Shortest way to convert all PHP types to string

Question

I'm writing a general system that I hope will one day be applicable to fields such as medicine (i.e. it will be "scientific").

I think the best way is to represent all the data in php with strings (true will be "true", false will be "false" and so on). The reason for this is that in php any value has a unique string representation (such as the php code itself).

I am posting this question to speed up the design process of this program.

Some values ​​are easily converted to strings: numbers, booleans, etc.

Some are not easy: objects, arrays, resources.

I think the format for transferring objects and arrays is basically json, but I'm not sure if it matches exactly. This is better than what I currently have (nothing), but at least at some point I'd like to refine it to a point.

Any ideas?

Answer 1

This is indeed an ambitious goal; so ambitious that it would be foolish to try.

Now, you probably don't really mean "can do anything for anyone", but the fact that you're trying to express that without setting any limits is relevant to your question. This makes it unnecessarily difficult for you to find a serialization format.

For example, you mentioned Resources, which PHP uses for things like database connections, opening file handles, etc. They are ephemeral pointers to something that live for a while and then disappear, and serializing them is not only unsupported in PHP, but also makes almost no sense.

Instead of trying to cover "everything", you need to consider what types of data you actually need to process. Maybe you'll mainly use classes defined within the system, so you can define any format you want to represent them. Maybe you want to process an arbitrary collection of key-value pairs, in the form of a PHP array. You might want to leave room for future extensions, but that's just about flexibility of the format, not a concrete answer right now.

From there, you can look for the property you want and shop around:

• JSON is a very popular "lowest common denominator" format. Its main disadvantage is that it has no way of representing specific custom types, everything must consist of lists and key-value pairs (I like to say "JSON has no classes").
• XML is a little less popular than it used to be, but is very powerful and can be used to define custom languages ​​and types. It's quite verbose, but compresses well - many modern file formats are actually zip archives containing compressed XML files.
• PHP serialization format is really only suitable for short-term in-app purposes, such as caching data. It's fairly concise and closely tied to PHP's type system, but there are security concerns if the user has influence over the data, as described in the unserialize man page.
• There are even more concise formats that are not limited to human-readable representation, if that is a relevant factor for you.

Obviously, the list is endless...