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

* Implement POST /files endpoint for APIv4

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

.gitignore

@@ -71,6 +71,7 @@ web/sass-files/sass/.sass-cache/
 data/*
 webapp/data/*
 api/data/*
+api4/data/*
 
 enterprise
 

api/file.go

@@ -4,9 +4,6 @@
 package api
 
 import (
-	"bytes"
-	_ "image/gif"
-	"io"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -16,7 +13,6 @@ import (
 	"github.com/mattermost/platform/app"
 	"github.com/mattermost/platform/model"
 	"github.com/mattermost/platform/utils"
-	_ "golang.org/x/image/bmp"
 )
 
 func InitFile() {
@@ -35,12 +31,6 @@ func InitFile() {
 }
 
 func uploadFile(c *Context, w http.ResponseWriter, r *http.Request) {
-	if len(utils.Cfg.FileSettings.DriverName) == 0 {
-		c.Err = model.NewLocAppError("uploadFile", "api.file.upload_file.storage.app_error", nil, "")
-		c.Err.StatusCode = http.StatusNotImplemented
-		return
-	}
-
 	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
@@ -70,48 +60,12 @@ func uploadFile(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	resStruct := &model.FileUploadResponse{
-		FileInfos: []*model.FileInfo{},
-		ClientIds: []string{},
+	resStruct, err := app.UploadFiles(c.TeamId, channelId, c.Session.UserId, m.File["files"], m.Value["client_ids"])
+	if err != nil {
+		c.Err = err
+		return
 	}
 
-	previewPathList := []string{}
-	thumbnailPathList := []string{}
-	imageDataList := [][]byte{}
-
-	for i, fileHeader := range m.File["files"] {
-		file, fileErr := fileHeader.Open()
-		defer file.Close()
-		if fileErr != nil {
-			http.Error(w, fileErr.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		buf := bytes.NewBuffer(nil)
-		io.Copy(buf, file)
-		data := buf.Bytes()
-
-		info, err := app.DoUploadFile(c.TeamId, channelId, c.Session.UserId, fileHeader.Filename, data)
-		if err != nil {
-			c.Err = err
-			return
-		}
-
-		if info.PreviewPath != "" || info.ThumbnailPath != "" {
-			previewPathList = append(previewPathList, info.PreviewPath)
-			thumbnailPathList = append(thumbnailPathList, info.ThumbnailPath)
-			imageDataList = append(imageDataList, data)
-		}
-
-		resStruct.FileInfos = append(resStruct.FileInfos, info)
-
-		if len(m.Value["client_ids"]) > 0 {
-			resStruct.ClientIds = append(resStruct.ClientIds, m.Value["client_ids"][i])
-		}
-	}
-
-	app.HandleImages(previewPathList, thumbnailPathList, imageDataList)
-
 	w.Write([]byte(resStruct.ToJson()))
 }
 
@@ -239,11 +193,9 @@ func getFileInfoForRequest(c *Context, r *http.Request, requireFileVisible bool)
 		return nil, NewInvalidParamError("getFileInfoForRequest", "file_id")
 	}
 
-	var info *model.FileInfo
-	if result := <-app.Srv.Store.FileInfo().Get(fileId); result.Err != nil {
-		return nil, result.Err
-	} else {
-		info = result.Data.(*model.FileInfo)
+	info, err := app.GetFileInfo(fileId)
+	if err != nil {
+		return nil, err
 	}
 
