[Bug]: Cannot import CSV file with specified text.

[dawounit]

Expected behavior

The CSV file will be imported properly and a preview will be generated.

Actual behavior

It shows the message "Uploaded no valid preview file." instead of preview and the error "Uploaded file not valid, not creating any queue items and doing any cleanup." occurs when trying to execute import.

Steps to reproduce

Create import configuration. Select CSV as file format. Try to load file with below contents:

columnA;columnB
Some value;<a href=

[kingjia90]

Confirming the problem, it looks like finfo is confused when detecting html code

data-importer/src/DataSource/Interpreter/CsvFileInterpreter.php

Line 77 in 43fb412

$mime = finfo_file($finfo, $path);

Thinking of a solution for this but might be a third-partyish issue

See also https://core.trac.wordpress.org/ticket/47448

confirming also that problem persist when quoting the code and set the enclosure to " or ', and is not related by the fact that the last cell is an html code (can be anywhere)

[dawounit]

I think the real problem is the extension of the downloaded file. If I download the "data.csv" file, its name changes to "upload.import" after downloading on the server. This is misleading for "finfo_file" because there is no metadata in the csv file and you can only rely on the contents and extension of the file. The extension ("import") cannot match any mime type and the content contains html, so this fits best. Leaving the file extension "csv" solves this problem without having to expand the list of accepted mime types.

[kingjia90]

it's a good input but i've tried to change to not change the file extension from .csv and the finfo_file still fails

More details
finfo uses unix file command, so it's at even lower level.
https://stackoverflow.com/a/45964722

On the opposite end, changing to symfony mime type guesser also doesn't help since

since is based on finfo as well https://symfony.com/doc/current/components/mime.html#guessing-the-mime-type:~:text=one%20of%20them%20based%20on%20the%20PHP%20fileinfo%20extension.

[dvesh3]

Fixed by #374