[feature] Stream files via reader (#404)

* serve files via reader rather than byte slice

* close readcloser when we're done with it

* cast reader to readcloser

internal/api/client/fileserver/servefile.go

@@ -19,7 +19,7 @@
 package fileserver
 
 import (
-	"bytes"
+	"io"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
@@ -91,6 +91,15 @@ func (m *FileServer) ServeFile(c *gin.Context) {
 		return
 	}
 
+	defer func() {
+		// if the content is a ReadCloser, close it when we're done
+		if closer, ok := content.Content.(io.ReadCloser); ok {
+			if err := closer.Close(); err != nil {
+				l.Errorf("error closing readcloser: %s", err)
+			}
+		}
+	}()
+
 	// TODO: if the requester only accepts text/html we should try to serve them *something*.
 	// This is mostly needed because when sharing a link to a gts-hosted file on something like mastodon, the masto servers will
 	// attempt to look up the content to provide a preview of the link, and they ask for text/html.
@@ -100,5 +109,5 @@ func (m *FileServer) ServeFile(c *gin.Context) {
 		return
 	}
 
-	c.DataFromReader(http.StatusOK, content.ContentLength, format, bytes.NewReader(content.Content), nil)
+	c.DataFromReader(http.StatusOK, content.ContentLength, format, content.Content, nil)
 }

internal/api/model/content.go

@@ -18,14 +18,16 @@
 
 package model
 
+import "io"
+
 // Content wraps everything needed to serve a blob of content (some kind of media) through the API.
 type Content struct {
 	// MIME content type
 	ContentType string
 	// ContentLength in bytes
 	ContentLength int64
-	// Actual content blob
-	Content []byte
+	// Actual content
+	Content io.Reader
 }
 
 // GetContentRequestForm describes a piece of content desired by the caller of the fileserver API.

internal/processing/media/getfile.go

@@ -83,9 +83,11 @@ func (p *processor) GetFile(ctx context.Context, account *gtsmodel.Account, form
 		switch mediaSize {
 		case media.SizeOriginal:
 			content.ContentType = e.ImageContentType
+			content.ContentLength = int64(e.ImageFileSize)
 			storagePath = e.ImagePath
 		case media.SizeStatic:
 			content.ContentType = e.ImageStaticContentType
+			content.ContentLength = int64(e.ImageStaticFileSize)
 			storagePath = e.ImageStaticPath
 		default:
 			return nil, gtserror.NewErrorNotFound(fmt.Errorf("media size %s not recognized for emoji", mediaSize))
@@ -101,21 +103,22 @@ func (p *processor) GetFile(ctx context.Context, account *gtsmodel.Account, form
 		switch mediaSize {
 		case media.SizeOriginal:
 			content.ContentType = a.File.ContentType
+			content.ContentLength = int64(a.File.FileSize)
 			storagePath = a.File.Path
 		case media.SizeSmall:
 			content.ContentType = a.Thumbnail.ContentType
+			content.ContentLength = int64(a.Thumbnail.FileSize)
 			storagePath = a.Thumbnail.Path
 		default:
 			return nil, gtserror.NewErrorNotFound(fmt.Errorf("media size %s not recognized for attachment", mediaSize))
 		}
 	}
 
-	bytes, err := p.storage.Get(storagePath)
+	reader, err := p.storage.GetStream(storagePath)
 	if err != nil {
 		return nil, gtserror.NewErrorNotFound(fmt.Errorf("error retrieving from storage: %s", err))
 	}
 
-	content.ContentLength = int64(len(bytes))
-	content.Content = bytes
+	content.Content = reader
 	return content, nil
 }