Parsing the query string in a request

A URL is a complex object. It contains at least six separate pieces of information. More information can be included via optional elements.

A URL such as http://127.0.0.1:5000/dealer/hand/?cards=13&$format=json has several fields:

• http is the scheme. https is for secure connections using encrypted sockets.
• 127.0.0.1 can be called the authority, although "network location" is a more common term. Sometimes it's called the host. This particular IP address means the localhost and is a kind of loopback to your computer. The name localhost maps to this IP address.
• 5000 is the port number and is part of the authority.
• /dealer/hand/ is the path to a resource.
• cards=13&$format=json is a query string, and it's separated from the path by the ? character.

The query string can be quite complex. While not an official standard, it's possible (and common) for a query string to have...