File Upload Component

Function

a!fileUploadField( label, labelPosition, instructions, helpTooltip, target, fileNames, fileDescriptions, maxSelections, value, saveInto, required, requiredMessage, disabled, validations, validationGroup, buttonStyle, buttonSize, accessibilityText, showWhen, uploadMethods, buttonDisplay, placeholder, showVirusScanMessage )

Allows users to upload one or more files. To upload files outside of a start form or task, use a!submitUploadedFiles() in the saveInto parameter of a submit button or link. Uploaded documents are not accessible until after form submission.

Permitted file extensions can be controlled via the File Upload settings in the Admin Console.

See Also:

• Document
• Document or Folder

Parameters

Usage considerations

Submitting files

When files are uploaded in the file upload component, they are saved to a temporary folder. They are not saved to the target until they are submitted.

In start forms and tasks, on the button used to submit the form, make sure that the submit parameter set to true. When this button is clicked, the uploaded files will be saved to the target.

Outside of start forms and tasks, use a!submitUploadedFiles() in the saveInto parameter of a button or link. This button or link could be used to submit the files, as in this a!submitUploadedFiles() example, or the entire form, as in this example. When this button is clicked, the uploaded files will be saved to the target folder.

Give end users Editor permissions to the target

In order to submit an uploaded file, users must have at least Editor permissions to the target folder or document.

For portals, give the portal service account Editor permissions to the target folder or document.

Any error saving the new document or version causes submission to be canceled and an error to be displayed to the user.

Avoid saving unnecessary files

In a start form or task

For a start form or task, both the cancel and submit buttons will usually have the submit parameter set to true. As soon as one of these buttons are clicked, any uploaded files will be saved to their target.

To avoid saving files from a canceled form, configure the cancel flow in the process model to handle the unnecessary files. If the target is a folder, delete any uploaded files. If the target is a document, revert the file upload via a new version of the document.

Outside of a start form or task

If you are using the file upload component outside of a start form or task, use a!submitUploadedFiles() in the saveInto parameter of a button or link. Do not use it in the file upload component's saveinto parameter. This ensures that the file is only saved to the target when the user is ready to submit it.

See a!submitUploadedFiles() for more information.

For portals, test the file upload in a published portal

To make sure files will be uploaded correctly in a portal, publish the portal and test the file upload on the portal website. The file may seem to submit correctly when you test it in the interface object, but it may not work in the portal itself. For example, if the portal service account doesn't have Editor permissions to the target folder, you will see an error in the portal, but not in the interface object.

See a!submitUploadedFiles() for more information on testing and troubleshooting uploading documents in portals.

Uploading new versions of multiple files

The file upload component may not be used to upload new versions of multiple files. To accomplish that, use one component for each file to replace.

Using the uploadMethods parameter

The uploadMethods parameter is only supported within the Appian Mobile application. This parameter allows you to limit the upload methods a mobile user has access to when tapping an upload button.

For example, this can be helpful to ensure users do not upload photos of a signature instead of drawing their signature within the application.

Uploaded file size limit

In portals, the size limit for uploaded files is 10 MB. Everywhere else, the file size limit is 1GB.

Saving a task as a draft with an uploaded file

If a user has uploaded a file to a task, they won't be able to save the task as a draft unless it is an offline-enabled task that they are viewing on Appian Mobile. They can remove the file or files to save the task as a draft.

Uploaded files are stored as temporary documents until submission

When a file is uploaded, the component updates with a temporary document representing the uploaded file. Between the upload and the submission, the file on the server is an inactive temporary file and not accessible except through fv! variables described in the File Name, File Description, and Validations parameters. This is the only way to access file metadata before the file upload is submitted.

If a file is uploaded but is never submitted, the temporary file is automatically deleted after 30 days.

If enabled in Admin Console, uploaded files are scanned for viruses

If real-time virus scanning is enabled for file uploads in the Admin Console, the uploaded file will always be scanned for viruses, regardless of whether the virus scanning message is shown.

Some characters in file names are replaced

If any of the following characters appear in a filename, they are replaced by underscores after submitting the file upload: \ / " ; : | ? ' < > *.

Examples

Click EXPRESSION to copy and paste an example into the Interface Definition to see it displayed.

File upload in a start form or task

This example shows how to use the file upload component in an interface that will be used in a start form or task.

Keep in mind that if you don't use this interface in a start form or task, on the Submit button, you would need to replace submit: true with saveInto: a!submitUploadedFiles(). See File upload outside a start form or task for more information.

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a!localVariables(
  local!file,
  a!formLayout(
    label: "File Upload Form",
    instructions: "Use this example in a start form or task",
    contents: {
      a!fileUploadField(
        label: "Upload File",
        /* Replace this with a constant of type Folder in your environment */
        target: cons!FOLDER_CONSTANT,
        value: local!file,
        saveInto: local!file
      )
    },
    buttons: a!buttonLayout(
      primaryButtons: {
        a!buttonWidget(
          label: "Submit",
          /* If you don't set the submit parameter to true, the signature will not be uploaded */
          submit: true,
          style: "PRIMARY",
          loadingIndicator: true
        )
      },
      secondaryButtons: {
        a!buttonWidget(
          label: "Cancel",
          value: true,
          saveInto: {},
          submit: true,
          style: "NORMAL",
          validate: false
        )
      }
    )
  )
)

Displays the following:

File upload outside a start form or task

This example shows how to use the file upload component outside of a start form or task using a!submitUploadedFiles() in the saveInto parameter of a button. See a!submitUploadedFiles() for more examples.

