feat: call getPreviewData (url unfurling) in a separate thread

Fixes #1678

src/app/chat/view.nim

@@ -1,6 +1,7 @@
 import NimQml, Tables, json, sequtils, chronicles, times, re, sugar, strutils, os, strformat
 import ../../status/status
 import ../../status/mailservers
+import ../../status/libstatus/chat as libstatus_chat
 import ../../status/libstatus/accounts/constants
 import ../../status/libstatus/mailservers as status_mailservers
 import ../../status/libstatus/types
@@ -386,11 +387,17 @@ QtObject:
   proc copyToClipboard*(self: ChatsView, content: string) {.slot.} =
     setClipBoardText(content)
 
-  proc getLinkPreviewData*(self: ChatsView, link: string): string {.slot.} =
-    try:
-      $self.status.chat.getLinkPreviewData(link)
-    except RpcException as e:
-      $ %* { "error": e.msg }
+  proc linkPreviewDataWasReceived*(self: ChatsView, previewData: string) {.signal.}
+
+  proc linkPreviewDataReceived(self: ChatsView, previewData: string) {.slot.} =
+    self.linkPreviewDataWasReceived(previewData)
+
+  proc getLinkPreviewData*(self: ChatsView, link: string, uuid: string) {.slot.} =
+    spawnAndSend(self, "linkPreviewDataReceived") do:
+      var success: bool
+      # We need to call directly on libstatus because going through the status model is not thread safe
+      let response = libstatus_chat.getLinkPreviewData(link, success)
+      $(%* { "result": %response, "success": %success, "uuid": %uuid })
 
   proc joinChat*(self: ChatsView, channel: string, chatTypeInt: int): int {.slot.} =
     self.status.chat.join(channel, ChatType(chatTypeInt))

src/status/chat.nim

@@ -218,9 +218,6 @@ proc clearHistory*(self: ChatModel, chatId: string) =
   let chat = self.channels[chatId]
   self.events.emit("chatHistoryCleared", ChannelArgs(chat: chat))
 
-proc getLinkPreviewData*(self: ChatModel, link: string): JsonNode =
-  result = status_chat.getLinkPreviewData(link)
-
 proc setActiveChannel*(self: ChatModel, chatId: string) =
   self.events.emit("activeChannelChanged", ChatIdArg(chatId: chatId))
 

src/status/libstatus/chat.nim

@@ -201,14 +201,16 @@ proc muteChat*(chatId: string): string =
 proc unmuteChat*(chatId: string): string =
   result = callPrivateRPC("unmuteChat".prefix, %*[chatId])
 
-proc getLinkPreviewData*(link: string): JsonNode =
+proc getLinkPreviewData*(link: string, success: var bool): JsonNode =
   let
     responseStr = callPrivateRPC("getLinkPreviewData".prefix, %*[link])
     response = Json.decode(responseStr, RpcResponseTyped[JsonNode], allowUnknownFields = false)
 
   if not response.error.isNil:
-    raise newException(RpcException, fmt"""Error getting link preview data for '{link}': {response.error.message}""")
+    success = false
+    return %* { "error": fmt"""Error getting link preview data for '{link}': {response.error.message}""" }
 
+  success = true
   response.result
 
 proc getAllComunities*(): seq[Community] =

ui/app/AppLayouts/Chat/ChatColumn/MessageComponents/LinksMessage.qml

@@ -12,6 +12,7 @@ Column {
     property string linkUrls: ""
     property var container
     property bool isCurrentUser: false
+    readonly property string uuid: Utils.uuid()
     spacing: Style.current.halfPadding
 
     ListModel {
@@ -32,6 +33,7 @@ Column {
 
         delegate: Loader {
             id: linkMessageLoader
+            property bool fetched: false
             property var linkData
             property int linkWidth: linksRepeater.width
             active: true
@@ -51,6 +53,37 @@ Column {
                     linkMessageLoader.sourceComponent = linkMessageLoader.getSourceComponent()
                 }
             }
+            Connections {
+                target: chatsModel
+                onLinkPreviewDataWasReceived: {
+                    let response
+                    try {
+                        response = JSON.parse(previewData)
+
+                    } catch (e) {
+                        console.error(previewData, e)
+                        return
+                    }
+
+
+                    if (response.uuid !== root.uuid) return
+
+                    if (!response.success) {
+                        console.error(response.result.error)
+                        return undefined
+                    }
+
+                    linkData = response.result
+
+                    if (linkData.contentType.startsWith("image/")) {
+                        return linkMessageLoader.sourceComponent = unfurledImageComponent
+                    }
+                    if (linkData.site && linkData.title) {
+                        linkData.address = link
+                        return linkMessageLoader.sourceComponent = unfurledLinkComponent
+                    }
+                }
+            }
 
             function getSourceComponent() {
                 // Reset the height in case we set it to 0 below. See note below
@@ -75,19 +108,11 @@ Column {
                     return enableLinkComponent
                 }
                 if (linkWhiteListed) {
-                    const data = chatsModel.getLinkPreviewData(link)
-                    linkData = JSON.parse(data)
-                    if (linkData.error) {
-                        console.error(linkData.error)
-                        return undefined
-                    }
-                    if (linkData.contentType.startsWith("image/")) {
-                        return unfurledImageComponent
-                    }
-                    if (linkData.site && linkData.title) {
-                        linkData.address = link
-                        return unfurledLinkComponent
+                    if (fetched) {
+                        return
                     }
+                    fetched = true
+                    return chatsModel.getLinkPreviewData(link, root.uuid)
                 }
                 // setting the height to 0 allows the "enable link" dialog to
                 // disappear correctly when appSettings.neverAskAboutUnfurlingAgain