literakl
commented
3 years ago Optimistic locking algorithm:
getSlug(dbClient, caption) {
const slug = generate from caption;
const item = dbclient.items.findOne({slug}, {projection: {_id: 1}});
if (!item) return slug;
else {
const items = dbClient.items.find({ slug with ${slug} prefix },{projection: {_id: 1}}).toArray;
items.forEach(foundSlug => { extract numeric part and find the largest value });
return ${slug}-${biggestId + 1}
}
}
Slug is the last part of URL, it is not unique.
{ "_id" : "1f2kd8dp73gk", "info" : { "slug" : "third-question" } } { "_id" : "1f2kd8dq73y4", "info" : { "slug" : "today-blog" } } { "_id" : "1f2kd8dqnrxo", "info" : { "slug" : "1-day-ago-blog" } }
http://localhost:8080/p/akbar/b/hello-world-blog-create-validation
Saving the blog with the same slug will result in an error (not visible in UI). Create api.js#getSlug(dbClient, String) method that will generate slug for the input and seek it as a prefix between all slugs. If it exists, it will either create 'slug-1', or
slug-${last + 1}