Get $_POST from multiple checkboxes without name key including '[]' - php

Question

What is the best solution to get the $_POST data from multiple checkboxes that have the same name attribute, WITHOUT using something like this;
<input type="checkbox" name="some_value[]">
<input type="checkbox" name="some_value[]">
I'm using Unbounce to make a landing page, and they currently don't offer any way of setting the name attribute to something custom including the '[]' to denote to PHP to put the values in an array.

Answer 1

You can read the POST data yourself using something like:
$formData = file_get_contents('php://input');
However, for parsing the "application/x-www-form-urlencoded", you'll want to find a third-party library somewhere, as all of the native PHP options exhibit the same behaviour (later keys override earlier ones) that you would find with the normal $_POST structure.
Here's a "toy" implementation of a user-land version of parse_str(), with the added bonus that 'duplicate' values are turned into an array. I make no claims as to the quality of this code to handle all the possible edge-cases of "application/x-www-form-urlencoded" data:
<?php
$form = file_get_contents('php://input');
$arg_sep = ini_get('arg_separator.input');
$max = ini_get('max_input_vars');
$token = strtok($form, $arg_sep);
$data = [];
while (false !== $token && $processed < $max) {
if (false !== ($pos = strpos($token, '='))) {
list($key, $value) = explode('=', $token);
$value = urldecode($value);
if (strlen($key)) {
if (isset($data[$key])) {
if (is_array($data[$key])) {
array_push($data[$key], $value);
} else {
$data[$key] = [$data[$key], $value];
}
} else {
$data[$key] = $value;
}
}
}
$token = strtok($arg_sep);
++$processed;
}
var_dump($data);
For comparison, here are the guts of PHP's internal implementation - note that there is much more to it than this, but this is the heart of the key/value parsing logic:
switch (arg) {
case PARSE_GET:
case PARSE_STRING:
separator = (char *) estrdup(PG(arg_separator).input);
break;
case PARSE_COOKIE:
separator = ";\0";
break;
}
var = php_strtok_r(res, separator, &strtok_buf);
while (var) {
val = strchr(var, '=');
if (arg == PARSE_COOKIE) {
/* Remove leading spaces from cookie names, needed for multi-cookie header where ; can be followed by a space */
while (isspace(*var)) {
var++;
}
if (var == val || *var == '\0') {
goto next_cookie;
}
}
if (++count > PG(max_input_vars)) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Input variables exceeded " ZEND_LONG_FMT ". To increase the limit change max_input_vars in php.ini.", PG(max_input_vars));
break;
}
if (val) { /* have a value */
size_t val_len;
size_t new_val_len;
*val++ = '\0';
php_url_decode(var, strlen(var));
val_len = php_url_decode(val, strlen(val));
val = estrndup(val, val_len);
if (sapi_module.input_filter(arg, var, &val, val_len, &new_val_len TSRMLS_CC)) {
php_register_variable_safe(var, val, new_val_len, &array TSRMLS_CC);
}
efree(val);
} else {
size_t val_len;
size_t new_val_len;
php_url_decode(var, strlen(var));
val_len = 0;
val = estrndup("", val_len);
if (sapi_module.input_filter(arg, var, &val, val_len, &new_val_len TSRMLS_CC)) {
php_register_variable_safe(var, val, new_val_len, &array TSRMLS_CC);
}
efree(val);
}
next_cookie:
var = php_strtok_r(NULL, separator, &strtok_buf);
}