Google Maps - Caching - Methods

Question

Ok! So I have spoken to a google representative about this issue, however since I am not enterprise level, he can't push me to tech support and suggested that I use the SO for answers. Here is the question...

In Google Maps Terms it states the following:

(b) No Pre-Fetching, Caching, or Storage of Content. You must not pre-fetch, cache, or store any Content, except that you may store: (i) limited amounts of Content for the purpose of improving the performance of your Maps API Implementation if you do so temporarily (and in no event for more than 30 calendar days), securely, and in a manner that does not permit use of the Content outside of the Service; and (ii) any content identifier or key that the Maps APIs Documentation specifically permits you to store. For example, you must not use the Content to create an independent database of "places" or other local listings information.

This led me to originally believe that google would not allow caching of any type of information. However, then I read the following:

When to Use Client-Side Geocoding

The basic answer is "almost always." As geocoding limits are per user session, there is no risk that your application will reach a global limit as your userbase grows. Client-side geocoding will not face a quota limit unless you perform a batch of geocoding requests within a user session. Therefore, running client-side geocoding, you generally don't have to worry about your quota.

Two basic architectures for client-side geocoding exist.

Run the geocoding and display entirely in the browser. For instance, the user enters an address on your page. Your application geocodes it. Then your page uses the geocode to create a marker on the map. Or your app does some simple analysis using the geocode. No data is sent to your server. This reduces load on your server, but doesn't give you any sense of what your users are doing.

Run the geocode in the browser and then send it to the server. For instance, the user enters an address. Your application geocodes it in the browser. The app then sends the data to your server. The server responds with some data, such as nearby points of interest. This allows you to customize a response based on your own data, and also to cache the geocode if you want. This cache allows you to optimize even more. You can even query the server with the address, see if you have a recently cached geocode for it, and if you do, use that. If you don't, then return no result to the browser, and let it geocode the result and send it back to the server to for caching.

So one side says you cannot cache, the other side tells you, you should. Another solution it states is to always use clientside when you can, but then this becomes a grey area as well, because both examples state that you must have a user input data. What if the jquery read data from a div or span and then geocoded the information? The user wouldn't have actually done the geocode,but it was still done client-side? I'm trying to create a site that has a bunch of events generated by users and this site could get pretty loaded, so I am trying to determine the best practice in being able to do this. Google suggested here, so before you go and say this is "off-topic" please note, this is where they stated me to post.

Any feedback would be greatly appreciated.

Answer 1

The first quote does not explicitly forbid caching data at all. It is ambiguous as to how much you can cache (what number explicitly is "limited amounts"?) but it does not forbid caching.

You are allowed to cache the data if it helps improve the performance of your site as long as you retain the data for no longer than 30 days and do not make it available in any way to any other service except the service that originally retrieved the data.

Regarding user interaction - if your user explicitly enters a page with the expectation that they will be shown geocoded information I would assume that this would fulfill "user interaction".

As an example from a project I worked on last year I had it set up to do the following: - Show markers on the map - If the user clicked a marker they were shown a popup with data from the cache if available, otherwise a geocode would be performed and the returned information would be cached along with the date/time of the cache.

Another page of the site showed a history of these markers at 5 minute intervals throughout the day. If cached data was present (from clicking the map marker as in the previous part) this would be shown, otherwise a geocode would be performed and the data cached as before. The user clicking to run the report was (in my opinion) enough "user interaction" to not count as pre-fetching as the user had to manually select a timeframe before the report would be displayed.

A cronjob then ran every day at midnight which would go through each record with cached data over 25 days old and remove it.

As it was I was caching much less than 10% of the marker positions being shown (20+ markers being updated every minute, but the report was being run on maybe 3-5 markers each day and only geocoding data for every 5th point).