[英]Mongoose create document if doesn't exist
I am making a simple url shortener(Mong db, Node js). 我正在制作一个简单的网址缩短器(Mong db,Node js)。 Here is my model:
这是我的模型:
var urlSchema = new mongoose.Schema({
shortUrl: String,
longUrl: String,
created: {
type: Date, default: Date.now
},
clicks: {
type: Number, default: 0
}
});
I have a function getRandomString6() that returns 6 random characters string. 我有一个函数getRandomString6()返回6个随机字符串。
var string = getRandomString6();
I want to implement this "pseudocode" algorithm: 我想实现这种“伪代码”算法:
1 var string = getRandomString6();
2 if there is document with shortUrl == string
3 go to step 1
4 else
5 create new document with shortUrl=string
How to do that? 怎么做?
It's pretty easy to achieve, this sample should help to get idea 这很容易实现,该示例应有助于获得想法
function getValidShortUrl(cb) {
var str = getRandomString6();
MODEL.findOne({
shortUrl: str
}, function(err, doc) {
if(err) return cb(err);
else if (doc) return getValidShortUrl(cb);
else cb(null, str);
});
}
getValidShortUrl(function(err, shortUrl) {
if(err) {
// error
} else {
// shortUrl is valid url that doesn't exist in schema
}
});
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