updated for PHP7 tests

extras/core.php

 <?php
- 
+
 // get the HTTP method, path and body of the request
 $method = $_SERVER['REQUEST_METHOD'];
 $request = explode('/', trim($_SERVER['PATH_INFO'],'/'));
 $input = json_decode(file_get_contents('php://input'),true);
- 
+
 // connect to the mysql database
-$link = mysqli_connect('localhost', 'user', 'pass', 'dbname');
+$link = mysqli_connect('localhost', 'php-crud-api', 'php-crud-api', 'php-crud-api');
 mysqli_set_charset($link,'utf8');
- 
+
 // retrieve the table and key from the path
 $table = preg_replace('/[^a-z0-9_]+/i','',array_shift($request));
 $key = array_shift($request)+0;
- 
-// escape the columns and values from the input object
-$columns = preg_replace('/[^a-z0-9_]+/i','',array_keys($input));
-$values = array_map(function ($value) use ($link) {
-  if ($value===null) return null;
-  return mysqli_real_escape_string($link,(string)$value);
-},array_values($input));
- 
-// build the SET part of the SQL command
-$set = '';
-for ($i=0;$i<count($columns);$i++) {
-  $set.=($i>0?',':'').'`'.$columns[$i].'`=';
-  $set.=($values[$i]===null?'NULL':'"'.$values[$i].'"');
+
+if ($input) {
+  // escape the columns and values from the input object
+  $columns = preg_replace('/[^a-z0-9_]+/i','',array_keys($input));
+  $values = array_map(function ($value) use ($link) {
+    if ($value===null) return null;
+    return mysqli_real_escape_string($link,(string)$value);
+  },array_values($input));
+
+  // build the SET part of the SQL command
+  $set = '';
+  for ($i=0;$i<count($columns);$i++) {
+    $set.=($i>0?',':'').'`'.$columns[$i].'`=';
+    $set.=($values[$i]===null?'NULL':'"'.$values[$i].'"');
+  }
 }
- 
+
 // create SQL based on HTTP method
 switch ($method) {
   case 'GET':
   case 'DELETE':
     $sql = "delete `$table` where id=$key"; break;
 }
- 
+
 // execute SQL statement
 $result = mysqli_query($link,$sql);
- 
+
 // die if SQL statement failed
 if (!$result) {
   http_response_code(404);
   die(mysqli_error());
 }
- 
+
 // print results, insert id or affected row count
 if ($method == 'GET') {
   if (!$key) echo '[';
 } else {
   echo mysqli_affected_rows($link);
 }
- 
+
 // close mysql connection
 mysqli_close($link);