I'm pretty sure all programmers have had to write code to upload an image at some point, and I'm pretty sure most of you have used a timestamp as the image name. Well...I recently ran into a situation where this is a bad idea, let me explain why.
Don't use timestamps
Let's run through a scenario with some code. Let's take an array of names and concatenate a timestamp onto those names and see what happens.
$names = collect([
'0' => 'Jonathon',
'1' => 'Justin',
'2' => 'Sally',
'3' => 'Sally',
]);
$testArray = [];
foreach ($names as $name) {
$testArray[] = $name . '-' . time();
}
dd($testArray);
$results = array:3 [▼
0 => "Jonathon-1636344452"
1 => "Justin-1636344452"
2 => "Sally-1636344452"
3 => "Sally-1636344452"
];
Did you notice all the timestamps are the same. This is because the snippet of code ran so quick that the timestamp never changed, it never had a chance to get to the next time.
I ran into this exact situation recently. I was uploading multiple images at ones, storing them on Amazon S3 and saving the path to the database. When I saved the images I set the file name to time() . '.jpg';
, which obviously causes an issue because now I have duplicate files named the same thing and duplicate file paths stored in the database.
Whats the solution?
Well...I'm sure there are a lot of solutions, but the main thing is that on each loop you want to get a unique value each time. So..What I did was used the Laravel Str::random(8)
helper function. And this is what we get:
$names = collect([
'0' => 'Jonathon',
'1' => 'Justin',
'2' => 'Sally',
'3' => 'Sally',
]);
$testArray = [];
foreach ($names as $name) {
$testArray[] = $name . '-' . Str::random(8);
}
dd($testArray);
$results = array:4 [▼
0 => "Jonathon-SeTNhsmL"
1 => "Justin-2sjRUxg8"
2 => "Sally-Laytdn5m"
3 => "Sally-6cUDA5Cd"
]
As you can see we're now getting a unique value each time. Keep in mind the longer the string, the better your chances of returning only unique values if you have a large dataset.
If you have another solution, comment below. I'd like to hear them!
Top comments (2)
Excellent post. Another technique for generating unique file names would be to rely on the database as the source of truth. Usually when you upload a file you also save a record in the database for that file. You can include the primary key value of the record in the file name to make it unique.
I have also seen UUIDs being used as file names which is more akin to your solution.
These are also excellent solutions.