uploadFile(file, params)

Sends a binary file to the server via XMLHttpRequest. Supports progress tracking, abort handling, and both File objects and FileEntry (filesystem API).

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When to Use

Use uploadFile when uploading a file binary directly to a backend service endpoint. It is the underlying transport used by the upload pipeline — called automatically when a widget processes files from drag-and-drop or file picker events.

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Signature

uploadFile(file, params);

Param	Type	Description
file	File or FileEntry	The file to upload
params	Object	Upload options — service name, metadata, and any extra fields

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How It Works

uploadFile(file, params)
  │
  ├── Create XMLHttpRequest
  ├── Bind widget event hooks (onAbort, onLoad, onUploadEnd, onUploadProgress, ...)
  ├── Resolve service URL
  │     → params.service or default "media.upload"
  │     → full URL: bootstrap().svc + service
  │
  ├── Build metadata header
  │     → { filename, mimetype, filesize, socket_id, ...params }
  │     → JSON-stringified into "x-param-xia-data" header
  │     → Content-Type: "application/octet-stream"
  │
  ├── Auth headers injected via makeHeaders()
  │
  └── Send the file body
        → file.file(cb) → FileEntry → cb(f) → xhr.send(f)
        → plain File      → xhr.send(file)
        → on send error   → onUploadError({ error, file, params })

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Metadata Sent Per Request

File metadata is not sent in the body — it is encoded as a JSON string in the x-param-xia-data header:

Field	Source
filename	encodeURI(file.name)
mimetype	file.type
filesize	file.size
socket_id	this.get(socket_id) or Visitor.get(socket_id)
...params	Any extra fields passed in params

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Widget Event Hooks

uploadFile binds widget methods as XHR event handlers — if the method exists on this, it is attached automatically:

Widget method	XHR event	When it fires
onAbort	xhr.upload.onabort	Upload was aborted
onReadystatechange	xhr.upload.onreadystatechange	Ready state changes on upload
onUploadError	xhr.upload.onerror	Network or upload error
onLoad	xhr.upload.onload	Upload transfer completed
onUploadEnd	xhr.upload.onloadend	Upload ended (success or failure)
onUploadProgress	xhr.upload.onprogress	Progress event — { loaded, total }

The response itself (readystatechange on the main xhr) is handled by the internal onReadyStateChange function:

Server status	Behavior
200	Calls this.onUploadResponse(data) if defined
0	Silently ignored (aborted or not started)
Other	Calls this.onUploadError(this.pendingItem) if defined

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Service Resolution

By default, files are uploaded to media.upload. Pass a custom service in params to override:

// Default — uploads to media.upload
uploadFile(file, { hub_id, pid });

// Custom service
uploadFile(file, { service: "my_module.upload", hub_id, pid });

params.service is removed from the metadata header before sending — it is only used to build the URL.

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Return Value

Returns the XMLHttpRequest instance. Use it to call .abort() if needed:

const xhr = uploadFile(file, params);

// Cancel the upload later
xhr.abort();

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Quick Reference

Behavior	Detail
HTTP method	POST
File body	Sent as binary via xhr.send(file)
Metadata	Encoded in x-param-xia-data header
Auth headers	Auto-injected via makeHeaders
Default service	media.upload
FileEntry support	✅ via file.file(cb)
Returns	XMLHttpRequest instance