 	// only let users access files visible in a channel, unless they're the one who uploaded the file

api4/api.go

@@ -143,6 +143,7 @@ func InitApi(full bool) {
 	InitTeam()
 	InitChannel()
 	InitPost()
+	InitFile()
 	InitSystem()
 
 	app.Srv.Router.Handle("/api/v4/{anything:.*}", http.HandlerFunc(Handle404))

api4/apitestlib.go

@@ -4,7 +4,10 @@
 package api4
 
 import (
+	"bytes"
+	"io"
 	"net/http"
+	"os"
 	"reflect"
 	"runtime/debug"
 	"strconv"
@@ -17,6 +20,8 @@ import (
 	"github.com/mattermost/platform/model"
 	"github.com/mattermost/platform/store"
 	"github.com/mattermost/platform/utils"
+
+	s3 "github.com/minio/minio-go"
 )
 
 type TestHelper struct {
@@ -398,3 +403,66 @@ func CheckErrorMessage(t *testing.T, resp *model.Response, errorId string) {
 		t.Fatal("incorrect error message")
 	}
 }
+
+func readTestFile(name string) ([]byte, error) {
+	path := utils.FindDir("tests")
+	file, err := os.Open(path + "/" + name)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	data := &bytes.Buffer{}
+	if _, err := io.Copy(data, file); err != nil {
+		return nil, err
+	} else {
+		return data.Bytes(), nil
+	}
+}
+
+func cleanupTestFile(info *model.FileInfo) error {
+	if utils.Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
+		endpoint := utils.Cfg.FileSettings.AmazonS3Endpoint
+		accessKey := utils.Cfg.FileSettings.AmazonS3AccessKeyId
+		secretKey := utils.Cfg.FileSettings.AmazonS3SecretAccessKey
+		secure := *utils.Cfg.FileSettings.AmazonS3SSL
+		s3Clnt, err := s3.New(endpoint, accessKey, secretKey, secure)
+		if err != nil {
+			return err
+		}
+		bucket := utils.Cfg.FileSettings.AmazonS3Bucket
+		if err := s3Clnt.RemoveObject(bucket, info.Path); err != nil {
+			return err
+		}
+
+		if info.ThumbnailPath != "" {
+			if err := s3Clnt.RemoveObject(bucket, info.ThumbnailPath); err != nil {
+				return err
+			}
+		}
+
+		if info.PreviewPath != "" {
+			if err := s3Clnt.RemoveObject(bucket, info.PreviewPath); err != nil {
+				return err
+			}
+		}
+	} else if utils.Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
+		if err := os.Remove(utils.Cfg.FileSettings.Directory + info.Path); err != nil {
+			return err
+		}
+
+		if info.ThumbnailPath != "" {
+			if err := os.Remove(utils.Cfg.FileSettings.Directory + info.ThumbnailPath); err != nil {
+				return err
+			}
+		}
+
+		if info.PreviewPath != "" {
+			if err := os.Remove(utils.Cfg.FileSettings.Directory + info.PreviewPath); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}

api4/context.go

@@ -382,12 +382,24 @@ func (c *Context) RequirePostId() *Context {
 	return c
 }
 
+func (c *Context) RequireFileId() *Context {
+	if c.Err != nil {
+		return c
+	}
+
+	if len(c.Params.FileId) != 26 {
+		c.SetInvalidUrlParam("file_id")
+	}
+
+	return c
+}
+
 func (c *Context) RequireTeamName() *Context {
 	if c.Err != nil {
 		return c
 	}
 
-	if !model.IsValidTeamName(c.Params.TeamName){
+	if !model.IsValidTeamName(c.Params.TeamName) {
 		c.SetInvalidUrlParam("team_name")
 	}
 
@@ -401,7 +413,7 @@ func (c *Context) RequireChannelName() *Context {
 
 	if !model.IsValidChannelIdentifier(c.Params.ChannelName) {
 		c.SetInvalidUrlParam("channel_name")
-	} 
+	}
 
