Query via API using Tags

[Wingnut2.0]

When requesting point values for a given datasource via API, is it possible to filter results by tags? An example tag being

"site":"Denver"

How would the request be appended to filter by Denver?

/rest/v1/point-values/DS_Example/latest-data-source-single-array?

Thank you.

[phildunlap]

Hi Wingnutz,

I would guess you've downloaded the 3.3 beta! Thanks for checking out the new features!

You should be able to use tags.tag in RQL expressions, like,

eq(tags.site,Denver)

I did notice in providing this answer that it won't work in the RQL DataPointQuery.query(rql) method in scripting environments in the beta, but i fixed it up so that this should be available in the release. It should be working in the API in your version, but you will need to use the V2 /rest/v2/data-points endpoints.

[phildunlap]

Sorry, I got caught up in the first part of the question and glossed past the second -

The /rest/v1/{dataSourceXid}/latest-data-source-single-array does not take RQL to filter down its result set. I do not believe any of the point values endpoints take an RQL query to describe the points values are sought from, but it's a good idea. I'll make mention of it.

[phildunlap]

It sounds like the way to do this will be multiple requests. You will have to request the data points from the V2 /rest/v2/data-points endpoint, then compose a list of their XIDs and either GET that from the V1 point-values endpoints or POST it (if the URL is too large) to the V2 point-values endpoints.

[Wingnut2.0]

Thank you, Phil. The query by dataSource certainly sounds more fun to me, but I appreciate you providing a complete solution.

The 3.3 beta is great - tags will open up a world of opportunities and the JWT functionality is appreciated by all.

[phildunlap]

Ha! Certainly! I can provide an even more complete solution, since it doesn't sound like it'll be implemented by us....

If one were to need such an endpoint, one could clone our ma-modules-public repo and modify the V2 point values endpoint by adding a function like

    @ApiOperation(
            value = "Get point values arrays by RQL",
            notes = "Get multiple arrays of point values by an RQL query string",
            response = PointValueTimeModel.class,
            responseContainer = "Object")
    @RequestMapping(method = RequestMethod.POST, value = "/{rqlQuery}/multiple-arrays/latest")
    public ResponseEntity<PointValueTimeStream<PointValueTimeModel, LatestQueryInfo>> rqlLatestPointValuesAsMultipleArrays(
            HttpServletRequest request,
            @ApiParam(value = "RQL", required = true, allowMultiple = false)
            @PathVariable String rqlQuery,
            @ApiParam(value = "Query Information", required = true, allowMultiple = false) 
            @RequestBody
            XidLatestQueryInfoModel info,
            @AuthenticationPrincipal User user) {
        List<String> xids = new ArrayList<>();
        RQLParser rqlParser = new RQLParser();
        ConditionSortLimitWithTagKeys conditions = DataPointDao.instance.rqlToCondition(rqlParser.parse(rqlQuery));
        if(!user.isAdmin())
            conditions.addCondition(DataPointDao.instance.userHasPermission(user));
        
        DataPointDao.instance.customizedQuery(conditions, new MappedRowCallback<DataPointVO>() {
            @Override
            public void row(DataPointVO item, int index) {
                xids.add(item.getXid());
            }
        });
        
        if(info.getXids() != null)
            for(int k = 0; k < info.getXids().length; k+=1) {
                if(!xids.contains(info.getXids()[k]))
                    xids.add(info.getXids()[k]);
            }
        
        return generateLatestStream(user, info.createLatestQueryInfo(request.getServerName(), request.getServerPort(), false, false), xids.toArray(new String[xids.size()]));
    }

to com.infiniteautomtion.mango.rest.v2.PointValueRestController.java in the Mango API project.

And then you could query at /rest/v2/point-values/{rqlQuery}/multiple-arrays/latest after building / installing that modified module. You would of course have to be mindful of this customization thereafter. But, it's possible.

[Wingnut2.0]

Hello Phil,

With tags being available for a few months now, has any additional thought been given to adding this feature to the core?

Thank you

[phildunlap]

Hi Wingnut2.0,

I made an argument for it when this came up, but the pushback of "You can request those points, then compile a request for the values from them," was strong. If you can expand on the value of having it in a simple single request, you may find more traction for it than I did. That's why I just supplied the code here.