1 files changed, 94 insertions, 0 deletions
diff --git a/internal/api/client/fileserver/servefile.go b/internal/api/client/fileserver/servefile.go
new file mode 100644
index 000000000..9823eb387
--- /dev/null
+++ b/internal/api/client/fileserver/servefile.go
@@ -0,0 +1,94 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package fileserver
+
+import (
+	"bytes"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+)
+
+// ServeFile is for serving attachments, headers, and avatars to the requester from instance storage.
+//
+// Note: to mitigate scraping attempts, no information should be given out on a bad request except "404 page not found".
+// Don't give away account ids or media ids or anything like that; callers shouldn't be able to infer anything.
+func (m *FileServer) ServeFile(c *gin.Context) {
+	l := m.log.WithFields(logrus.Fields{
+		"func":        "ServeFile",
+		"request_uri": c.Request.RequestURI,
+		"user_agent":  c.Request.UserAgent(),
+		"origin_ip":   c.ClientIP(),
+	})
+	l.Trace("received request")
+
+	authed, err := oauth.Authed(c, false, false, false, false)
+	if err != nil {
+		c.String(http.StatusNotFound, "404 page not found")
+		return
+	}
+
+	// We use request params to check what to pull out of the database/storage so check everything. A request URL should be formatted as follows:
+	// "https://example.org/fileserver/[ACCOUNT_ID]/[MEDIA_TYPE]/[MEDIA_SIZE]/[FILE_NAME]"
+	// "FILE_NAME" consists of two parts, the attachment's database id, a period, and the file extension.
+	accountID := c.Param(AccountIDKey)
+	if accountID == "" {
+		l.Debug("missing accountID from request")
+		c.String(http.StatusNotFound, "404 page not found")
+		return
+	}
+
+	mediaType := c.Param(MediaTypeKey)
+	if mediaType == "" {
+		l.Debug("missing mediaType from request")
+		c.String(http.StatusNotFound, "404 page not found")
+		return
+	}
+
+	mediaSize := c.Param(MediaSizeKey)
+	if mediaSize == "" {
+		l.Debug("missing mediaSize from request")
+		c.String(http.StatusNotFound, "404 page not found")
+		return
+	}
+
+	fileName := c.Param(FileNameKey)
+	if fileName == "" {
+		l.Debug("missing fileName from request")
+		c.String(http.StatusNotFound, "404 page not found")
+		return
+	}
+
+	content, err := m.processor.MediaGet(authed, &model.GetContentRequestForm{
+		AccountID: accountID,
+		MediaType: mediaType,
+		MediaSize: mediaSize,
+		FileName:  fileName,
+	})
+	if err != nil {
+		l.Debug(err)
+		c.String(http.StatusNotFound, "404 page not found")
+		return
+	}
+
+	c.DataFromReader(http.StatusOK, content.ContentLength, content.ContentType, bytes.NewReader(content.Content), nil)
+}