 	return c
 }
@@ -417,5 +429,3 @@ func (c *Context) RequireEmail() *Context {
 
 	return c
 }
-
-

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
+}

api4/file_test.go

@@ -0,0 +1,151 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package api4
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/mattermost/platform/app"
+	"github.com/mattermost/platform/model"
+	"github.com/mattermost/platform/utils"
+)
+
+func TestUploadFile(t *testing.T) {
+	th := Setup().InitBasic().InitSystemAdmin()
+	defer TearDown()
+	Client := th.Client
+
+	user := th.BasicUser
+	channel := th.BasicChannel
+
+	var uploadInfo *model.FileInfo
+	var data []byte
+	var err error
+	if data, err = readTestFile("test.png"); err != nil {
+		t.Fatal(err)
+	} else if fileResp, resp := Client.UploadFile(data, channel.Id, "test.png"); resp.Error != nil {
+		t.Fatal(resp.Error)
+	} else if len(fileResp.FileInfos) != 1 {
+		t.Fatal("should've returned a single file infos")
+	} else {
+		uploadInfo = fileResp.FileInfos[0]
+	}
+
+	// The returned file info from the upload call will be missing some fields that will be stored in the database
+	if uploadInfo.CreatorId != user.Id {
+		t.Fatal("file should be assigned to user")
+	} else if uploadInfo.PostId != "" {
+		t.Fatal("file shouldn't have a post")
+	} else if uploadInfo.Path != "" {
+		t.Fatal("file path should not be set on returned info")
+	} else if uploadInfo.ThumbnailPath != "" {
+		t.Fatal("file thumbnail path should not be set on returned info")
+	} else if uploadInfo.PreviewPath != "" {
+		t.Fatal("file preview path should not be set on returned info")
+	}
+
+	var info *model.FileInfo
+	if result := <-app.Srv.Store.FileInfo().Get(uploadInfo.Id); result.Err != nil {
+		t.Fatal(result.Err)
+	} else {
+		info = result.Data.(*model.FileInfo)
+	}
+
+	if info.Id != uploadInfo.Id {
+		t.Fatal("file id from response should match one stored in database")
+	} else if info.CreatorId != user.Id {
+		t.Fatal("file should be assigned to user")
+	} else if info.PostId != "" {
+		t.Fatal("file shouldn't have a post")
+	} else if info.Path == "" {
+		t.Fatal("file path should be set in database")
+	} else if info.ThumbnailPath == "" {
+		t.Fatal("file thumbnail path should be set in database")
+	} else if info.PreviewPath == "" {
+		t.Fatal("file preview path should be set in database")
+	}
+
+	// This also makes sure that the relative path provided above is sanitized out
+	expectedPath := fmt.Sprintf("teams/%v/channels/%v/users/%v/%v/test.png", FILE_TEAM_ID, channel.Id, user.Id, info.Id)
+	if info.Path != expectedPath {
+		t.Logf("file is saved in %v", info.Path)
+		t.Fatalf("file should've been saved in %v", expectedPath)
+	}
+
+	expectedThumbnailPath := fmt.Sprintf("teams/%v/channels/%v/users/%v/%v/test_thumb.jpg", FILE_TEAM_ID, channel.Id, user.Id, info.Id)
+	if info.ThumbnailPath != expectedThumbnailPath {
+		t.Logf("file thumbnail is saved in %v", info.ThumbnailPath)
+		t.Fatalf("file thumbnail should've been saved in %v", expectedThumbnailPath)
+	}
+
+	expectedPreviewPath := fmt.Sprintf("teams/%v/channels/%v/users/%v/%v/test_preview.jpg", FILE_TEAM_ID, channel.Id, user.Id, info.Id)
+	if info.PreviewPath != expectedPreviewPath {
+		t.Logf("file preview is saved in %v", info.PreviewPath)
+		t.Fatalf("file preview should've been saved in %v", expectedPreviewPath)
+	}
+
+	// Wait a bit for files to ready
+	time.Sleep(2 * time.Second)
+
+	if err := cleanupTestFile(info); err != nil {
+		t.Fatal(err)
+	}
+
+	_, resp := Client.UploadFile(data, model.NewId(), "test.png")
+	CheckForbiddenStatus(t, resp)
+
+	_, resp = th.SystemAdminClient.UploadFile(data, channel.Id, "test.png")
+	CheckNoError(t, resp)
+}
+
+func TestGetFile(t *testing.T) {
+	th := Setup().InitBasic().InitSystemAdmin()
+	defer TearDown()
+	Client := th.Client
+	channel := th.BasicChannel
+
+	if utils.Cfg.FileSettings.DriverName == "" {
+		t.Skip("skipping because no file driver is enabled")
+	}
+
+	fileId := ""
+	var sent []byte
+	var err error
+	if sent, err = readTestFile("test.png"); err != nil {
+		t.Fatal(err)
+	} else {
+		fileResp, resp := Client.UploadFile(sent, channel.Id, "test.png")
+		CheckNoError(t, resp)
+
+		fileId = fileResp.FileInfos[0].Id
+	}
+
+	data, resp := Client.GetFile(fileId)
+	CheckNoError(t, resp)
+
+	if data == nil || len(data) == 0 {
+		t.Fatal("should not be empty")
+	}
+
+	for i := range data {
+		if data[i] != sent[i] {
+			t.Fatal("received file didn't match sent one")
+		}
+	}
+
+	_, resp = Client.GetFile("junk")
+	CheckBadRequestStatus(t, resp)
+
+	_, resp = Client.GetFile(model.NewId())
+	CheckNotFoundStatus(t, resp)
+
+	Client.Logout()
+	_, resp = Client.GetFile(fileId)
+	CheckUnauthorizedStatus(t, resp)
+
+	_, resp = th.SystemAdminClient.GetFile(fileId)
+	CheckNoError(t, resp)
+}

