如何检查两个时间戳之间的范围不与其他两个时间戳重叠

Question

I'm using laravel with mongodb and I've got an overlapping issue when storing new data in database. I want to set this feature for user to store a new post in the database and also set a timer so the post get published at the requested timestamp and also be removed in a specific timestamp in the future. Everything is managed and tested but the only issue is overlapping.

The post data looks like this:

    "title" : "Some title",
    "body"  : [ dummy body data ... ],
    "tags"  : [ some tags here ...],
    "publish_at"   : "1595740000", //timestamp
    "unpublish_at" : "1595741111"  //timestamp

And I'm storing the data in database:

 /**
 * Store a newly created resource in storage.
 *
 * @param StoreRequest $request
 * @return \Illuminate\Http\JsonResponse
 */
public function store(StoreRequest $request)
{
    $data = $request->validated();

    #Here I want to do the validation of timestamps
    #Using Post::all() I can access all of the posts in the database

    $count = Post::where('name', $data['name'])->count();
    if ($count !== 0) {
        // just a sample validation
        return 'name_already_exists';
    } else {
        Post::Create([
            "title" => $data['title'],
            "body" => $data['body'],
            "tags" => $data['tags'],
            "is_active" => true,
            "publish_at" => Carbon::parse($data['publish_at'])->timestamp,
            "unpublish_at" => Carbon::parse($data['unpublish_at'])->timestamp,
        ]);
        return "resource created";
    }

}

Everything looks good, However, In case the user is adding different posts for being published and unpublished in the future. I need to check the new post timestamps not to overlap any other posts timestamps from database.

So far, I think I have to check 3 conditions here,

1. the range between new post timestamps doesn't overlap any of others, The major problem
2. the new post publish_at timestamp be bigger than now(), which I know how to do it
3. the new post unpublish_at timestamp be bigger than publish_at timestamp, which also I know how to do it

The Laravel version is 6.18, the Mongodb ORM package is Jenssegers/Mongodb which is pretty similar to eloquent ORM and the Carbon package is also installed.

Thank you so much.

Answer 1

the check is straight forward:

if($a->publish_at > $b->unbublish_at || $a->unpublish_at < $b->publish_at)
    return true;

this will give indication that a specific post $a is not overlapping with specific post $b. notice that i'm not checking the second and third condition that you mentioned, since you considering them done before. All you need to do is just iterate all over the yet unpublished post and check each one of them for no collision situation with a new post.