Systematically downloading files stored in a relation

oriol

Hi everyone,

I'm building an app which is used to keep records, and some of these records have files attached to them. I want to be able to download all files currently shown in the table, for example, or downloading all files related to an item, be it with frontend or backend functions. I'm open to doing it via an API, but that seems to give me only the internal filename of the file. Is there a way I can download those files from the internal filename, without having to go into /data/files in the server?

Thanks!

gabriel

If you have a files attribute on a form, you can use a frontend function to access the corresponding download links. This frontend function is called "app.get_field_file_links()" - this is how you access it:

This provides an array of download links that you can do whatever you want with - including starting downloads. Please note however, that these download links are connected to the current user session and will expire eventually - so you should use them right away.

oriol

Thanks for the reply, it's very helpful. I wanted to follow up to ask if there was a way of getting those links from a list instead of a field, since i need to download files from multiple items using one click (think a "download all manuals" button at the end of a list of products that the user filtered).

gabriel

List values are currently not accessible in any way, so unfortunately there is no way to achieve this easily.

It is possible to retrieve the corresponding meta data via backend function (eg. the same data that a list would show) and then build the download URLs yourself. But this would be some work - I would guess about 2-3h for someone experienced.

oriol

Hi Gabriel sorry for the late followup. I can't seem to be able to reference the "docs" column in my "products" relation:

SELECT docs INTO attribute_id
FROM {ber_db}.[products]
WHERE id = PRODUCT_ID;

Are the file columns named different?

Thanks

gabriel

If you use the placeholders (like you did in the FROM area), you always get the correct names. Columns are named after their attributes one-to-one - but placeholders protect you, should you rename attributes or try to delete still referenced attributes later.

What is docs for an attribute type?

oriol

I'm basically trying to get the metadata for all files in a column, build the url and send it to the frontend to download.

gabriel

files attributes are handled a bit differently. Because files can have multiple versions, and can be hard-linked in multiple places, they are not simply stored in a column.

To get file meta data, you need to call the instance function instance.files_get() with the corresponding attribute and record ID (eg. give me the files of record X, from files attribute Y).

This returns an array of the type instance.file_meta, which includes all file meta data for all files assigned to the chosen record. The call and the returned data is explained in the instance function context help: