I have a node.js server with restify. I want to send it a get request that has an array of names in it. I think the request should look like this (but I am not sure about it):
/users?names=bob,joe,michael,joey
Is this query correct?
How do I get the names I send on the node.js server?
The W3C recommendation is that one key can be repeated multiple times with multiple values:
GET /users?names=bob&names=joe&names=michael&names=joey
Good systems will be designed to handle this format of data and be able to recognize multiple keys to group them within an array.
You do not need to specify query variables in your route:
// perform: GET /users?names=bob&names=joe&names=michael&names=joey
server.get('/users', function (req, res) {
// All your query vars from the GET request are in req.query
res.json(req.query.names);
});
Related
I know how to source stream from an entity via a POST request, but I want to be able to also create a source stream from the query parameters of a GET request.
I know i can get query parameters to a case class via a as[] directive, but it seems like a miss to have to wrap that in a source in order to source stream it.
The query parameters that are part of the URL are not "streamed" from the client, rather they are part of the request line. Therefore, when you have an HttpRequest object in your memory you have already consumed enough space to hold the query parameters. This means that you lose any back-pressure benefits from using a Source. I recommend analyzing why you want to create a Source in the first place...
If you absolutely have to create a Source out of the parameters then you can use the parameterSeq Directive:
val route =
parameterSeq { params : Seq[(String, String)] =>
val parameterSource : Source[(String, String), _] = Source(params)
}
I'm developing a website using the MEAN stack (MongoDB/Express/Angular/Node).
I have a product schema with 12 different fields/properties, including size, color, brand, model, etc. What is the best and most efficient way to filter products, in Angular or on the server-side?And how can i chain the results if the client had selected more than one property?What would that look like?
Assuming there will be a lot of products, it will be too much to download to the client in order to filter using Angular. It doesn't scale very well. As the list of products gets bigger and bigger, it will be less and less performant. The better way would, generally, be to let MongoDB do the filtering for you. It's very fast.
But, you can control the filtering from Angular by posting to the server the filtering term you want on the endpoint used for that method of filtering, for example, using the http module
http.post('/api/filter/' + methodOfFiltering, { 'term': termtoFilterBy }, function(dataReturned) {
// use dataReturned to do something with the data
});
Put this in an angular service method, so you can inject it into any of your controllers/components.
Create an endpoint that will use the method and the keyword in the mongoose query. I'm assuming that you're using Express for your server routes.
app.post('/api/filter/:method', function(req, res) {
var method = req.params.method;
var termToFilterBy = req.body.term;
productSchema.find({method: termToFilterBy}, function(err, products) {
res.send(products);
});
});
Let me know if this helps.
In traditional REST API, we should define our API like this:
GET /api/things -> get all
POST /api/things -> create
GET /api/things/:id -> get one
PUT /api/things/:id -> update
DELETE /api/things/:id -> delete
How should i define another 'get one' endpoint for querying data by any other field other than id? For example:
GET /api/things/:title -> get one by title (this sure does not work since the api isn't aware of URL parameter names)
GET /api/things/title/:title ? this does not work for me at all..
GET /api/things?title=whatever (this cannot be defined at all. When i write this in my index.js:
router.get('?title=whatever', controller.getByTitle);
I get this:
SyntaxError: Invalid regular expression: /^?title=whatever\/?$/: Nothing to repeat
at RegExp (native)
ID should be an unique identifier. Given one ID, you should return one resource at most. That's why an URI like GET /api/things/:id makes sense.
For other properties which may or may not be unique, you can have more than one result, so use the GET /api/things endpoint and pass query parameters : /api/things?title=mytitle.
app.get('/api/things', function (req, res) {
console.log(req.query.title); //mytitle
ThingModel.find({
title: req.query.title
}, function (err, things) {
res.send(things);
});
});
I come here because I am searching (like the title mentionned) to do a query from geotools (through geoserver) to get feature from a solr index.
To be more precise :
I saw on geoserver user manual that i can do query on solr like this in http :
http://localhost:8080/geoserver/wfs?service=WFS&version=1.1.0&request=GetFeature
&typeName=mySolrLayer
&format="xxx"
&viewparams=q:"mySolrQuery"
The important part on this URL is the viewparams that I want to use directly from geotools.
I have already test this case (this is a part of my code):
url = new URL(
"http://localhost:8080/geoserver/wfs?request=GetCapabilities&VERSION=1.1.0";
);
Map<String, String> param = new HashMap();
params.put(WFSDataStoreFactory.URL.key, url);
param.put("viewparams","q:myquery");
Hints hints = new Hints();
hints.put(Hints.VIRTUAL_TABLE_PARAMETERS, viewParams);
query.setHints(hints);
...
featureSource.getFeatures(query);
But here, it seems to doesn't work, the url send to geoserver is a normal "GET FEATURE" request without the viewparams parameter.
I tried this with geotools-12.2 ; geotools-13.2 and geotools-15-SNAPSHOT but I didn't succeed to pass the query, geoserver send me all the feature in my database and doesn't take "viewparams" as a param.
I need to do it like this because actually the query come from another program and I would easily communicate this query to another part of the project...
If someone can help me ?
There doesn't currently seem to be a way to do this in the GeoTool's WFSDatastore implementations as the GetFeature request is constructed from the URL provided by the getCapabilities document. This is as the standard requires but it may be worth making a feature enhancement request to allow clients to override this string (as QGIS does for example) which would let you specify the additional parameter in your base URL which would then be passed to the server as you need.
Unfortunately the WFS module lives in Unsupported land at present so unless you have resources to work on this issue yourself and can provide a PR to implement it there is not a great chance of it being implemented.
I am trying to solve a problem that has been blocking me for a month
I am bulding the backend of an application using Node.js & Redis and due to our structure we have to transfer data from one redis table to another (What I mean by table is the one's that we use "select" i.e. "select 2")
We receive a lot of request and push a lot of response in a sec, and no matter how much I tried I could not stop data getting mixed. Assume we have a "teacherID" that has to be stored inside Redis table #2. And a "studentID" that has to be stored in Redis table #4. How matter what I tried (I've checked my code multiple times) I could not stop teacherID getting into studentID. The last trick I've tried was actually placing callback at each select.;
redisClient.select(4, function(err) {
if(err)
console.log("You could not select the table. Function will be aborted");
else {
// Proceed with the logic
}
});
What could be the reason that I cannot simply stop this mess ? One detail that drivers me crazy is that it works really well on local and also online however whenever multiple request reach to server it gets mixed. Any suggestions to prevent this error? (Even though I cannot share the code to NDA I can make sure that logic has been coded correctly)
I'm not sure about your statement about having to "transfer data from one redis table to another". Reading through your example it seems like you could simply have two redis clients that write to different databases (what you called "tables").
It would look similar to this:
var redis = require("redis");
var client1 = redis.createClient(6379, '127.0.0.1');
var client2 = redis.createClient(6379, '127.0.0.1');
client1.select(2, function(err){
console.log('client 1 is using database 2');
});
client2.select(4, function(err){
console.log('client 2 is using database 4');
});
Then, wherever your read/write logic is, you just use the appropriate client:
client1.set("someKey", "teacherID", function(err){
// ...
});
client2.set("someKey", "studentID", function(err){
// ...
});
You can obviously encapsulate the above into functions with callbacks, nest the operations, use some async library, etc. to make it do whatever you need it to do. If you need to transfer values from database 2 to database 4 you could do a simple client1.get() and client2.set().