PLT-3105 Files table migration (#4068)

* Implemented initial changes for files table

* Removed *_benchmark_test.go files

* Re-implemented GetPublicFile and added support for old path

* Localization for files table

* Moved file system code into utils package

* Finished server-side changes and added initial upgrade script

* Added getPostFiles api

* Re-add Extension and HasPreviewImage fields to FileInfo

* Removed unused translation

* Fixed merge conflicts left over after permissions changes

* Forced FileInfo.extension to be lower case

* Changed FileUploadResponse to contain the FileInfos instead of FileIds

* Fixed permissions on getFile* calls

* Fixed notifications for file uploads

* Added initial version of client code for files changes

* Permanently added FileIds field to Post object and removed Post.HasFiles

* Updated PostStore.Update to be usable in more circumstances

* Re-added Filenames field and switched file migration to be entirely lazy-loaded

* Increased max listener count for FileStore

* Removed unused fileInfoCache

* Moved file system code back into api

* Removed duplicate test case

* Fixed unit test running on ports other than 8065

* Renamed HasPermissionToPostContext to HasPermissionToChannelByPostContext

* Refactored handleImages to make it more easily understandable

* Renamed getPostFiles to getFileInfosForPost

* Re-added pre-FileIds posts to analytics

* Changed files to be saved as their ids as opposed to id/filename.ext

* Renamed FileInfo.UserId to FileInfo.CreatorId

* Fixed detection of language in CodePreview

* Fixed switching between threads in the RHS not loading new files

* Add serverside protection against a rare bug where the client sends the same file twice for a single post

* Refactored the important parts of uploadFile api call into a function that can be called without a web context

webapp/utils/async_client.jsx

@@ -715,6 +715,32 @@ export function getPostsAfter(postId, offset, numPost, isPost) {
     );
 }
 
+export function getFileInfosForPost(channelId, postId) {
+    const callName = 'getFileInfosForPost' + postId;
+
+    if (isCallInProgress(callName)) {
+        return;
+    }
+
+    Client.getFileInfosForPost(
+        channelId,
+        postId,
+        (data) => {
+            callTracker[callName] = 0;
+
+            AppDispatcher.handleServerAction({
+                type: ActionTypes.RECEIVED_FILE_INFOS,
+                postId,
+                infos: data
+            });
+        },
+        (err) => {
+            callTracker[callName] = 0;
+            dispatchError(err, 'getPostFile');
+        }
+    );
+}
+
 export function getMe() {
     if (isCallInProgress('getMe')) {
         return null;
@@ -923,34 +949,6 @@ export function getSuggestedCommands(command, suggestionId, component) {
     );
 }
 
-export function getFileInfo(filename) {
-    const callName = 'getFileInfo' + filename;
-
-    if (isCallInProgress(callName)) {
-        return;
-    }
-
-    callTracker[callName] = utils.getTimestamp();
-
-    Client.getFileInfo(
-        filename,
-        (data) => {
-            callTracker[callName] = 0;
-
-            AppDispatcher.handleServerAction({
-                type: ActionTypes.RECEIVED_FILE_INFO,
-                filename,
-                info: data
-            });
-        },
-        (err) => {
-            callTracker[callName] = 0;
-
-            dispatchError(err, 'getFileInfo');
-        }
-    );
-}
-
 export function getStandardAnalytics(teamId) {
     const callName = 'getStandardAnaytics' + teamId;
 
@@ -1432,8 +1430,8 @@ export function regenCommandToken(id) {
     );
 }
 
-export function getPublicLink(filename, success, error) {
-    const callName = 'getPublicLink' + filename;
+export function getPublicLink(fileId, success, error) {
+    const callName = 'getPublicLink' + fileId;
 
     if (isCallInProgress(callName)) {
         return;
@@ -1442,7 +1440,7 @@ export function getPublicLink(filename, success, error) {
     callTracker[callName] = utils.getTimestamp();
 
     Client.getPublicLink(
-        filename,
+        fileId,
         (link) => {
             callTracker[callName] = 0;