app/file.go

@@ -15,6 +15,7 @@ import (
 	"image/jpeg"
 	"io"
 	"io/ioutil"
+	"mime/multipart"
 	"net/http"
 	"net/url"
 	"os"
@@ -370,6 +371,54 @@ func GeneratePublicLinkHash(fileId, salt string) string {
 	return base64.RawURLEncoding.EncodeToString(hash.Sum(nil))
 }
 
+func UploadFiles(teamId string, channelId string, userId string, fileHeaders []*multipart.FileHeader, clientIds []string) (*model.FileUploadResponse, *model.AppError) {
+	if len(utils.Cfg.FileSettings.DriverName) == 0 {
+		return nil, model.NewAppError("uploadFile", "api.file.upload_file.storage.app_error", nil, "", http.StatusNotImplemented)
+	}
+
+	resStruct := &model.FileUploadResponse{
+		FileInfos: []*model.FileInfo{},
+		ClientIds: []string{},
+	}
+
+	previewPathList := []string{}
+	thumbnailPathList := []string{}
+	imageDataList := [][]byte{}
+
+	for i, fileHeader := range fileHeaders {
+		file, fileErr := fileHeader.Open()
+		defer file.Close()
+		if fileErr != nil {
+			return nil, model.NewAppError("UploadFiles", "api.file.upload_file.bad_parse.app_error", nil, fileErr.Error(), http.StatusBadRequest)
+		}
+
+		buf := bytes.NewBuffer(nil)
+		io.Copy(buf, file)
+		data := buf.Bytes()
+
+		info, err := DoUploadFile(teamId, channelId, userId, fileHeader.Filename, data)
+		if err != nil {
+			return nil, err
+		}
+
+		if info.PreviewPath != "" || info.ThumbnailPath != "" {
+			previewPathList = append(previewPathList, info.PreviewPath)
+			thumbnailPathList = append(thumbnailPathList, info.ThumbnailPath)
+			imageDataList = append(imageDataList, data)
+		}
+
+		resStruct.FileInfos = append(resStruct.FileInfos, info)
+
+		if len(clientIds) > 0 {
+			resStruct.ClientIds = append(resStruct.ClientIds, clientIds[i])
+		}
+	}
+
+	HandleImages(previewPathList, thumbnailPathList, imageDataList)
+
+	return resStruct, nil
+}
+
 func DoUploadFile(teamId string, channelId string, userId string, rawFilename string, data []byte) (*model.FileInfo, *model.AppError) {
 	filename := filepath.Base(rawFilename)
 
