How to show a friendly error message using Open-flash-charts2?

Question

If my JSON data-file comes from a database result set and that result set is empty, how do I tell OFC2 to display an error message, instead of crashing because of a malformed JSON string?

Answer 1

Add tags for javascript and actionscript-3 to this question and you should get a load more views and useful responses than you currently are, with more precise details than I am giving. Post the actual JSON string that is causing you the problem and that you would like to be guarded against. That way people can suggest a regexp to catch it, treating it as a string rather than as JSON data at some point before JSON.decode() happens.

In more detail:

You can catch it in two places. One route is to switch over to using the javascript interface to OFC2 and use client side javascript to detect the bad string. This allows you to modify the JSON string client side. See http://teethgrinder.co.uk/open-flash-chart-2/tutorial-5.php for that approach. One downside is that the clients must have javascript enabled for this to work.

Alternatively, since OFC2 is LGPL, you or an actionscript developer can dive into the OFC2 source code and do the same thing there. I am not an actionscript developer so you are better off ensuring you get a reply from one.

The main thing is to add those two tags to this question. 22 Views is way too low for a question with a bounty of 500. Hope this helps.

Answer 2

Several solution avenues are possible, depending on your level of access to the server and your knowledge of JavaScript and/or any server-side platforms.

With access to database Depending on the kind of data you are displaying, it might be possible to add dummy records for those queries that would otherwise have returned an empty set. If you have access to the query definition, you may check for the empty set in the DB-query. For example, if you're on MS SQL Server you could check the condition with some T-SQL statements.

With access to server If you have access to the server side script generating the dataset, add a condition that returns some default value that OFC2 will handle correctly.

With access to another server or serverlocation If you don't have access to the specific script, you may consider creating a new script at another location that queries the original script and replaces empty results with the default value.

Client-side only You can add the JavaScript open_flash_chart_data function (see tutorial) to replace empty datasets. OFC2 can use that function as data source.

Hope this helps.