcore.Level
 	postFlagParse = []func(){}
 )
@@ -22,10 +22,10 @@ func init() {
 	var err error
 	_ = err
 
-	// app
+	// -- app
 	flag.StringVar(&httpAddr, "addr", os.Getenv("HTTP_ADDR"), "Server address")
 
-	// log
+	// -- log
 	flag.StringVar(&logLevel, "log-level", os.Getenv("LOG_LEVEL"), "Log level")
 	qpostFlagParse(func() {
 		err := zapLogLevel.UnmarshalText([]byte(logLevel))
@@ -34,7 +34,7 @@ func init() {
 		}
 	})
 
-	// OBS
+	// -- OBS
 	flag.StringVar(&defaultObsOpts.Endpoint, "obs-endpoint", os.Getenv("OBS_ENDPOINT"), "OBS host")
 	flag.StringVar(&defaultObsOpts.Region, "obs-region", os.Getenv("OBS_REGION"), "OBS region")
 	flag.BoolVar(&defaultObsOpts.Secure, "obs-secure", ok1(strconv.ParseBool(os.Getenv("OBS_SECURE"))), "OBS secure transport")
@@ -43,12 +43,25 @@ func init() {
 	flag.BoolVar(&defaultObsOpts.RedirectSecure, "obs-redirect-secure", ok1(strconv.ParseBool(os.Getenv("OBS_REDIRECT_SECURE"))), "OBS redirect secure transport")
 	flag.StringVar(&defaultObsOpts.HostRedirect, "obs-host-redirect", os.Getenv("OBS_HOST_REDIRECT"), "OBS host redirect")
 
-	// obsSignedUrlExpiry, err = time.ParseDuration(os.Getenv("OBS_SIGNED_URL_EXPIRY"))
-	// if err != nil {
-	// 	// max signed value
-	// 	obsSignedUrlExpiry = time.Duration(^uint64(0) / 2)
-	// }
-	// flag.DurationVar(&obsSignedUrlExpiry, "obs-signed-url-expiry", obsSignedUrlExpiry, "OBS ")
+	// redirect http code
+	var obsRedirectCode = int64(defaultObsOpts.RedirectCode)
+	if obsRedirectCodeStr := os.Getenv("OBS_REDIRECT_CODE"); obsRedirectCodeStr != "" {
+		obsRedirectCode, err = strconv.ParseInt(obsRedirectCodeStr, 10, 64)
+		if err != nil {
+			obsRedirectCode = int64(defaultObsOpts.RedirectCode)
+		}
+	}
+	flag.IntVar(&defaultObsOpts.RedirectCode, "obs-redirect-code", int(obsRedirectCode), "OBS redirect http code")
+
+	// url expiry
+	var obsUrlExpiry = defaultObsOpts.URLExpiry
+	if obsUrlExpiryStr := os.Getenv("OBS_URL_EXPIRY"); obsUrlExpiryStr != "" {
+		if obsUrlExpiry, err = time.ParseDuration(obsUrlExpiryStr); err != nil {
+			obsUrlExpiry = defaultObsOpts.URLExpiry
+		}
+	}
+	flag.DurationVar(&defaultObsOpts.URLExpiry, "obs-url-expiry", obsUrlExpiry, "OBS url expiry")
+
 }
 
 func qpostFlagParse(f func()) {
@@ -77,6 +90,8 @@ func main() {
 		"obs_endpoint", defaultObsOpts.Endpoint,
 		"obs_redirect_secure", defaultObsOpts.RedirectSecure,
 		"obs_host_redirect", defaultObsOpts.HostRedirect,
+		"obs_redirect_code", defaultObsOpts.RedirectCode,
+		"obs_url_expiry", defaultObsOpts.URLExpiry.String(),
 	)
 
 	client := unwrap1(newObsClient(defaultObsOpts))

obs.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/url"
 	"reflect"
+	"time"
 	"unsafe"
 
