问题描述
我试图在 express js 中设置一个无限制的查询参数。但我不知道我应该如何在我的代码中实现它。我正在使用 MongoDB aggeration
我想构建在多个 $match
阶段搜索的无限方面
工作方式如下:
'http://localhost:4000/search?text=mango'
'http://localhost:4000/search?text=mango&key=brand&value=rasna' //unlimited facets.
'http://localhost:4000/search?text=mango&key=brand&value=rasna&key=color&value=yellow' //unlimited facet parameters
这是我的代码:
app.get("/search",async(request,response) => {
try {
const textsearch = request.query.text;
var keystore = request.query.key; //storing `key` in 'keystore'
var valuestore = request.query.value; //storing `value` in `valuestore`
if (keystore,valuestore) {
facetjson = [
{
'$match': {
[keystore]: `${valuestore}` //Storing key and value in $match
}
}
]
const Pipeline = [{
'$search': {
'text': {
'query': `${textsearch}`,'path': 'title',}
}
},{
'$limit': 5
}
]
//Pushing 'facetjson' array into Pipeline array to make a filtered search possible.
const newitem = insert(Pipeline,Pipeline.length - 1,facetjson)
let result = collection.aggregate(newitem).toArray();
response.send(result);
} else {
const Pipeline = [{
'$search': {
'text': {
'query': `${textsearch}`,{
'$limit': 5
}
]
let result = collection.aggregate(Pipeline).toArray();
response.send(result);
};
} catch (error) {
response.status(500).send({ message: error.message });
}
})
(JSfiddle 代码示例)[https://jsfiddle.net/divyanshuking/z0vo589e/]
==> 我知道我每次都必须在 $match
数组中为单个 Pipeline
传递 Key
, Value
对。做了很多谷歌搜索,我发现我必须使用 Rest Parameter
(...keystore,...valuestore)
。但我不知道如何实现这一点。你们有什么更好的主意来解决这个问题吗? 请帮助我:
解决方法
为什么不使用 forEach 之类的东西
function endPoint (req,res) {
const queriesFound ={}
req.query.forEach(query=>{
queriesFound[query]=query;
}
QueriesFound will be an object
{ “Name”:”Name”,“AnotherParam”:”AnotherParam” }
}
//QueriesFound 将是一个对象
{ “姓名”:“姓名”,“另一个参数”:“另一个参数” }
,您的请求 URL 的查询参数结构错误。如果你想在 URL 中传递多个 kay/value 对,正确的结构是这样的:
- 'http://localhost:4000/search?text=mango&brand=rasana&color=yellow
此代码应与此 URL 结构配合使用:
app.get("/search",async(request,response) => {
try {
//We need "search pipeline stage" in all conditions. whether we got a key/value pair in query or not.
//so we use "search stage" when declare pipeline array;
let pipeline = [{
'$search': {
'text': {
'query': `${request.query.text}`,'path': 'title',}
}
}];
//If there are keys/values pairs in the query parameters,we add match stage to our pipeline array;
if(request.query) {
let match = {},hasMatchSatge = false;
for(let item in request.query){
if(item !=== 'text'){
match[item] = request.query[item];
hasMatchStage = true;
}
}
if(hasMatchStage) pipeline.push({'$match': match});
}
//Finally,we add our "limit stage" to the pipeline array;
pipeline.push({'$limit' : 5});
let result = collection.aggregate(pipeline).toArray();
response.status(200).send(result);
} catch (error) {
response.status(500).send({ message: error.message });
}
})