generate a csv listing of your favorite cryptocurrencies, suitable for importing into a google sheet

gecko.php

<?php

// usage:
//     http://.../gecko.pgp??q=bitcoin,ethereum,solana,polkadot
// or
//     http://.../gecko.pgp??q=mycrypto.csv
// where mycrypto.csv contains the id of a coin on each line.
// Find the exact id of your coin in this list:
//     https://api.coingecko.com/api/v3/coins/list
// See this doc for more info:
//     https://www.coingecko.com/en/api/documentation

header("Content-Type: text/plain");
$coins = array('bitcoin', 'ethereum', 'harmony');
if (! array_key_exists('q', $_GET)) {
    $_GET['q'] = 'ethereum';
}
if (preg_match('/\.csv$/', $_GET['q'])) {
    $lines = file($_GET['q']);
    $coins = '';
    foreach ($lines as $L) {
	if (preg_match('/^#/', $L) || preg_match('/^\s*$/', $L)) continue;
	if (preg_match('/^([\w-]+)/', $L, $matches)) {
	    $coins .= ",$matches[1]";
	}
    }
    $coins = substr($coins, 1);
} else {
    $coins = $_GET['q'];
}
$gecko = "https://api.coingecko.com/api/v3/simple/price?ids=$coins&vs_currencies=usd&include_market_cap=true";
$data = json_decode(file_get_contents($gecko), true);
$all_coins = array_keys($data);
function cmp_market_cap($a, $b) {
    global $data;
    if ($data[$a]['usd_market_cap'] < $data[$b]['usd_market_cap']) {
	return -1;
    } elseif ($data[$a]['usd_market_cap'] > $data[$b]['usd_market_cap']) {
	return 1;
    } else {
	return 0;
    }
}
usort($all_coins, "cmp_market_cap");
print("coin_name,price,market_cap\n");
foreach (array_reverse($all_coins) as $coin) {
    $info = $data[$coin];
    printf("$coin,$info[usd],%0.3f\n", $info[usd_market_cap]/1e9);
}
?>

mycrypto.csv

bitcoin
harmony
ethereum
cardano
solana
polkadot
bitcoin-cash
nexo
maxcoin
matic-network
yield-guild-games
gatechain-token
binancecoin
dfyn-network