Character-set conversion: PHP's iconv won't work - php

Question

We have some internal dashboards with PHP backend used for uploading CSV files. Recently we
found some CSVs would fail to parse: the fgetcsv function returns false, which is super nasty since we couldn't determine the actual problem in CSV (for e.g. at which line no it is experience issues, which characters is it unable to digest etc.)
We narrowed down the problem to character-set encoding: CSVs generated from Windows machines were failing. Linux's iconv command was able to fix the CSVs for us
iconv -c --from-code=UTF-8 --to-code=ASCII path/to/uncleaned.csv > path/to/cleaned.csv
while it's PHP equivalent didn't work (tried using both //IGNORE//TRANSLIT options).
$uncleaned_csv_text = file_get_contents($source_data_csv_filename);
$cleaned_csv_text = iconv('UTF-8', 'ASCII/IGNORE//TRANSLIT', $uncleaned_csv_text);
file_put_contents($source_data_csv_filename, $cleaned_csv_text);
..
$headers = fgetcsv($source_data_csv_filename)
While we can use PHP's exec function to run the shell command
it is less than ideal
the practise is forbidden in our organisation from security viewpoint (Travis doesn't let it pass through)
Is there any alternative way to achieve this CSV 'cleaning'?
UPDATE-1
We explored several other options, none of which worked for us
regex based cleaning
forceutf8 package
mb_convert_encoding (as suggested by discussions)
UPDATE-2
Upon echoing the sha1 digest of CSV's text before and after subjecting it to PHP's iconv function, we found that iconv is not doing any change
Also in my case, mb_check_encoding on original CSV's text outputs true regardless of input query: windows-1252, ascii, utf-8

Answer 1

I've been working on a plugin (in Wordpress) that handles csv-files for a while now (with a 5/5 star rating) and I've been using mb_convert_encoding() with no issues. I know I have users that uses both windows and Linux.
Basically:
(TO UTF-8, FROM: Windows-1252)
$cleaned_csv_text = mb_convert_encoding($uncleaned_csv_text, 'UTF-8', 'Windows-1252');
If you don't know the original's encoding (maybe better in your case):
(TO UTF-8)
$cleaned_csv_text = mb_convert_encoding($uncleaned_csv_text, 'UTF-8');
UPDATE:
Here is a more complete answer which I hope you will find useful: I've used file() together with str_getcsv() etc:
<?php
$file = "csvfiles/pricelist.csv"; //This is Windows-1252 encoded
//Load a csv file into an array $content_arr
$content_arr = array_map(function($v) {
$delimiter = ';';
return str_getcsv($v, $delimiter);},
file( $file ));
//Do encoding row by row
//and include end of line based on the item in the array $content_arr
$csv = array_map(function($v) {
return mb_convert_encoding($v[0], 'UTF8','Windows-1252') . detect_eol($v[0]);},
$content_arr);
//Save modified file in UTF8
file_put_contents('csvfiles/pricelist_modified.csv', $csv);
//Detects the end-of-line character of a string.
//
//function from
//https://stackoverflow.com/questions/11066857/detect-eol-type-using-php/11066858#11066858
function detect_eol( $str )
{
static $eols = array(
"\0x000D000A", // [UNICODE] CR+LF: CR (U+000D) followed by LF (U+000A)
"\0x000A", // [UNICODE] LF: Line Feed, U+000A
"\0x000B", // [UNICODE] VT: Vertical Tab, U+000B
"\0x000C", // [UNICODE] FF: Form Feed, U+000C
"\0x000D", // [UNICODE] CR: Carriage Return, U+000D
"\0x0085", // [UNICODE] NEL: Next Line, U+0085
"\0x2028", // [UNICODE] LS: Line Separator, U+2028
"\0x2029", // [UNICODE] PS: Paragraph Separator, U+2029
"\0x0D0A", // [ASCII] CR+LF: Windows, TOPS-10, RT-11, CP/M, MP/M, DOS, Atari TOS, OS/2, Symbian OS, Palm OS
"\0x0A0D", // [ASCII] LF+CR: BBC Acorn, RISC OS spooled text output.
"\0x0A", // [ASCII] LF: Multics, Unix, Unix-like, BeOS, Amiga, RISC OS
"\0x0D", // [ASCII] CR: Commodore 8-bit, BBC Acorn, TRS-80, Apple II, Mac OS <=v9, OS-9
"\0x1E", // [ASCII] RS: QNX (pre-POSIX)
"\0x15", // [EBCDEIC] NEL: OS/390, OS/400
"\r\n",
"\r",
"\n"
);
$cur_cnt = 0;
$cur_eol = "\r\n"; //default
//Check if eols in array above exists in string
foreach($eols as $eol){
$char_cnt = mb_substr_count($str, $eol);
if($char_cnt > $cur_cnt)
{
$cur_cnt = $char_cnt;
$cur_eol = $eol;
}
}
return $cur_eol;
}

Answer 2

This can't be deemed as a solution (since we didn't even determine the root cause of the problems), but rather a hack.
We asked people using Windows machines to do this for uploading CSVs
Upload CSV to Google Sheet (File > Import)
Download the created Sheet back as a CSV (File > Download > Comma-separated values)
Then use that downloaded CSV for uploading on dashboard
Credits to #RohitChandana for suggesting this workaround