Reducing WebAPI calls by using LocalStorage

by Ben Thompson | Mar 4, 2020 | Dynamics 365, Javascript, License Power, PCF, Power Apps

When Microsoft introduced the WebAPI call limits for Dynamics 365 and the Power Platform back in October last year we started to look for approaches that allow you to reduce the number of calls we made to the webAPI services within the Common Data Service.

Microsoft have actually done a lot of work in this area by using etags within their results and ensuring their client side api (XRM.Webapi utilises it to minimise the number of api calls required) which works wonders on a record level but doesn’t help when you need to run queries to gather results instead of retrieving individual records.

And our Licence management software (License Power) needs to run queries as the standard question is “does this environment / instance have a vaild license for this solution called XYZ?” Which means that every time we needed to answer that question we would need to run a query and that would eat into the 5,000 – 20,000 requests a user is allowed every day.

To fix that the only solution we had to find a way that we could avoid running retrieveMultiple requests and replace them with standard retrieve requests so we disappeared to google and found a suitable solution and we found it by using localStorage within the browser.

Now I could spend a lot of time talking about localStorage and it’s strengths and weaknesses – but that is for another day. What is worth saying is that Dynamics makes full use of it to reduce download times after first installation and you should never store anything secure within it. However that isn’t an issue here as I don’t want to store anything secure I just need to know that the record (license) I want to check exists and what the GUID of the record is.

Using LocalStorage

So as you might have guessed from reading the previous paragraph by using local storage we can store the results of a previous query and use it as the basis of the subsequent query. Which means that in our case, after the initial retrieveMultiple request with the returned GUID stored in localStorage – I can access the GUID from local storage as required and use the caching within Xrm.WebApi.retrieve to retrieve the record in when required at no cost due to Xrm.WebApi’s caching functionality.

So without further ado the sample code.

	var item= localStorage.getItem(license);
	if (item===null || !item.id ){
		// we need to get the record from the system
		Xrm.WebApi.retrieveMultipleRecords("hdn_license", "?$select=hdn_licensexml,hdn_expirydate,hdn_licenseid&$filter=hdn_product eq '"+license+"'").then(
			function success(result) {
				if (result.entities.length>0){
					let cache={
						id: result.entities[0].hdn_licenseid,
						etag: result.entities[0]["@odata.etag"]
					};
					localStorage.setItem(license, JSON.stringify(cache) );
					nextStage(result.entities[0]);
					
				}
				else {
					// something has gone wrong here.
				}
			},
			function(error) {  
				console.log("Error: " + error.message);  
			}  
		);
	}
	else {
	
	// this is the retrieve version
		Xrm.WebApi.retrieveRecord("hdn_license", item, "?$select=hdn_licensexml,hdn_expirydate,hdn_licenseid").then(
			function success(result) {
				//ready to call the next stage	
				if (storedrecord.etag===result["@odata.etag"]){}
				else {
					let cache={
						id: result.hdn_licenseid,
						etag: result["@odata.etag"]
					};
					localStorage.setItem(license, JSON.stringify(cache) );
					// you may wish to do other things here if say child records are cached against this parent record
				}
				nextStage(result.entities[0]);
				
				
			},
			function(error) {  
				// invalidate the cache as somethings gone wrong
				localStorage.removeItem(license);
				console.log("Error: " + error.message);
				
			}  
		);
	}

And finally, a quick explanation:-

The code checks for a stored item in the localStorage of the browser.
If no stored record exists, the code calls retrievemultiple (API cost involved) retrieves the record and caches the information for the next time it’s required.
If a local stored record does exist, we use the information contained within it, to retrieve the record using the stored GUID via a retrieve request. This should be at no cost as between the browser and the logic built into Xrm.Webapi and the Power Platform as a whole, the record will be retrieved from a cache instead of requiring a database call.