# Attachments: Download and Save

# Overview

Nettskjema allows users to upload attachments with their form submissions. This vignette explains how to use the functions provided in this package to list, retrieve, and save these attachments efficiently.

# Listing Attachments

Before downloading any attachments, it’s useful to list the available files.

## Listing attachments for a specific submission

Each submission ID may have associated attachments. Use `ns_list_submission_attachments()` to retrieve information about the available attachments.

    library(nettskjemar)
    # Example: List attachments for a specific submission
    submission_id <- 27685292
    ns_list_submission_attachments(submission_id)
    #>   submissionId  answerId elementId externalElementId textAnswer
    #> 1     27685292 158263134   1641713      attachment_1  sølvi.png
    #>   answerAttachmentId  filename mediaType   size elementType
    #> 1             538819 sølvi.png image/png 628613  ATTACHMENT
    #>   attachment.answerAttachmentId attachment.filename attachment.mediaType
    #> 1                        538819           sølvi.png            image/png
    #>   attachment.size counter
    #> 1          628613       1

This function returns a `data.frame` with details such as the attachment ID, original filename, and standardized filename.

## Listing all attachments for a form

To list all attachments across multiple submissions for a form, use `ns_list_form_attachments()`.

    # Example: List attachments for an entire form
    formid <- 123823
    ns_list_form_attachments(formid)
    #>    formid formId submissionId  answerId elementId externalElementId  textAnswer
    #> 16 123823 123823     27685292 158263134   1641713      attachment_1   sølvi.png
    #> 32 123823 123823     27685302 158263185   3525020      attachment_2 marius.jpeg
    #>    answerOptionIds externalAnswerOptionIds elementType         createdDate
    #> 16                                          ATTACHMENT 2023-06-01T20:57:15
    #> 32                                          ATTACHMENT 2023-06-01T20:58:33
    #>           modifiedDate subElementId answerAttachmentId    filename  mediaType
    #> 16 2023-06-01T20:57:15           NA             538819   sølvi.png  image/png
    #> 32 2023-06-01T20:58:33           NA             538820 marius.jpeg image/jpeg
    #>      size attachment.answerAttachmentId attachment.filename
    #> 16 628613                        538819           sølvi.png
    #> 32  89494                        538820         marius.jpeg
    #>    attachment.mediaType attachment.size counter
    #> 16            image/png          628613       1
    #> 32           image/jpeg           89494       1

# Downloading Attachments

Once you have identified the attachments, you can download them using `ns_get_attachment()`.

    #| label: dl1

    # Example: Download a single attachment
    attachment_id <- "12345"
    ns_get_attachment(attachment_id, path = "downloaded_file.pdf")

If `path` is not provided, the function returns the response object without saving the file.

# Saving All Attachments

## For a Single Submission

Use `ns_get_submission_attachments()` to download and save all attachments associated with a single submission.

    #| label: dl2

    # Example: Save all attachments for a submission
    ns_get_submission_attachments(submission_id)

This function supports two filename conventions:

- “standardized” (default): Creates filenames based on submission ID and a counter.
- “original”: Uses the filenames as they were uploaded.

To save attachments using the original filenames:

    #| label: dl3

    ns_get_submission_attachments(submission_id, filenames = "original")

You can also specify an output directory:

    #| label: dl4

    ns_get_submission_attachments(submission_id, output_dir = "my_attachments/")

## For an Entire Form

To download and save all attachments from a form:

    #| label: dl5

    ns_get_form_attachments(formid)

As with submission attachments, you can specify a filename format and output directory:

    #| label: dl6

    ns_get_form_attachments(
      formid,
      filenames = "original",
      output_dir = "all_attachments/"
    )

# Summary

This vignette demonstrated how to: - List attachments for submissions and forms. - Retrieve individual attachments. - Save attachments using different naming conventions.

By using these functions, you can efficiently manage Nettskjema file attachments within your R workflow.