Internet Part 4:

Let's add the idea that we want to get specific things over the internet. This is essentially what a web app is. It gets information but formatted in a specific way beyond just spitting out static files. In order to take more specific input, we need to specify what we want in a more complex way. The getting and formatting of this data is what this class is all about.

Naming of Resources/Pages and Categorization of Data

Each thing we request is a resource
URLs are a specficication for the location of a resource
We format the request for the resources in a particular syntax
We can request web pages through the browser
We can request JSON through javascript
(We can request either through either)
URLs are formatted similarly to file paths
There is a root path, and then a set of resources
Each web dev chooses a way to format the order of a URL

Elements of a URL

URL stands for Uniform Resource Locator, and it's just a string of text characters used by Web browsers, email clients and other software to format the contents of an internet request message.

Let's breakdown the contents of a URL:

Note. Draw the following on the board

    http://www.example.org/hello/world/foo.html?foo=bar&baz=bat#footer
    \___/  \_____________/ \__________________/ \_____________/ \____/
  protocol  host/domain name        path         querystring     hash/fragment

    http://www.example.org:3000/hello/world/foo.html?foo=bar&baz=bat#footer
    \__/  \_____________/ \__/\__________________/ \_____________/ \____/
protocol|host/domain name|port|      path         | querystring   | hash/fragment

protocol

the most popular application protocol used on the world wide web is HTTP. Other familiar types of application protocols include FTP, SSH, GIT, FILE, HTTPS

host/domain name

the host or domain name is looked up in DNS to find the IP address of the host - the server that's providing the resource. This may include a subdomain, which in it's simplest sense is like a folder on the server. www is actually a subdomain and is often used by default on servers, allowing you to omit it in the URL sometimes.

path

web servers can organise resources into what is effectively mimicking files in directories; the path indicates to the server which file from which directory the client wants

querystring

the client can pass parameters to the server through the querystring (in a GET request method); the server can then use these to customise the response - such as values to filter a search result

hash/fragment

the URI fragment is generally used by the client to identify some portion of the content in the response; interestingly, a broken hash will not break the whole link - it isn't the case for the previous elements

The Schema above is from Tuts +

Express Internet 2