Implement upload and get file endpoints for APIv4 (#5396)

* Implement POST /files endpoint for APIv4

* Implement GET /files/{file_id} endpoint for APIv4

1 files changed, 114 insertions, 0 deletions

diff --git a/api4/file.go b/api4/file.go
new file mode 100644
index 000000000..b486fc220
--- /dev/null
+++ b/api4/file.go
@@ -0,0 +1,114 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package api4
+
+import (
+	"net/http"
+	"net/url"
+	"strconv"
+
+	l4g "github.com/alecthomas/log4go"
+	"github.com/mattermost/platform/app"
+	"github.com/mattermost/platform/model"
+	"github.com/mattermost/platform/utils"
+)
+
+const (
+	FILE_TEAM_ID = "noteam"
+)
+
+func InitFile() {
+	l4g.Debug(utils.T("api.file.init.debug"))
+
+	BaseRoutes.Files.Handle("", ApiSessionRequired(uploadFile)).Methods("POST")
+	BaseRoutes.File.Handle("", ApiSessionRequired(getFile)).Methods("GET")
+
+}
+
+func uploadFile(c *Context, w http.ResponseWriter, r *http.Request) {
+	if r.ContentLength > *utils.Cfg.FileSettings.MaxFileSize {
+		c.Err = model.NewLocAppError("uploadFile", "api.file.upload_file.too_large.app_error", nil, "")
+		c.Err.StatusCode = http.StatusRequestEntityTooLarge
+		return
+	}
+
+	if err := r.ParseMultipartForm(*utils.Cfg.FileSettings.MaxFileSize); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	m := r.MultipartForm
+
+	props := m.Value
+	if len(props["channel_id"]) == 0 {
+		c.SetInvalidParam("channel_id")
+		return
+	}
+	channelId := props["channel_id"][0]
+	if len(channelId) == 0 {
+		c.SetInvalidParam("channel_id")
+		return
+	}
+
+	if !app.SessionHasPermissionToChannel(c.Session, channelId, model.PERMISSION_UPLOAD_FILE) {
+		c.SetPermissionError(model.PERMISSION_UPLOAD_FILE)
+		return
+	}
+
+	resStruct, err := app.UploadFiles(FILE_TEAM_ID, channelId, c.Session.UserId, m.File["files"], m.Value["client_ids"])
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	w.WriteHeader(http.StatusCreated)
+	w.Write([]byte(resStruct.ToJson()))
+}
+
+func getFile(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireFileId()
+	if c.Err != nil {
+		return
+	}
+
+	info, err := app.GetFileInfo(c.Params.FileId)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	if info.CreatorId != c.Session.UserId && !app.SessionHasPermissionToChannelByPost(c.Session, info.PostId, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	}
+
+	if data, err := app.ReadFile(info.Path); err != nil {
+		c.Err = err
+		c.Err.StatusCode = http.StatusNotFound
+	} else if err := writeFileResponse(info.Name, info.MimeType, data, w, r); err != nil {
+		c.Err = err
+		return
+	}
+}
+
+func writeFileResponse(filename string, contentType string, bytes []byte, w http.ResponseWriter, r *http.Request) *model.AppError {
+	w.Header().Set("Cache-Control", "max-age=2592000, public")
+	w.Header().Set("Content-Length", strconv.Itoa(len(bytes)))
+
+	if contentType != "" {
+		w.Header().Set("Content-Type", contentType)
+	} else {
+		w.Header().Del("Content-Type") // Content-Type will be set automatically by the http writer
+	}
+
+	w.Header().Set("Content-Disposition", "attachment;filename=\""+filename+"\"; filename*=UTF-8''"+url.QueryEscape(filename))
+
+	// prevent file links from being embedded in iframes
+	w.Header().Set("X-Frame-Options", "DENY")
+	w.Header().Set("Content-Security-Policy", "Frame-ancestors 'none'")
+
+	w.Write(bytes)
+
+	return nil
+}