 	"github.com/minio/minio-go/v7"
@@ -21,10 +22,17 @@ type obsOptions struct {
 	BucketName string
 
 	RedirectSecure bool
+	RedirectCode   int // HTTP redirect status code
+	URLExpiry      time.Duration
 	HostRedirect   string
 }
 
-var defaultObsOpts obsOptions
+const maxURLExpiry = time.Duration(int64(^uint64(0) / 2))
+
+var defaultObsOpts = obsOptions{
+	URLExpiry:    maxURLExpiry,
+	RedirectCode: http.StatusMovedPermanently, // 301
+}
 
 func newObsClient(opts obsOptions) (*minio.Client, error) {
 	client, err := minio.New(opts.Endpoint, &minio.Options{

server.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"fmt"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -24,8 +25,6 @@ type serverOptions struct {
 	Logger *zap.Logger
 	OBS    *obsOptions
 
-	ObjectExpiry time.Duration
-
 	S3 *minio.Client
 }
 
@@ -99,11 +98,12 @@ func (s *server) handle(ctx *fasthttp.RequestCtx) {
 	}
 
 	// compose initial request
+	expireSeconds := int64(s.opts.OBS.URLExpiry / time.Second)
 	req, err := newRequest(s.opts.S3, ctx, http.MethodGet, requestMetadata{
 		presignURL:  true,
 		bucketName:  bucketName,
 		objectName:  objectName,
-		expires:     1, // to trigger presigned generator
+		expires:     expireSeconds, // to trigger presigned generator
 		queryValues: url.Values{},
 	})
 	if err != nil {
@@ -120,8 +120,28 @@ func (s *server) handle(ctx *fasthttp.RequestCtx) {
 		return
 	}
 
+	var statusCode = s.opts.OBS.RedirectCode
+
+	// custom "expiry"
+	var exp string
+	if expiry := s.opts.OBS.URLExpiry; expiry == maxURLExpiry || expiry <= 0 {
 		// clear given params, set max signed value for expire, and re-presign.
-	exp := strconv.FormatInt(int64(^uint64(0)/2), 10) // ~250years
+		exp = strconv.FormatInt(int64(^uint64(0)/2), 10) // ~250years
+	} else {
+		// we can't allow a permanent redirect here since we already have
+		// expiry set, the redirected url needs to be updated.
+		if statusCode == http.StatusMovedPermanently || (statusCode < 300 || statusCode > 399) {
+			statusCode = http.StatusTemporaryRedirect
+		}
+
+		expireAt := time.Now().UTC().Add(s.opts.OBS.URLExpiry)
+		exp = strconv.FormatInt(int64(expireAt.Unix()), 10)
+		// set object cache lifetime
+		if statusCode == http.StatusTemporaryRedirect {
+			ctx.Response.Header.Set("Cache-Control", fmt.Sprintf("max-age=%d", expireSeconds))
+			ctx.Response.Header.Set("Expires", expireAt.Format("Mon, 02 Jan 2006 15:04:05 GMT"))
+		}
+	}
 	req.Header.Set("Expires", exp)
 	req.URL.RawQuery = ""
 	req = signer.PreSignV2(*req, value.AccessKeyID, value.SecretAccessKey, 0, isVirtualHostStyle)
@@ -130,6 +150,7 @@ func (s *server) handle(ctx *fasthttp.RequestCtx) {
 	query := req.URL.Query()
 	query.Set("Expires", exp)
 	req.URL.RawQuery = s3utils.QueryEncode(query)
+
 	if s.opts.OBS.RedirectSecure {
 		req.URL.Scheme = "https"
 	} else {
@@ -140,7 +161,7 @@ func (s *server) handle(ctx *fasthttp.RequestCtx) {
 		req.URL.Host = hostRedirect
 	}
 
-	ctx.Redirect(req.URL.String(), http.StatusMovedPermanently)
+	ctx.Redirect(req.URL.String(), statusCode)
 }
 
 func (s *server) Run() {