Uncaught Error: Call to a member function fetch() on string - php

Question

I'm trying to update database rows with api calls, but for some reason it comes up with this error:
Uncaught Error: Call to a member function fetch() on string
I'm not sure what it means by function on a string, since i apply it to an mysqli_stmt object.
This is how the put file looks like:
if (isset($authlvl)) {
if (ctype_space($authlvl) == false && $authlvl >= 3) {
if (isset($id) && ctype_space($id) == false) {
if (isset($id) && ctype_space($id) == false && $id !== null) {
$rule = $id;
$request = 'id';
} else if (isset($username) && ctype_space($username) == false && $username !== null) {
$rule = $username;
$request = 'username';
} else if (isset($email) && ctype_space($email) == false && $email !== null) {
$rule = $email;
$request = 'email';
} else if (isset($password) && ctype_space($password) == false && $password !== null) {
$rule = $password;
$request = 'password';
} else if (isset($image) && ctype_space($image) == false && $image !== null) {
$rule = $image;
$request = 'image';
} else {
$request = "1";
$rule = "2";
}
$post = new Post($db);
$result = $post->post($request, $rule);
$result->bind_result($previd, $prevusername, $prevemail, $prevpassword, $previmage, $prevauthlvl);
$result->store_result();
$num = $result->num_rows();
if ($num > 0) {
while ($result->fetch()) {
$put = new Put($db);
$result = $put->update(
isset($username) ? preg_replace('/\s+/', '', $username) : null,
isset($email) ? preg_replace('/\s+/', '', $email) : null,
isset($password) ? preg_replace('/\s+/', '', $password) : null,
isset($image) ? preg_replace('/\s+/', '', $image) : null,
isset($authlvl) ? preg_replace('/\s+/', '', $authlvl) : null,
$previd,
$prevusername,
$prevemail,
$prevpassword,
$previmage,
$prevauthlvl
);
echo $result;
}
} else {
echo "Couldn't update row. Reason: 404 Not Found";
}
} else {
echo "A valid id is required!";
}
} else {
echo "You are not authorized to peform this request!";
}
} else {
echo "You are not authorized to peform this request!";
}
The $username, $email ect... are calculated by a huge if statement mess, which i will not include right now, cause it has a lot of rows in use, but here is a small part of it:
$content = file_get_contents('php://input');
if (strpos($content, "email") !== false) {
$email = substr($content, (strpos($content, "email")) + 10, ((strpos($content, "-", strpos($content, "email"))) - strpos($content, "email")) - 12);
}
here is the post file, which does the post request:
class Post
{
private $conn;
public $id;
public $username;
public $email;
public $password;
public $image;
public $authlvl;
public function __construct($db)
{
$this->conn = $db;
}
public function post($request, $rule)
{
$format = "s";
if ($request == "id") {
$query = "SELECT * FROM users WHERE id=?";
$format = "i";
} else if ($request == "username") {
$query = "SELECT * FROM users WHERE username=?";
} else if ($request == "email") {
$query = "SELECT * FROM users WHERE email=?";
} else if ($request == "password") {
$query = "SELECT * FROM users WHERE password=?";
} else if ($request == "image") {
$query = "SELECT * FROM users WHERE image=?";
} else {
$query = "SELECT * FROM users";
}
if ($stmt = $this->conn->prepare($query)) {
$stmt->bind_param("" . $format . "", $rule);
$stmt->execute();
return $stmt;
} else {
echo "invalid string";
}
}
}
I'm testing the api with postman.
What i've already tried:
Storing the result inside the post file.
Redefining $stmt to the $stmt->execute() which gives me an false boolean error.
Converting the part in PDO (later found out you couldn't mix OOP with PDO)
Hard coded variables inside the put file, which also fails
If anyone has a solution, let me know :)

Answer 1

while ($result->fetch()) {
$put = new Put($db);
// Here you reassign $result which now is a string.
$result = $put->update(
isset($username) ? preg_replace('/\s+/', '', $username) : null,
isset($email) ? preg_replace('/\s+/', '', $email) : null,
isset($password) ? preg_replace('/\s+/', '', $password) : null,
isset($image) ? preg_replace('/\s+/', '', $image) : null,
isset($authlvl) ? preg_replace('/\s+/', '', $authlvl) : null,
$previd,
$prevusername,
$prevemail,
$prevpassword,
$previmage,
$prevauthlvl
);
echo $result;
}
You are reassigning $result in your loop.
So it executes once and then produces the above error message.