track in-progress preflights (fixes #2965) (#3004)

* track in-progress preflights (fixes #2965)

* Update assets/js/phoenix_live_view/upload_entry.js

---------

Co-authored-by: Chris McCord <chris@chrismccord.com>

assets/js/phoenix_live_view/live_uploader.js

@@ -94,7 +94,11 @@ export default class LiveUploader {
   }
 
   static filesAwaitingPreflight(input){
-    return this.activeFiles(input).filter(f => !UploadEntry.isPreflighted(input, f))
+    return this.activeFiles(input).filter(f => !UploadEntry.isPreflighted(input, f) && !UploadEntry.isPreflightInProgress(f))
+  }
+
+  static markPreflightInProgress(entries){
+    entries.forEach(entry => UploadEntry.markPreflightInProgress(entry.file))
   }
 
   constructor(inputEl, view, onComplete){
@@ -104,6 +108,9 @@ export default class LiveUploader {
       Array.from(LiveUploader.filesAwaitingPreflight(inputEl) || [])
         .map(file => new UploadEntry(inputEl, file, view))
 
+    // prevent sending duplicate preflight requests 
+    LiveUploader.markPreflightInProgress(this._entries)
+
     this.numEntriesInProgress = this._entries.length
   }
 

assets/js/phoenix_live_view/upload_entry.js

@@ -15,9 +15,10 @@ import DOM from "./dom"
 export default class UploadEntry {
   static isActive(fileEl, file){
     let isNew = file._phxRef === undefined
+    let isPreflightInProgress = UploadEntry.isPreflightInProgress(file)
     let activeRefs = fileEl.getAttribute(PHX_ACTIVE_ENTRY_REFS).split(",")
     let isActive = activeRefs.indexOf(LiveUploader.genFileRef(file)) >= 0
-    return file.size > 0 && (isNew || isActive)
+    return file.size > 0 && (isNew || isActive || !isPreflightInProgress)
   }
 
   static isPreflighted(fileEl, file){
@@ -26,6 +27,14 @@ export default class UploadEntry {
     return isPreflighted && this.isActive(fileEl, file)
   }
 
+  static isPreflightInProgress(file){
+    return file._preflightInProgress === true
+  }
+
+  static markPreflightInProgress(file){
+    file._preflightInProgress = true
+  }
+
   constructor(fileEl, file, view){
     this.ref = LiveUploader.genFileRef(file)
     this.fileEl = fileEl