@@ -527,3 +576,11 @@ func generatePreviewImage(img image.Image, previewPath string, width int) {
 		return
 	}
 }
+
+func GetFileInfo(fileId string) (*model.FileInfo, *model.AppError) {
+	if result := <-Srv.Store.FileInfo().Get(fileId); result.Err != nil {
+		return nil, result.Err
+	} else {
+		return result.Data.(*model.FileInfo), nil
+	}
+}

i18n/en.json

@@ -1165,6 +1165,10 @@
     "id": "api.file.upload_file.too_large.app_error",
     "translation": "Unable to upload file. File is too large."
   },
+  {
+    "id": "api.file.upload_file.bad_parse.app_error",
+    "translation": "Unable to upload file. Header cannot be parsed."
+  },
   {
     "id": "api.file.write_file.configured.app_error",
     "translation": "File storage not configured properly. Please configure for either S3 or local server file storage."
@@ -3519,6 +3523,10 @@
     "id": "model.channel_member.is_valid.user_id.app_error",
     "translation": "Invalid user id"
   },
+  {
+    "id": "model.client.read_file.app_error",
+    "translation": "We encountered an error while reading the file"
+  },
   {
     "id": "model.client.connecting.app_error",
     "translation": "We encountered an error while connecting to the server"

model/client4.go

@@ -4,7 +4,11 @@
 package model
 
 import (
+	"bytes"
 	"fmt"
+	"io"
+	"io/ioutil"
+	"mime/multipart"
 	"net/http"
 	"strings"
 )
@@ -112,6 +116,14 @@ func (c *Client4) GetPostRoute(postId string) string {
 	return fmt.Sprintf(c.GetPostsRoute()+"/%v", postId)
 }
 
+func (c *Client4) GetFilesRoute() string {
+	return fmt.Sprintf("/files")
+}
+
+func (c *Client4) GetFileRoute(fileId string) string {
+	return fmt.Sprintf(c.GetFilesRoute()+"/%v", fileId)
+}
+
 func (c *Client4) GetSystemRoute() string {
 	return fmt.Sprintf("/system")
 }
@@ -156,6 +168,25 @@ func (c *Client4) DoApiRequest(method, url, data, etag string) (*http.Response,
 	}
 }
 
+func (c *Client4) DoUploadFile(url string, data []byte, contentType string) (*FileUploadResponse, *Response) {
+	rq, _ := http.NewRequest("POST", c.ApiUrl+url, bytes.NewReader(data))
+	rq.Header.Set("Content-Type", contentType)
+	rq.Close = true
+
+	if len(c.AuthToken) > 0 {
+		rq.Header.Set(HEADER_AUTH, c.AuthType+" "+c.AuthToken)
+	}
+
+	if rp, err := c.HttpClient.Do(rq); err != nil {
+		return nil, &Response{Error: NewAppError(url, "model.client.connecting.app_error", nil, err.Error(), 0)}
+	} else if rp.StatusCode >= 300 {
+		return nil, &Response{StatusCode: rp.StatusCode, Error: AppErrorFromJson(rp.Body)}
+	} else {
+		defer closeBody(rp)
+		return FileUploadResponseFromJson(rp.Body), BuildResponse(rp)
+	}
+}
+
 // CheckStatusOK is a convenience function for checking the standard OK response
 // from the web service.
 func CheckStatusOK(r *http.Response) bool {
@@ -595,6 +626,46 @@ func (c *Client4) GetPostsForChannel(channelId string, page, perPage int, etag s
 	}
 }
 
