Smart WordPress FAQs

Here you find the answers to the most common questions regarding Smart WordPress by Velocious.io:

General Questions

[faq question=”Is this plugin free?”]Yes, it is free. [/faq]

[faq question=”How to install Smart WP?”]The Installation is free and easy. Install Smart WP like every other plugin via the WordPress plugin directory. [/faq]

[faq question=”Does this plugin work with my theme/other plugins/host?”]Smart WP is programmed that every theme/other plugin/host that adheres to standard WordPress development practices should work without a problem in combination.

However, if you find a problem feel free to contact us, we will try to find a solution. [/faq]

[faq question=”What is a 304 Not Modified Status Code?”]The 304 Not Modified Status Code is a signal from the server (e.g., your WordPress installation) to his clients (e.g., your visitor’s browser). A 304 Status Code tells a client that the version of a page that he has already cached does not differ from the online version generated by the server.

If a client receives this signal, it will not proceed to download the online version. Instead, it uses the locally available one.

This results in faster page loads and reduces server bandwidth. [/faq]

[faq question=”What is the ETag-Header?”]The ETag (or Entity Tag) ist an HTTP Header used to validate cached responses. Its unique value is generated by combining different properties of your content (ID, Content, Publishing Date, …).

When a server receives an ETag from a browser, it will compare this ETag to the latest one generated on the server.  By doing that he can identify if the version the client already has stored differs from the most recent version.

If those two versions match, the server knows that both versions of the resource are the same. In this case, it will answer with a 304 Status Code. This code tells the browser that nothing has changed and that it is safe to use the cached resources.[/faq]

[faq question=”What is the difference between a weak and a strong ETag?”]A strong ETag guarantees that if two resources have the same ETag used for representation, those two resources are in fact byte-for-byte identical. There are no differences between those two files.

A weak Etag however only promises some kind of “semantic equivalence”. Two resources with the same weak ETAG are very similar to each other, but there may be small differences between those two files.

An example:

You may have an “Upvote counter” on your pages that increases its count every time a user clicks it.

A weak ETag generated for a page like this would be the same before and after the upvote, as the upvoted page still has the same content, the same heading, and the same comments. In this case, a different vote count would still produce the same ETags.

But a strong ETag generated for this page would not be the same before and after the upvote, as the upvoted page is not byte for byte equivalent to the older version. Therefore, a different vote count would produce two nonmatching ETags.[/faq]

[faq question=”What is the Last-Modified-Header?”]The Last-Modified Header is an HTTP Header that displays the date, and the time at wich the current resource was last modified. This header is used to check if a cached version of a resource differs from its online version.

If the versions appear to be the same, the server returns a 304 Status Code. This status code signals the client nothing has changed and that he is safe to use his cached version.[/faq]

[faq question=”What is the Cache-Control-Header?”]The Cache-Control Header is an HTTP header that specifies two things: The period a resource should be cached and the way this caching should take place.

A very basic example for a Cache-Control Header looks like this:

Cache-Control: max-age=3600

This example means that it is safe for a client to use the cached version of a resource for up to one hour (3600 seconds = 1 hour). After this time, the client has two options.

Either it checks if the cached version is still valid by comparing his ETAG (or his  Last-Modified value) with the online version.

Or – if neither an ETag or a Last-Modified-Header are defined – it deletes the cached version and loads the new one.

PS: As the Cache-Control header specifies many different directives and the possible combinations of these directives are numerous, I recommend to read Google’s “Web Fundamentals Guide” on caching.[/faq]

Plugin Specific Questions

[faq question=”What is Old Content?”]Old content (in the context of this plugin) is any content which is older than the plugins “Old Content Threshold” setting specifies. Therefore, when using the Smart WordPress Plugin, you define yourself which content is old.[/faq]

[faq question=”Why should you specify a different caching time for older content?”]On most sites old content does not get any updates at all, whereas newly published articles might get some edits or receive new comments every other hour.

So it is often safe to increase the caching time on old articles to save additional server resources and improve loading times for your users.[/faq]

[faq question=”What will remove existing Headers do?”]In some cases, your WordPress installation already generates some of the headers provided by this plugin. To get rid of them, just use this option and delete any of the headers supported by this plugin before adding the new ones.[/faq]