Keep in mind that if you use this interface in a start form or task, on the Submit button you would need to replace saveInto: a!submitUploadedFiles() with submit: true. See File upload in a start form or task for more information.

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a!localVariables(
  local!file,
  local!submissionSuccessful,
  local!errorCode,
  {
    a!fileUploadField(
      label: "File Upload",
      labelPosition: "ABOVE",
      saveInto: local!file,
      value: local!file,
      /* Replace this with a constant of type Folder in your environment */
      target: cons!AS_DOCUMENTS_FOLDER_POINTER
    ),
    a!buttonArrayLayout(
      buttons: {
        a!buttonWidget(
          label: "Submit",
          style: "PRIMARY",
          /* If you don't use a!submitUploadedFiles(), the signature will not be uploaded */
          saveInto: a!submitUploadedFiles(
            onSuccess: a!save(local!submissionSuccessful, true),
            onError: {
              a!save(local!submissionSuccessful, false),
              a!save(local!errorCode, fv!error)
            }
          )
        )
      },
      align: "END"
    )
  }
)

Displays the following:

File upload with the icon style and no files

Use the interactive editor below to test out your code:

To test out different file upload styles and placeholder texts, change the value of the buttonDisplay parameter to "LABEL_AND_ICON" and enter a different text value for the placeholder parameter.

Single file upload

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a!localVariables(
  local!coverLetter,
  a!fileUploadField(
    label: "Cover Letter",
    /* Replace this with a constant of type Folder in your environment */
    target: cons!FOLDER_CONSTANT,
    maxSelections: 1,
    value: local!coverLetter,
    saveInto: local!coverLetter
  )
)

Displays the following:

Signature-capture only field on the Appian Mobile application

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a!localVariables(
  local!signature,
  a!fileUploadField(
    label: "Signature",
    /* Replace this with a constant of type Folder in your environment */
    target: cons!FOLDER_CONSTANT,
    maxSelections: 1,
    value: local!signature,
    saveInto: local!signature,
    uploadMethods: "SIGNATURE"
  )
)

Resulting behavior: Users in the Appian Mobile application, when tapping on the "Signature" file upload button, are instantly prompted to draw their signature and cannot use other upload methods such as taking a photo.

Using fv! variables

These examples demonstrate how to use the fv! variables available in the File Name, File Description, and Validations parameters to set file metadata or create complex validations.

Add one of the following parameter configurations to a file upload component to achieve the desired behavior.

Swap spaces for underscores in file names

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fileNames: substitute(fv!files.name, " ", "_")

Set file descriptions to a value plus file index

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fileDescriptions: "Application ABC-123 attachment " & fv!index

All files must be PDFs

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validations: a!localVariables(
  local!invalidExtensions: difference(upper(fv!files.extension), "PDF"),
  if(
    length(local!invalidExtensions) > 0, 
    "Attachments must be pdf files. Remove: " & 
      index(fv!files, "name", wherecontains(local!invalidExtensions, upper(fv!files.extension)), {}), 
    ""
  )
)

No files may be PDFs

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validations: if(
  contains(upper(fv!files.extension), "PDF"), 
  "Attachments must not be pdf files. Remove: " & 
    index(fv!files, "name", wherecontains("PDF", upper(fv!files.extension))), 
  ""
)

Files may only be PNG or JPG

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validations: a!localVariables(
  local!invalidExtensions: difference(upper(fv!files.extension), { "PNG", "JPG" }),
  if(
    length(local!invalidExtensions) > 0, 
    "Attachments must be images. Remove: " & 
      index(fv!files, "name", wherecontains(local!invalidExtensions, upper(fv!files.extension)), {}), 
    ""
  )
)

Files must be larger than 5MB

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validations: if(
  or(fv!files.size < 5000000),
  "Attachments must be at least 5MB. Remove: " &
    index(fv!files, "name", where(fv!files.size < 5000000), {}),
  ""
)

Files must be smaller than 5MB

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validations: if(
  or(fv!files.size > 5000000), 
  "Attachments may not exceed 5MB. Remove: " & 
    index(fv!files, "name", where(fv!files.size > 5000000), {}), 
  ""
)

Up to five files are allowed

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validations: if(length(fv!files) > 5, "Only 5 attachments are allowed", "")

Exactly five files are required

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validations: if(not(length(fv!files) = 5), "5 files must be attached", "")

At least five files are required

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validations: if(length(fv!files) < 5, "There must be at least 5 attachments", "")

Feature compatibility

Old versions

There are older versions of this interface component. You can identify older versions by looking at the name to see if there is a version suffix. If you are using an old version, be sure to refer to the corresponding documentation from the list below.

To learn more about how Appian handles this kind of versioning, see the Function and Component Versions page.

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