+// File Section
+
+// UploadFile will upload a file to a channel, to be later attached to a post.
+func (c *Client4) UploadFile(data []byte, channelId string, filename string) (*FileUploadResponse, *Response) {
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+
+	if part, err := writer.CreateFormFile("files", filename); err != nil {
+		return nil, &Response{Error: NewAppError("UploadPostAttachment", "model.client.upload_post_attachment.file.app_error", nil, err.Error(), http.StatusBadRequest)}
+	} else if _, err = io.Copy(part, bytes.NewBuffer(data)); err != nil {
+		return nil, &Response{Error: NewAppError("UploadPostAttachment", "model.client.upload_post_attachment.file.app_error", nil, err.Error(), http.StatusBadRequest)}
+	}
+
+	if part, err := writer.CreateFormField("channel_id"); err != nil {
+		return nil, &Response{Error: NewAppError("UploadPostAttachment", "model.client.upload_post_attachment.channel_id.app_error", nil, err.Error(), http.StatusBadRequest)}
+	} else if _, err = io.Copy(part, strings.NewReader(channelId)); err != nil {
+		return nil, &Response{Error: NewAppError("UploadPostAttachment", "model.client.upload_post_attachment.channel_id.app_error", nil, err.Error(), http.StatusBadRequest)}
+	}
+
+	if err := writer.Close(); err != nil {
+		return nil, &Response{Error: NewAppError("UploadPostAttachment", "model.client.upload_post_attachment.writer.app_error", nil, err.Error(), http.StatusBadRequest)}
+	}
+
+	return c.DoUploadFile(c.GetFilesRoute(), body.Bytes(), writer.FormDataContentType())
+}
+
+// GetFile gets the bytes for a file by id.
+func (c *Client4) GetFile(fileId string) ([]byte, *Response) {
+	if r, err := c.DoApiGet(c.GetFileRoute(fileId), ""); err != nil {
+		return nil, &Response{StatusCode: r.StatusCode, Error: err}
+	} else if data, err := ioutil.ReadAll(r.Body); err != nil {
+		return nil, &Response{StatusCode: r.StatusCode, Error: NewAppError("GetFile", "model.client.read_file.app_error", nil, err.Error(), r.StatusCode)}
+	} else {
+		return data, BuildResponse(r)
+	}
+}
+
+// General Section
+
+// GetPing will ping the server and to see if it is up and running.
 func (c *Client4) GetPing() (bool, *Response) {
 	if r, err := c.DoApiGet(c.GetSystemRoute()+"/ping", ""); err != nil {
 		return false, &Response{StatusCode: r.StatusCode, Error: err}
@@ -603,6 +674,3 @@ func (c *Client4) GetPing() (bool, *Response) {
 		return CheckStatusOK(r), BuildResponse(r)
 	}
 }
-
-// Files Section
-// to be filled in..

store/sql_file_info_store.go

@@ -3,6 +3,9 @@
 package store
 
 import (
+	"database/sql"
+	"net/http"
+
 	"github.com/mattermost/platform/einterfaces"
 	"github.com/mattermost/platform/model"
 	"github.com/mattermost/platform/utils"
@@ -91,7 +94,11 @@ func (fs SqlFileInfoStore) Get(id string) StoreChannel {
 			WHERE
 				Id = :Id
 				AND DeleteAt = 0`, map[string]interface{}{"Id": id}); err != nil {
-			result.Err = model.NewLocAppError("SqlFileInfoStore.Get", "store.sql_file_info.get.app_error", nil, "id="+id+", "+err.Error())
+			if err == sql.ErrNoRows {
+				result.Err = model.NewAppError("SqlFileInfoStore.Get", "store.sql_file_info.get.app_error", nil, "id="+id+", "+err.Error(), http.StatusNotFound)
+			} else {
+				result.Err = model.NewLocAppError("SqlFileInfoStore.Get", "store.sql_file_info.get.app_error", nil, "id="+id+", "+err.Error())
+			}
 		} else {
 			result.Data = info
 		}